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Home Inspection > Heating > Flashcards

Heating Flashcards

1
Q

Describe how a furnace works

A

Gas, oil or electricity transferred to air

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2
Q

Describe how a boiler works

A

Water is the heat transfer medium

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3
Q

What fuels are used for generating heat?

A

Oil, natural gas, propane, fossil fuels, wood

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4
Q

Natural gas piping can be these materials

A

Steel, copper, or plastic

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5
Q

Steel gas piping should be protected from rust by

A

Coatings or wraps/cathodic protection

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6
Q

Risers that extend above grade should be

A

Metal

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7
Q

What is typically laid with pipe to help locate it

A

A copper tracer wire

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8
Q

Gas piping indoors can be these materials

A

Steel, copper, corrugated stainless steel tubing (CSST) coated with PVC

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9
Q

Why might natural gas copper piping not be permitted in homes?

A

Sulphur in natural gas can react with it

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10
Q

Natural gas metres can be inside or outside, but they need this

A

Isolating valves (shut offs)

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11
Q

Natural gas piping vertical support is required

A

At every floor

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12
Q

What do regulators on natural gas metres do

A

Discharge gas through a release event, 3 feet from sources of ignition, windows, doors, appliance, intakes, or exhaust, and 10 feet from mechanical intakes

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13
Q

Where do shut off valves need to be for each natural gas appliance

A

In the same room as the appliances

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14
Q

Describe natural gas appliance connecters

A

Flexible, metal piping or direct connection (unless earthquake prone)
2 to 3 feet long
Should not pass through walls, ceilings, floors

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15
Q

Where should natural gas outlets be for a barbeques and fireplaces?

A

Outside the hearth and in the same room

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16
Q

What should be installed where a natural gas horizontal pipe feeds an appliance and what is it called?

A

A sediment trap/drip leg
Called a dirt pocket

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17
Q

Where is the natural gas usually bonded to?

A

Supply plumbing

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18
Q

Is propane stored as a gas or a liquid

A

Liquid

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19
Q

How high are propane tanks filled

A

80% capacity to allow for expansion

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20
Q

Are propane tanks stored above ground or below grade

A

Either or

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21
Q

What is a propane tanks location determined by

A

The size of the tank

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22
Q

Where should propane tanks be stored?

A

10 feet from buildings and sources of ignition

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23
Q

Why should propane tanks not be covered by roofs?

A

Relief valves discharge straight up

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24
Q

Gas burners can be these gases

A

Propane or natural gas

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25
Q

Describe how burners operate

A

Fed from an electrically operated valve and mixed with air and ignited

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26
Q

Three most common burners.

A

Ribbon
Monoport
Ring

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27
Q

Describe a mono port burner

A

Newer burners
conversion gas burners
fan assisted

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28
Q

Describe two stage modulating furnaces

A

Low and high firing rate, rather than on and off. More efficient.

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29
Q

Which type of burners are especially prone to plugging with debris

A

Ribbon

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30
Q

How can rust happen in a burner?

A

If humidifiers or air conditioners above leak into furnace, or if exhaust gases condense

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31
Q

Natural gas needs a lot of air to burn. What are the consequences of restricted air

A

Condensation, costs, carbon monoxide poisoning

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32
Q

Describe burner flashback

A

Common on start up and with ribbon burners
Some ignited gas spilled out of the front of the heating system

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33
Q

What help prevent damage from burner flashback?

A

Heat shields

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34
Q

What is considered most of the brains of the heating system?

A

Gas valves. Electrically operated.

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35
Q

Describe the fail safe feature of gas valves

A

Fail in closed positions

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36
Q

Describe a heat shield

A

Metal plate that prevents flames from coming out of the front of the burner

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37
Q

Is a heat shield normally removed during home inspection

A

No

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38
Q

When should a specialist be called in regards to a heat shield

A

When there is evidence of scorching

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39
Q

Describe the three main ignition system types

A

Pilot, spark, or hot surface

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40
Q

What kind of pilot do older gas-fired heating systems have

A

A continuous pilot

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41
Q

What does a thermocouple do?

A

Make sure the pilot is on before allowing gas valve to open

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42
Q

Newer systems have what kind of pilot

A

Intermittent pilot that is ignited by a spark plug

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43
Q

What do high-efficiency systems use instead of a pilot

A

A hot surface ignition

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44
Q

Which burns hotter, oil, or gas

A

Oil

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45
Q

What kind of tank material is fuel oil stored in

A

Steel or fibreglass tank

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46
Q

Where are the fillpipe and vent pipes for oil?

A

Outside

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47
Q

What is required around oil tanks for spillage?

A

A Dyke

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48
Q

Why is an oil tank cylindrical?

A

To prevent from being blown over

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49
Q

Where can oil leaks occur?

A

In the tank, filter, oil, line

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50
Q

Where does rust occur in an oil tank and why?

A

At the bottom, because rust occurs due to condensation in the tank and water is heavier than oil

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51
Q

When should you keep an oil tank full and why?

A

In the summer to minimize condensation

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52
Q

Describe how oil burners work

A

Fan forces air into combustion chamber, pump forces oil into combustion chamber, nozzle converts oil into a fine mist, ignition ignites it

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53
Q

List the atomizing oil burner parts

A

Electrodes, nozzle, blast tube, or draft tube, primary controller, transformer/igniter, motor, fan, fuel pump

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54
Q

Describe combustion chamber refractory

A

Found in oil fired boilers and furnaces
Contains the flame in a controlled area
Similar material to fire brick
Protects other heating system components from flame
Located in the heat exchanger
Deteriorate over time and not easily accessible

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55
Q

Primary control does what and is located where

A

Prevents burner from operating if not safe
Mounted on exhaust or on burner

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56
Q

Newer burners use this for primary control

A

Cadmium sulphide eye or photocell

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57
Q

What is the risk of pressing the reset button in more than once on an oil burner

A

Can cause an accumulation of oil in a combustion chamber

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58
Q

What is dilution air also called

A

Draft air

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59
Q

What should be provided is a burner if in an enclosed room or a closet

A

Ventilation
(louvres in the furnace room door)

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60
Q

How much draft air and combustion air do you need to burn one cubic foot of natural gas any furnace?

