Carrier 48TC 04 Series Service And Maintenance Instructions page 75

Table 33 – Humidi- - MiZer Troubleshooting
PROBLEM
Reheat1 (Subcooling) Mode Will Not
Activate
Reheat2 (Hot Gas Reheat) Mode Will Not
Activate
No Dehumidification Demand
Reheat Control Board (RCB)
Relay Operation
Cooling Liquid Valves Operation
CSV (Sizes 04- -12) (Type 1):
Open in Cool (De- -energized)
Close in Reheat1 and Reheat2 (Energized)
CLV (Size 14) (Type 2):
Open in Cool (De- -energized)
Close in Reheat1 and Reheat2 (Energized)
LDV: 3- -way (Size 16) (Type 3):
NO: Open in Cool (De- -energized)
Close in Reheat 1 and Reheat 2
(Energized)
NO: Close in Cool (De- -energized) Open
in Reheat 1 and Reheat 2 (Energized)
Reheat Discharge Valve Operation
Supply (Indoor) Fan Motor Not Running in
Reheat2 Mode
CAUSE
No Dehumidification Demand.
Outdoor temperature too low.
General Cooling Mode problem.
Faulty Reheat Control Board (RCB) relay operation. See "Reheat Control Board (RCB) Relay Operation" below.
Cooling Liquid Valve open.
No Dehumidification Demand.
Outdoor temperature too low.
General Cooling Mode problem.
Faulty Reheat Control Board (RCB) relay operation. See "Reheat Control Board (RCB) Relay Operation" below.
Cooling Liquid Valve open.
Reheat Discharge Valve closed.
Relative humidity set- - point is too high - - Hu-
midistat.
No humidity signal.
No 24V signal to input terminals.
24V signal to input terminal J1A- - 2.
No power to output terminals.
Relay outputs do not change state.
Reheat1 or Reheat2 will not activate.
Check RCB Pin J2- - 2 for 24V
Check RCB Pin J2- - 2 for 0V
Check RCB Pin J2- - 2 for 24V
Solenoid Coil Burnout (CLV, LDV)
Stuck valve.
Reheat2 will not activate
DSV, DSV1, RDV, RDV1:
Check for RCB Pin J2- - 5 for 24V.
DSV2, RDV2: Check for RCB Pin J2- - 5 for 24V.
Reheat Control board:
No Input on RCB pin J1B- - 4.
RCB Relay failure at output RCB pin JB- - 2
75
SOLUTION
See "No Dehumidification Demand" below.
Compare outdoor temperature to LTLO setting. Normal operation.
See Cooling Service Troubleshooting.
See "Cooling Liquid Valves Operation" below.
See "No Dehumidification Demand" below.
Compare outdoor temperature to LTLO setting. Subcooling (Re-
heat1) operation.
See Cooling Service Troubleshooting.
See "Cooling Liquid Valves" below.
See "Reheat Discharge Valve (RDV) " below.
Check/decrease setting on accessory Humidistat.
Check wiring at RCB: Pin J1A- - 1
Check Humidistat or Humidity Sensor
Check Low Temperature Lockout (LTLO) switch status and
wiring.
Check wiring at RCB: Pin J1A- - 1
Check Low Temperature Lockout (LTLO) switch status and
wiring.
Check wiring and voltage at RCB: Pin J2- - 1
Check Control Terminal Board (CTB): Terminal R
Check TRAN primary, secondary circuit breaker
Check TRAN2 primary, secondary circuit breaker (when
used).
Check wiring.
Check for Thermostat Heating Demand (W1).
If YES, normal operation.
if NO, check wiring.
Replace faulty Reheat Control Board (RCB).
Replace faulty Reheat Control Board (RCB).
See "Reheat Control Board (RCB) Relay Operation".
Check continuous voltage is less than 10%.
Check under- - voltage is less than 10%
Check for missing coil assembly parts.
Check for damaged valve enclosing tube.
Replace CLV valve. Replace Filter Drier.
See "Reheat Control Board (RCB) Relay Operation"
See "Reheat Control Board (RCB) Relay Operation".