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RANGER1
06-06-2013, 01:27 PM
After some opinions on a Frick with differential oil pressure feed system. Nh3 -10 sst +35sct, water cooled oil cooler. If oil injection regulating valve feeding into rotors is open to far, what medium to long term result would you get apart from lower than normal discharge temp. Thanks

RANGER1
06-06-2013, 11:34 PM
I will also add that it runs on a VSD down to 25hz.

HVACRsaurus
06-06-2013, 11:50 PM
Sounds like you know more than you are saying here. With conditions described, at low speed it's probably pumping more oil than refrigerant, an energy penalty at least. Long term could lead to bearing failure, I know of instances where oil compression was causing the compressor to make a hell of a noise with all sorts of internal stresses due to too much oil injection.

Magoo
07-06-2013, 01:04 AM
Hi Ranger1 I have a small Frick screw, similar operating conditions and VSD, it has wear in capacity slide. Modified control to keep fully loaded on capacity slide and VSD does capacity control, seems to have stopped any further wear after last strip down and inspection. I have kept minimum hertz to 35. max at 60. I had overcurrent issues with lower than 35Hz and capacity slide at 100%.

RANGER1
07-06-2013, 01:13 AM
Sounds like you know more than you are saying here. With conditions described, at low speed it's probably pumping more oil than refrigerant, an energy penalty at least. Long term could lead to bearing failure, I know of instances where oil compression was causing the compressor to make a hell of a noise with all sorts of internal stresses due to too much oil injection.

I am only trying to confirm what I am thinking, no secrets or anything. What I do know is screw failed with approx. 30 000 hours on it. Oil injection open all the way thinking it may have caused oil compression under all loads! Male thrust failed toward suction end eventually causing seizure.

RANGER1
07-06-2013, 01:17 AM
Hi Ranger1 I have a small Frick screw, similar operating conditions and VSD, it has wear in capacity slide. Modified control to keep fully loaded on capacity slide and VSD does capacity control, seems to have stopped any further wear after last strip down and inspection. I have kept minimum hertz to 35. max at 60. I had overcurrent issues with lower than 35Hz and capacity slide at 100%.

This ones a bit bigger 233 Frick, wasn't sure if orifice in oil injection was enough to control oil flow into rotors, but Danfoss 25 mm regulating valve fully open on inspection. There was no hint of potential seizure, it just seized while running.

Magoo
07-06-2013, 01:44 AM
Hi Ranger 1.ouch!! that is a large compressor to crash. Some one playing with danfoss reg valve. not understanding implications of over injection. The thrusts would have lost tolerance with extra loading.

RANGER1
03-07-2013, 09:07 AM
Is this process really working? because i also do this process and the result is nothing good.
Can you tell me again how you did this...?

Can you elaborate on your question, as not sure what you are referring too.

Superfridge
05-07-2013, 11:04 PM
The orifice built into the compressor oil injection port is sized for max amount of oil at given FRICK design conditions. Is the orifice in place? Does the compressor run unloaded at 25hz? As said above, the pumped oil to gas ratio would be excessive I would think. I would be contacting FRICK to see if the comp is running within design. Could perhaps have oil injection thermstaticly controled?

Segei
05-07-2013, 11:45 PM
You can compare discharge temperature and oil inlet temperature. Usually, it is 50-60F difference. If this difference significantly lower than these numbers, probably too much oil going in.

RANGER1
06-07-2013, 07:57 AM
Coolware has a standard 82C discharge temp for everything in their selection software. Oil injection orifice is in with oil injection regulating valve throttled. JCI put it in with a motor that to small as well. Compressor limited to 28hz & would have to check if it unloads at this minimum speed. Any idea what Frick do with oil injection? Do they turn it on/off on discharge temp or speed?