A

15 ft.³ of each

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61
Q

What do natural draft appliances require?

A

Extra dilution, or draft air to ensure air moves up the chimney

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62
Q

What are the differences between oil burners and gas furnaces?

A

Oil burners, have a stronger fan that draws air in. Gas furnaces rely on natural draft. (newer have fans.)

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63
Q

Which tend to have more problems, gas furnaces or oil burners

A

Gas furnaces

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64
Q

How do high-efficiency gas furnaces bring in outside air

A

Directly through a pipe with pressure sensors

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65
Q

What is a draft hood also called

A

Draft diverter

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66
Q

Where is a draft hood usually found

A

In gas heating systems

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67
Q

What does a draft hood or draft diverter do?

A

Allows room air to be drawn into exhaust system to help exhaust move up the chimney
Cools exhaust air as it mixes

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68
Q

What is backdrafting or spillage

A

House, air pressure is lower than outdoor and exhaust gases spill out of the draft hood

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69
Q

Describe vent connecters

A

Galvanized steel pipe, 4 to 10 inches in diameter, sloped, quarter inch per foot

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70
Q

Vent connecter clearances from combustibles for gas and oil

A

Gas: 6”
Oil: 9”

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71
Q

Can modern high efficiency, gas systems be discharged in plastic pipes through the building rather than up the chimney and why

A

Yes. Because they remove so much heat.

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72
Q

What is the problem with a vent connector that is too long

A

They may cool gases and lead to condensation

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73
Q

What is the problem with undersized vent connectors?

A

Restrict flow of gases

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74
Q

What is the problem with oversized vent connectors?

A

May allow gases to linger

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75
Q

When should special vent connecter collars be used?

A

When passing through combustible materials

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76
Q

There have been recalls on these mid efficiency, Vents

A

High temperature plastic vents (HTPV’s)

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77
Q

What kind of chimneys are unsuitable for gas and why?

A

Unlined chimneys (exposed brick, or concrete). Condensing exhaust gases could damage the chimney.

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78
Q

Chimney liner can be what materials

A

Metal, clay tile, asbestos cement pipe

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79
Q

Where more than one appliance vents into a chimney, where should the smaller and larger vents be?

A

Smaller vent should be above the larger vent

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80
Q

Can attached houses share a chimney

A

Yes

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81
Q

Can chimneys have more than one flue

A

Yes. Each home can have 1 to 2

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82
Q

Where is deterioration common on masonry chimneys?

A

At the top where inside condensation occurs

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83
Q

If sand or pieces of brick are at the base of the chimney, what should be considered?

A

A liner

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84
Q

Can two appliances share a single flue and why

A

No. Exhaust from one can enter the home from the other.

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85
Q

Can a furnace and a fireplace share a flue

A

No

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86
Q

Chimney flues, without metal liners should have

A

A clean out door at the base to remove debris

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87
Q

What are the implications of buildup of debris at the bottom of a chimney?

A

It could block the flue and exhaust into house

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88
Q

What should be provided at each floor level around a chimney?

A

Fire blocking (noncombustible insulation)

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89
Q

Metal chimney vents for gas furnaces are what type and how much clearance do they need

A

B-vent. 1 inch clearance.

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90
Q

Metal chimney vents for oil furnaces are what type and how much clearance do they need

A

L-Vent. 3 inch clearance oil burns hotter.

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91
Q

Woodburning appliances need these wall systems

A

Triple wall systems. Higher temperatures than oil. 2 inch vent clearance.

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92
Q

If a metal chimney is 10 years old or older, why should it be inspected regularly?

A

Rust and gases can deteriorate inside of the chimney

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93
Q

What are the two types of bimetallic thermostats?

A

Mercury bulb, or magnet

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94
Q

Describe a bimetallic thermostat operation (mercury)

A

Central hub of coil is attached to temperature setting dial
Turning knob down means it Hass to get cooler for mercury to roll down and close contact
When warm, strip, tries to straighten out and mercury rolls away

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95
Q

Where should thermostats not be located?

A

In draughty areas, near heat, sources or areas that get direct sunlight

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96
Q

What is Maxximum set back on the thermostat and why?

A

Less than 10°F. Cooler temperatures create higher humidity which causes condensation.

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97
Q

Blowers usually run when the furnace is on, but why might they be continuously run?

A

For clearing house air

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98
Q

What can cause a thermostat to function improperly

A

Dirt, not level or not properly calibrated

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99
Q

What is a thermostat anticipator?

A

A device that prevents overshoot or short cycling and shuts off just before the temperature is reached

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100
Q

Furnaces use ducts. Boilers use

A

Pipes to move heated water to radiators

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101
Q

Describe a heat exchanger operation

A

Air is warmed as it passes over a hot metal box

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102
Q

What are the three main gas and oil furnace components

A

Heat exchanger, burner, blower

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103
Q

Should return registers be low or high and why?

A

Low on each floor, because cold air falls

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104
Q

What kind of gas furnaces are used above short crawlspaces

A

Downflow furnaces

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105
Q

What is an electric furnace similar to and why?

A

A hair dryer. Cool air is blown over a hot element.

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106
Q

Electric furnaces do not have these components

A

No burner, heat exchanger, or vent

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107
Q

A typical electric furnace element is how many watts

A

5000

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108
Q

What is a furnace sequencer?

A

A staged furnace that turns on heating element one by one and avoids electrical surge

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109
Q

How do auxiliary Plenum heaters work with furnaces?

A

They will try to heat the house until it can’t keep up then the furnace turns on

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110
Q

What is the most critical component of a gas and oil burner?

A

Heat exchanger. Separates house air being heated from burning fuel.

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111
Q

In the heat exchanger, burning fuel never comes in contact with house air. What is this called?

A

Indirect fired heating system

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112
Q

Modern heat exchangers have these to slow airflow and increase efficiency

A

Dimpled or curved surfaces

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113
Q

Average life expectancy of a heat exchanger

A

18 to 25 years

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114
Q

Potential causes of rusted heat exchangers

A

Defective, humidifiers, leaking condensate trays from air conditioning, moisture from damp basement

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115
Q

When is a specially protected heat exchanger recommended

A

When swimming, pool chemicals, paint, strippers, chemicals, and hair salons can cause rust

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116
Q

What is part of regular maintenance for a heat exchanger?

A

Flushing

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117
Q

Motors for blowers can be mounted internally to drive it directly. How do external motors operate

A

They drive the blower with pulleys and a belt

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118
Q

What does an ECM stand for?

A

Electronically commutated motors

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119
Q

Why are electronically commutated motors more efficient?

A

Larger range of operating speeds

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120
Q

What does PSC stand for?

A

Permanent split capacitor motor

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121
Q

Are permanent split capacitors more or less efficient

A

Less

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122
Q

Most common problems with blowers or blower motors

A

Burnt out motors or worn bearings
Dirt buildup causing vibration, blower becomes loose, bearings fail

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123
Q

Describe the functions of a fan/limit switch

A

Keeps fan blowing after burner is shut off until air feels cool
Shut off burner if furnace overheats

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124
Q

When can short cycling occur?

A

When the fan limit switch is out of adjustment or thermostat and exchanger problems

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125
Q

What could happen if the limit switch is too high?

A

It could overheat and ignite dust inside ductwork

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126
Q

Describe an older furnaces pilot

A

Continuously burning that ignites gas when main valve opens

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127
Q

What is a thermocouple?

A

A heat sensor that verifies the pilot is on

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128
Q

What is hot surface ignition? Also called.

A

Electronic ignition

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129
Q

What is a form of primary control?

A

Heat or flame sensors

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130
Q

Oil burners are typically spark ignited. What does primary control do?

A

Heat or flame sensors stop the dumping of fuel

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131
Q

Why does condensate from burners need to be neutralized before entering drains?

A

It can be slightly acidic from combustion gases

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132
Q

Some furnaces have this to detect gases, escaping out of the front of the burner

A

Is spillage switch

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133
Q

What is it called when gases escape out of the front of the burner

A

Backdrafting

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134
Q

What is an air proving switch also called

A

A differential switch

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135
Q

What does an air proving switch or differential switch do?

A

Senses pressure differential across the fans in furnaces with induced draft fans

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136
Q

Where do air filters sit

A

In the return air Plenum, upstream of the blower

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137
Q

Where is filter support?

A

On the blower side of the air filter

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138
Q

Why are electronic filters better?

A

They can remove pollen and cigarette smoke particles by electronically charged plates of opposite polarity

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139
Q

What kind of noises are normal on electronic filters?

A

Sparking or crackling noises

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140
Q

What kind of filters help absorb odors?

A

Activated, charcoal, filters down stream of electronic filter plates

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141
Q

Which direction should the arrow on a filter point

A

Arrow indicating airflow should point to the blower

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142
Q

Some furnaces may have this to combat winter air

A

Humidifier

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143
Q

Describe a drum type humidifier

A

Mounted on return air duct with a bypass duct to supply Plenum
Should not be directly above heat exchanger

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144
Q

What is a trickle humidifier also called

A

Cascade

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145
Q

What is a trickle humidifier do

A

Allows water to fall over a special pad. High-quality.

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146
Q

These humidifiers are rarely seen residentially

A

Atomizing and steam generating

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147
Q

Why might a drum humidifier tray overflow?

A

Mineral deposits clogging water supply valve

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148
Q

What is needed if an air conditioning unit is connected to the furnace to prevent AC coil ice up due to short circulating of airflow

A

A humidifier duct damper

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149
Q

Where should a humidifier be installed in a furnace?

A

On the return duct, not the supply Plenum above the heat exchanger

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150
Q

Where are return air registers often located

A

In hallways and stairwells

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151
Q

Where should supply registers be located?

A

And your exterior walls, below windows, and return opposite (warm wall)

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152
Q

What should rooms without a return register have

A

A 1 inch gap for air flow to return

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153
Q

Does supply or return air duct work accumulate debris

A

Return

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154
Q

What is a simple way to improve heating in a room

A

Blocking off a return register

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155
Q

Where should supply or return air grills not be and why?

A

In garage is, as fumes may be drawn into the house

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156
Q

Slab on grade houses with forced air often have ducts embedded in the foundations. What can be the problem with this?

