I recently switched an air cooled chiller (trane) that I had to replaced R22 with R438a. Both circuits only had 30-40 psi standing pressure. I repaired all the leaks found. Pressure tested and pulled a vacuum to 400 microns overnight. Pushed in the R438a (liquid) to 150lbs (total 170lbs). I charged the rest while running. I've got 3 compressor's each circuit. 1- 10 ton 2- 15 ton. After 5 mins of run time the 4 large compressor's(2 each circuit) are pulling LRA @ 164 amps. The smaller compressor's for each circuit is running fine. Each circuit is in Tandem with 3 compressor's. My Question is has anyone had any problems with the R438A with compressor's over 15 ton's.
HVACNINJA78
Are they the 3D scroll compressors? If so, it was determined years ago that the 400 series of refrigerants is very risky to use as a drop in on top of mineral oil. First one I did took out the compressor before I was off the roof. That was one week before I saw the bulletin explaining not to do that.
This is going to get expensive!
Needs POE oil for oil return and suction filters for all the crap the POE will be bringing back!
Needs POE oil for oil return and suction filters for all the crap the POE will be bringing back!
Trane recommends only R22 and R438A has oil return issues on large systems, medium temp systems, and those with long piping runs. The refrigerant manufacturer recommends at least 25% of the mineral oil gets changed out to POE
Ouch, try to save the customer some money and end up spending more. New compressors is still cheaper than a new unit. Maybe.
438 is your only option
Just remember
1) oil change to POE.
Suction Filter
No choice with semis. It’s a gamble. No manufacture will authorize a change of refrigerants.
Just remember
1) oil change to POE.
Suction Filter
No choice with semis. It’s a gamble. No manufacture will authorize a change of refrigerants.
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