GSZH5 Service Manual

76
SERVICING



Status Description Troubleshooting Information
Solid Yellow "RUN"
Module has power and operating
normally
Supply voltage is present at module terminals
Solid Red "TRIP"
Thermostat demand signal Y is
present, but the compressor is
not running
1. Compressor protector is open
• Check for high head pressure
• Check compressor supply voltage
2. Outdoor unit power disconnect is open
3. Compressor circuit breaker or fuse(s) is open
4. Broken wire or connector is not making contact
5. High pressure switch open if present in system
6. Compressor contactor has failed open
Yellow "ALERT"
Flash Code 1
Long Run Time; Compressor is
running extremely long run
cycles indicative of low capacity
due to a system low-side fault
1. Low refrigerant charge
2. Evaporator blower is not running
• Check blower relay coil and contacts
• Check blower motor capacitor
• Check blower motor for failure or blockage
• Check evaporator blower wiring and connectors
• Check indoor blower control board
• Check thermostat wiring for open circuit
3. Evaporator coil is frozen
• Check for low suction pressure
• Check for excessively low thermostat setting
• Check evaporator airflow (coil blockages or return air filter)
• Check ductwork or registers for blockage
4. Faulty metering device
• Check TXV bulb installation (size, location and contact)
• Check if TXV/fixed orifice is stuck closed or defective
5. Liquid line restriction (filter drier blocked if present in system)
6. Thermostat is malfunctioning
• Check thermostat sub-base or wiring for short circuit
• Check thermostat installation (location, level)
Yellow "ALERT"
Flash Code 2
Compressor (Pressure) Trip;
Discharge pressure out of limits
or compressor overloaded
1. Condenser fan is not running
• Check fan capacitor
• Check fan wiring and connectors
• Check fan motor for failure or blockage
2. High head pressure
• Check high pressure switch if present in system
• Check if system is overcharged with refrigerant
• Check for non-condensable in system
3. Condenser coil poor air circulation (dirty, blocked, damaged)
Yellow "ALERT"
Flash Code 3
Short Cycling; Compressor is
running only briefly
1. Thermostat demand signal is intermittent
2. Time delay relay or control board defective
3. Low or high pressure switch is cycling
"ALERT" Flash Codes