A

Can collapse when poured or fill up with water

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157
Q

Up until the 70s all systems were similar efficiency. What was the general operating steady state efficiency

A

80%

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158
Q

When a conventional furnace is not operating, what is happening

A

Warm house air is escaping of the chimney just maintaining adequate draft for exhaust gases

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159
Q

On gas fired systems, how is some fuel wasted

A

By keeping the pilot on

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160
Q

Average seasonal efficiency of a boiler or furnace

A

55 to 65% for conventional

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161
Q

Describe mid efficiency furnaces

A

They have a secondary heat exchanger, but are mostly conventional systems with modifications to reduce off cycle losses (draft fan in exhaust)

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162
Q

What does SEER stand for?

A

Seasonal energy efficiency ratio

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163
Q

High-efficiency furnaces are also known as

A

Condensing furnaces because exhaust gases condensate from being so cool

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164
Q

One of the main products of burning natural gas is

A

Water

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165
Q

High-efficiency furnaces have this many heat exchangers

A

2 to 3

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166
Q

High efficiency furnaces are this efficient

A

90% or more

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167
Q

How do combination heating systems work?

A

They use the water heater to heat the house. hot water flows to the plumbing system or to a fan coil unit. The fan blows air across the coil with hot water.

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168
Q

Water from a boiler can heat the home through these outlets

A

Radiators or radiant floor heating

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169
Q

Combination heating systems can also be used to heat the water in the tank. What is this called?

A

Indirect systems

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170
Q

What is the issue with combination heating systems?

A

Modest capacity. Many are undersized for homes.

171
Q

What are used if a combination system is to be operated at high temperatures

A

Tempering valves

172
Q

What is the issue with ductwork in regards to combination heating systems?

A

Most homes are not designed to handle these high volumes of air, and they have reliability problems

173
Q

Life expectancy of combination heating systems

A

5 to 10 years

174
Q

Hot water boilers are also called

A

Hydronic heating

175
Q

How do you hot water boilers work?

A

The heat by moving hot water through pipe loops

176
Q

Where is the heat from the hot water boiler distributed

A

At radiators, convectors, baseboards

177
Q

Do hot water boilers, boil water

A

No, sir.

178
Q

What are the three components of a hot water boiler?

A

Burner, heat exchanger, and pump

179
Q

Electric hot water boilers have this rather than the heat exchanger

A

Electric heating elements

180
Q

Older systems of hot water boilers, relied on gravity and convection. What do newer systems use?

A

A circulating pump

181
Q

Modern boilers are closed. Systems and water is under pressure. What do they require?

A

An expansion tank for pressure build up

182
Q

Describe when an expansion tank gets waterlogged?

A

Air in the expansion tank gets absorbed into water, and the tank has to be drained

183
Q

What do expansion tanks have to ensure no air absorption?

A

Diaphragm or bladder that separates water and air

184
Q

What is the definition of waterlogged?

A

When an expansion tank has no air and it can’t accept more water

185
Q

Describe a pressure reducing valve

A

Connects boiler to plumbing
If pressure drops below 15 psi, it allows water in
Backflow preventer stops water from system into house plumbing

186
Q

Describe a low-water cut out

A

In large boilers, it shuts off heat when water levels are too low

187
Q

What are the 3 operating and safety controls for 1) high temperature and 2) pressure and for 3) when the water levels are too low called

A

High temperature limit
Pressure relief valve
Low-water cut out

188
Q

These radiators are common in older homes

A

Cast-iron radiators

189
Q

What are an alternative to radiators?

A

Hot water convectors

190
Q

What are convectors

A

Cast iron, copper tubing with aluminum fins. Take up less space than radiators.

191
Q

Baseboard hot water distribution systems can be these materials

A

Steel, copper, polybutylene

192
Q

What happens when an a radiator has air trapped in it

A

It will not fill with water and not heat properly

193
Q

Trapped air in a radiator can be released through this

A

A bleed valve

194
Q

What may resolve heating issues with radiators and convectors?

A

Adding more water by adjusting the water make up valve

195
Q

Why does cast iron result in more even heating?

A

Takes more time to cool down and heat up

196
Q

What can be placed behind radiators to help direct heat?

A

Reflective materials. Aluminum foil faced insulation boards.

197
Q

Piping on most hot water heating systems is black steel non-galvanized. Modern systems may be these materials.

A

Copper, plastic piping, polybutylene, or crosslinked polyethylene (PEX)

198
Q

Is draining water from a radiator every summer recommended

A

No. Pipes will deteriorate quicker.

199
Q

What material has problems with plumbing/fittings, but not so much with hot water heating

A

Polybutylene

200
Q

Why is polybutylene piping to a baseboard convector not good practice

A

Can connections may leak due to pressure

201
Q

What are zone valves?

A

Motorized valves for areas controlled by different thermostats

202
Q

Thermostats can control these for radiators in different zones

A

Different circulating pumps

203
Q

Radiant, hot water system piping can be where

A

In floors are ceilings, which radiate heat into rooms

204
Q

Radiant, hot water system piping in concrete should be how far below and how far apart

A

3 inches below concrete and 4 to 12 inches apart

205
Q

Which temperatures are higher or lower, radiant heating systems OR radiator/convector systems

A

Temperatures in radiant, heating systems are lower

206
Q

What is a home run in the boiler system?

A

Discrete loops, feeding different parts of the home from a single manifold at the boiler

207
Q

What materials are used in a radiant, hot water system?

A

Polybutylene and PEX

208
Q

Radiant, hot water systems can be damaged by

A

Building settlement

209
Q

How does rust occur in a radiant, hot water system?

