Unit Review : Heating Systems & Human Comfort Comprehensive Self-Assessment Flashcards
1
Q
1. The steam pressure on a steam grid humidifier should be in the range of: A. 20 kPa to 30 kPa (2.9 to 4.4 psi) B. 25 kPa to 45 kPa (3.6 to 6.5 psi) C. 40 kPa to 55 kPa (5.8 to 8 psi) D. 30 kPa to 60 kPa (4.4 to 8.7 psi) E. 35 kPa to 70 kPa (5.1 to 10.2 psi)
A
E. 35 kPa to 70 kPa (5.1 to 10.2 psi)
2
Q
- A typical range for the pressure setting of an automatic fill valve (pressure reducing valve) in a hot water heating system is:
A. 50 to 100 kPa B. 80 to 103 kPa C. 100 to 200 kPa D. 103 to 125 kPa E. 125 to 150 kPa
A
D. 103 to 125 kPa
3
Q
3. To determine the tension in a blowers driving belt, a force of about \_\_\_\_\_ should be applied. A. 25 N (5.6 pounds force) B. 30 N (6.7 pounds force) C. 45 N (10 pounds force) D. 75 N (17 pounds force) E. 20 N (4.5 pounds force)
A
C. 45 N (10 pounds force)
4
Q
4. To avoid cavitation in the pump and drawing air into the system, a positive pressure at the highest point of the system should be maintained of at least: A. 100 kPa (14.5 psi) B. 76 kPa (11 psi) C. 52 kPa (7.5 psi) D. 20 kPa (2.9 psi) E. 12 kPa (1.7 psi)
A
E. 12 kPa (1.7 psi)
5
Q
- To avoid cavitation in the pump the pressure at the highest point of the system should be at least equivalent to a head of water of:
A. 1.2 m (4 ft.)
B. 0.9 m (3 ft.)
C. 1.5 m (4.9 ft.)
D. 2 m (6.6 ft.)
E. 2.2 m (7.2 ft.)
A
A. 1.2 m (4 ft.)
6
Q
6. The activated carbon will adsorb odour-causing gases up to about \_\_\_\_\_ of its own weight after which it has to be replaced. A. 5% B. 30% C. 15% D. 10% E. 20%
A
E. 20%
7
Q
7. A room thermostat should be mounted on an inside about \_\_\_\_\_ above the floor and in the wall about path of natural air circulation when the heating system is off. A. 4.5 m (180 in) B. 1.5 m (60 in) C. 2.5 m (100 in) D. 3.5 m (140 in) E. 4.0 m (157 in
A
B. 1.5 m (60 in)
8
Q
- The thermostat equipped with a coil-shaped bimetal element operating a mercury bulb switch is quite sensitive, having a temperature differential of less than:
A. 1°C (1.8°F) B. 2°C (3.6°F) C. 3°C (5.4°F) D. 5°C (9°F) E. 10°C (18°F)
A
A. 1°C (1.8°F)
9
Q
9. Low pressure hot water heating installations are limited to less than \_\_\_\_\_ water pressure. A. 100 kPa (14.5 psi) B. 1000 kPa (145 psi) C. 206 kPa (30 psi) D. 500 kPa (73 psi) E. 103 kPa (15 psi)
A
C. 206 kPa (30 psi)
10
Q
10. In the electronic filter dust particles are charged by passing the contaminated airflow through an ionizing zone formed by an arrangement of wires charged with \_\_\_\_\_ volts DC potential. A. 13 000 B. 15 000 C. 10 000 D. 12 000 E. 60 000
A
A. 13 000
11
Q
11. In the electronic filter the collector plates are charged with \_\_\_\_\_ volts DC. A. 5000 B. 6000 C. 1000 D. 15 000 E. 13 000
A
B. 6000
12
Q
12. Activated alumina chemisorbant is particularly suitable for the removal of: A. O2 B. N2 C. CO2 D. CO E. H2S
A
E. H2S
13
Q
- The system of mechanical air intake, natural exhaust can supply fresh air in all of the following ways except:
A. By a propeller fan mounted in the outside wall
B. By installing a fresh air supply duct in a warm air heating system
C. By unit ventilators that draw in a controlled amount of outside air
D. By an exhaust fan mounted in the outside wall
E. By use of a makeup air heater
A
D. By an exhaust fan mounted in the outside wall
14
Q
14. In all systems, the vertical pipes to the various floors are called the: A. Mains B. Risers C. Return lines D. Steam lines E. Steam pipes
A
B. Risers
15
Q
15. One of the causes of insufficient steam supply to the heating units can be attributed to: A. Improper pitch restricting drainage B. Air vents passing air C. Valves on mains wide open D. Piping over sized restricting flow E. Bypassing of steam to supply line
A
A. Improper pitch restricting drainage
16
Q
- When dealing with electrical controls transformer refers to:
A. A device used to change AC voltage from one value to another
B. A device consisting of a solenoid coil, which operates load carrying contacts when the coil is energized
C. A term that refers to the normal electric supply voltage
D. A term that refers to wiring or other electrical devices using 30 volts or less
