Carrier 50HE003-006 Installation Instructions Manual page 70

Table 37—Humidi-MiZer™ Adaptive Dehumidification System Subcooling Mode Service Analysis
PROBLEM
Subcooling Mode (Liquid Reheat)
Will Not Energize.
Low System Capacity.
Loss of Compressor Superheat
Conditions with Subcooling/Reheat
Dehumidification Coil Energized.
Table 38—Humidi-MiZer™ Adaptive Dehumidification System Hot Gas Reheat Mode Service Analysis
PROBLEM
Reheat Mode Will Not Energize.
Loss of Compressor Superheat
Conditions with Subcooling/Reheat
Dehumidification Coil Energized.
Excessive Superheat.
Demand Control
Ventilation (DCV)
Below set High
(DCV LED Off) (Free Cooling LED Off)
Low
(Free Cooling LED On)
Above set High
(DCV LED On) (Free Cooling LED Off)
Low
(Free Cooling LED On)
*For single enthalpy control, the module compares outdoor enthalpy to the ABCD set point.
†Power at N terminal determines Occupied/Unoccupied setting:
**Modulation is based on the supply-air sensor signal.
††Modulation is based on the DCV signal.
***Modulation is based on the greater of DCV and supply-air sensor signals, between minimum position and either maximum position (DCV) or fully open (sup-
ply-air signal).
†††Modulation is based on the greater of DCV and supply-air sensor signals, between closed and either maximum position (DCV) or fully open (supply-air sig-
nal).
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).
CAUSE
No power to control transformer from
evaporator-fan motor.
No power from control transformer to hot gas
line solenoid valve
Hot gas line solenoid valve will not operate.
Low refrigerant charge or frosted evaporator coil.
Thermostatic expansion valve (TXV).
Liquid line solenoid valve will not operate.
Hot gas line solenoid valve will not close.
Table 39—EconoMi$er IV Input/Output Logic
INPUTS
Enthalpy*
Y1
Outdoor Return
Low On On
On Off
Off Off
High On On
On Off
Off Off
Low On On
On Off
Off Off
High On On
On Off
Off Off
24 vac (Occupied), no power (Unoccupied).
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. 59-62.
2. Evaporator coil frosted; check and replace low-pres-
sure switch if necessary.
1. Check TXV bulb mounting, and secure tightly to suc-
tion line.
2. Replace TXV if stuck open or closed.
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 closed; replace.
1. Check charge amount. Charge per Fig. 59-62.
2. Evaporator coil frosted; check and replace low-pres-
sure switch if necessary.
1. Check TXV bulb mounting, and secure tightly to suc-
tion line.
2. Replace TXV if stuck open or closed.
Valve is stuck, replace valve.
Valve is stuck; replace valve.
Compressor
Stage Stage
Occupied
Y2
1 2
On On Minimum position
On Off
Off Off
On Off Modulating** (between min.
position and full-open)
Off Off
Off Off Minimum position
On On Modulating†† (between min.
position and DCV maximum)
On Off
Off Off
On Off Modulating***
Off Off
Off Off
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REMEDY
REMEDY
OUTPUTS
N Terminal†
Unoccupied
Damper
Closed
Modulating** (between
closed and full-open)
Closed
Modulating†† (between
closed and DCV
maximum)
Modulating†††