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View Full Version : setting up hp lp



citytosurf
04-02-2009, 02:41 PM
what to set you hp lp to on a medium temp cool room with thermostat and not a pump down system running on r404a just wanna set the hp lp up as a safety device

Slatts
04-02-2009, 02:59 PM
Look through the manual I linked you to in your other thread. If you have to look it up it'll stay in your head longer perhaps.;)
It's 1 AM where you are, don't you have to work tomorrow?

citytosurf
04-02-2009, 03:04 PM
Look through the manual I linked you to in your other thread. If you have to look it up it'll stay in your head longer perhaps.;)
It's 1 AM where you are, don't you have to work tomorrow?
yeah going to bed now have to go get this jobsorted in the morning

Slatts
04-02-2009, 03:10 PM
OK, set the HP to cut out at 350 PSI (given the weather you've been having you may need to go as high as 375) and in at say 270. Not a good idea to use a manual reset HP on a food cold room.
Set LP cut in to 85PSI and when your room is set up, superheat is good and everything is down to temp, check your operating pressure, set your cut out 3 or 4 PSI below that. If the room ices up the pressure will drop and the system will drop out on LP till the coil heats up enough. That won't happen till the ice is gone.