On left side of the control board will be the test terminals, short them with screwdriver and the diagnostic light will flash an error code
No power
- Starter or breaker tripped possible faulty compressor start windings, a hard start kit can be used to make unit work but with my experience it only lasts a few months.
2 Flash high-pressure problems red wires run to HP switch
- Water Condenser should have 10-degree difference between water going in and water going out.
- Refrigerant charge could be over charged check subcooling.
- Faulty high-pressure switch test switch at normal pressures it should be normally closed.
- In heating mode possible low/no airflow over the Evaporator.
- Faulty TXV bulb loss of charge or plug/stuck valve
My experience 1 Refrigerant 410a cooling H-600 PSI L-50 PSI and dropping frost between TXV and air coil, trip on high pressure Heating H-350 PSI L-75 PSI cold between TXV and water condenser, trip on water coil low temperature Found TXV stuck closed I replaced both filter/dryers, TXV, vacuum to 500 microns, new refrigerant system works perfectly now H-350 L-150
My experience 2 Refrigerant 410a H-350 L-125 high-pressure switch open. Faulty switch need to recover refrigerant replace high-pressure switch (one two red wires run to) and two filter/dryers. Leak test with 150-PSI nitrogen, Vacuum down to 500 microns. Recharge
3 Flashes low pressure/ loss of charge Blue & Brown wires to LP/LOC switch
Refrigerant charge lost due to leak
Most leaks will be found at the access fittings where we connect our gauges. I have found leaks at water condenser, Evaporator, and on copper line where they had rubbed against each other until it created a hole. If 0 pressure leak search with 150 Lb nitrogen repair leak vacuum all moisture out of system to 500 microns, recharge by weighing in refrigerant.
When arriving at a system you find it has 0 PSI Refrigerant pressure most likely the leak will be located on the liquid or discharge side of the system. Climate Master leaks are very hard to find in the past I have found them on the evaporator. Pressure tests may seem to hold due to the small leak, But if 0 PSI then you do have a leak. Look for oil stains anywhere on piping pressure test, refrigerant leak detector until you find the leak.
4 flashes Water coil low temperature limit grey wires to FP1 sensor
- Cooling mode reduced or no water flows to water condenser.
- Bad thermistor click here to see Temp/Ohm chart and compare. Temp/Ohm chart on page 11
- Faulty TXV bulb loss of charge or plug/stuck valve
My experience Refrigerant 410a cooling H-600 PSI L-50 PSI and dropping frost between TXV and air coil, trip on high pressure Heating H-350 PSI L-75 PSI cold between TXV and water condenser, trip on water coil low temperature Found TXV stuck closed I replaced both filter/dryers, TXV, vacuum to 500 microns, new refrigerant system works perfectly now H-350 L-150
5 Flashes Air coil low temperature limit Violet wires to FP2 sensor
- low refrigerant charge
- faulty TXV
- cooling mode reduced or no air flow.
- Bad thermistor click here to check Temp/Ohm chart and compare. Temp/Ohm chart in page 11
My experience
Blower motor seized or low air flow
low refrigerant Refrigerant 410a high-240 low-55 superheat 77 subcooling 0 Found high service valve leaking – replace cores and caps. Recharge unit with 2lb 6 oz high- 320 low-120 superheat 9 subcooling 10
6 Flashes Condensate fault Yellow wire to condensate sensor
- Blocked drain.
- Always have Trap installed next to heat pump.
7 Flashes over/under voltage
- Compare main power supply voltage and 24VAC before and during operation.
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furnace trouble shooting help 