Pressure relief valve ?

John Abbott

Does anyone know of a 30lb pressure relief that non toxic antifreeze will not leak by? I am a heating professional and expansion tanks are sized appropriately so it is not a pressure issue.I keep the concentrations as low as possible and maintain the PH but to no avail. I hate antifreeze and only use it when unavoidable, but sometimes it is.

John

Al Letellier_9

leaking safety on A/F

I agree with your feelings about A/F, and use it only when it's the lesser of two evils. As to leak proof safeties...I haven't found one yet. Do they exist? Maybe someone has found one, but...

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Tony Conner_2

Has Anyone...

...spoken directly to safety & relief valve manufacturers? They might have different seats and/or valves available for applications like glycol service.

You could look at rupture disks - they get used in applications where the corresponding safety or reliefs would be far too expensive (as in huge) or where leakage is a problem. I have no idea how small/inexpensive they go, though.

One of the big downsides of ruptures disks is that they're a one-shot deal, like an electrical fuse. If they pop, that's it - they have to be replaced. And until they are - they remain open venting steam or vapour, or draining all the liquid filled system above them.

I have heard of process applications where a rupture disk is located just ahead of a relief, in order to deal with leakage problems. As far as I know, you have to take this into account for the relief valve capacity, and it can mean going up a size. I sure wouldn't do it on a boiler unless the manufacturer approved of it.