52
TROUBLESHOOTING
Unit Troubleshooting —
Refer to Tables 31-33.
Table 31 — Humidi-MiZer™ Adaptive Dehumidification System Subcooling Mode Service Analysis
Table 32 — Humidi-MiZer Adaptive Dehumidification System Hot Gas Reheat Mode Service Analysis
PROBLEM CAUSE REMEDY
Subcooling Mode (Liquid Reheat)
Will Not Energize.
No power to control transformer from
evaporator-fan motor.
Check power source and evaporator-fan relay. Ensure all
wire connections are tight.
No power from control transformer to liquid line
solenoid valve.
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.
Liquid line solenoid valve will not operate. 1. Solenoid coil defective; replace.
2. Solenoid valve stuck open; replace.
Liquid line solenoid valve will not open. Valve is stuck closed; replace valve.
Low System Capacity. Low refrigerant charge or frosted evaporator coil. 1. Check charge amount. Charge per Fig. 60-62.
2. Evaporator coil frosted; check and replace low-
pressure switch if necessary.
Loss of Compressor Superheat
Conditions with Subcooling/Reheat
Dehumidification Coil Energized.
Thermostatic expansion valve (TXV). 1. Check TXV bulb mounting, and secure tightly to suc-
tion line.
2. Replace TXV if stuck open or closed.
PROBLEM CAUSE REMEDY
Reheat Mode Will Not Energize. No power to control transformer from
evaporator-fan motor.
Check power source and evaporator-fan relay. Ensure all
wire connections are tight.
No power from control transformer to hot gas
line solenoid valve.
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.
Hot gas line solenoid valve will not operate. 1. Solenoid coil defective; replace.
2. Solenoid valve stuck closed; replace.
Low refrigerant charge or frosted evaporator coil. 1. Check charge amount. Charge per Fig. 60-62.
2. Evaporator coil frosted; check and replace low-
pressure switch if necessary.
Loss of Compressor Superheat
Conditions with Subcooling/Reheat
Dehumidification Coil Energized.
Thermostatic expansion valve (TXV). 1. Check TXV bulb mounting, and secure tightly to suc-
tion line.
2. Replace TXV if stuck open or closed.
Excessive Superheat. Liquid line solenoid valve will not operate. Valve is stuck; replace valve.
Hot gas line solenoid valve will not close. Valve is stuck; replace valve.
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