I'll bet this is the last problem I have with this heat pump! The compressor seems locked. I've had to replace the dual capacitor twice in two years and the two pole breaker once. I think I've eked out every bit of service I'm going to get from this 15 year-old Trane. It uses R-22.
I assume the compressor is finished, could I be wrong? It hums for a few seconds every thirty seconds or so. I replaced the capacitor with a spare I bought the last time, no joy. Is it worth it to just replace the compressor? Could I just replace the whole outside unit? Should I plan on replacing everything? Any suggestions on brands to buy? Are the newer units and refrigerants significantly more efficient?
Also, the pressure is spot on for an idle system. I have had to add about two pounds every two years. I've got a good sniffer and have yet to find the leak. I surely beat the shit out of it this summer, I kept the house at 68...I like it cool! In the winter I keep it at 63.
They make a little box called a Compressor Analyzer, but all it's doing is ohming out the windings and making sure the voltage is right and the run cap is good. You can do that by hand.
When they get tired, the widings start to go - and you can't tell when it's welded inside that steel can. About the only way is to get an Acid Test Kit and see if the refrigerant is going sour from a burn.
You can flush the lineset and evap core, add some Acid Away and fresh Filter-Driers, and either change the compressor (I would try to stuff a Scroll Compressor in there if you do) or the entire condensing unit. Entire brand new condensing units are available with Mineral Oil for R-22, but they can't ship them with R-22 pre-installed due to the clowns at the EPA. Which is fine, they come empty with a vacuum on, add your own R-22 from a bottle when you get it all welded together.
Spend a bit more and get a pound of the good Silver-Braze - it flows So Much Better than the cheap low-silver crap. Fills bigger gaps too, if you have to start Frankenstein-ing the plumbing together. And either way you go, if it doesn't have both a Low Pressure and a High Pressure Safety and a Break Delay Timer, add them before you put it in service.
Much nicer to have the safety trip out before the new compressor burns up from something stupid like low charge, or head pressure from a bad condenser fan motor or clogged inlet screen to the TXV or Orifice.
If you do one at the Shop running on 3-Phase it MUST have a decent phase monitor watching the incoming line AND the compressor terminals. Fuses blow, and one pole on the contactor always goes bad first.
Phase Monitors and Break Delays are a lot cheaper than Compressors.
Does it have a starting relay, or is it permanent split-capacitor? If there is no starting relay to cut in an extra capacitor, then it is pretty likely the compressor is kaput. Possibly a hard-start kit could get it to start, but it would be almost certain to get worse soon. So, if there's no starting relay, I'd say you are right. If there is, check the start cap, relay and all associated wiring for bad connections.
Hacking heat pumps is a bit harder than straight A/C systems, everything has to be sized correctly, and heat pump compressors have different ratings than home A/C units (designed to tolerate higher discharge pressure).
The risk of replacing the outside unit is that you may already have had a hermetic burnout that spewed corrosive debris into the inside heat exchanger and lines. That is practically impossible to clean out. If this has happened, an expert can detect it from examining the lines and oil traces, and know the entire system is toast. If you do replace the compressor or complete outside unit and there WAS a hermetic burnout, the new compressor will have a VERY short life, maybe 2 weeks or so.
No start cap. I started shopping for a whole new system. So far I found a 3 ton new system for $1706. Now I have to find an installer, I don't want the responsibility.
I think you'll find most outfits would be VERY leery of replacing only part of a system where a hermetic burnout could have happened. And, you could have a MAJOR mess if somebody was willing to get involved in it without careful testing to be sure it had not happened.
Anyway, with a 15 year-old system, it could be real hard to assure system compatibility between the components. So, I think you are doing the right thing here, as most of the cost is in the section with the compressor, anyway. $1700 doesn't sound bad if it is a good system.
Actually, Nu-Calgon has an acid flush kit that's designed specifically for the purpose of cleaning the evaporator and lineset after a burn-out..
--pretty sure that it's called Rx-11.
In a nut shell, prior to removing the burnt-out condensor, the old refrigerant is recovered for disposal, and then both service valves are closed off....next, both of the schrader cores are removed and then the system is repeatedly flushed with the neutralizing solution, left to sit a few minutes, and the solution purged back out with dry nitrogen...repeating this procedure as-needed till the solution consistantly comes out a clear color.
After that, the old condensor is removed and the new one is brazed onto the old lineset and then the lineset and evaporater are evacuated before finally opening up the valves on the new unit, starting the compressor and adjusting the final charge.
purpose of cleaning the evaporator and lineset after a burn-out..
is recovered for disposal, and then both service valves are closed off....next, both of the schrader cores are removed and then the system is repeatedly flushed with the neutralizing solution, left to sit a few minutes, and the solution purged back out with dry nitrogen...repeating this procedure as-needed till the solution consistantly comes out a clear color.
old lineset and then the lineset and evaporater are evacuated before finally opening up the valves on the new unit, starting the compressor and adjusting the final charge.
Well, I'll believe that a mild burnout, where the breaker tripped very soon after the fault occurred can be cleaned up with these procedures. I think a bunch of outfits make solutions for this. But, if there is a major burnout or one that just went on for a long time, it fills the entire evaporator with ashes, corrosion deposits and other debris, and you just can't wash it all out no matter how you try.
But, a lot of professional techs have tried to fix hermetic burnouts with stuff like this, and then had another burnout within two weeks.
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