A

Non oxygen barrier polybutylene may pass oxygen into boiler water

210
Q

Seasonal boiler efficiencies
Conventional
Mid

A

Conventional 60%
Mid 80%

211
Q

Boiler life expectancies
Mid cast iron
Mid steel
Mid copper

A

Mid cast iron: 25 to 50 years
Mid steel: 20 to 35 years
Mid copper: 15 to 25 years

212
Q

Unlike hot water heating, steam boiler radiators and piping are this when at rest

A

Filled with air

213
Q

Describe the operation of the steam boiler

A

When steam is generated, air is displaced and released through vents in a radiator or piping

214
Q

What happens when steam hits radiators

A

It condenses, and it is returned to the boiler to be reheated

215
Q

Describe one pipe steam boiler system

A

Single pipe on each radiator, condensate fluids, back through the same pipe
Needs a second pipe to be converted into a hot water system

216
Q

Can the hot water system be one pipe?

A

No. Needs to be two

217
Q

Describe a two pipe steam boiler system

A

One pipe for steam, one pipe for condensate

218
Q

What components do steam boiler radiators have

A

Control valves and air vent or steam traps

219
Q

What is a steam boiler pressuretrol?

A

Operating device and safety device
First device that should shut off the burner with rising steam pressure

220
Q

Describe a low-water cut out on a steam boiler

A

Externally mounted, and have a blow down valve for monthly testing

221
Q

What discharges steam on a steam boiler

A

Pressure relief valve

222
Q

What is a Hartford loop and equalizer pipe in a steam boiler?

A

Prevents water level from dropping as a result of a leak in a return pipe or pressure in balance between supply and return

223
Q

What happens if a pipe slope is incorrect in a steam boiler system

A

The system can be noisy and heat unevenly

224
Q

What is the rule with draperies around electric heat?

A

Should be kept 8 inches above heaters or 3 inches in front if 1 inch above the floor

225
Q

What should not be located above electric heaters?

A

Receptacles. Cords may touch.

226
Q

What is the shadow effect in electric radiant heat?

A

Radiant heat works like sunlight, so it feels cool in the shade

227
Q

Five common components in central heating systems

A
  1. Thermostats.
  2. Burners.
  3. Heat exchangers.
  4. Pipes or ducts.
  5. Outlets (radiators or registers.)
228
Q

Gravity hot water systems rely on what to move water

A

Convection

229
Q

There must be a working space of how much in front of service end of the furnace

A

30 inches

230
Q

Minimum clearances on central heating system, should be found where

A

Nameplate

231
Q

Gas fireplaces that are not direct vent must not be installed in

A

Bedrooms, bathrooms, closets

232
Q

Furnaces may be in the garages if

A

Protected and isolated from combustibles

233
Q

Heating sources that generate a spark/flame/glow must be where in the garage

A

18 inches above garage floor because fumes tend to collect on near floor

234
Q

When can a heating appliance be installed on the garage floor?

A

When it is enclosed in a separate compartment with exterior access and combustion air is drawn from outside the garage

235
Q

What are the requirements for attic furnaces

A

Should be within 20 feet from access opening with the opening being 22 to 30 inches
24 inches wide solid floor to access opening

236
Q

Size and number of outlets depend on

A

House square footage, climate zone, furnace capacity, seal insulation

237
Q

Rooms larger than this need two or more outlets

A

150 ft.²

238
Q

What devices can help achieve balance in a heating system?

A

Dampers inside ducting or throttling valves in hot water heating systems

239
Q

How did heat rise in an old warm air heating system?

A

Gravity fed without a fan

240
Q

What does AFUE stand for?

A

Annualized fuel utilization efficiency

241
Q

Condensing furnaces use this to extract more heat from the flue

A

The second heat exchanger

242
Q

Condensing furnaces require what to exhaust combustion gases, and why

A

A forced draft because the cool gases don’t rise very quickly. So they can be vented horizontally

243
Q

Approved materials for gas piping

A

Rigid galvanized steel, rigid black steel, CSST flexible, gas tubing

244
Q

Not approved materials for gas piping

A

Cast iron, copper, brass, aluminum (exceptions are made for copper and brass tubing for natural gas with low amounts of hydrogen sulphide)

245
Q

Copper connecters for natural gas may be subject to corrosion from

A

Sulphur compounds

246
Q

Why are aluminum tubing connections not recommended for natural gas?

A

They are soft and tend to leak

247
Q

Why does warm air displace cool air in a room which returns to the furnace?

A

Warm air takes up more space and exerts more pressure

248
Q

In some older homes, these are in place rather than return air ducts

A

A Plenum in a wall or floor cavity

249
Q

What is the safety implications of having no return ducts

A

Return air may contain combustion gases.

250
Q

Gravity, fed systems typically feature large furnaces with

A

Oversize ducts sticking out of the top of the housing (octopus)

251
Q

Why do gravity fed systems often lack air filters?

A

Because the airflow is so sluggish, a filter may stop it

252
Q

A gravity fed system is also called

A

Octopus furnace

253
Q

An octopus furnace will probably be wrapped with what and require what

A

Wrapped with asbestos and require a hazmat assessment

254
Q

Describe a forced air heating system

A

Furnace with a burner that heats a heat exchanger, vent flues, blower, fan, supply, return

255
Q

Blue flames in burners indicate

A

Hotter and complete combustion

256
Q

Flame deflection or movement inside a burner or smells may indicate

A

A cracked heat exchanger

257
Q

What does soot in a burner indicate

A

Incomplete combustion

258
Q

Heat exchangers contain the burner, flame and directs

A

Fluegases to vent pipe

259
Q

What causes heat exchanger metal fatigue, and cracking?

A

Each time the exchanger heats , metal expands, and contracts

260
Q

A cracked heat exchanger could cause

A

Levels of carbon dioxide and carbon monoxide

261
Q

Most furnaces that have been used over how long are in efficient and should be replaced

A

20 years

262
Q

Three main thermostatic switches

A

Thermostat, fan control, high limit control

263
Q

Thermostat should be installed how to work correctly

A

Clean, level, securely mounted

264
Q

What is short cycling?

