floating head pressures-nh3

[unilevermike]

We recently installed the hench system to control electrical costs. The problem is getting the head pressure to stay stable. We reun 3 boosters @ 2 psig suction 32 discharge 4 high stage 32 suction 140 discharge . problem is head pressures are floating from 146 down to 100 psig creating an unstable condition and cooler than recomended oil temps on the high stages . Anyone have a suggestion on remedy for this problem? Thanks Mike

[RANGER1]

unilevermike,
What is your oil temps getting down too?

Also what type or screws are you running?

In some cases a AMOT type valve is installed to bypass oil cooler
Another way is a seperate cooling tower for oil coolers is used, cycing fan or VFD
to control water temp.

[unilevermike]

We are running mycom 23m and 250 vsd's the internediate side is where the issue is, oil temps are getting into the 103 f range and starting some carryover. sorry took so long to respond, Mike

[Segei]

What kind of oil cooling do you have? Thermosyphon, liquid injection....
What did Hench tell you about this issue?

[Magoo]

The fun envolved with saving a dollar on operating costs. Everyone forgets about system balances for the sake of efficiency.
Spend a thousand dollars to save ten dollars.

[mbc]

what is your oil type ?
do have oil seperator after frist stage? does it works ? does oil retuning to comperssor?

[ghanghas85]

Dear all i have installed an new ammonia refrigeration system with priority vessel and de superheater. Now i m facing a problem that my pressure going to 16 bar and compressor get trip on high discharge pressure.i have also installed an temp transmitter in main discharge header but its temp goes upto 46 deg c.I have installed 2 Phe desuperheater and below the desuperheater 4 nos. phe condenser in parallel .I have taken condensers inlet tappings from bottom of de superheater outlet header. I have made an common condensate liquid header from condenser to Priority vessel. The height difference between condenser outlet bottom and condensate header top is 50 mm and condensate header bottom to liquid level in priority vessel is 1.2 mtr. I have given an vent line from priority vessel to desuperheater main inlet header. kindly give your valuable advise to resolve the high discharge pressure problem.

[ghanghas85]

Dear all i have installed an new ammonia refrigeration system with priority vessel and de superheater. Now i m facing a problem that my pressure going to 16 bar and compressor get trip on high discharge pressure.i have also installed an temp transmitter in main discharge header but its temp goes upto 46 deg c.I have installed 2 Phe desuperheater and below the desuperheater 4 nos. phe condenser in parallel .I have taken condensers inlet tappings from bottom of de superheater outlet header. I have made an common condensate liquid header from condenser to Priority vessel. The height difference between condenser outlet bottom and condensate header top is 50 mm and condensate header bottom to liquid level in priority vessel is 1.2 mtr. I have given an vent line from priority vessel to desuperheater main inlet header. kindly give your valuable advise to resolve the high discharge pressure problem.

[josei]

Dear all i have installed an new ammonia refrigeration system with priority vessel and de superheater. Now i m facing a problem that my pressure going to 16 bar and compressor get trip on high discharge pressure.....i kindly give (sic) your valuable advise to resolve the high discharge pressure problem.

Ghang what means "priority vessel"; also check original design and installation docs and let us know your ideas based on it, without your modifications.
Good Luck

[TXiceman]

Mike see my response in the other thread you started on the same subject.

Ken