Carrier 38GXC - Manual (Page 21)

21
DIAGNOSTIC CHARTS (CONT.)
Outdoor coil clean?
Clean coil. Problem
persists?
Indoor filter clean?
Clean filter. Problem
persists?
Check indoor fan
motor
Replace indoor fan
motor.
Normal suction,
high head?
High head, high
suction?
High head, low
suction?
Yes
Yes
Yes
No
No No
Problem solved
Problem solved
No No
No No
No
Yes
Yes
Yes
Yes Yes Yes
Check application
limits.
Non condensables
in sys. Pump down
and recharge unit
See note below *
* Restriction in system. Check capillary tube and check for damage to liquid line between indoor and
outdoor units.
Connect low side gauge
at suction service valve.
Measure discharge temp.*
Unit is overcharged.
Reclaim charge and
weigh in correct charge
Outdoor coil clean?
Clean coil. Problem
persists?
Indoor filter clean?
Clean filter. Problem
persists?
Check indoor fan
motor
Replace indoor fan
motor.
Normal suction,
high head?
High head, high
suction?
High head, low
suction?
Yes
Yes
Yes
No
No No
Problem solved
Problem solved
No No
No No
No
Yes
Yes
Yes
Yes Yes Yes
Check application
limits.
Non condensables
in sys. Pump down
and recharge unit
See note below *
* Restriction in system. Check capillary tube and check for damage to liquid line between indoor and
outdoor units.
Connect low side gauge
at suction service valve.
Measure discharge temp.*
Unit is overcharged.
Reclaim charge and
weigh in correct charge
A09368
Fig. 36 – Unit Not Running Optimally
Visually check outdoor
Unit for ice blockage. **
Check reversing valve.
Go to flow chart 12
No
Yes
Yes
Check defrost sensor. Ok?
Go to flow chart 2
No
Replace sensor
Check application limits.
Ok?
* To supplement flow chart 9
** Check for blockage on outdoor coil and drain pan. Are the holes in drain pans blocked?
No
Beyond operating range
Yes
Yes
Check ambient conditions.
Prime icing?
Explain to customer
Visually check outdoor
Unit for ice blockage. **
Check reversing valve.
Go to flow chart 12
No
Yes
Yes
Check defrost sensor. Ok?
Go to flow chart 2
No
Replace sensor
Check application limits.
Ok?
* To supplement flow chart 9
** Check for blockage on outdoor coil and drain pan. Are the holes in drain pans blocked?
No
Beyond operating range
Yes
Yes
Check ambient conditions.
Prime icing?
Explain to customer
A09369
Fig. 37 – Unit Not Running Optimally (HP in Heating*)
38/
40GX
C
(Q
)