Trouble Shooting Guide

1.High head pressure and high back pressure:

A.Condenser coil clogged or restricted.

B.Condenser fan motor defective.

C.Air in the system.

D.Refrigeration overcharge.

2.Low back pressure and low head pressure:

A.Expansion valve restriction.

B.Refrigerant undercharged.

C.Leak in system.

3.Pressures normal – cabinet warm:

A.Refrigerant undercharged.

B.Control set too warm.

4.Compressor starts and runs – but cycles on overload:

A.Low voltage.

B.Overload protector defective.

C.High head pressure (see#1).

5.Compressor will not start – hums, but cycles on overload:

A.Low voltage.

B.Relay defective.

C.Overload defective.

D.High head pressure (see #1).

6.Cabinet sweating:

A.High ambient humidity.

B.Defective condensate heater.

7.Cabinet not cycling – coil blocked with frost:

A.Defective temperature controller.

B.Refrigerant overcharged.

C.Location too hot.

D.Condenser clogged.

E.Condenser fan motor defective.

F.Defrost heater not operating.

8.Gravity coil will not defrost (coil loaded with ice or frost)

A.Solenoid in timer sticking closed, preventing unit from going defrost.

B.Defrost termination thermostat is defective.

C.Safety thermostat is defective.

D.Timer defrost is not set at minimum 34 minutes

E.Defective defrost coil heater.

9.Defrost cycle too long.

A.Defective time clock solenoid.

B.Defective defrost end thermostat and/or defective safety thermostat.