Carrier 48TC 04 Series, Service And Maintenance Instructions

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Table 33 -- Humidi--MiZer

Troubleshooting (cont)
PROBLEM CAUSE SOLUTION
Compressor Not Running in Reheat2 Mode.
Reheat Control board:
No Input on RCB pin J1B--4.
RCB Relay failure at output RCB pins J1A--5
and J1B--1.
See “Reheat Control Board (RCB) Relay Operation” .
Low Latent Capacity in Subcooling or Hot
Gas Reheat Modes.
Cooling Liquid Valve open or leaking. See “Cooling Liquid Valves Operation” above.
Low Sensible Capacity in Normal Cool or
Subcooling Reheat Modes.
Reheat Discharge Valve open or leaking. See
“Reheat Discharge Valve (RDV)”
above.
Low Suction Pressure and high Superheat
During Normal Cooling Mode.
General Cooling Mode Problem. See Cooling Service Troubleshooting.
Reheat Discharge Valve open or leaking. See “Reheat Discharge Valve (RDV)” above.
Low Suction Pressure and High Discharge
Pressure During Reheat1 and Reheat2 (Type
1).
TXV in Humidi--MiZer coil not controlling super-
heat.
Check TXV operation or mounting. Repair or replace.
Loss of Compressor Superheat Conditions in
Reheat1 and Reheat2 Modes (Type 1).
TXV in Humidi--MiZer coil not controlling super-
heat.
Check TXV bulb mounting. Secure bulb tightly to suction line
and cover with proper insulation. Replace TXV if stuck closed or
open.
Reheat Discharge 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.
Circuit 2 Will Not Operate With Circuit 1
Off.
Normal Operation. Motormaster outdoor fan control
requires operation of Circuit 1.
None.
Econ --- Economizer
FPT --- Freeze Protection Thermostat .
IFM --- Indoor (Supply) Fan motor .
LSV --- Liquid Solenoid Valve .
LTLO --- Low Temperature Lockout
REHEAT ---Connection Strip REHEAT (on CTB)
48TC