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numty4
07-09-2008, 08:39 AM
hi i'm abit new to the trade,i've got a prestcold l300 with 50 ish psi suction,and the head is getting very hot and leaking head bolts.is it possible to referb the head or tell the owner he needs a new one.would listen any help.

monkey spanners
07-09-2008, 06:43 PM
Is the compressor pumping ok? If the system is short of refrigerant the compressor will run hot. If it is not pumping ok (leaking valves or blown head gasket) this will make it run hot also.

If it is pumping ok, but is just leaking refrigerant from the head bolts then you can replace the head and valveplate gaskets.

If the compressor is not pumping properly and has been running hot for a long time (i've seen compressor bodies warp due to overheating) or has a lot of hours on it, which is likely will an 'L' body prestcold i'd be fitting a new or rebuilt compressor.
I would also have a look at the fins on the condenser as if these are in poor condition it may be a better option to replace the whole condensing unit.
What refrigerant is it running on? Whats it cooling?

Jon

chemi-cool
07-09-2008, 07:06 PM
The best way to check the valves is to shot the suction, force the compressor to run to the deepest vacuum and stop it.
If it holds vacuum, than its OK and just need to check the valve plate gaskets. If not, open the head and see if it is a broken valve or gasket.

If it gets too hot, there must be a problem.....

numty4
08-09-2008, 07:21 AM
hi,it is on 134a,and should be cooling fres herbs,thanks for the advise.

numty4
08-09-2008, 07:26 AM
hi,i tried pumping it down and it realy struggled to drop into a vacuum.broken suction valves?thanks for the help.

monkey spanners
08-09-2008, 05:14 PM
Sounds like worn valves. Sometimes after the compressor has been off for a few minutes you can here the valves whistling if they are worn.
Sounds like its time for a new/rebuilt compressor or new unit. If you go for this why not take the head off of the old one before it goes to the rebuilders and have a look at how they work just to see.

Jon

sedgy
19-10-2008, 04:08 PM
hi tell me what type of gas its on + whats the head pressure
sedgy