problem with frick screw volume

[samlee12]

Having trouble with Frick screw mod# RWF 11 222 E. At 0 percent load i have a volume of 5 but when the screw starts to load up my volume starts to drop to min. Vi of 2.2.When the compressor reaches 100 percent i get a message saying unload, increase volume on the micro it is showing that it is giving signal to increase but the Vi will only go to 2.88 Vi.Checked the wiring checked the solenoid every thing in normal but Vi will not increase. When the compressor is unloading my Vi will increase as my capacity decreases.Called Frick to ask them there input into the situation he asked me to give him the voltage readings for the slide vavle and slide stop valve. My voltages for capacity fully unloaded min. position i have voltage fo 3.8 v on the loaded max position voltage is 4.65, for the slide stop voltage at min. is 3.26 and at max is 4.53. Frick told me the voltage read by slide stop seems to be fine but capacity voltage seems out of whack. Told me the slide valve sensor probably faulty and causing me to have trouble with volume. I don't see how the capacity sensor or slide valve position can affect my volume was wondering if anybody has come across this problem.
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[Magoo]

Regulate the oil flow to load vav, first impression is that the screw is loading too fast, hence all current protection systems are saying unload. The volume ratio relay will ramp up, the unload vav will drop. Check that oil pressure regulation differential control is correct, oil temps can unset the whole thing, client fiddlers are the prime culprates. With screws , "slow and easy " is the main thing.
magoo

[samlee12]

First thing i checked was the oil regulating valves both were wide open . closed both valves and opened both 1/4 turn. still did not make a difference. Oil pressure running at 130 psi and temp at 125 degrees f.

[J.D]

The micro takes slide valve position into consideration when it moves the slide stop, as well as suction and discharge pressures. If the voltage is incorrect from the sensor, the micro may not position the slide stop in a suitable position for the existing operating conditions.

[Tung]

Samlee12:
your e-mail pls,
some information might be helpful to this case.

[josef]

Compressor Vi increase: The volume ratio Vi is in creased
when MSS solenoid valve YY3 is energized and oil fl ows from
the oil manifold through valve ports P and A to com pres sor
port SC3, enters the increase side of the cylinder and overcomes
the decrease spring tension. Si mul ta neous ly, oil fl ows
from SC4 port through valve ports B and T to compressor
suction. Check both coil, one will show different values.

[samlee12]

Checked both solenoid coils they both work, even if i manually open yy3 it will still not increase vi. Suspect mechanical damage. Going to change slide valve sensor upon frick's advise then if that does not work going to look for mechanical problem unless someone has other ideas.Thanks J.D, frick told me same info, ordered new slide valve sensor.

[samlee12]

Hey Magoo, When i said i checked the oil regulating valves i mean the two small shut off valve on compressor housing not the five small needle valve on the solenoid block.The operators may have messed with the needle valves on the block, If they did mess with them how do i set them up properly, do i turn them all the way in and turn them out so many turns?

[samlee12]

Sorry for taking so long to post. While i was on vacation another tech went to look at problem.He found that i was trying to calibrate slide valve and volume at high load conditions and high compression ratio that was causing calibrating problem. He shut off most of the load and re-calibrated slide and volume, compressor volume is now functioning properly.Lesson learned never try to calibrate at high load conditions, never though of that, hats off to my coworker, thanks Jason.

[Grizzly]

Sorry for taking so long to post. While i was on vacation another tech went to look at problem.He found that i was trying to calibrate slide valve and volume at high load conditions and high compression ratio that was causing calibrating problem. He shut off most of the load and re-calibrated slide and volume, compressor volume is now functioning properly.Lesson learned never try to calibrate at high load conditions, never though of that, hats off to my coworker, thanks Jason.

Sam.
In my opinion it takes a mature engineer to admit when He is wrong!

You have and fair play to you.
I applaude you!
(After all if you are not making mistakes, you probaly arn't doing anything?);)
Grizzly