E. The electric switch configuration of a relay
A
A. A device used to change AC voltage from one value to another
17
Q
17. The Hartford loop prevents steam pressure from forcing boiler water back into the return line should the: A. Boiler pressure get to high B. Feedwater supply fail C. Check valve fail to close D. Water level get to high E. Boiler temperature be to high
A
C. Check valve fail to close
18
Q
- The admission of fresh air into a room should be such that:
A. The air is spread over the floor area
B. Stagnant pockets of air are created
C. The air does not strike directly on the occupants
D. The air strikes directly on the occupants
E. The air is spread over the ceiling area
A
C. The air does not strike directly on the occupants
19
Q
19. A warm air heating system consists of a centrally located heating furnace or heat exchanger an all except: A. A circulating pump B. A supply duct system C. A return duct system D. Supply outlets E. Return grilles
A
A. A circulating pump
20
Q
20. From the plenum warm air flows into the \_\_\_\_\_ system which distributes the air. A. Register B. Return duct C. Grille D. Plenum E. Supply duct
A
E. Supply duct
21
Q
- The piping and heating units of a steam heating system must be so arranged that:
A. Steam can flow freely from all heating units
B. Steam can flow in insufficient quantities to all heating units
C. The condensate can be returned freely to these units
D. The condensate can be returned freely to the boiler
E. The air can be contained in the heating units and piping
A
D. The condensate can be returned freely to the boiler
22
Q
- One of the advantages of a forced warm air heating system is:
A. Temperature distribution is not uniform
B. The ducts can not be enclosed within walls and ceilings
C. The furnace must be located on the same floor
D. The air may be cleaned by filters.
E. The air can not be humidified
A
D. The air may be cleaned by filters.
23
Q
- Thermal conductance (C) is the:
A. Thermal heat flow (transmission) through unit areas of a wall, door, window, etc., for every degree temperature difference between the air/fluid inside and the air/fluid outside. (W/m²K or W/m²°C) (Btu/hr/ft²R or Btu/hr/ft²°F)
B. Quantity of heat flow from all mechanisms, in unit time, under the conditions prevailing at that time (Q or W)
C. Thermal heat flow, by conduction only, through a unit area of a single uniform type of material (W/m°C) (Btu/hr/ft²°F)
D. Thermal heat flow through a unit area of a non-uniform, composite material when a unit average temperature difference is established between the surfaces (W/m²°C) (Btu/hr/ft²°F)
E. Reciprocal of thermal conductance, it is the value of a given material’s ability to resist heat transfer or flow (m²°C/W) (ft²°F/Btu/hr)
A
D. Thermal heat flow through a unit area of a non-uniform, composite material when a unit average temperature difference is established between the surfaces (W/m²°C) (Btu/hr/ft²°F)
24
Q
- Thermal transmittance or U-factor (U) is the:
A. Thermal heat flow (transmission) through unit areas of a wall, door, window, etc., for every degree temperature difference between the air/fluid inside and the air/fluid outside. (W/m²K or W/m²°C) (Btu/hr/ft²R or Btu/hr/ft²°F)
B. Quantity of heat flow from all mechanisms, in unit time, under the conditions prevailing at that time (Q or W)
C. Thermal heat flow, by conduction only, through a unit area of a single uniform type of material (W/m°C) (Btu/hr/ft²°F)
D. Thermal heat flow through a unit area of a non-uniform, composite material when a unit average temperature difference is established between the surfaces (W/m²°C) (Btu/hr/ft²°F)
E. Reciprocal of thermal conductance, it is the value of a given material’s ability to resist heat transfer or flow (m²°C/W) (ft²°F/Btu/hr)
A
A. Thermal heat flow (transmission) through unit areas of a wall, door, window, etc., for every degree temperature difference between the air/fluid inside and the air/fluid outside. (W/m²K or W/m²°C) (Btu/hr/ft²R or Btu/hr/ft²°F)
25
```
25. To prevent larger particles from reaching the circulating pump, it is common practice to install a temporary _____ in the suction line.
