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Participant

Join Date: May 2012
Posts: 3

### Why Increase In NH3 Suction Pressure On Off Load

05/09/2012 5:03 AM

Hi

It's my first time to work in an NH3 refrigeration plant, but can some please explain to me why the suction pressure of the screw compressors always rise even if their is no load on the plant and what is the danger of not lowering it to the set point. any other basic literature on the system will be highly appreciated.

the plant is of capacity 10 tons.

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Guru

Join Date: Jan 2007
Location: Kennewick, WA, USA, Thulcandra - The Silent Planet (C.S. Lewis)
Posts: 2810
#1

### Re: Why Increase In NH3 Suction Pressure On Off Load

05/09/2012 5:31 PM

Pleas fill in the information requested:

When unit is off:

Suction Pressure = ?

Discharge Pressure = ?

When unit is on (and "warmed up"):

Suction Pressure = ?

Discharge Pressure = ?

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Participant

Join Date: May 2012
Posts: 3
#2

### Re: Why Increase In NH3 Suction Pressure On Off Load

05/10/2012 1:58 AM

when unit is off:

Suction

pressure = 5.69bar but keeps increasing max allowable is 6bar

Temp = 23.4oC

Superheat = 11.5oC

Discharge

pressure = 5.11bar also keeps increasing but max allowable <16bar

Temp = 25oC

superheat = 15.8oC

when unit is on and warmed up

Suction

pressure = 3.92 bar

Discharge

pressure = 8bar limited to <16bar

Thanks