[jonhaddigan]

Our thermostat comes on, the air handler blows, but the outside unit does not come on. We tested the capacitor, its fine. We replaced the single. Pole contactors with a double pole, everything seems to test fine but the fan and compressor don't come on. When we manually override the contactor it will run but blows hot air inside.

 

[yuri]

Is it a heat pump?

Post brand and model #.

Do you have 24 volts AC at the contactor coil?

If it is a heatpump and you press the contactor in and the reversing valve is in heat mode you will get heat. Need to see if the thermostat is sending 24 volts on the Y wire to the outdoor unit and contactor. Check between Y and C out there or at the furnace.

 

[jonhaddigan]

It's a Trane split system 2TWB

 

[jonhaddigan]

Getting 24 volts at the coil. When manually pushing in the contactor heat comes out

 

[yuri]

It looks like a heat pump which I don't see many of where I am.

If you are getting 24 volts across the coil it should pull in unless the contactor is sticking. Need to check across the coil and NOT to ground or you can get fooled.

However the reversing valve should be in the cooling position as it gets a signal at the same time to move it to cool ( unless it is a brand that does not, Rheem I believe ). If it is getting the signal and you push the contactor in it should cool.

Check back here later as there may be some techs here who know that unit better.

 

[jonhaddigan]

Thank you

 

[yuri]

Yur Welcome.:biggrin2:

My comrade Beenthere knows Trane and there will be others here within 8 hours or tomorrow.

 

[roughneck]

What's the voltage across the coil?

 

[jonhaddigan]

24 volts

 

[supers05]

If there is 24v across the coil of the contactor, and it's not pulled in, then it's dead. Replace it.

Cheers!

 

[jonhaddigan]

I replaced the contactor and still same issues. Is it possible the contactor is faulty or can something else cause this?

 

[BayouRunner]

Are you measuring 24 volts at the contactor or at the connections coming into the condenser? The contactor you purchased has a 24 volt coil?

 

[jonhaddigan]

At the contactor is 24 volts and the coil is a 24 volt coil.

 

[BayouRunner]

if it has 24 volts at contactor and is not pulling in then the contactor is faulty. I find the odds of having your old contactor and new contactor bad are not too likely though. You mentioned earlier when you engaged contactor unit was producing heat. So I am assuming you are getting 220 volts. It's hard to tell over the internet but I have to ask so I can understand. When you are measuring 24 volts, you are measuring with a lead on each side of coil and not to ground right?

 

[jonhaddigan]

220 coming in but 24 at ground.

 

[jonhaddigan]

I will go check it at coil only and see what I get

 

[BayouRunner]

Ok you don't want to measure at ground for the low voltage. You only want to measure at the two prongs for the coil. I'll try and guide you through if I can. Can you measure where the low voltage wires come in to the condenser and see if you have 24 volts there? Do not measure to ground. With a heat pump there will be more wires coming in but you should have one common wire and possibly two wires reading at 24 volts. It may only be one, just depends on your setup. I am trying to determine if your problem is in the condenser, air handler or tstat

 

[beenthere]

You may have loss the common, or have an open high or low pressure switch. Check for 24 volts at the contactors coil, by placing the leads of your meter on each low voltage post at the same time. Turn of the breaker to the outdoor unit before doing this, so you don't slip and short out line to low voltage.

 

[jonhaddigan]

Voltage at coil is 0. Coming into condenser is 24 from 1 wire

 

[jonhaddigan]

I found the yellow wire from Stat at 24 volts and a blue wire from Stat that has been chewed through with 0 volts coming out.