[D2L Practice] 104D

Question 1

Why are electrical thermostats preferred over electromechanical?

1) more accurate
2) more reliable
3) auto-changeover functions
4) all of the above

Answer 1

All of the above

Question 2

Heat anticipators in a thermostat are adjustable

T or F

Answer 2

True

Question 3

A furnace will operate in heat mode if the heat anticipator fails

T or F

Answer 3

False

Question 4

What is a high limit control used for in a residential furnace?

Answer 4

shut off gas valve if heat exchanger becomes too hot

Question 5

If the differential is set too small on a fan cut in cut out switch, what will happen to the device its controlling?

Answer 5

short cycling

Question 6

What is a fan cut in cut out switch 120DF - 140DF used for in a residential furnace?

Answer 6

Cuts in(activate) the fan at 140 DF and cuts out(deactivate) the fan at 120 DF

Question 7

What does the low pressure switch control in your blue bin project?

1) condenser fan
2) compressor
3) timer
4) both a & b

Answer 7

both a & b

Question 8

Where is the high limit switch mounted?

Answer 8

heat exchanger

Question 9

What is a manual reset on a high pressure switch?

Answer 9

needs to be physically reset

Question 10

What temperature should a high pressure switch be set to?

Answer 10

135DF

Question 11

Cut–out(deactivate) on a low pressure control is set by?

Answer 11

cut in - differential

Question 12

What is the cut out if cut in is set to 80 psig with a 20 psig differential?

Answer 12

60 psig

Question 13

What does an OFC protect?

Answer 13

compressor running without oil

Question 14

What is net oil pressure?

Answer 14

oil pump pressure minus crankcase pressure