Retrofitting condensing units with hi efficiency ecm

[gtojohn]

The outdoor fan motor on my 15 seer trane/american standard condensing unit went out yesterday. I found out today that even though its only 7yrs old its out of warranty. It was equipped with a ecm motor for a whopping $480 i could get the oem replacement. Specs show 825 rpm 1/3 hp. Part of the 15 seer is gained from the ecm motor. A quick check of rescue motors and options and I've found the mars azure 10874 ecm replacement for $130 locally. I went ahead and bought 2. It was a quick and easy swap out. Paraphrasing the pamplet " measuring amps won't be a good indicator of efficiency because of its low power factor." Fan amps were .6 at 246vac with total condensor amps at 6.0 for 2 tons. Unfortunately i don't have before amps for this unit but I suspect close to the same. Next retrofit my older 2006 ruud 14 seer 2 ton unit. Originally a 850 rpm 1/10 hp psc motor. Motor amps .6 and condensing unit total amps 7.4 amps. 15 minutes later and new motor is in place. New motor amps .6 but total unit amps at 6.7amps. I'm not totally sure why. Is it the low power factor or is the additional hp is condensing more and reducing head pressure for the same .6 amps as before. More importantly is the savings of .7 amps at 240v for a savings of 168 watts.