A/C repair dropped my power usage by 45%!

[gtojohn]

Folks, its been a long time since I've been here. My time is so limited I don't spend much time on the web anymore. This fortunate accident seems big enough I should share with like minded people.

My 2 ton Ruud r-22 unit locked its compressor after the 4th of July. Its 12 yrs old, a little early to fail and I'd rather not deal with complete replacement until the Fall. I installed a slightly used compressor, from 14 seer Ruud installed for a month before the coils were stolen. It was sealed and has sat for a couple of years. Both copeland compressors were rated for 21btu the only difference was the newer one designed for Puron 410a...It was a bit of a gamble but the family was out of town. I recharged the system with NU22B, it looks to be compatible with poe and mineral oil residual.

It runs a bit weird. High side at 160psi, Low side 78psi about 48f. I get a 14f differential at 100f outdoor ambient. High pressure line cool to touch, 84f. Checked it last night after dark and it was sweating...a bit like a minisplit. My previous wattage was around 1800 watts, current power usage is 1000w!!! Dropped about 45%! Very unexpected! And yes its still cools the house!

I've been tracking our power usage and its gone down about 5kw a day. The wife hasn't complained about it not cooling as well either. My guess is the savings coming from the new compressor being designed to pump to 400psi against a more restrictive metering device, less head pressure less power.

I will put together part numbers and pics for those interested.