Lennox Central Air issue??

Old 05-11-14, 09:11 AM
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Lennox Central Air issue??

I have a Lennox Pulse Furnace with a 12 SEER A/C unit that was working fine at the end of last year, but this year I decided to test it out, and it's a NO go.

If I switch the button to Cool on my Honeywell programmable thermostat, and the switch to Auto, the Condenser is running outside, but the inside fan blower doesn't, and I can't hear the compressor kick in.

If I switch the fan to on from auto, the inside fan blower turns on, and the condenser still runs, but I get no cooling.

Am I low on refrigerant?
Old 05-11-14, 10:31 AM
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I'd start with tstat. Sounds like a control issue which tstat is main control. I'd say the G terminal in stat has gone bad. Are you sure compressor is coming online. You should have cooling with stat set at fan on cool mode. Lennox are great units but so many unneeded safety devices. It's crazy a 2.00 part shutting down a 2500.00 system. I'm unsure about your unit but there has been a recall on PVC vent lines. If you have PVC contact local lennox dealer and they should replace at no cost to you. PVC has failed and even caught fire in some cases.
Old 05-11-14, 10:57 AM
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If the condensor fan is running.... then the compressor should be also. You can check the copper lines at the condensor to see if the larger one is cold.

If you were low on freon - then neither the condensor fan or the compressor would be running.
Old 05-11-14, 12:10 PM
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^Only if the condenser has a low pressure cutoff, and it would have to be nearly empty i would thing.
Old 05-11-14, 12:38 PM
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I agree , sounds like the furnace is not getting the green wire 24 VAC from the tstat ? The indoor fan should come on , when the tstat is calling for cool , whether the condenser works or not ?

I would look for a loose or broken green wire at the tstat or the furnace ?

God bless

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