Moisturemiser Dehumidification Subcooler Service Analysis - Carrier 48HJD005-007 Installation, Start-Up And Service Instructions Manual

Table 35 — MoistureMiser Dehumidification Subcooler Service Analysis
PROBLEM
Subcooler will not energize.
Subcooler will not deenergize.
Low system capacity.
Loss of compressor superheat
conditions with subcooler
energized.
CAUSE
No power to control transformer from
evaporator-fan motor.
No power from control transformer to liquid line
solenoid valve
Liquid line solenoid valve will not operate.
Liquid line solenoid valve will not open.
Low refrigerant charge or frosted evaporator
coil.
Thermostatic expansion valve (TXV).
42
REMEDY
Check power source and evaporator-fan relay. Ensure
all wire connections are tight.
1. Fuse open; check fuse. Ensure continuity of wiring.
2. Low-pressure switch open. Cycle unit off and allow
low-pressure switch to reset. Replace switch if it will
not close.
3. Transformer bad; check transformer.
1. Solenoid coil defective; replace.
2. Solenoid valve stuck open; replace.
Valve is stuck closed; replace valve.
1. Check charge amount. Charge per Fig. 47-51.
2. Evaporator coil frosted; check and replace low-
pressure switch if necessary.
1. Check TXV bulb mounting, and secure tightly to
suction line.
2. Replace TXV if stuck open or closed.