Table 4-2. Troubleshooting (Cont)

Corrective Action

Probable

Cause

Malfunction

e. Securely clamp bulb to suction line

e. R e m o t e b u l b o f e v a p o r a t o r e x -

after insuring that there is solid

pansion valve or bypass expansion

metal to metal contact along the

valve not in good contact with

entire length of the bulb. Replace

r e f r i g e r a n t s u c t i o n line or not

damaged insulation around the

properly insulated.

bulb and the suction line (para 4-

62).

Replace defective component (para 4-

9. C o m p r e s s o r

cycles

intermittently.

Defective time delay relay or com-

40 or 4-41).

pressor relay.

Refer to malfunction No. 4.

10. High pressure cutout trips ex-

Restricted or insufficient condenser

air flow.

cessively.

Refer to malfunction No. 3.

11. L O W pressure cutout trips ex-

Restricted or insufficient evaporator

air flow.

cessively.

a. R e p l a c e d e f e c t i v e c o m p o n e n t s

a. D e f e c t i v e h e a t e r t h e r m o s t a t , m o d e

12. No heat, Fan motor runs

(para 4-51, 4-44 or 4-37).

selector switch or circuit breaker.

correctly.

b. Refer to fig. 1-5 for electrical check

b. D e f e c t i v e w i r i n g .

points.

Check connections for

tightness and wiring for shorted

conditions. Repair defective wiring

(para 4-49 and 4-53).

13. Low heat only, Fan motor runs

a. R e p l a c e d e f e c t i v e c o m p o n e n t s

a. D e f e c t i v e t e m p e r a t u r e c o n t r o l

(para 4-45, 4-41 or 4-44).

correctly.

thermostat, heater control relay or

mode selector switch.

b. Refer to fig. 1-5 for electrical check

b. D e f e c t i v e w i r i n g .

points. Check connections for

tightness and wiring for shorted

conditions. Repair defective wiring

(para

4-49

and

4-53).

c. R e f e r t o m a l f u n c t i o n N o . 5 .

c. N o p o w e r t o l o w v o l t a g e c o n t r o l

circuit.

a. R e f e r t o m a l f u n c t i o n N o . 3 .

14. lnsufficient

heating.

Fan

motor

insufficient

a. Restricted or

runs correctly and heater controls

evaporator air flow.

b. R e p l a c e d e f e c t i v e h e a t i n g e l e m e n t s

operating properly.

b. D e f e c t i v e h e a t i n g e l e m e n t ( s ) .

(para 4-50).

c. R e f e r t o f i g u r e 1 - 5 f o r e l e c t r i c a l

c. D e f e c t i v e w i r i n g .

check points. Check connections

for tightness and wiring for shorted

conditions. Repair defective wiring

(para 4-49 and 4-53).

a. C l e a n f a n w h e e l s a n d a l i g n s o t h a t

15. A i r c o n d i t i o n e r n o i s y .

a. Fan wheels out of balance, binding

they turn freely without in-

or dirty.

terference with housings or guards.

If wheel is out of balance after

cleaning replace with a new wheel

(para

4-30

and

4-31).

b. Tighten set screws and check to

b. F a n w h e e l s l o o s e o n d r i v e s h a f t .

insure that the key is in place (para

4-30 and 4-31).

c. T i g h t e n m o u n t i n g s c r e w s w h i c h

c. F a n m o t o r l o o s e o n m o u n t .

secure the motor to the partition

and the motor mounting bracket

(para 4-34).

d. T i g h t e n f o u r b o t t o m c o m p r e s s o r

d. C o m p r e s s o r

m o u n t s loose.

mounting bolts (para 4-58).

Section VI. MAINTENANCE OF PANELS, COVERS, SCREENS,

GUARDS

AND

GRILLES

4-11. Top Panel

4-10.

General

a. General. Removal of the top panel is

Refer to Figures 1.1 and 1.2 for the location of

n e c e s s a r y to provide access for servicing the heating

panels, covers, screens, guards and grilles.

4-5