A

When the fan control setting is to close and turns off and on rapidly

265
Q

What happens when the thermocouple at the pilot cools?

A

Pilot safety control valve shuts off the gas flow

266
Q

Fuel oil fired systems use what switches

A

Buy metallic stack switch or a photo electric cell

267
Q

Glow plugs or hot surface ignition systems require

A

Ignition proving devices

268
Q

Forced air heating systems must have adequate separation between

A

Combustion and recirculating air to operate properly

269
Q

The opening to a return air duct should be 10 feet from

A

Furnace firebox, and draft diverter

270
Q

Furnaces in sealed areas Need openings where?

A

Within upper 12 inches and lower 12 inches of enclosure

271
Q

Dust or dirt along furnace compartment door edges indicates

A

Low pressure and insufficient combustion air

272
Q

In larger rooms of ordinary tightness, space it’s self can provide combustion air unless

A

Other fans use that air. It can cause negative pressure and pull in combustion gases.

273
Q

Inspections should include the blower fan compartment. If it is older, what should you do?

A

Turn off the master shut off switch. Modern furnaces have automatic disconnect switches.

274
Q

If a blower access door is loose or missing, what could happen

A

Flue gases could be drawn into the blower

275
Q

Older furnaces have these motors that require lubrication and belts adjusted

A

Squirrel cage fans with blower motors

276
Q

Do modern furnaces need lubrication

A

They are self lubricating, and do not have belts

277
Q

Blower noises could indicate

A

Worn bearings or a loose fan belt

278
Q

Air filters should be checked how often and changed how often

A

Checked monthly and changed, or cleaned twice annually

279
Q

Air filters prevent this on AC units

A

Dust accumulation on evaporator coils

280
Q

These disposable electrostatic filter are 3 to 4 times larger and need replacing less

A

Pleated

281
Q

These filters are very thick and very efficient

A

Media filters

282
Q

After removing the air filter, where should you look and for what?

A

Look into the Plenum for dust and asbestos (gray or white paper tape)

283
Q

Air return ducting, and Plenum should be

A

Airtight

284
Q

Furnaces on concrete floors, or wood platforms might have gaps between

A

Furnace and plenum floor which can cause spillage or mixing of supply and combustion air

285
Q

2 supply configurations for forced air heating systems

A
  1. Radial distribution system in which each branch runs from the furnace.
  2. Extended Plenum system with rectangular duct as a trunk line with branches.
286
Q

Furnace plenums should be at least how high above ground

A

4 inches above ground

287
Q

Sheet metal and rigid fibrous ducting need support every

A

6 feet

288
Q

Soft ducting should have this every 4 feet

A

Galvanized strapping

289
Q

Air flowing over asbestos tape in a heat register have what implications

A

May circulate fibres through the house. Recommend any asbestos in the airflow be abated.

290
Q

If supply registers have dark soot deposits what may it indicate

A

Cracked heat exchanger, or a faulty draft

291
Q

What can help homeowners lower consumption?

A

Humidifiers because moist air feels warmer

292
Q

Combustion produces

A

Water vapour and toxic gases

293
Q

Six venting methods for heating appliances

A
  1. Terra-cotta lined masonry flus or rigid, cement, asbestos flues (transite)
  2. Type B, Vents typically double wall metal vent piping.
  3. Type BW Vents, oval shaped type B Vince designed for above wall furnaces
  4. type L vents for fuel oil fired appliances.
  5. Plastic PVC pipe fence for high-efficiency condensing appliances.
  6. Integral vent assemblies for a direct venting.
294
Q

Venting materials that heat up slowly may restrict the upward flow of fluegases due to the cooler temperatures. What is recommended?

A

Galvanized Steel vent piping

295
Q

These clothes dryer vents are not approved

A

Ungalvanized, blue metal and aluminum vent piping

296
Q

In the metal and masonry vents, should the vertical or horizontal portion be longer

A

Vertical should be 1/3 longer than the horizontal portion. Prevent spillage.

297
Q

What vent pipes are considered vertical

A

45° angles and beyond

298
Q

Vent dampers must be designed to prevent the burner from

A

The burner from firing up when in closed position

299
Q

Flus or vent connecters are connected to

A

A draft hood at the furnace

300
Q

A rusted or discoloured draft hood could indicate

A

Spillage (unburned gases)
Backdrafting

301
Q

Dampness at the draft hood can indicate

A

Spillage. Placing mirror there, to see if it fogs.

302
Q

Hot water and steam heating systems are also called

A

Hydronic heating systems, because both use water for heat

303
Q

Are hot water or steam heating systems efficient

A

Steam systems are not efficient. Heat is slow to arrive.

304
Q

How is a steam boiler distinguishable from the hot water boiler?

A

Buy a site glass or level gauge, which shows the water level inside the boiler

305
Q

In a steam boiler, the upper water edge of a level is called

A

Meniscus. It should be in the upper part of the sight glass when cold.

306
Q

Steam systems have what kind of valve that replenishes the boiler

A

Float valve

307
Q

What is a pressure control valve also called

A

Pressuretrol

308
Q

Banging radiator noise in a steam heating system can be caused by

A

Steam blocked by water ponding in the pipes. Shimming the radiator to slope downward to the inlet pipe usually resolves this.

309
Q

Where do gravity, hot water systems have an expansion tank?

