Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Plumbing Year 4 > Sequence of operation of residential controls > Flashcards

Sequence of operation of residential controls Flashcards

1
Q

From the following description identify the component listed below. Is usually a single-phase, fractional hp motor.

Fan motor

Transformer

Fan control switch

Thermostat

A

Fan motor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

From the following description identify the component listed below. Is the operating controller for the appliance.

Fan motor

Transformer

Fan control switch

Thermostat

A

thermostat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

From the following description identify the component listed below. Supplies a millivolt signal to the automatic pilot valve section in the combination gas valve.

Transformer

Fan control switch

Thermocouple

High-limit switch

A

thermocouple

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the maximum VA output rating for a class 2 transformer

A

100 VA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

the temperature to which a thermostat is set is called the:

A

Set point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What term describes a furnace that starts and stops frequently due to a lack of air movement through the heat exchanger?

A

High-limit cycling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

If the circulating air fan continues to run after the heat exchanger is cooled past 90° F, the air that is circulated to be quite cool in the building. Which Fan-limit control setting must be adjusted to correct the problem?

A

Fan-off switch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

While troubleshooting a thermostat a technician measures 24 V across the “R” and “W” contacts with the switch in the closed position. What is the most likely problem?

A

Heat anticipator is burned out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

A technician is troubleshooting a “No Heat” call on a 24 Volt control system. After the control circuit has been verified and power has been confirmed at the gas valve, how can the integrity of the gas valve be confirmed?

A

Using the continuity function of a multimeter, check the gas valve coil and replace the gas valve if this test shows an open circuit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The 120 V heating system derives its name from its control circuit power rating 120 V.

T or F

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

A transformer is typically required for a 120 V heating system.

T or F

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Thermostats utilized for commercial applications most likely have heat anticipators incorporated in their construction.

T or F

A

false

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

With direct reference to the operating cycle of a commercial unit heater, what should be the next occurrence after the “Fan-on” setting has been reached?

A

The fan starts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What adjustments to the fan-limit settings should be made by the technician when commissioning or performing routine maintenance on a commercial heating appliance?

A

As per manufacturer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a common design incorporated into the gas valve of larger heating appliances?

A

Two stage (step) design

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What significant design change was incorporated in thermostats due to environmental concerns January 1, 2006?

A

Prohibited use of mercury filled bulb contacts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Older mercury bulb thermostats can be disposed of in any trash receptacle.

T or F

A

false

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Spring-Activated, snap-action exposed contacts utilize what control principle to operate?

A

Bimetal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

For a cooling application, the thermostat contacts must __________when the room temperature falls.

A

open

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Name the terminal connections on basic heating and cooling
R
W
Y
G
C

A

R - Power
W - Heat (WARM)
Y - Cool (CHILLY)
G - Fan (FANG)
C - Common

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

From the list below, which of the following would not be recommended when installing a thermostat?

A

Near other sources of heat or any position subjected to cold drafts, out of direct sunlight, away from any heat producing appliances

22
Q

It is recommended to use the built-in thermometer when calibrating a thermostat.

T or F

A

False

23
Q

The thermostat anticipator is wired in___________ with the thermostat contacts on a heating thermostat and in parallel to the contacts on a cooling thermostat.

A

Series

24
Q

The purpose of the anticipator is to compensate for the extra heat that is put into the room after burner shuts down.

T or F

A

True

25
Q

Any measurable temperature above or below the thermostat set point is called;

A

Offset

26
Q

The recommended way to calibrate a heat anticipator is;

A

Physically measure the control circuit amperage and set the anticipator to the measured amperage

27
Q

The anticipator may also be adjusted to change the cycle times of the appliance.

A

True

28
Q

Programmable thermostats;

a) Provide multiple set-point values

b) Allow for appliance operation during different
day time periods

c) Increase efficiency of the heating/cooling
system

d) All of the above

A

All of the above

29
Q

What term describes a combustion fan operating for a predetermined time prior to the ignition sequence?

A

Pre-purge

30
Q

With direct reference to the operational sequence of a mid-efficient furnace, what device must be last be activated before the ignition sequence can occur?

A

Air proving switch

31
Q

A mid-efficient furnace would fall under which category of the B-149.1 gas code?

A

class I

32
Q

The high-limit switch located in the heat exchange area of a mid-efficient furnace is normally of what design?

A

Snap-disc bimetal

33
Q

Where would a technician locate a VSS on a mid-efficient furnace?

A

Located near the vent outlet of the furnace

34
Q

A VSS or FRS would typically be;

A

Manual reset

35
Q

Spark and hot surface ignition systems would have trial for ignition time than an intermittent pilot ignition system.

A

A shorter

36
Q

Newer hot surface ignitors are constructed from .

A

Silicon nitride (NEWtride)

37
Q

Older mid-efficient furnaces would normally have blower speed/s.

a) one

b) more than one

c) non-adjustable

d) adjustable

A

More than one AND Adjustable

38
Q

Many of the new high-efficient furnaces utilize _________to improve operational efficiency through all firing rates and heating loads.

A

VAriable speed DC motors

39
Q

Which of the following would not be considered an input to an electronic control board?

A

Hot surface ignitor

40
Q

With reference to the operational sequence of a mid-efficient furnace, the delay-on timing sequence for the circulating air fan is adjustable.

T of F

A

False

41
Q

With reference to the operational sequence of a mid-efficient furnace, if the combustion fan is operating but the hot surface ignitor fails to operate, what would be the first component for a technician to check?

A

Air switch

42
Q

How can a technician determine the proper circulating fan speed required for a mid-efficient furnace?

A

air temperature test

43
Q

If the measured heat rise in a furnace is higher than the manufacturers specification, how can a technician correct the problem?

A

Increase circulating air fan speed

44
Q

Changing circulating air fan speed on a mid-efficient furnace is done;

A

Manually

45
Q

Blower off delay adjustments are typically set by the manufacturer and are non-adjustable.

T or F

A

false

46
Q

While verifying blower off delay setting on a mid-efficient furnace, a technician observes that the circulating air fan is de-energized with a discharge air plenum temperature of 120 °F. What can be done to correct this problem?

A

Increase the delay off time

47
Q

Some electronic control boards or ignition control centres come equipped with light-emitting diodes (LEDs). What is the primary purpose of these LEDs?

A) Identify operational sequence

B) Show fault conditions

C) Assist with troubleshooting

A

Show fault conditions AND Assist with troubleshooting

48
Q

Manufacturers provide generic troubleshooting guides that apply to any appliance of the same design.

T or F

A

False

49
Q

If a technician were to perform an upgrade to an existing heating system to a cooling, where would the evaporator coil be installed?

A

In the discharge (warm) air plenum

50
Q

What speed is typically used by default for the circulating air fan during cooling mode?

A

High

51
Q

What component of the control system must be checked (verified) for capacity when adding cooling components to an existing system?

A

Transformer VA

DO this when adding any component

Plumbing Year 4 (28 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions