Coil leak in the outside heat pump unit

by Rajesh P
(Long island, Ny)

Our heat ( Lennox, 5 ton ) went out a week ago. Tried everything by our heating guy- even changed the thermostat. Turns out that there is a leak in the outside coil.

One HVAC serviceman sent over by the landlord said there was a leak in the compressor. I don't even know if they opened the condenser unit. So I'm not sure how he isolated the leak to the compressor right away.

Said I had to replace the whole unit outside AND the unit inside air handler Benz of incompatibility issues that would arise. Also said that the compressor leaked because of a faulty motor that I had replaced 3 summers ago! I find that very very hard to believe.

Finally, I had my own independent diagnostics done. I was there when is new guy showed me the oil stains on the radiator aluminum mesh right where the coils were running. NOT THE COMPRESSOR.

So now the big question is- can the outside coils be replaced without replacing the compressor?

Could a lower RPM motor @ 825 rpm cause high pressure build up in the system to cause a leak?

I know this may be a bit confusing. But any help would be appreciated.


Rcp, NY

Dadan replies:

Hey, Rajesh

Some HVAC manufacturer still makes r22 replacement parts. (I’m presuming it is r22 central ac unit). The outside coil can always be replaced. The only problem is,

Does the HVAC manufacturer have your specific coils? If there is coil that match your model number, yes you can replace it. You need to know your HVAC branch and find that branch number and call them.

“lower RPM motor @ 825 rpm cause high pressure build up in the system to cause a leak” are you referring to condenser motor?

I don’t know the correct RPM for you condenser motor. A condenser motor that is not doing or rotating the correct RPM will cause heat buildup in the condenser unit. The compressor should shut off due to high pressure.

There was problem with the condenser coil leak due to higher prices of copper. Some HVAC manufacturer decided to stretch copper tube. This result saves them money; however, this also cause leak in their condenser coil.

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Lennox cool leak
by: Rajesh

Thanx guys again for your input.
Continuing my saga of the coil leak.

Now the Lennox dealership is saying the " aftermarket wrong motor " caused high pressures to cause the leak in the coils and the compressor.

Said there was no check of amperage , there was no blade calibration , and a " million things that could have been done wrong" to recap, I had a fan motor replaced 3 years ago ... It was a 825 rpm as opposed to the original 1050 rpm motor.

Can it really be true what he said? I thought it was too far fetched , especially given the plethora complaints of leaking coils in their units.

All I had to do is google it, and voila! Plenty of similar coil leaks. So, any words of wisdom?

Heat coils leak.
by: Rajesh

Thanks guys for your insight. Knowing what u just told me will Help me negotiate with the landlord to pay for the repairs/ replacements.

Yes, Dadan, it is the condenser coil I was referring to. The ones that are enclosed in the peripheral round alumini fins/mesh. Somehow the landlords HVAC man ( a Lennox dealer) insists that the compressor leaked because of the" faulty" motor. The original condenser fan motor had 1075 3-phase. The one we have on is 825 rpms, 3 phase.

And I don't understand why it would allow the pressure to build up and cause a leak like the HVAC guys insist.
Thanks again for your insights and help.

Coil leak
by: whulme

The last reply is correct, but may I suggest you call Lennox direct to get the right answer about a condenser coil to be found. Most HVAC companies are going to tell you no, replace the system.

You will need to have the model and serial number off the data plate of the outdoor condenser.

Alternate route is replacing the outdoor condenser with a dry r-22 straight cool condenser and switch the system from heat pump to resistance heat/cool only system.

You will need to confirm you have aux. heat strips in your air handler and set the thermostat up correctly for this application.

Good Luck!

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