Hill Rack

[barrkeys]

Hey Guys,
I have a Hill rack Mod. AT4H4500RCM1, with some three comps, 4DK3R16METSK800,only two are working, i have to change the liquid line drier cores every 3 to 4 monts, they are totaly plugged.
R409 refrigerant, Suction is 20psig, discharge is 193psig, drop leg temp. is 113*F, outside temp 83*F, all cond fans are working. Have to clean out TXV screens on a regular basis.

Non condensibles in reciever ?

[jpsmith1cm]

Verify that all motors are rotating the correct direction.

If that doesn't help, clean the condenser.

I would also do an oil change and repeated drier changes to clean the system up.

Have you looked into why one compressor isn't running?

[barrkeys]

JP,

Comp. has bin down for a while, blows fuses.

Went on roof air coming out of fans is not warm.

What affect would rotaion have on a three phase pump ?

Is there a way to clean out reciever ?

[jpsmith1cm]

I meant rotation of the condenser fans, sorry if I was not clear.

Reciprocating pumps don't care which direction they rotate.

I'd check the wiring to that dead pump, verify that it is OK, then take action as needed.

The air coming off the condenser..... Does it come straight up out of the fan or off at an angle?

Short of recovering gas, removing any access plates and using tools to attempt to scru b it, I don't see a way to 'clean' the receiver.

Why do you suspect non-condensibles? Your symptoms don't support that diagnosis.

[FSE_]

If your blowing fuses, you may have a burn out and if it is not valved off, including the oil return line, you moving crud into the system.

[barrkeys]

Comp.is valved off.
Suspect non condesibles beause of condition of cores.

How can I have such a low discharge pressure and high drop leg temp ?

[jpsmith1cm]

Looking at PT chart, I don't think your head pressure or subcooling are out of line.

193 head is about 118 degrees condensing and 113 degrees gives about 5 degrees SC. Fairly typical on a rack system.


Non condensibles will cause high head pressure. You've got a dirty system. I'd change cores daily if it were one of mine.

[pherman]

changing oil and changing suction filters might not hurt either...

[Phase Loss]

that sure is a high condensing pressure and drain leg temperature for a 83* ambient. your condenser most likely needs to be cleaned. any chance you took a discharge line temperature reading? willing to bet its scorching hot and burning your oil then plugging your driers.

[Phase Loss]

also non-condensable's are not your issue. 193# R-409a is 118*SCT and your drain leg is at 113*, that is only 5* off and most likely ambient subcooling.

[barrkeys]

Thanks Guys,

Doing oil, and oil filter change today, and will change drier cores accordingly.

[mseng]

If you have felt suction cores they will hold a lot of dirt and as the oil passes through them it will pick some of it back up. So if the oil is discolored then change the suction cores also.