rack oil separator isolation porcedure

[coldkeeper1]

Dear fellows:
I need to pull open an oil separator located in the discharge line of a supermarket rack system to check the mesh screen and buoy mechanism. In order to isolate the separator, upstream I can shut all of the compressor´s discharge service valves. But downstream the separator there is no service shut-off valve but rather a differential discharge pressure regulator. It´s my understanding that this regulator, when energized, remains 100% open. When de-energized, it begins to close but never to a full shut-off. Is it possible to somehow completely close this regulator when the system is off, in order to isolate the separator from the condenser inlet? Thank you.

[Slatts]

I'm a little confused. could you draw a diagram in MSpaint or some such and post it?

[REEFERMAN4U]

Check the condensers outside, most reliable installers will have ball valves for isolating different coils. .04c

[dirtyboy103us]

there should be ball valves to isolate the system so you can pull it apart to clean some where

i have never seen a rack with out them

there sould be one on the dicharge line just after the ddr and one going to suction lines for hot gas defrost

[icemeister]

Isolation shutoff valves are optional on most rack systems, so I've seen a lot of them without valves. I've got one rack now with no high side valves at all between the compressor discharge and the receiver inlet.

When I worked for a chain in Connecticut (years ago) we specified that all remote components like the condenser, reclaim coils, etc have isolation ball valves. That worked fine until one day on a walk-through an installer's fitter pointed out to one of the "Suits" how expensive these valves were.

This Suit, or "glorified bagboy"...ie, Vice President...subsequently sent my boss a memo stating how much money we could save on installations.

....and so it goes.

[pherman]

your boss should have sent a memo back about how much longer and more expensive any repair would take without the ball valves

[icemeister]

your boss should have sent a memo back about how much longer and more expensive any repair would take without the ball valves

I sent a memo to that effect to my boss, the Director of Construction & Engineering. I think he just wiped his butt with it.

He didn't care about such things because Store Maintenance was under someone else's budget.

[crackertech]

Isolation shutoff valves are optional on most rack systems, so I've seen a lot of them without valves. I've got one rack now with no high side valves at all between the compressor discharge and the receiver inlet.

When I worked for a chain in Connecticut (years ago) we specified that all remote components like the condenser, reclaim coils, etc have isolation ball valves. That worked fine until one day on a walk-through an installer's fitter pointed out to one of the "Suits" how expensive these valves were.

This Suit, or "glorified bagboy"...ie, Vice President...subsequently sent my boss a memo stating how much money we could save on installations.

....and so it goes.

All my rackrs have isolation valves high side and low but some still leak by
making it a fun day.

[gerryboy00]

Is it possible to somehow completely close this regulator when the system is off, in order to isolate the separator from the condenser inlet? Thank you.

NO

[coldkeeper1]

Hi again.
I´ve been looking for any kind of hidden islolation valve but there is none. What I´ve got here is a very long pipe run from my separator, through the discharge differential pressure regulator up to the remote condenser inlet valve. I guess I´m going to have to shut all the compressors´discharge service valves, do the same with the condenser inlet valve, recover the refrigerant left in the piping between these two points and then pull apart the separator. Same procedure if someday the DDPR fails. All of this because the installer/manufacturer couldn´t afford to put an insolation valve right after the DDPR.
For SLATS: just to clarify, the piping goes like this: compressors´discharge service valves, common discharge manifold, helical oil separator, discharge differential pressure regulator, long pipe run, remote condenser inlet valve. Thank you all for your interest and comments.

[Slatts]

I'm trying to start a revolution. Some of the explanations in the forums are so convoluted I get a head ache just reading them.
a couple of minutes with a graphics program could save half a dozen posts.
Doesn't have to be a master piece, just clear and labelled.

[frigeguy]

Hi again.
I´ve been looking for any kind of hidden islolation valve but there is none. What I´ve got here is a very long pipe run from my separator, through the discharge differential pressure regulator up to the remote condenser inlet valve. I guess I´m going to have to shut all the compressors´discharge service valves, do the same with the condenser inlet valve, recover the refrigerant left in the piping between these two points and then pull apart the separator. Same procedure if someday the DDPR fails. All of this because the installer/manufacturer couldn´t afford to put an insolation valve right after the DDPR.
For SLATS: just to clarify, the piping goes like this: compressors´discharge service valves, common discharge manifold, helical oil separator, discharge differential pressure regulator, long pipe run, remote condenser inlet valve. Thank you all for your interest and comments.

Sounds to me like you found it. Just a trick I use in these cases, before you start pump down a couple of your larger systems on the rack, 3-4 psig. Then shut the pumps off one at a time isolateing the discharge as you go. Finally shut the inlet to the condensor, and dump the remaining discharge gas back into the systems you pumped down when you started. I would have new float in hand because you don't need to repete this if there is a problem.

[frigeguy]

NO

I like this answer the best