15000 BTU Window A/C heat pump conversion

[jeff5may]

OK, so I was at my buddy's house figuring out how to insulate his garage, and his neighbor needed help patching his leaking porch roof. While surveying the job site, I happened upon this stray unit in his scrap pile:


It is a Whirlpool 240 volt model rated at 18000 BTU. Looking into the unit, the compressor only says 15000 btu on its nameplate, so I'm only rating this one at 15k for this discussion. Long story short, neighbor guy gave me the unit as partial payment for helping him with his roof. It don't leak no more.

Having run my previous window shaker concoction to death, I now have lots of parts I can rob from it if I need them. I brought it over to dude's house and did some work to it while doing his insulating with him. I gutted the control system and the reversing valve from it. The refrigeration loop was whole in the old unit when I retired it, the main failure was the fan motor mount. One of the outdoor fan blades had cracked due to a collision with some ice during defrost; after I fixed the blade it was a little off balance. It ran for a long time before the motor mount got loose. At the end of the winter, it got a new home sitting doing nothing in the barn.

I tried using the itty-bitty berns-o-matic torches on the new subject, but gave up after going through two bottles of oxygen.

I basically got a few lines separated from the donor unit and the patient. Not wanting to waste money on gas, I gave up on this toy set. I went next door and borrowed neighbor's oxyacetylene bottles and vintage oxweld torch. Looks just like this victor:


If you are doing more than just a tiny amount of gas brazing or welding, don't bother with a propane blowtorch or the toy set above. Just buy, rent, borrow, or beg a real torch off someone somewhere. I finished the whole rest of the surgery on the patient unit in less time with the real torch than it took me to halfway take apart stuff with the toy one. I learned my lesson this time, the toy set will be used for soldering jewelry and such from now on.

Here are pics of what I've done so far:

The original compressor discharge line was tapped into with a bullet piercing valve to drain the factory charge of R-22. The shiny spot down low is where I closed up the pierced hole. This line was rerouted to a reversing valve gleaned from the retired unit. The shroud for the outdoor HX (and some of the drain pan) was rusted through, so I stuck some scraps of R-max board in along the bottom to minimize air leaks that would serve to bypass the HX and reduce efficiency.