View Full Version : Condo Heat Pump

08-19-2011, 06:49 AM
Came across a Skymark (JCI) heat pump in a highrise building which seems to be giving me odd readings. Its a 2 ton chasis/cabinet unit. with water cooled condenser (from cooling tower)

Found unit with shot compressor, so we replaced it with a new compressor. Checked for leaks and tested ok.
After vacuuming it down to about 400 microns we added freon as per mfg specs. We noticied that the txv valve was freezing up and the evaporator was not getting cold at all. Low side pressures were about 20-30psi and high side was at 200psi. Compressor keeps cutting out after 2-3 minutes on high pressure. tried to add more freon but still nothing.

Could it be a dirty txv valve? or dirty water cooled condenser?
what is the best way to clean water cooled condenser heat pumps?

08-19-2011, 02:16 PM
I will back flush the water condenser. check the strainer if it has one and what i do is turn off the water to the unit, disconnect the supply line from the building piping and put in bucket. turn on the return side valve to back flow a couple gallons of water through the condenser coil. this will also help clear any debris that might have got into the small orifice of the water flow regulator.
Another note when working on hydronic heat pumps check your water in and water out temps. most of the time your looking for around 10-20 degrees delta. this number does change dependent on water flow and such.