Troubleshooting a Trane Heatpump

[2devnull]

Hi,
I have a Trane Heatpump system (With ECM in air handler). Worked well but started not to blow cold or even cool anymore. Both Condenser and Evaporator sides power on and their respective fans spin. Filter is new and clean. I had it charged (R22) where it then blew cool for a day then went back to just air. I connected my manifold guages and thermistor to liquid line and used the emerson app. It reports charge is correct (12 sub-cool written on unit, I measure 14 per emerson app).

Would like some help troubleshooting. Two of the lines on the reversing valve are very hot but no line is cold anywhere in the system.

Please let me know if you need more info.

 

[WorthFlorida]

You have a leak on the high pressure side. That is between the compressor to the outside coils to the expansion valve at the air handler. Since it is R22 don’t bother to fix it. 2020 R22 is outlawed from being imported so it is expensive now. You probably paid dearly for that charge and it’s all gone in one day. If it was on the low pressure side it would take a few days to leak out.

If it was a bad reversing valve you’d be blowing heat. Does the compressor kick on? Most units work the same but I think Trane is opposite. From the thermostat 24v is brought to the reversing valve for cooling, no voltage and it is in heat mode. But for trane this could be opposite. I need to look it up.

 

[Sponsor]

 

[2devnull]

You have a leak on the high pressure side. That is between the compressor to the outside coils to the expansion valve at the air handler. Since it is R22 don’t bother to fix it. 2020 R22 is outlawed from being imported so it is expensive now. You probably paid dearly for that charge and it’s all gone in one day. If it was on the low pressure side it would take a few days to leak out.

If it was a bad reversing valve you’d be blowing heat. Does the compressor kick on? Most units work the same but I think Trane is opposite. From the thermostat 24v is brought to the reversing valve for cooling, no voltage and it is in heat mode. But for trane this could be opposite. I need to look it up.

If it is all leaked out, why does it measure a correct charge?

 

[WorthFlorida]

Who put in the R22? Was it from a fresh tank? The expansion valve might be plugged. What are the low and high side readings. Have you switched to to heat mode with the electric aux not energized. Does it blow heat? The air over the condensing coils will be cool in heat mode.
Are you sure the stinking ECM fan motor in the air handler is running correctly. Mine recently wasn’t running at 100%. The fan would ram up then way down in RPMs. Who can hear the the fan running inconsistently. It caused icing on the coils, no heat coming off the condenser coils and blowing only cool air at the air handler until the ice melted. Cost was $345 for diagnostics and labor. The fan motor was under warranty.

 

[2devnull]

A guy who does commercial HVAC. I don't think it was a fresh tank. I suspect their is some blockage somewhere also. I can take the reasons today and let you know. In heat mode, it does blow hot.

The ECM seems to be operating correctly. No coils icing occurring.

 

[WorthFlorida]

Just be sure in heat mode the electric aux heater was not on. It’s controlled at the thermostat.

With R22 so expensive some may used old R22 from another unit that was evacuated. Therefore it could be contaminated that might have gummed up the works. However it was low before it was recharged, therefore there is s leak somewhere anyway.

You haven’t answered one question, is the compressor running? Where are you in Florida?

 

[2devnull]

yes, I suspect it is not clean stuff....the guy is an idiot as he should have made proper checks....but he used to be cheap now charges too much so looking to replace him.

I tried to find a test to see if the compressor is working yesterday but couldn't find a reliable one. With the fan spinning, it is hard to hear anything. What would be a reliable check?

I'm in north central florida by Clermont area.

 

[WorthFlorida]

A common part that fails is the relay switch that closes the 220v to the compressor and fan motor. Some fans are 120v and others 220 but they still use the same relay. With the cutoff switch disconnected remove the leads for the fan at the relay. Check the contacts on the relay and you may find they’re worn out with an old unit. Reconnect the power. You should hear the compressor kick on. The relay is usually Double pole but some are single pole meaning it only opens on side.

 

[2devnull]

I am not seeing a wire coming out of the fan to the relay to be able to disconnect the fan. It seems to only be going to the contactor and dual-run capacitor.

 

[WorthFlorida]

disconnect at the contactor. Sorry, I call then relays.