Trouble Shooting Commercial

Question 1

Why dose the blower need to be checked at start up

Answer 1

Ensure is turning in proper direction

Question 2

What’s the main purpose of crankcase heater

Answer 2

Prevent refrigerant migrating and mixing with crankcase oil

Question 3

Crank case heater is shown how in diagram

Answer 3

Resistor

Question 4

Crankcase heater keeps oil to what temperature

Answer 4

Higher then the lowest temp in the system

Question 5

How long before you can do a start up on conditioner with crankcase energized

Answer 5

12 hours

Question 6

If compressor is rotating in wrong direction it will say

Answer 6

Circuit failure to pressurize

Question 7

When will the blower turn off when heating cycle stops

Answer 7

90-180 seconds

Question 8

What’s the fireye , flame sensor control do

Answer 8

Ignites the flame and monitors it

Question 9

Airflow switch will do what if no airflow is detected

Answer 9

The burners will turn off

Question 10

Combination gas valve is used , valves opens the burner control is in ……mode

Answer 10

PTFI mode

Question 11

What’s FSC

Answer 11

Flame safety control

Question 12

How are airflow switches constructed

Answer 12

Single pole double throw

Question 13

Modulating gas opens to achieve amount of gas needed true or false

Answer 13

True

Question 14

How to reset fSC

Answer 14

Push reset
Turn power off
Turn power back on

Question 15

Unit should be installed no Less then

Answer 15

14” above ground surface

Question 16

How to adjust airflow switch

Answer 16

Adjust screw until airflow light comes on and turn it back 1/2 a turn

Question 17

Dual duct systems are how efficient

Answer 17

Energy Inefficient

Question 18

Dual duct system use how much of the airstream at all time

Answer 18

100 percent

Question 19

Dual duct VAV systems have what to mix air

Answer 19

Mixing box

Question 20

Two types of MUA

Answer 20

Direct gas fired
Indirect gas fired

Question 21

MUA air flow across burner should be

Answer 21

2500-3200 fpm

Question 22

Modulating bypass damper or profile plate is used for what

Answer 22

Maintain air flow velocities

Question 23

Electric control panel performs many functions, including

Answer 23

Ignition and flame supervision
Safety interlocks
Temperature control

Question 24

Most manufacturers provide fans with maximum external pressure at

Answer 24

2 to 3 inches water column

Question 26

Hoods are sloped out side for what reason

Answer 26

Min effects from wind with bird screen to reduce lager particulate

Question 27

V Bank filter rack is good for what reason

Answer 27

Larger filter area Ruduces static pressures

Question 28

Dampers on MUA are designed to operate how

Answer 28

Fully open or closed

Question 29

End switch will stop burners from lighting until ?

Answer 29

The dampers are fully opened

Question 30

HRV’S are designed to operate how

Answer 30

Balanced state

Question 31

Defrost mode in HRV will come into effect when

Answer 31

Outside temp is -5 c or below

Question 32

ERV works how

Answer 32

Transfers heat and moisture through the exchanger

Question 33

Finals steps of install are as per ?

Answer 33

Engineers intent and design

Question 34

Gas supply pressures are set at ?

Answer 34

5.5 WC to 13 wc