A. Filter
B. Blank
C. Disc
D. Screen
E. Strainer
```
E. Strainer
26
26. Some of these advantages of electricity as a source of heat over other heating systems include the following except:
A. The operation of the heating devices very noisy
B. The equipment requires less space
C. Individual room temperature control is easily obtained
D. The cost of installation is lower
E. No combustion and combustion gases
A. The operation of the heating devices very noisy
27
27. An air washer is installed on the suction side of the fan so as to:
A. Add latent heat to the air
B. Avoid leakage of water through the joints
C. Add sensible heat to the air
D. Add moisture to the air
E. Avoid leakage of air through the joints
B. Avoid leakage of water through the joints
28
```
28. When the air washer is used for dehumidification, the spray water must be _____ temperature of the entering air.
A. Cooled below the dry bulb
B. Heated above the dry bulb
C. Heated above the dew point
D. Cooled below the dew point
E. Cooled below the wet bulb
```
D. Cooled below the dew point
29
```
29. The humidification process refers to adding _____ to the air.
A. Water vapour or moisture
B. Heat
C. Temperature
D. Enthalpy
E. Steam
```
A. Water vapour or moisture
30
```
30. A fin coil consists of one or more rows of parallel tubes fitted with fins to _____ exchange.
A. Decrease the rate of heat
B. Increase the rate of heat
C. Increase the temperature
D. Decrease the temperature
E. Increase the flow rate
```
B. Increase the rate of heat
31
31. With a warm air heating system if there is insufficient heat throughout the building the trouble could be:
A. The bonnet temperature is at least 65°C (150°F)
B. Occupied and unoccupied areas receiving adequate heat
C. An adequate amount of air is supplied to all rooms and to provide good air distribution
D. Air filters are dirty
E. The thermostat is accurate
D. Air filters are dirty
32
32. Flow control valves are necessary in each circuit of hot water heating multi-zone pump system to:
A. Prevent continued circulation of hot water after the circulator has been stopped by the zone control
B. Increase the circulation flow
C. Balance the circulation flow in all circuits
D. Increase the efficiency of the zone heating
E. Prevent additional steam flow in the zone
A. Prevent continued circulation of hot water after the circulator has been stopped by the zone control
33
33. In the two-pipe direct return hot water heating system, the heating units are:
A. Supplied from the main and the return from each convector is connected back to the main again downstream from the supply connection
B. Equipped with its own circulating pump
C. All supplied with water at the same temperature and the return from each convector flows the long way around to return to the boiler
D. All supplied with water at the same temperature and the return from each convector flows by the shortest and most direct route back to the boiler
E. Connected in series so the water circulates from the hot water supply main directly through all the convectors to the return main
D. All supplied with water at the same temperature and the return from each convector flows by the shortest and most direct route back to the boiler
34
```
34. The advantage of an all mechanical ventilation system is that the system supplies a controlled amount of _____ air and distributes it in such a way that any discomfort to the occupants is avoided.
