Carrier 40GXC Service Manual page 21

DIAGNOSTIC CHARTS (CONT.)
Outdoor coil clean? Outdoor coil clean?
Yes Yes
Indoor filter clean? Indoor filter clean?
Yes Yes
Check indoor fan Check indoor fan
Yes Yes
Connect low side gauge Connect low side gauge
at suction service valve. at suction service valve.
Measure discharge temp.* Measure discharge temp.*
No No
Normal suction, Normal suction,
high head? high head?
Yes Yes
Non condensables Non condensables
in sys. Pump down in sys. Pump down
and recharge unit and recharge unit
* Restriction in system. Check capillary tube and check for damage to liquid line between indoor and * Restriction in system. Check capillary tube and check for damage to liquid line between indoor and
outdoor units. outdoor units.
Check defrost sensor. Ok? Check defrost sensor. Ok?
Check ambient conditions. Check ambient conditions.
* To supplement flow chart 9 * To supplement flow chart 9
** Check for blockage on outdoor coil and drain pan. Are the hol e s in drain pans blocked? ** Check for blockage on outdoor coil and drain pan. Are the hol e s in drain pans blocked?
No No Clean coil. Problem Clean coil. Problem
persists? persists?
No No Clean filter. Problem Clean filter. Problem
persists? persists?
No No Replace indoor fan Replace indoor fan
motor motor
Yes Yes
Check application Check application
limits. limits.
No No
High head, high High head, high
suction? suction?
Unit is overcharged. Unit is overcharged.
Reclaim charge and Reclaim charge and
weigh in correct charge weigh in correct charge
Fig. 36 – Unit Not Running Optimally
No No
Visually check outdoor Visually check outdoor
Unit for ice blockage. Unit for ice blockage. ** **
Yes Yes
No No
Go to flow chart 2 Go to flow chart 2
Yes Yes
No No
Check application limits. Check application limits.
Ok? Ok?
Yes Yes
Prime icing? Prime icing?
Yes Yes
Explain to customer Explain to customer
Fig. 37 – Unit Not Running Optimally (HP in Heating*)
No No
Problem solved Problem solved
Yes Yes
No No
Problem solved Problem solved
Yes Yes
motor. motor.
No No
High head, low High head, low
suction? suction?
Yes Yes
See note below * See note below *
Check reversing valve. Check reversing valve.
Go to flow chart 12 Go to flow chart 12
Replace sensor Replace sensor
Beyond operating range Beyond operating range
21
Yes Yes
A09368
A09369