Old Kysor/Warren Rack, Mechanical Pressure Control Staging Settings.. Help?

[WT70]

Would Like some advice on what set points to use on setting up staging of the compressors on an older rack I am serviceing.

Its an old Kysor/Warren (or Sherrer.. cannot remember right now) that runs on mechanical controls. The rack had been running wide open for who knows how long. A quote is currently being worked up for an Einstein controller for both racks at this store, but int he mean time, I would like to get the compressors cycling on mechanical.

It's R222, 20deg suction header. (43psig)

Compressors:

All Copeland

2 3DS3R17ME. This compressor is listed on copelands OPI as a HT comp at 116,000btu. They are 10 HP comps.

1 3DS3F46KE. This compressor is listed on copelands OPI as a LT comp at 37,500btu. It is 7HP

1 3DB3A100E. This actually is a MT compressor. 87,000btu. 7.5HP

So. Any suggestions other than changing the 3 compressors to MT compressors?

Thanks in advance!

[icemeister]

Here's the Kysor/Warren I&O Manual:

http://www.kysorwarren.com/docs/uplo...07_Systems.pdf

What you're looking for may (or may not) be in there.

[WT70]

Did not have what I needed for this issue, but helped clear up another. Thanks.

[MikeySq]

i dont think you have to change any pumps

his would be my opinion, run the 3DS3F46KE as #1 lead pump cut in 30 out 10

stage the 2 3Ds3's as #2 and #3 and set the 3DB3A as #4

try
#2 at in 43 out 38
#3 at in 45 out 40
#4 at in 47 out 42

what ever you find and try you will have to monitor the operation and make sure your defrosts are spaced properly, i would also run the pressure controls from the suction header and not the compressor bodies. i would also set controls with N2 and digital gauges, works better, even if you have johnson microset controls its hard to use the numbers on the control.

Mike

[WT70]

Thanks, I'll try that when I get back to it next week. The settings are a bit tighter than I would have put them, which is why I asked for help!

If the customer does not go for the E2 install, we are going to put the microset controls on it, just was not sure of the proper setup.

Does anyone know of a simple digital controller that will stage the compressors? I know the best route is an E2 or similar, but wasn't sure of other options.

[icemeister]

You might want to check this one out...

http://www.dixell.com/digital-contro...fansc-32x74mm/

[dangpgt97]

Who makes them electronic t-stats you see on older condensers for fan cycling? The ones with 1 pressure transducer and you can link the electronic controls all together. If you gotta go without cpc this may be easier and more accurate. Just a thought.

[MikeySq]

Who makes them electronic t-stats you see on older condensers for fan cycling? The ones with 1 pressure transducer and you can link the electronic controls all together. If you gotta go without cpc this may be easier and more accurate. Just a thought.

are you referring to the JOhnson 450 series possibly??

[dangpgt97]

Found it.

System 350 Pressure Controls

http://www.johnsoncontrols.com/publi...rols/p352.html

I think these would work.

[emcontrols]

Not impressed with the 450 series, 350 series im a believer.

[NANOTECH]

Just installed a new altech cheap worked great for just staging the compressors!!

http://www.altechcontrols.com/mcc.asp

[mseng]

Raise the suction cut-in just as high as you can and still maintain temperatures. For example a 20 rack running R-22 I would give it a cut-in of #44 and let the Alteh do the work. This will allow the compressors to cycle and keep the temp.