Grasso Head over heating need urgent help

[salman]

i am working on RC412 Grasso one of its head and cyclinder is over heating next to check valve , i have changed the check valve , also changed the head and vlve inside but it didnt worked and now changed the piston conecting rod and rings as well still it is over heating the seleve is clean . need urgent assistance and guide lines thanx

[NoNickName]

Is the head where the safety valve is?
Did you check against possible blow by of the safety valve?

[salman]

Is the head where the safety valve is?
Did you check against possible blow by of the safety valve?

yes it is the head where safety valve is i have changed the safety valve as well any more suggestion on the safety vallve blow checking procedure will apreciate it

[GHAZ]

Hi salman is this a 2 stage compound compressor ,and is it the final discharge stage ,may be the other stages are not loading up fullly and the comression ratio is to high and causing high temperatures, or is the oring on top of the liner between the discharge plate missing and causing blow back of hot gas

[salman]

Hi salman is this a 2 stage compound compressor ,and is it the final discharge stage ,may be the other stages are not loading up fullly and the comression ratio is to high and causing high temperatures, or is the oring on top of the liner between the discharge plate missing and causing blow back of hot gas
It is single stage compressor other pistons are working just fine

[NH3LVR]

This may not be your problem, and probably is not, but it happened to me.
I spent a Summer in a plant in Alaska. They had three RC-611 on a freezing tunnel.
One of them had the paint burnt off one cylinder. I took it apart and did not see anything wrong. I pulled another head and found the safety head spring was an inch shorter that the other one.

[NoNickName]

Ok, then, the problem is 99% due to the safety valve or high discharge pressure. The valve keeps blowing back hot gas to the suction. You can't test it when installed; you will have the remove it and test it on a rig.

[Grizzly]

Hi Salman.
All the guys here are highly experienced and have given good advise.
The general consensus is that there is something wrong within the individual cylinder and I tend to agree.
read the following extracted from one of the GRASSO manuals.


If there is any doubt about the proper performance
of this LP pressure relief valve, then this relief valve
should be renewed immediately. When a pressure
relief valve works improperly, discharge gas starts
circulating through the cylinder head, which makes
this cylinder head feel much warmer compared to
other cylinder heads.
That having been said do not discount NH3LVR's comment.
Sadly I think you will have to keep looking.
Just a thought I know you have changed the LP relief valve.
Did you check it's valve seat within it's housing for damage or foreign material stuck to it.
What refrigerant are you running on?
You could have a wire drawn seat?
Good luck and don't forget to let us know how you got on!
Sorry for asking the obvious but you could be having a bad day and forgot the obvious?
I know I do sometimes!

Grizzly

[Frank Day]

Hi Salman,

Have you done a leak test on the discharge valve assembly on that cylinder ?

[D.D.KORANNE]

what about superheat ? in nh3 excessive head heating could be traced to NMT 10K superheat .

[salman]

what about superheat ? in nh3 excessive head heating could be traced to NMT 10K superheat .
what is the best way for tracing super heat? NH3
i am working on lp relief valve

[salman]

Thank you guys for all your help the problem has been sorted out it was gaskit in between the liner which had crumbled and was damaged because wasnt properly fitted correctly during the last maintenance.
I am also buyer for RC12 series used compressors up to six cyclinder if you have any please contact me thanx again for all your help

[Frank Day]

Hi Salman,

Great to hear you came right, I'm a Grasso fan, good gear.

Frank Day