YORK heat pump

[sean88]

I was working on a 2 ton York heat pump, cased evaporator coil with gas heat today. It had a bad schader valve and was low on charge. I evacuated the unit, pressure tested, to look for other leaks and put 5 lbs of R-22 back in.

While charging the unit I noticed control panel red light in the condensing unit was flashing 4 times. Unfortunately there was no info on the unit(surprise) which would tell me what the 4 flashes meant. I haven't worked on many Yorks so I've got no clue what the code is. It looks to be about 10 yrs old, again no nameplate info could be found.

Also the unit didn't have any pressure switches. After charging the unit the low pressure side was still low. I suspect a dirty coil since there were no air filters installed on the unit. I didn't want to keep pumping refrigerant in plus it worked fine in heat mode. I didn't have time to inspect the coil since the customer didn't want to pay overtime. So, I've got to go back Monday to finish the job.

So back to my orginal question, does anyone know what the 4 flashes mean? And what else might cause a low suction and head pressure. Outdoor temp was about 75 and indoors it was 80.

[airconman]

Discharge temp did not reach approx. 90 degrees F within 1 hour of compressor operation.
which could be..... compressor overload, beings you were low on refrigerant, I'd say that would be a place to start.
discharge sensor?
Liquid line sensor?
low pressures would be not enough refrigerant, my first choice. Restriction somewhere? check your subcooling? Whats your liquid line temp and pressure?

[tecman]

Most York heat pumps do have a pressure switch. The older ones just has a high pressure cutout switch, newer have lo and hi ones.

As for the number of flashes on the York controller:

2 = discharge pressure over 400 psig
3 = discharge line temp over 275 F
4 = discharge line temp did not hit 90 F with 1 hour of call for compressor
5 = 2 defrosts in 1 hour
7 = OD Sensor open or shorted
8 = Liquid line sensor open or shorted
9 = Bonnet sensor shorted

You may want to jot these down for future reference

paul

[filterchanger]

reversing valve might be sticking

[airworx]

all guesses without subcooling and superheat. low suction with low superheat indictes low airflow across evap. low suction with high superheat check subcooling, low subcooling means low charge, normal or high subcooling means restriction. pressures really dont tell much without subcooling and superheat.

[beenthere]

As airworx said, not enough info.
Also how long is the line set, york is precharged for 15' line set.

[sean88]

Thanks Tecman-just currious what is a bonnet sensor? The power head on the txv?

I had 30 F super heat, the liquid line pressure was about 145 psi. Didn't check sub cooling. I'll do that tomorrow. I'm betting on a dirty evap coil since the unit didn't go off on high head pressure.

I did check the reversing valve and it's working ok.

[HVAC Pro]

Did you work on it for more than 90 minutes with the thermostat calling and the disconnect pulled?

[sean88]

Found the problem today. The coil was filthy. It looked like it was wearing a fur coat. Cleaned it up all the temps came into line.

[tecman]

never saw one or an official description, but I believe it is a temp sensor for a fuel/heatpump sensor, to indicate when the indoor evap coil incoming air temp is too high (furnace running) for the heat pump to safely run. It, I assume, would lock out the compressor when this temp is above a limit.

paul

[beenthere]

tecman, you got it ight.

The new Affinity heatpumps have it also.