A

In the attic. Should have a relief valve on the boiler

310
Q

Leaks on a new boiler in the snow belt may have been caused by

A

Frozen water piping due to a fuel line that got clogged or a fuel tank that didn’t get refilled

311
Q

Boiler temperature is measured by

A

And aquastat. Turns fuel on or off.

312
Q

What is internal boiler pressure measured by that’s indicated by a gauge

A

Altitude

313
Q

What are common causes of excessive boiler temperature

A

Stuck fill valve, water exchange coil leak, ruptured expansion tank, waterlogged expansion tank

314
Q

Where should circulating pumps be installed in a hot water or steam heating system?

A

On the distribution return pipe just before the boiler

315
Q

What is a draft hood also called

A

A draft diverter

316
Q

Floor room heaters should be supported on

A

Concrete slabs 3 inches above ground or suspended 6 inches above ground

317
Q

A gas fired appliance vent should vent where on the roof

A

2 feet above the roof, and 2 feet higher than any portion of the building within 8 feet

318
Q

These furnaces have special double horizontal vents

A

Direct vent wall furnaces

319
Q

Where should gas fireplaces terminate?

A

At least 4 feet from a door or window. Or 1 foot above they do not require a vent pipe that extends above the roof.

320
Q

Do gas fireplaces need to be vented above the roof

A

Nope

321
Q

Where is a central AC typically installed in the split system

A

With condenser at the building exterior and the evaporator adjacent to the interior furnace equipment

322
Q

Some central AC units have electric heaters for

A

Keeping lubricating oil from absorbing refrigerant

323
Q

Outside temperatures should be at least what to operate central AC

A

65°F

324
Q

How do you check the running load amps on the central AC

A

With an ammeter

325
Q

Where will you find the normal RLA on a central AC

A

Equipment ID plate

326
Q

A reading of what percentages of RLA is normal on central AC units

A

60 to 90%. More indicates refrigerant, overcharge, or bad compressor.

327
Q

A defective compressor or low, refrigerant central AC will give what reading

A

A low RLA reading

328
Q

Where should a central AC condenser be regards to the ground

A

4 inches above

329
Q

Frost on central AC lines or coils could be from

A

Insufficient airflow. Filter debris

330
Q

What is another function of AC?

A

Dehumidifying

331
Q

AC condensate may be discharged into a laundry tub if

A

Proper air brake is maintained

332
Q

What is suggested to reduce cold air loss in central AC

A

A trap

333
Q

If a furnace or evaporator unit is installed in an attic above a finish the ceiling, what is required

A

A secondary condensate line

334
Q

Where should AC evaporator coils be located?

A

On the downflow side of the heat exchanger

335
Q

Describe heat pumps

A

Like an AC that extracts heat from the exterior and move is it inside or extracts from inside and out puts outside

336
Q

Two types of heat pumps

A

Air to air
Water to air (geothermal)

337
Q

Main difference between a heat pump in AC

A

Reversing valve that changes direction of refrigerant flow

338
Q

Heat pumps have an accumulator to

A

Keep refrigerant from entering compressor

339
Q

Metering devices on heat pumps do this

A

Controls refrigerant that flows the coils to absorb heat

340
Q

What are the rules to inspecting a heat pump?

A

Inspect using thermostat control only. No change in heating or cooling mode.
Should be energized 24 hours before operation

341
Q

What is passive distribution?

A

Gravity furnaces. (octopus.)

342
Q

Describe the ducting and registers on a gravity furnace

A

Several registers on one duct, on inside walls.
One cold air return on main floor near outside wall
No fan or filter

343
Q

What is power distribution?

A

Forced air heating

344
Q

Is a baseboard heater is 100% efficient

A

Yes, but the voltage drop is not

345
Q

Describe a BTU

A

British thermal unit. Amount of heat required to raise the temperature of 1 pound of water by 1°F.

346
Q

Three ways of heat transfer

A

Radiation, conduction, convection

347
Q

What does the draft hood do?

A

Pulls dilution room air into vent to push warm products of combustion out

348
Q

What should you look for on any gas appliance?

A

A drip leg

349
Q

Describe mid efficiency heating system

A

Induced draft fan pushes exhaust gases out and pulls combustion air in
Forced draft, then pushes air into burner

350
Q

Induced draft fan and forced draft fan. Which pushes and which pulls

A

Induced pulls combustion air in. First draft fan pushes air into burner.

351
Q

Where is the blower on a high-efficiency gas furnace?

A

At the top

352
Q

What can be the problem with adding a high-efficiency system?

A

Conventional furnaces, ran hotter, so duct work with size for that. Using a high-efficiency in place might not heat as quickly so it has to run longer.

353
Q

Describe a Plenum

A

Last spot where heated air hits before ductwork

354
Q

What is a pressure gauge on a boiler also called

A

And indicator

355
Q

What is the boiler system damper called

A

Barometric damper

356
Q

Fuel fired heating should be serviced

A

Annually

357
Q

Radiators have these two things on them

A

Thermostatic valve and an air vent

358
Q

What is floor heating also called

A

Thermonet

359
Q

Describe a district heating system

A

Biomass plant feeds a community with heat. Usually steam.

360
Q

Describe geothermal heat

A

Heat pump from the ground. Hot Springs etc..

361
Q

Ways of heat generation

A

Combustion, electric resistance, refrigeration (heat pump)

362
Q

And in adequate amount of this can lead to carbon monoxide

A

Combustion air

363
Q

Is return air the same as combustion air

A

No. They are separate. Look for combustion air supply. (grill on door, high and low.)

364
Q

Can freestanding, natural gas, stoves, be in living rooms

A

Yes. But not in the bedrooms.