A. Filtered and heated
B. Heated and humidified
C. Filtered and cooled
D. Cooled and dehumidified
E. Filtered and humidified
```
A. Filtered and heated
35
35. One of the advantages of introducing a controlled amount of ventilation air into a building is:
A. Ventilation air can be filtered reducing the labour and expense involved in cleaning and redecorating
B. The air will not have to be cooled in summer
C. The air will not have to be heated in winter
D. The ventilation air is introduced through the air conditioning equipment maintain a negative pressure within the building
E. The positive pressure will cause an outward escape of air through cracks, windows, and doors, and increase infiltration
A. Ventilation air can be filtered reducing the labour and expense involved in cleaning and redecorating
36
```
36. The presence of air in a steam heating system is undesirable since it will:
A. Decrease the condensate pressure
B. Promote corrosion in the system
C. Increase heat transfer beyond design
D. Increase the steam flow
E. Contaminate the makeup water
```
B. Promote corrosion in the system
37
37. The gravity hot water heating system had a disadvantage of:
A. Circulation is difficult to maintain to radiators on the same level as the boiler
B. Simple operation and low maintenance
C. There is a quick response to changes in heat demand
D. The minimum water temperature is limited to 77°C (171°F)
E. Small pipe sizes to keep flow resistance to a minimum
A. Circulation is difficult to maintain to radiators on the same level as the boiler
38
38. If there is restricted air flow through a heating unit the operator should check all but:
A. The filter is not plugged
B. Curtains are restricting the air flow
C. Damper plates are fully closed
D. A carpet is not restricting the air flow
E. Air passages are not restricted
C. Damper plates are fully closed
39
39. Compared to a steam heating system, which of the following is a disadvantage of a hot water heating system?
A. The water temperature can be varied more readily in relation to the ambient temperature
B. There is a greater danger of damage due to freezing in a hot water system
C. Hot water boilers are smaller and more compact
D. The piping slope is not as critical as proper condensate drainage is not as important
E. Maintenance costs are usually less in a hot water system, due to the fact that traps are not required and also because there is less corrosion in the piping
B. There is a greater danger of damage due to freezing in a hot water system
40
40. With a warm air heating system if there is insufficient heat throughout the building the trouble could be:
A. The bonnet temperature is at least 65°C (150°F)
B. Unoccupied areas receiving too much heat
C. An adequate amount of air is supplied to all rooms and to provide good air distribution
D. Air filters are clean
E. The thermostat is accurate
B. Unoccupied areas receiving too much heat
41
41. Compared to a steam heating system, which of the following is a disadvantage of a hot water heating system?
A. The water temperature can be varied more readily in relation to the ambient temperature
B. There is a greater danger of damage due to freezing in a hot water system
C. Hot water boilers are smaller and more compact
D. The piping slope is not as critical as proper condensate drainage is not as important
E. Maintenance costs are usually less in a hot water system, due to the fact that traps are not required and also because there is less corrosion in the piping
B. There is a greater danger of damage due to freezing in a hot water system
42
42. What is the name given to the furnace type that has the return air enter the top and the supply air leave the bottom of the system?
```
A. Lowboy furnace
B. Upflow furnace
C. Highboy furnace
D. Horizontal flow furnace
E. Downflow furnace
```
E. Downflow furnace
43
43. What is the name given to the furnace type that has the return air enter the bottom and the supply air leave the top of the system?
```
A. Upflow furnace
B. Lowboy furnace
C. Highboy furnace
D. Horizontal flow furnace
E. Downflow furnace
```
A. Upflow furnace
44
44. The diverter fittings in hot water heating systems make use of a _____ section that reduces the pressure in the return connection and induces a flow of water through the radiator or convector.
```
A. Reduced size
B. Venturi
C. Over sized
D. Wind
E. Orifice
```
B. Venturi
45
```
45. One of the causes of insufficient steam supply to the heating units can be attributed to:
A. Proper pitch unrestricted drainage
B. Air vents passing air
C. Valves on mains partly closed
D. Piping over sized restricting flow
E. Bypassing of steam to supply line
```
C. Valves on mains partly closed
46
```
46. The centrifugal blower, or fan used in warm air furnaces are of the double inlet type with _____ vanes or blades.
A. Backward straight
B. Forward airfoil
C. Backward curved
D. Forward curved
E. Backward airfoil
```
D. Forward curved
47
```
47. In many steam heating systems the condensate discharged by the steam traps from the heating equipment drains by gravity into a:
A. Deaerator
B. Hotwell
C. Condensate receiver
D. Drain
E. Sump
```
C. Condensate receiver
48
48. The quartz lamp electric infrared heating element is a:
A. Tube similar to a fluorescent tube
B. Metal tube 9.5 mm (3/8 in) in diameter and up to 198 cm (78 in) in length
C. coiled nickel-chrome element enclosed in an air-filled quartz tube with capped ends
D. Bulb similar to an incandescent light bulb
E. sealed quartz tube filled with inert gas containing a tungsten filament supported by tantalum spacer
E. sealed quartz tube filled with inert gas containing a tungsten filament supported by tantalum spacer
