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This morning I noticed that my main floor wasn't cooling. I found the condensation pump full ( little giant model VCMA-15ULS ). I disconnected the hose from the unit to the pump, drained it, dumped the pump and reconnected it.

The aprilaire 8446 display unit clicks when I turn down the temperature but the hvac unit itself ( model FA4CNF030, doesn't show manufacturer ) never comes on. I've tried turning the circuit on / off at the power panel.

I also tried swapping out pumps with another and disconnecting the switch that is in the pan at the bottom of the unit for condensation flooding. Each time I powered the unit off and even hit reset on the aprilaire control unit at the wall.

What else can I do to try and get this puppy to come alive?

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Is there power going to the furnace? Is there power to the condensation pump? – SteveR May 6 '12 at 17:45
Do you have Fuses? – lqlarry May 6 '12 at 19:22
You said you disconnected the switch that is in the pan. Did you just disconnect it or actually bypassing it by bridging the terminals? – used2could May 14 '12 at 3:12

2 Answers 2

Your condensation pump won't cut out your HVAC unit. If it were a pump failure you would have water all over the floor. That's all that would happen. Your unit not coming on could be caused by many different problems. Checking the power is good. Did you see if the thermostat was displaying cooling? is the temperature set low enough for the thermostat to call for cooling? Is the power switch located on the unit in the on (up) position? Any thing more than that will require a professional mechanic to come out and diagnose.

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The first thing to check is if the air handler will come on when you turn the heat on. If the air handler will kick on and circulate air but not when you call for AC than you may have low refrigerant pressure.

Most AC systems have a switch that prevents the AC from running with low pressure to avoid damage to the compressor. If this is the case then I'd recommend calling a local AC repair service to have them charge the system.

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