365
Q

Gas regulators have these inside

A

Diaphragm and vent

366
Q

What is an opening in a Plenum and what does it do?

A

A spill grill. Allows air to be pushed out of Plenum for Burner

367
Q

On a mod number, how many BTUs if it says 75

A

75,000 BTUs

368
Q

On a serial number if it says 9111 what does that mean?

A

Made in 1991 in November

369
Q

If a dryer or other appliance is in the same room as a furnace, how should you operate them?

A

With the door closed and test for proper combustion air and possible Backdraft

370
Q

What is a humidifier made in the cooling season and why

A

A bypass damper. Short circuiting through humidifier can ice up the coil.

371
Q

Do you want to dehumidifier in the summer or winter and why?

A

Dehumidifier in the summer. Cooling air inside the house = relative humidity rises and air becomes damp. If not AC coil might be iced up

372
Q

Describe a B vent

A

Do a wall so less clearance is needed

373
Q

Is it OK to smell gas around a meter?

A

Yes. Regulator is releasing small amount.

374
Q

What kind of connections on a natural gas metre do you want to see?

A

Flexible in case the house moves

375
Q

What is the wire on a gas line to the metre for?

A

A tracer to locate

376
Q

What kind of metal is on gas meters?

A

Painted black steel

377
Q

What sits on the floor and prevents cool air from spilling out?

A

Cold combustion air diffuser

378
Q

What is flame rollout?

A

Flames can come out of the front of the device from backdrafting

379
Q

Vent connecters need to slope

A

Up

380
Q

What does corrosion on a heat exchanger indicate

A

Acidic condensation gases, running back down flue

381
Q

What do flames wavering indicate?

A

Cracked heat exchanger

382
Q

What is a tail pipe?

A

Transfer pipe between primary and secondary combustion

383
Q

What is the secondary heat exchanger also called

A

Exhaust de coupler

384
Q

How many cubic feet for every thousand BTUs of combustion air

A

50 ft.³

385
Q

Every thousand feet above sea level, derate BTUs by

A

4%

386
Q

The primary control fire eye is also called

A

Cadmium photocell

387
Q

What is located in an oil furnace in a refractory that provides flame

A

Blast tube

388
Q

What is the ceramic combustion chamber at the burner also called

A

Fire pot or refractory

389
Q

What would be considered the brains of the furnace?

A

Electronic control board

390
Q

Primary control at the vent connecter is also called

A

Stack relay

391
Q

What does the barometric damper do?

A

Regulates chimney draft

392
Q

What does an aquastat do?

A

Controls, circulating pump, and high temperature in limit switch

393
Q

Is it OK to see water at a boiler?

A

Yes. Pressure relief valves can do this.

394
Q

How much clearance for boilers?

A

18 inches

395
Q

Chimney Capps should be

A

Concrete and overhang

396
Q

This converts DC to AC

A

Inverter

397
Q

Solar backfeed Maxximum in a panel

A

20%

398
Q

Where should the photo voltaic AC disconnect to be?

A

At the metre

399
Q

What is a material defect mean?

A

Financial or safety problem

400
Q

This indicates that it is a closed system boiler

A

Check valve (Tpr)

401
Q

NOT required to inspect

A

Heat exchanger
Humidifier
Electronic air filter
Solar space heating
Determine heat supply adequacy or distribution balance

402
Q

Difference between mid efficiency and conventional furnace

A

Induced or forced draft fans

403
Q

Difference between mid efficiency and high

A

Secondary heat exchanger

404
Q

Where is the induced draft fan and forced draft fan

A

Induced= after heat exchanger, before vent. Pulls air
Forced= before burner, pushes air

405
Q

Natural draft fans are also called

A

Atmospheric

406
Q

High efficiency furnaces have this exhaust characteristic

A

Slow. Pull out as much heat as possible

407
Q

What can rust around a draft hood indicate

A

Back drafting

408
Q

What is make up air

A

Outside air into heating ducts

409
Q

Danger of operating furnace without fan cover

A

Negative pressure

410
Q

Airflow in a drum type humidifier direction

A

From supply to return. Sensor in cold air return

411
Q

Report must describe
1
2

A

1) fuel or energy source
2) heating method

412
Q

Warm air rising off the pavement on a hot day would be heat transfer by

A

Conduction

413
Q

Vent connecter should be in regards to length

A

As short as possible

414
Q

Three things that cause friction loss in duct systems

A

Long length, elbows, dirt

415
Q

Describe the sequence of operation of conventional gas furnace

A

Call for heat
Sense the pilot
Turn on gas
Since the temp of air and heat exchanger
Turn on blower
Thermostat satisfied
Turn off gas
Since the temp at heat exchanger
Turn off blower

416
Q

The furnace vent discharging below the soffit will

A

Cause warm, moist exhaust to go up in the attic

417
Q

Three problems induced draft fans may have

A

Corrosion, seized, cracked, electrical malfunction

418
Q

Three problems oil burners might have

A

Clogged, leaking, fail to ignite

419
Q

Two advantages of a water heating system

A

Easy zone control, maybe integrated with house water system

420
Q

Heat exchangers separate

A

The combustion air from house air

421
Q

A mid efficiency induced draft gas furnace is manifolded with a natural draft water heater. Is this a concern?

A

Not if the vent is large enough to handle both

422
Q

If a heat exchanger fails in a conventional efficiency furnace, will there be soot build up on the burner side of the heat exchanger

A

No

423
Q

Define relative humidity

A

How full of water the air is relative to the maximum amount of water you can hold at a given temperature

424
Q

Define relative humidity

A

How full of water the air is relative to the maximum amount of water it can hold at a given temperature

Home Inspection (13 decks)

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