S1, N1, U1 & U2

Question 1

What is the usual “watts per unit length” rating of standard density baseboard heaters?

Answer 1

820W per meter

Question 2

Where in a room should baseboard heaters be mounted?

Answer 2

At floor level, centred along a wall and preferably under a window

Question 3

What type of heater is installed at ceiling height?

Answer 3

A Unit heater

Question 4

Residential electric furnaces are usually available in both single-phase and three-phase ratings from ______ kw to _____ kw

Answer 4

4kw to 50kw

Question 5

What type of heater unit can be used with certain oil-fired, force air furnaces?

Answer 5

A Plenum Heater

Question 6

Residential water heaters are commonly available in ____ kW and ____ kW

Answer 6

3kW and 4.5kW

Question 7

What are three types of thermostats commonly used is residential space heating applications?

Answer 7

Line Voltage
Low Voltage
Electronic

Question 8

If a heat lamp using a medium-base lampholder is installed in a residential bathroom, does it have to be on a separate heating branch circuit? Y or N

Answer 8

No

Question 9

Where are the supply registers of force-air furnace normally located?

Answer 9

Around the perimeter of each room

Question 10

What is the purpose of the heat exchanger in a gas-fired furnace?

Answer 10

To separate the products of combustion from the air

Question 11

The typical efficiency of a gas-fired furnace is between ____ % - ___ %

Answer 11

70%-80%

Question 12

How many conductors are commonly needed between the furnace and the room thermostat? And what is the magnitude of the voltage that they carry?

Answer 12

2 or 3c
24v

Question 13

Which does the room thermostat control directly, the gas valve or the blower motor?

Answer 13

Gas Valve

Question 14

After the thermostat opens, which shuts off first, the blower motor or the gas burner?

Answer 14

The gas burner

Question 15

What is the purpose of the anticipator resistor in the room thermostat?

Answer 15

To limit the set point overshoot to an acceptable value

Question 16

What is the purpose of the thermocouple? Is it necessary?

Answer 16

It uses thermoelectric generation to create a small voltage when heated.
No.

Question 17

List three conditions that may cause overheating of the heat exchanger

Answer 17

Room thermostat contacts stuck
Blower does not run
Insufficient air flow

Question 18

What prevents the heat exchanger from overheating?

Answer 18

The high limit over heat safety thermostat will close the gas valve

Question 19

What are the Typical settings for the blower control/overheat safety thermostat?

Answer 19

1. Blower off 90 degrees
2. Blower on 130 degrees
3. High limit off 104 degrees

Question 20

Where should an electronic air cleaner be installed on a furnace?

Answer 20

In the return air duct

Question 21

Describe how an electronic air cleaner filters the air?

Answer 21

The ionizing section charges the dust particles which are then attracted to the charges collection plates

Question 22

Why should the electronic air cleaner be interlocked with the blower motor?

Answer 22

To prevent the accumulation of ozone

Question 23

What is the purpose of a damper?

Answer 23

To regulate air flow

Question 24

Wiring for HVAC control components is usually ____v

Answer 24

24v

Question 25

To double the airflow rate, the fan hp should be increased ____ times

Answer 25

8 times

Question 26

What are the **failsafe positions** for the outside, exhaust and return air **dampers**?

Answer 26

Outside exhaust damper (Normally Closed) Air damper (Normally Open)

Question 27

How does the damper actuator achieve its failsafe position?

Answer 27

When power fails

Question 28

What are two methods of providing mechanical cooling in an HVAC system?

Answer 28

Chilling cooler tower Refrigeration

Question 29

What is the typical set point for a mixed air controller?

Answer 29

13 degrees

Question 30

The purpose of the minimum position device

Answer 30

**Prevents** the **outside air damper from closing**

Question 31

What does the term economizer control mean?

Answer 31

When the **outside air is warmer** than the return air

Question 32

What are the typical fail safe positions for the hot and chilled water valves?

Answer 32

Hot water Valve Normally Open Chilled water valve Normally Closed

Question 33

Describe the function of a **duty cycle function**?

Answer 33

**Switches equipment off for short intervals** during occupied periods, saving electrical energy.

Question 34

Functions of an optimal start/stop program?

Answer 34

Adjusts the **warm up and cool down** timing

Question 35

A programmable thermostat combines the features of?

Answer 35

A standard thermostat and a electronic time clock

Question 36

What is demand limiting?

Answer 36

**Reduces** peak electrical demands of the building by **turning off** non essential loads during **peak hours**

Question 37

Three problems that can cause a pilot light to go out

Answer 37

Backdrafts Insufficient gas flow Thermocouple not fully flamed

Question 38

Two problems that could prevent a DSU system from lighting

Answer 38

Short electrode or conductor Spark path not crossing the gas burner

Question 39

A photovoltaic cell is made up of?

Answer 39

A semiconductor material such as silicon

Question 40

Domestic electric water heaters are mostly rated at?

Answer 40

3kW

Question 41

MI cables are mostly used as resistance elements in?

Answer 41

Heating cables

Question 42

The control transformer in a gas fired furnace is typically rated at ____v

Answer 42

120/24V

Question 43

What is the correct sequence of control for a complete heating cycle of a low efficiency gas fired furnace?

Answer 43

Fan On Burner On Burner Off Fan Off

Question 44

Purpose of a thermocouple in a gas furnace?

Answer 44

Indicates the presence of a pilot flame

Question 45

The anticipator in a thermostat is used to?

Answer 45

Prevent the room temperature from rising too far above set point

Question 46

A heat pump is used to?

Answer 46

Provide both heating and cooling in the same unit

Question 47

Which type of water heater is the most common in homes?

Answer 47

Storage tank water heaters

Question 48

What type of water heater that must have a large electrical capacity is?

Answer 48

Indirect water heaters