Carrier 48GC Series - Humidi- -Mizer System Troubleshooting

36
Humidi--MiZer
R
System Troubleshooting
Use the SystemVut control display or a CCN device to view the
cooling status display and the cooling diagnostic display. See
Optional Humidi--MiZer Dehumidification System starting on
page 17 for information on the cooling operation and the related
Humidi--MiZer system operation. Check the current alarms and
alarm history for any cooling alarm codes and correct any causes
(see Table 12 on page 32). Verify any unique control
configurations per installed site requirements or accessories.
If alarm conditions are corrected and cleared, operation of the
compressors, fans, and Humidi-MiZer system valves may be
verified by using the Service Test mode (see Table 4 on page 11).
In addition to general cooling service analysis (Table 14 on page
35), see Table 15 (below) for general Humidi-MiZer system service
analysis.
NOTE: Wiring, operation, and charge are different on a
Humidi-MiZer system unit compared to a standard unit.
Table 15 – Humidi-- MiZer System Service Analysis
PROBLEM CAUSE REMEDY
Subcooling Reheat Mode
Will Not Activate.
General cooling mode problem. See Cooling Service Analysis (Table 14).
No dehumidification demand. See No Dehumidification Demand, below.
Circuit CLV or RLV valve problem. See CLV or RLV Valve Operation, below.
Hot Gas Reheat Mode
Will Not Activate.
General cooling mode problem. See Cooling Service Analysis (Table 14).
No dehumidification demand. See No Dehumidification Demand, below.
CLV or RLV valve problem. See CLV or RLV Valve Operation, below.
Circuit RDV valve is not open. SeeRDVValveOperation,below.
Outdoor temperature too low.
Check Reheat Circuit Limit Temperatures
Unit ConfigurationsCoolingHumz Lockout OAT
No Dehumidification Demand.
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 (SetpointsSPRH)
Software configuration error
for accessory humidistat.
Check Space Humidity Switch (SETTINGS  UNIT CONFIGURATIONS
 SWITCH INPUTS CONFIGS  HUMSTAT CHANNEL)
Software configuration error
for accessory humidity sensor.
Check RH Sensor (SETTINGS  UNIT CONFIGURATIONS  ANALOG
INPUTS CONFIGS  SPRH SENSOR CHANNEL)
No humidity signal. Check wiring. Check humidistat or humidity sensor.
CLV or RLV Valve Operation.
No 24V signal to input terminals.
Check using Service t est mode
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 t ube.
Stuck valve. Replace valve. Replace filter drier.
RDV Valve Operation.
(NOTE: Normally Closed
When De-energized)
No 24V signal to input terminals.
Check using Service t est mode
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 t ube.
Stuck valve. Replace valve. Replace filter drier.
Low Sensible Capacity in Normal Cool
or Subcooling Reheat Modes.
RDV valve open or leaking. SeeRDVValveOperation,above.
Low Suction Pressure and High
Superheat During Normal Cool Mode.
General cooling mode problem. See Cooling Service Analysis (Table 14).
RDV valve open or leaking. SeeRDVValveOperation,above.
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.
LEGEND
CLV --- Cooling Liquid Valve
IOB --- I n p u t --- Ou t p u t B o a r d
LDV --- L i q u i d D i v e r t e r V a l v e
RDV --- Reheat Discharge Valve
RLV --- R e h e a t L i q u i d V a l v e
RH --- Relative Humidity