[Clayton27520]

Unit was not working but could make it run manually from the pole contactor. Fan blower works from thermostat. Replaced thermostat, capacitor, control board and 1pole contactor. Still same results.

Ideas on where to look next ?

 

[yuri]

Do you have 24 volts AC across the coil of the outdoor contactor. Do NOT measure to ground or you can get fooled. Must be across the coil. If not you have a low voltage wiring problem or a safety control in the outdoor unit which is open. Some have a manual reset button on a high pressure cutout which is attached to the liquid line somewhere. Follow the wiring from the contactor coil and you will find it.

 

[roughneck]

A few things here-
Never push the contactor in manually. Very dangerous.
Use your tools and electrical knowledge to troubleshoot before ordering parts. If you throw parts at it you'll run up a huge bill and still have a broken unit.
What readings led you to changing these parts? What readings are you getting now? Voltage across the contactor? Is there an overflow switch somewhere?

 

[Clayton27520]

Thanks, I'll take a look

 

[Clayton27520]

A few things here-
Never push the contactor in manually. Very dangerous.
Use your tools and electrical knowledge to troubleshoot before ordering parts. If you throw parts at it you'll run up a huge bill and still have a broken unit.
What readings led you to changing these parts? What readings are you getting now? Voltage across the contactor? Is there an overflow switch somewhere?

A friend that claims he knows HVAC gave me the parts list, all the parts total ~$100, cheaper than a service call by far and only took about 15 minutes to install. I know computers and cars this is my first venture into HVAC, wish they would through error codes.

Didn't take voltmeter with me but guess I will need it. I'll look for a cutout switch.

 

[roughneck]

Parts list? Was any diagnostic work done prior to replacing these things, or did you just replace what he said it could be? Are these all the correct parts for this unit?

 

[Clayton27520]

Like I stated earlier, friend said he new heat pumps. he spent some time on it and provide a list of part numbers. I ordered them and they all look identical. After installing I have the exact same issue, to me that means I replaced good parts with good parts and changed nothing. I'm out $100, no big deal. So I'm posting on a forum, What else is there ?

Not sure how it can be a overflow switch, seems like that would prevent it from coming on when manually pressing the pole switch. 24v, maybe something came loose so I'll check that

Are there any other switches/solenoids/sensors that can prevent it from turning on ?

 

[roughneck]

Overflow, float, or wet switches break control voltage not line voltage.

 

[beenthere]

As roughneck said. Float switches are connected to the low voltage control wires. So an open float switch can stop the outdoor unit from running.

An open low or high pressure switch can also. Did your friend put his gauges/manifold on the system to see if it has enough refrigerant in it to run. Pushing in the contactor on a system that is low on charge can be harmful to the compressor.

 

[Clayton27520]

I wasn't there but he did say he tested the refrigerant and it wasn't low. I didn't let it run but a few seconds, not sure what gets bypassed when you engage it that way. So there are also high and low pressure sensors that could cause these symptoms? I've seen the wiring diagram but are that pics that show physical location of these sensors/switches ?

 

[yuri]

If you follow the freon lines from the house back to the unit and then follow them inside the unit you may see them attached to the freon lines inside the unit. There will be 2 wires from each which join into the wires which go the the contactor.

Post the brand and model # and maybe we can help more.

Here is a link for a Lennox manual. Click on the XC15 and in the pdf file there is a pic on page 4. Your unit will be different.

2 green thingys with red buttons at the bottom of the pic



http://www.completeheating.ca/index.php/manuals1/lennox-air-conditioners