View Full Version : PRV? diaphram valve?

09-11-2015, 09:06 PM
Building out.

We've received our coolfit gear. We asked for a PRV to install at the end of the supply header to dump into the return header in case of over pressure. We have received a very impressive looking adjustable valve labeled as a diaphram valve;


Is this the what we need to protect our jackets?

Thanks for any comments

09-12-2015, 02:34 AM
Ideally you want a differential bypass valve and a pressure gauge just upstream (supply side) so you can dial in the supply side pressure to 15psi or whatever your jacket working pressure may be.

We used GF piping and GF themselves said that they don't make a differential bypass valve that works below 32F temperatures and were really expensive (> $500), so I ended up getting a Caleffi differential bypass valve on ebay and it works great, keeps the supply side at a constant 15psi whether 0 or all 7 tanks are requesting coolant. We got a 1 1/4" model (we have GF 75mm piping and used their adapters to go down to 1 1/4" metal threads), but because our chiller outlet is also 1 1/4" I figured this would be an adequate diameter.

That said, many people just use a diaphragm/butterfly/ball valve like you mention and that evidently works ok too. You'll want to adjust the valve pressure when no tanks are open, since this will be the highest pressure. But if too many tanks are requesting coolant, you're still going to be leaking some back to the return side through this valve instead of having 100% go to the jackets. It will also mean the supply-side pressure will vary more depending on how many tanks are requesting cooling. May not make much of a difference, I dunno.

09-12-2015, 08:22 PM
Thanks for the reply and insight. I guess my first question would be how did you plumb it inline with the GF run? Did you order GF parts to convert to standard MPT/FPT ?

09-13-2015, 01:33 AM
Yes. We used the GF ABS (non-insulated pipe) and insulated it ourselves with Armaflex. From the GF ABS 75mm pipe I think we needed a 75 -> 40mm reducer, then another GF adapter that went from 40mm ABS to 1 1/4" threaded, then had a couple 1 1/4" stainless T's, one for a thermometer, another for pressure, then the bypass valve, then the same GF products in reverse back to 75mm ABS for the return line.

For the drops we used 75mm T's that we reduced down to 1" threaded, then used our own valves: a manual ball valve then an electric valve on the supply side, and only a manual valve on the return. On the drop after the valve we used GF i-Fit which is flexible and cheap that we wrapped Armaflex around. It all works pretty well and in my part of the world at least, it wasn't much more expensive than PVC and the flexible i-Fit was far easier to work with.