General guidelines for water-cooled A/C and heat pumps

[montanabama]

Can someone give me some general tips for setting water reg valves on water cooled units? Specifically, what sort of delta T are we looking for? What sort of condensing temps/pressures? My incoming water temps to the condenser are very low, being fed from a building chiller. So, we're running around 48 degrees! The unit in question was originally on city water, which was around 55-60 degrees. I find my evap is freezing now, and I have to adjust the reg valve accordingly to bring up my leaving water temps and head pressure.
Is there a general rule of thumb you can give me for setting reg valves?
It's R-22 system, btw.

[Dallas Duster]

I would think you would want to set your valve for 200-225 discharge pressure. DeltaT is all going to depend on the valve opening up so it's irrelevant .
Wow 48 degree condenser water is cold if you ask me , how's your airflow?

[socotech]

Would you expect an air cooled condenser to run properly on a 48* ambient day?

[Tommy knocker]

What Dallas said.

[montanabama]

5 ton air handler on 5 ton semi hermetic compressor. Haven't checked airflow, but of course, all this was designed by the building engineer.
I agree thoroughly...48 degrees is mighty cold incoming water. I think there has been a lot of undersight by engineering. Might be looking at corrective options, like hot gas bypass, etc... I don't see this working as it stands.

[Elfshadow]

5 ton air handler on 5 ton semi hermetic compressor. Haven't checked airflow, but of course, all this was designed by the building engineer.
I agree thoroughly...48 degrees is mighty cold incoming water. I think there has been a lot of undersight by engineering. Might be looking at corrective options, like hot gas bypass, etc... I don't see this working as it stands.

Is this unit a heat pump or straight cool? If its a heat pump I'm really hoping its outfitted with a freezestat. Also are the water coils and piping insulated? If they aren't you might have condensation issues with the colder water.

[montanabama]

Straight A/C, thank goodness. Adequate insulation. Reg valve is cranked down pretty hard...I guess we watch and see.