17
Table 2 – Humidi-MiZer Troubleshooting
PROBLEM CAUSE REMEDY
Subcooling Reheat Mode
Will Not Activate.
General cooling mode problem. See Cooling Service Analysis (Table 3).
No dehumidification demand. See No Dehumidification Demand, below.
CRC relay operation. See CRC Relay Operation, below.
Circuit RLV, CLV or LDV valve pr oblem. See CLV, RLV or LDV Valve Operation, be low.
Hot Gas Reheat Mode
Will Not Activate.
General cooling mode problem. See Cooling Service Analysis (Table 3).
No dehumidification demand. See No Dehumidification Demand, below.
CRC relay operation. See CRC Relay Operation, below.
Circuit RLV, CLV or LDV valve pr oblem. See CLV, RLV or LDV Valve Operation, be low.
Circuit RDV valve is not open. SeeRDVValveOperation,below.
Outdoor temperature too low.
Check Reheat2 Circuit Limit Temperatures
(ConfigurationHMZRRA.LO and RB.LO)
using ComfortLink Scrolling Marquee.
No Dehumidification Deman d.
Relative humidity setpoint is
too low — Humidistat
Check/reduce setting on accessory humidistat.
Relative humidity setpoint is
too low — RH sensor.
Check Space RH Setpoints (SetpointsRH.SP and RH.UN) and
occupancy using ComfortLink Scrolling Marquee.
Software configuration error
for accessory humidistat.
Check Space Humidity Switch (Configuration
UNITRH.SW) using ComfortLink Scrolling Marquee.
Software configuration error
for accessory humidity sensor.
Check RH Sensor on OAQ Input (Configuration
UNITRH.S) using Comfo rtLink Scrolling Marquee.
No humidity signal. Check wiring. Check humidistat or humidity sensor.
CRC Relay Operation.
No 24V signal to input terminals.
Check using CoolReheat1 Valve Test (Service TestHMZRCRC)
using ComfortLink Scrolling Marquee.
Check MBB relay output.
Check wiring.
Check transformer and circuit breaker.
No power to output terminals. Check wiring.
Relay outputs do not change state. Replace faulty relay.
RLV, CLV or LDV Valve Operation
No 24V signal to input terminals.
Check using CoolReheat1 Valve Test (Service TestHMZRCRC)
using ComfortLink Scrolling Marquee.
Check CRC Relay Operation.
Check Wiring.
Check transformer and circuit beaker or fuses.
Solenoid coil burnout.
Check continuous over-voltage is less than 10%.
Check under-voltage is less than 15%.
Check for missing coil assembly parts.
Check for damaged valve enclosing tube.
Stuck valve. Replace valve. Replace filter drier.
RDV V alve Operation.
(NOTE: Normally Closed
When De-energized)
No 24V signal to input terminals.
Check using CoolReheat1 Valve Test (Service TestHMZRRHV.A or
RHV.B) using ComfortLink Scrolling Marquee.
Check MBB relay output.
Check wiring.
Check transformer and circuit breaker or fuses.
Solenoid coil burnout.
Check continuous over-voltage is less than 10%.
Check under-voltage is less than 15%.
Check for missing coil assembly parts.
Check for damaged valve enclosing tube.
Stuck valve. Replace valve. Replace filter drier.
Low Latent Capacity in Subcooling or
Hot Gas Reheat Modes.
CLV valve open or leaking. SeeCLVValveOperation,above.
Low Sensible Capacity in Normal Cool
or Subcooling Reheat Modes.
RDV valve open or leaking. SeeRDVValveOperation,above.
Low Suctio n Pressure and High
Superheat During Normal Cool Mode.
General cooling mode problem. See Cooling Service Analysis (Table 3).
RDV valve open or leaking. SeeRDVValveOperation,above.
Low Suction Pressure
and High Discharge Pressure.
General cooling mode problem. See Cooling Service Analysis (Table 3).
BothRLVandCLVvalvesclosed. See RLV and CLV Va lve Opera tio n, a bo ve.
RDV Valve Cycling On/Off.
Hot Gas Reheat mode low suction pressure limit.
Normal Operation During Mixed Circuit Subcooling and Hot Gas Reheat
Modes at Lower Outdoor Temperatures.
CircuitBWillNotOperateWith
Circuit A Off.
Normal operation. Motormaster outdoor fan con-
trol requires operation of circuit A.
None
LEGEND
CRC --- Cooling/Reheat Control.
CLV --- Cooling Liquid Valve..
RLV --- R e h e a t L i q u i d V a l v e..
RH --- Relative Humidity...
RDV --- Reheat Discharge Valve.
48HC
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