14
SERVICE INSTRUCTIONS (Trouble Shooting Guide)
1.
High head pressure and high back pressure:
A.
Condenser coil clogged or restricted.
B.
Condenser fan motor defective.
2.
Low back pressure and low head pressure:
A.
Restriction in system.
B. Refrigerant
undercharged.
C.
Leak in system.
3.
Pressures normal – cabinet warm:
A.
Coil blocked with frost or ice (see #4).
B. Refrigerant
undercharged.
C.
Control set too warm.
D.
Air screen disturbance.
4.
Coil blocked with frost or ice:
A.
Defective temperature control.
E.
P-trap in drain not installed.
B.
Time clock not operating properly.
F.
Doors aren’t sealing when closed.
C.
Improper time clock setting.
G.
Evaporator fan motor defective.
D.
Defrost heater not operating.
I.
Low voltage.
5.
Compressor starts and runs – but cycles on overload:
A. Low
voltage.
B.
Dropped phase (3 phase).
C.
Overload protector defective.
D.
High head pressure (see#1).
6.
Compressor will not start – hums, but cycles on overload:
A. Low
voltage.
B. Relay
defective.
C. Overload
defective.
D.
High head pressure (see #1).
7.
Special service situations:
If moisture or liquid is observed around or under a Master-Bilt cabinet, an immediate investigation
should be made by qualified personnel to determine the source of moisture or liquid. The investigation
made should determine if the cabinet is malfunctioning or if there is a simple housekeeping problem.
Moisture or liquid around or under a cabinet is a potential slip/fall hazard for persons walking by or
working in the general area of the cabinet.
Any cabinet malfunction or housekeeping problem that creates a slip/fall hazard around or under a
cabinet should be corrected immediately.
