Heat Pump Compressor Replacements

Ken D.

Good point. The rag should be placed to keep water from otherwise entering through the joints. My experience with the Heat Block pastes is they have a tendency to crust over where the paste touches the metal being brazed. This seems to compromise its wetting ability. And you also have to clean it off afterward.

John Starcher_4

What is your experience?

I have a client with a 4-year old York heat pump that has a siezed compressor. I'm guessing it was damaged from some recent re-occurring electrical problems we've had in our area.

I can get a warranty replacement from the local distributor, but I'm concerned. It seems like whenever changing a compressor in a heat pump, the reversing valve is likely to fail soon thereafter. Has anyone else experienced this? I've had it happen to me twice in the last 5-6 years. Even though line filters were installed as part of the compressor changeout, and we were very careful to not introduce any "debris" into the sealed system when changing compressors.

I would consider swapping out the entire outdoor unit, but it is 10 SEER and no longer available. A new 13 SEER unit would necessitate swapping the air handler, as well, and now we are getting into some serious cost.

Thoughts?

Starch

Eugene Silberstein 3

Seen it far to often....

Unfortunately, I've seen it far too often. The main reason for your problem is that too much heat is being applied to the area immediately surrounding the reversing. As we know, when changing a reversing valve, we must use a heat paste, such as THERMATRAP, or wet rags to prevent overheating the internals of the valve. Unfortunately, many technicians do not take the same precautions when replacing a compressor. Note that the compressor's discharge line is connected directly to the inlet port of the reversing valve.

Quite often, when the old compressor is removed from the system, we use our acetylene torch to do so. This heats up the discharge line and the reversing valve. In addition, when brazing in the new compressor, we once again heat the joint at the compressor, once again heating the reversing valve.

So, to make a long post just a little longer, make certain to place a heat sink paste around the discharge line at the reversing valve. Be sure that the paste makes contact around the entire circumference of the tubing to prevent heat from reaching the valve by conduction.

In the event you do not have a heat paste, you can wrap the reversing valve with damp rags. Just be careful to prevent the water from entering the sytsem.

jim lockard

And If

If the reversing valve is damaged before you change the compressor how would you know? J.Lockard

Ken D.

heat pump

By way of disclosure, I have been working with heat pumps since the mid 80's. Between 1988 and 2002 I worked on them almost exclusively. If the compressor is not running, you will not know the condition of the reversing valve unless it is damaged on the outside, such as a broken bleed cap tube. If the compressor is broken, not burnt, the reversing valve is probably OK. If the compressor is burned out, quote a rev. valve with the job. When a comp. burns, the oil and refrigerant react to create acids and sludge. A slow burn with the compressor running will circulate all this slop through the system. The rev. valve, being very close internal tolerances can be adversly affected. I will say this, one outfit I worked for 12 years, had parts and labor contracts. A new rev. valve was not included in a compressor change out. I had relatively few burned compressor jobs that the rev. valve was bad or failed in a short period of time. Clean up liquid and suction driers were a must. Having said that, if I had any say, the valve would be replaced with the comp. A quick compressor burn where the compressor did not run before it quit, the reversing valve would probably be OK. But you would have no way of knowing this. As far as replacing the valve, keep it cool while brazing. Heat one stub, apply your rod, and let it cool down before brazing the next stub. This metod will keep it from overheating. Use Heat Block or wet rag ( I prefer the wet rag). Hope this helps.

jim lockard

Next Question

Thank you Ken. Next question is what is the oldest heat pump that you would attempt to replace the compressor in Vs. replacement of the system? With the 13 SEER mandate Small res. systems 2 thru 5 ton H.P.s J.Lockard

Ken D.

Jim

Most places I've been have the cut off at 10 years. With the other components starting to go, they start nickle and diming you after that. Besides, the technology will catch up and make it economically more attractive to replace entire system.

Eugene Silberstein 3

Problem w/wet rags

If available, I definitely recommend Therma-Trap or other heat sink paste as mentioned in a previous post.

If not available, the wet rag route is also acceptable, but you have to be super careful. Quite often technicians will soak a rag and proceed to wrap the valve with it prior to brazing. The problem with this is that water tends to drip (believe it or not) and, once heated, a large amount of water vapor is produced. We need to be very careful and make every attempt to keep this water/vapor from entering the system.

jim lockard

sponge

A lot of time I use a sponge it holds more water and you can slip it between the service vales and the cabinet. J. Lockard

clammy

wet rag /spray bottle

When ever brazing compressors ,expansion ,solonoid and or service valves i have always used a wet rag and kept a spray bottle or squeze bottle of water to keep the rag wet but as always the right sized torch tip for the job is always helpfull ,new dryers and a good pressre testand a good deep vacume helps peace and good luck clammy

D lux_2

dont forget

to purge with a little N when brazing