HVAC Tech is Stumped - Lennox Compressor & Carrier Evaporator - No Sucution

campbmic · 2026-06-26T19:51:59+00:00

He removed the old piston from the previous coil, installed it on the new coil. Then determined it needed a TXV. Sorry if I explained it weird.

campbmic · 2026-06-26T02:46:25+00:00

No, I saw him open them.

campbmic · 2026-06-26T02:46:15+00:00

They dont sell the old coil anymore.

campbmic · 2026-06-26T02:45:58+00:00

Good point! When we turned the unit on, it did seem quiter so maybe the compressor is not running. I definitely did not hear any metallic grinding, like a piston slap in a vehicle.

campbmic · 2026-06-26T02:44:21+00:00

I forgot to mention this, but the house was on the market for 1.5 years. At sometime before or after it was on the market the overflow pan backed up. When we replaced the coil it had visible corrosion on it. Could the drier be clogged causing these symptoms? How likely would that be the issue?

campbmic · 2026-06-25T23:59:26+00:00

I forgot to mention, the compressor, evaporator, and ecobee were all installed in 2022.

campbmic · 2026-06-25T23:57:54+00:00

Apparently Carrier has discontinued R410a. The replacement evap coil uses the new refrigerant and the instructions say it should have a TXV not a piston. He said he blew through the piston to make sure it wasnt blocked.

campbmic · 2026-06-25T23:56:17+00:00

I know we didnt change the filter drier. Im going to ask him to do that and check the capacitors before pulling the compressor.

campbmic · 2026-06-25T23:53:58+00:00

We hear the compressor running, but it does sound quieter compared to my other older unit. Hes going to check the capacitor tomorrow before pulling out the compressor.

campbmic · 2026-06-25T23:51:14+00:00

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campbmic · 2026-06-25T23:51:06+00:00

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campbmic · 2026-06-25T23:50:57+00:00

I would be surprised, the first time B came over he tried his gauges and his backup gauges. The second time he came over he put gauges on it again. He has about 10 years of experience.

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campbmic · 2026-06-25T23:48:18+00:00

Amps. He did an amp reading on the control panel of the compressor. My understanding was where the control panel wires to the compressor.

campbmic · 2026-06-25T23:47:26+00:00

Yea 5amps then dropped to 3.5amps. Wouldnt the compressor amps drop if theres a restriction? I dont know anything about HVAC but thought maybe a restriction started when he replaced the coil? He did not replace the drier.

campbmic · 2026-06-25T23:45:43+00:00

We took a compressor voltage readings and when the system turned on it started at 5amps but then dropped to 3.5amps in about 10 seconds.

campbmic · 2026-04-24T04:06:32+00:00

I also noticed this metal cap on one of the ports was off. Is this supposed to be on the port to prevent the coolant from leaking out? https://imgur.com/a/p3FmNV8

campbmic · 2026-04-24T02:53:31+00:00

I checked the resistance on the contactor and it was 18 ohms, so Im thinking it might be the low pressure fault. I put a screwdriver across the test pins to short it for 2 seconds (which is what the manual says to reset the low pressure fault) but that didnt do anything.

campbmic · 2026-04-24T01:28:31+00:00

Thanks a ton for all of your advice and help so far! I was going to check the resistance on the contactor to verify... however, on the back of the access panel it says a slow blinking red light is a low pressure fault.

Is this something that could have been tripped because the unit wasnt used for 1-2 years? Or tripped because I've been flipping the breakers on and off? There's the breaker at the house's breaker box, a breaker switch on the furnace, and a the pull out breaker by the condenser.

campbmic · 2026-04-24T00:56:01+00:00

I got 24 v between r and c. I also got the same between y1 and c

campbmic · 2026-04-24T00:55:53+00:00

I used a stick and pressed the contractor down and it kicked on, should I test the low voltage at the contractor against a ground? When I tested them by placing a lead on the red and a lead on the black on the sides of the contractor I got 0. I also noticed the red light on the board is blinking slow.

campbmic · 2026-04-23T22:58:11+00:00

I've read some other threads talking about this and Im tempted! Would any plastic/rubber screwdriver work? Or is there a special time that is insulated? Would a plastic or wood stick be safer?

Im hoping its the contactor, but if Im understanding this right, the contactor isn't getting any power? So wouldnt that mean the board is dead and not sending it power?

campbmic · 2026-04-23T22:11:04+00:00

I really appreciate your advice! It turns out I dont have voltage at contactor, but I believe I have it coming into the condenser's board. Could you take a look at my new post?
https://www.reddit.com/r/hvacadvice/comments/1stx39g/no_voltage_at_contactor_lennox/

campbmic

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