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Mark Ridgway
21-06-2014, 03:47 PM
Can anyone assist with the following

We have a Mycom Compressor that runs to freeze down a spiral tunnel and at the side of the Mycom we have a Grasso SP2 compressor runs to freeze down a Polobed for ice lollies. Both compressors use the same liquid pumps, Surge Drum and receiver etc

The problem I have is both compressors are controlling at the SP Value but at the tunnel and polobed it is -22.0 when it should be -44.0. The only thing i can see different is the liquid pump pressure is at 0.8bar when we are used to seeing it at 1.75bar

If you require more info i will try but i dont have a refrigeration back ground

The Viking
21-06-2014, 07:44 PM
If you require more info i will try but i dont have a refrigeration back ground


We have a Mycom Compressor that runs to freeze down a spiral tunnel and at the side of the Mycom we have a Grasso SP2 compressor runs to freeze down a Polobed for ice lollies.

So I take it this process is quite important for your business and it's profit then?

Time to call a professional refrigeration engineer to help you.

Sorry but there is only so much that can be done over the internet.

:cool:

RANGER1
21-06-2014, 11:21 PM
Can anyone assist with the following

We have a Mycom Compressor that runs to freeze down a spiral tunnel and at the side of the Mycom we have a Grasso SP2 compressor runs to freeze down a Polobed for ice lollies. Both compressors use the same liquid pumps, Surge Drum and receiver etc

The problem I have is both compressors are controlling at the SP Value but at the tunnel and polobed it is -22.0 when it should be -44.0. The only thing i can see different is the liquid pump pressure is at 0.8bar when we are used to seeing it at 1.75bar

If you require more info i will try but i dont have a refrigeration back ground

Mark see below otherwise get Grizzly on the case, he will fix it.

Are refrigerant levels "normal" in surge drum?
Are you draining oil from low points of surge drum at regular intervals (usually when plant is shutdown & pressures up so not to suck in air).
Liquid pumps may have low point to drain oil as well (any oil is to much).
Do liquid pumps have differential protection to protect them.
Can you swap over to spare liquid pump if you have one & see if any difference, after checking levels & oil logging?

Would assume compressors are controlling at correct set point but unloaded more than normal (%load indication)

Magoo
21-06-2014, 11:59 PM
Low pump pressure would indicate low flow rate and performance at process end, caused by low liquid level in surge vessel, short of refrigerant, pump cavitation from rapid loading of compressors, minimum flow bypass open wide , or a flow bypass relief jammed open, liquid stacked up in condenser receiver, level regulation in surge vessel faulty.
Good idea is get a professional to sort which one is the problem.