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Thread: rack question
01-28-2007, 01:23 PM #1
Hey I've got a question about a hussman rack issue I saw Friday.
We found an empty receiver, and The LL from the roof was freezing cold. Tech said all the refrig is on the roof. He shut the A8 (?) valve and reciever level went to 20% (with heat reclaim operating).
What is the purpose of this? The valve bypasses the condenser and puts hot has right in the receiver. In this case it was wide open and over pressurizing the receiver while under pressurizing the line to the condenser, so gas wants to sit on the cold roof.....at least thats my interpretation.
I'm just not familiar with the scenerio where the receiver needs hot gas....I can assume this is to keep LL pressures up, but then we can cycle fans on the roof for that. Plus, the system has a subcooler on the liquid line, so why would we run a subcooler AND dump hot gas on some demand?
Thanks guys, for any help you can give me. I realize this is a somewhat elementary question, but it seems to make perfect sense until your actually standing there with a wrench in your hand, ya know?Guinness for strength
01-28-2007, 02:23 PM #2
The purpose of the bypass valve is keep the receiver pressurized when the holdback valve (IPR valve on the outlet of the condenser) closes. That valve is normally set 10-15 psi higher than your pressure drop through the condenser. It sounds like your rack is short of gas or the bypass valve is stuck open or set wrong. (more likely short of gas) Check out the sporlan site and do a search for headmaster literature. They have some good diagrams and information on how the whole setup works. www.sporlan.com
take a pressure reading on your discharge line as well as your receiver while all valves are open and you will see what is going on.
01-28-2007, 05:53 PM #3
Thanks John, yes the bypass valve was stuck open. I'm going to dig through Sporlans site for a while.....Guinness for strength
01-31-2007, 07:40 PM #4
greenears, the A8 is an inlet pressure regulator manufactured by R/S Division of Parker Hannifin. There is also a differential pressure regulator version of this valve.
Sporlan was acquired by Parker a little over 2 years ago, and we are still sorting things out.
The current A8 literature is not on the Sporlan site, but on the Parker site here: http://www.parker.com/ead/cm2.asp?cmid=1567 See the Flo-Con bulletin.