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Lennox Heat Pump shuts down

16K views 47 replies 7 participants last post by  Master of Cold 
#1 ·
I’m having problem with a 1996 Lennox heat pump Hp 026-037-7p
I believe the current problem was brought by the condenser fan
Going out over several weeks, and the unit getting to hot and short
cycling too many times. The condenser fan and coil have been replaced.
The air handler was replaced 1.5 years ago, it’s a APH made by York.

At this point, the System will run for several hours (7-20) then shuts down.
The contactor will be in the run position, but the fan and compressor will not run.
The circuit board has two lights that blink steady, indicating “normal operation’
The condenser fan will occasionally kick on and off during this shut down phase.
My neighbor let me use his gauges to see what’s happening during shut down.
I monitored the gauges every half hour and found them to be steady at 65/200
while the system is running.
When the unit shut down the gauges went to 125/160 after a half hour, 150/160.

When the unit shut down, I turned the thermostat to the off position, and give it 1-2
Hours to cool down. After an hour I re-start and found the gauges to be 55/180.
Ive taped a cooking thermometer to the top of the compressor and found it to be running at a consistent 165 degrees F.

Any thoughts?
Sully2
 
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#2 ·
Well first off your low on charge. Which will trip the thermal overload in the compressor. The fan not running is an indication of a defrost board problem.
You can take the black wire out of the relay (the thicker one) and put it on the top of the contactor, with the other black wires. This will bypass the relay and let the fan run.
You ned to have someone come out and find the leak, or at least charge it back up.
 
#4 ·
the fan is shooting the air up wards out of the condensing unit.
My neighbor who supposedly does ac work for a living looked at the gauges and said the charge is good. I just looked at the chart on the inner panel, and it says for r22 the hp036 should be 78 on the suction side. is 65 low enough to cause it to keep shutting down?

The unit always trips off around 3-4 am when the ambient outdoor temp gets close to 78 where the thermstat is set. like it wont come back on after it cycles off.

last night I found one of the 2 thermals overload sensors was a closed circuit. the sensor looks a bit warn out. I unhooked it from the board where it was plugged into "OF" and "PF". I'll replace that in the morning.

@Master- the condensor fan runs whenever the compressor decides to run. I'd rather not bypass the contactor. Thanks Guys
 
#5 ·
How hot was it outside and inside when he checked the pressure. SH and SC would tell whats going on with the charge, pressure doesn't tell you much.
 
#15 ·
And as you can see there is nothing between the call and the board. The call goes straight to and through the board and comes out the other side. There might be a pressure switch between the board and the high voltage fan/compressor "on", but I'm not sure.

Thanks guys, I can certainly use the help.
 
#17 ·
All right looky here.
Take the wires off of the board that go to the contactor.
Put one side of the contactor on the yellow thermostat wire. The other wire off of the contactor, connect that to the wire in the "c" terminal. Pull off the two wires that go to the reversing valve. Connect those to the "c" wire and orange or "o" terminal. That will get it running. After that you can find a board.
 
#23 ·
If there's a fee then I'm sure my boss will not be interested in paying it. I'm Houston, Texas, the hvac capitol of the world meaning more refrigeration and air conditioning systems per square mile than anywhere else on the planet. Every manufacturer there is is here, their distribition plants are the size of air plane hangars.

When I was on the phone with First American Home Insurance the other day they asked me if I'd like the txv for a three ton Carrier shipped to me, no charge. It's being sent to the office.
 
#27 ·
When I do a compressor or an evaporator there's piping modifications or plenum modifications that mostly are non covered. All of that goes to our overhead. When a home owner has the highest level of insurance, the platinum, then they're covered, disposal, recovery, mods, whatever. We just bill the insurance company.

For jobs outside of insurance we do it like everyone else does, you know.
 
#28 ·
Generally they aren't insurance companies. They're warranty companies.

Insurance pays to repair damage. Warranty pays to repair breakage.

Are you on a price guide.
 
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