Mcquay chiller help

[Kerik7]

Also posted this in aop. Not so sure which forum would have been best post. Thanks for any help. I am new to this sight and this is my first post although I have used you guys for help in the past. Anyways. I am working on a mcquay ALR130E. I keep getting an alarm of low oil/pwr on comp 4 and 3. Usually alternating and sometimes at the same time. Today circuit 1 is cutting off when comp 3 is activated. Little to no oil in sight glass on comp 1 and 3. Can't get oil to come back to compressors. Yesterday same prob on circuit 2 and circuit 1 was fine today circuit 2 is fine and 1 is acting up. Any suggestions or help would be great. Thanks
Karl

[will smith]

McQuay has compressors 1 and 3 on one circuit, 2 and 4 on another. If you don't see oil at the compressors, first question is-where is it? I'd look for a leak first off.
Which Microtech controller are you dealing with?

[Kerik7]

So I found the manual and did some research and found that my prob may be coming from the output board relays. Cleaned the board and connectors. No alarms in 3 days.

[IMCooltech]

you may also want to check your superheat. The ALR like high superheat around 18 to 20°

[Kerik7]

Thanks for that info about the sh. It was only 6-10 degrees when I took over unit. Adjusted it up to 12-14 so I may need to go some more.

[IMCooltech]

I would try to get it to 16°. Have you checked the Control Band? That is huge when running an ALR chiller. Let me know if you need the formula.

[steveoo]

check oil with both compresser's off,when they run gas is pulled throuh oil equlizer line from lag compresser,and pulling oil into crankcase,try closeing ball valve on eq line that will show how much oil you have,then re open eq line.

[Kerik7]

I did check the oil the way you described however I believe the oil prob has gone since the super heat has risen. Not sure about the control band. Any info is great. Trying to dial in this machine the best I can.

[steveoo]

3 to 4 deg.control band,greater delta T higher control band, 0.5 pulldown rate,7to 10 deg.start up. 1to1.5 shutdown works pretty good.240sec interstage time.[time between stage's]

[rahzip]

Make sure you have proper evap. water flow.