We have been having a lively discussion about installing hydrostatic relief valves on the oil coolers. I have seen this done before and seem to recall something from IIAR about them. Can anyone tell me if this is legal?
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We have been having a lively discussion about installing hydrostatic relief valves on the oil coolers. I have seen this done before and seem to recall something from IIAR about them. Can anyone tell me if this is legal?
For oil or refrigerant?
My apologies. On the refrigerant side. From what I have seen most manufacturers are installing them on the oil side.
Hydrostatic valves should be installed anywhere there is a possibility of locking up liquid refrigerant. This is not an issue only related to low temperature liquid or oil. Although, the low temp liquid can be worse than the others...
Do you know if they can replace standard gas relief valves for the refrigerant side of the oil cooler?
A hydrostatic valve does not need much capacity to relieve the pressure, so a hydro valve of the same size inlet connection as a gas duty relief might be acceptable. I say might because you need to verify the capacity requirements yourself.
More importantly though...you need to find a location in the system where you can dump the liquid from the hydro valve if it opens.
And...the differential pressure imposed by connecting the outlet of the relief valve back into the system has to be considered. Gas duty valves go to atmosphere most of the time, so they have a higher differential pressure to develop the flow capacity.
Check the IIAR piping handbook, they show diagram with PRV piped to atmosphere. Problem with Hydrostatic is isolation/evacuation. Wherever the Hydrostatic potentially relieves to then must also be evacuated for a true isolation. I have seen reliefs installed between a liquid pump's check valve and the isolation valve to relieve back to the LPR. Then question is does a Hydrostatic count as an isolation valve for pump down to remove a liquid pump to replace seal? Or do you then need to fully evacuate the LPR.... same question for an oil cooler with a hydrostatic.
I understand what you are saying Iceehot, however it is perfectly legal to install an isolation valve on the outlet side of the hydrostatic relief valve if it is locked open.
Do you meam it is a three way valve which can control oil temperature back to compressor? As usually it is often used to big screw compressor unit.
Hello mates,
I want to select a shell&tube thermosyphon oil cooler, but all available s/w I have calculate only evaporator, condenser or desuperheater applications. Any ideas??
Thanx in advance
Hi Guys
Be interested in more info on hydrostatic valves, installation and application
been having problems on oil cooler spiking out on hi temp, goes well for couple of days then suddenly drops out,
cheers
These appear to be two separate issues. If the oil temperature is spiking at odd times it is more likely due to a loss of liquid, if this is a thermosyphon oil cooler.Quote:
Originally Posted by Loafa
Hydrostatic valves on the other hand are something I feel should be provided at any location where liquid can be isolated by valves or inadvertently by any service requirement.
3-way valves for oil temperature control are different than a hydrostatic valve (this is a relief valve intended for use on liquid) or gas relief valve.Quote:
Originally Posted by ntfreezer
...We tried one season without 3-way valves for SAB202 and SAB283 and it was very bad for them...Quote:
Originally Posted by US Iceman
...and for as also...