oil press.

[jebar]

hi all,I have air cooled water chiller with receprocating compressor after one or two month of operation probleme of low oil pressure is started so,chiller is stopped whereas the ambinant temp. in the area 50.for quick treatment I change comp. oil with new oil (always I use oil type 4GS) .But the problem is remaind.can anyone help me to eleminate this problem,please.

[Grizzly]

jebar.
What type of recip are we talking about?
And what are the running conditions?
Meaning if certain recips run for long periods on part load.
Because the swept volume of the refrigerant is low.
You do not achieve good oil return.
Which means there is more oil going out into the system than is returning.
This the reduces system load further, compounding the problem.
If you suspect this may be the problem.
Shut off any others and force this Comp to load up. Drop the control set point if necessary.
You will need to run like this for a good while to check for the oil returning!
All this may be rubbish especially as your comp is new!!!!
Or runs at full load most of the time.
But it should at least eliminate or prove this as a possible cause.
Anyway good luck and keep us all informed please!
Grizzly

[jebar]

thank u grizzly my comp. is recip &run at full load most time the operation condition :diss.press=25bar,suc. press.=5bar,oil press=6-7bar.if u please tell me in detail how to check oil returning,with regards.

[GHAZ]

hi jebar what make of compressor are you using, because on some you can tweak up the oil pressure relief valve,or change micro oil filters,or do certain checks for other mechnical wear.if its not a system issue

[jebar]

hi GHAZ I tweak up the relief valve & cleaining the micro oil filter,but no response and the oil press = suction press.

[nike123]

What is compressor make and model#.

[RANGER1]

If it has an oil seperator and oil return float , check that crankcase and oil return line is not to hot .( approx 55-60 deg C maximum ) .
If it is to hot maybe oil return float is passing hot gas into sump causing hot thin oil .ie low oil pressure and oil carryover .
Is oil foaming in sight glass ?

[jebar]

hi all ccomp. type:MQplacementC908spw,140L,380volt.50hz,1450rpm fla=235,lra=747,displacement=437.

[jebar]

hi there is afoaming in the sight glass&comp type:MQC 908spw 140L.

[Grizzly]

Hi jebar.
Out of interest what oil level shown at the sight glass are you trying to maintain?
Grizzly

[nike123]

hi there is afoaming in the sight glass&comp type:MQC 908spw 140L.

I cannot find any reference to that compressor make and model#.

What is chiller make (McQuay perhaps??) and model#?

[jebar]

hi nike the chiller is McQUAY MODEL
ALRHA ST455.4 the comp. also mcquay recip.

[sterl]

This same Chiller as had the evaporator leak earlier post?

[GHAZ]

Hi jebar on the left from oil pump you the micro oil filter and oil pressure relief valve assembley,it has ( 6 )m12 bolts ,at about 1 oclock position it has (A) marked on it and next to it has a grub screw in it,take it out and put 1/4 npt flare fitting in it and put your gauges on it to see what pressure is comming in from the sump and oil pump. Next at 7 oclock position it has another grub screw ,take it out and put a 1/4 npt flare fitting,and put guages on to see what pressure you got through the micro filter and oil pressure relief valve,
(1) if pressures are different then you got blocked micro filter.
(2) if pressure is same ,then check oil pressure relief valve,look for cracks on the ball seat even a minute crack change it .
(3) if all this ok then check the conrod bearing shells,these on a new compressor hardly wear and the mains bearing because they are very fine tolerance and will seize up quickly if liquid or lack of lubrication is involved, i think you if you check the oil filters and pressure relief valve you might be ok. if need total rebuild help let us know and will help

[goshen]

hi this problem seems like a problem we had ,the ambient temp, and the high pressure ,like said before ,cause the oil to loose its visocity, and become very liquidy, not allowing oil pump to build pressure ,best idea is to either change oil to 5gs, or lower oil temp by lowering head pressure

[SUBCOOLEDGOOD]

Check subcooling (if TXV) - high subcooling - less volocity - less oil return.
lesser the subcooling means better volocity - better oil return.
It's worth a try!

[jebar]

hi mates &thanks for replay I want to tell you that the oil I used for comp. is 4GS its viscosity 300 sus at 4oc.Now when I operate the chiller the comp. stopped due oil protection &on the oil press. gague
reading =suction press.

[lowcool]

sounds like you might have liquid coming back,causing the oil to foam,diluting the oil and increasing compressor wear.if its a gear pump pull it apart and look for wear on front and rear faces,if some is evident your compressor is worn and requires rebuilding/reploacement

[jebar]

the compressor stop after 1 min cannot builte oil press.

[lowcool]

make sure screen on pick up is not blocked or pick up fallen off(i am not familiar with your compressor).if its ok,you will probably have to pull the pump apart.

have you recorded oil pressure above the suction pressure?

[goshen]

hi try reversing dirction of compressor this might help if the pump is warn only if it is a reciprocating comp
if all else failes it could be a time for a oil pump change /

[jebar]

Hi I will try to checke the screen & then inspect the gear oil pump (you mean just visual inspection or something else).about the reverse direction for compressor it is part winding (2 winding) is it possible.

[lowcool]

visual inspection ie scratched worn surfaces especially if it is uneven,their should be none or very little.if oil pressure doesnt work one way changing rotation will not fix the cause of premature failure,but if you swap the same legs over on the starting gear then i see no reason why it wont run backwards.

[headgear]

Have you checked the micro oil filter that is behind the circular plate on the front of the compressor? ( i think it is 8 bolts )