15
3/15 Rev. C 157872
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.
B.
Control set too warm.
C.
Air screen disturbance.
4.
Coil blocked with frost or ice:
A.
Defective temperature control
B.
Defective or disconnected coil sensor.
C.
Improper control setting.
D.
Ambient conditions above
75
°
F
E.
Pipe loop acts as a trap in drain not installed.
F.
Evaporator fan motor defective.
G.
Air screen disturbance.
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).
E.
Relay or Capacitor defective.
6.
Compressor will not start – hums, but cycles on overload.
A.
Low voltage.
B.
Relay defective.
C.
Overload protector defective.
D.
Start capacitor defective.
E.
High head pressure (see #1)
