Bruce T
Yes I have used them and they DO work!
However, they come with a 3/8ths compression fitting on them for you to run 3/8 copper tube to an approved drain.(and yes you have to keep it at least 1″ above the approved drain or use an air gap)
I use them in highrise buidings on water heaters under kitchen cabinets were space is too limited for use of an expansion tank, and there is too little space above the t-bar ceilings for an expansion tank..
They work the same as a Pressure relief valve only they are set to 125psi instead of 150.
All they really do is bleed off pressure if it is excess of 125 psi, (which is a waste of water).
I usually install a floor sink under the cabinets to drain my T&P valve,the watts expansion relief valve, the drain from the pan under the water heater, and condensate lines from A/C units.
They are expensive, but they are approved for use in Los Angelas in place of the expansion tank, so I use them to keep the inspectors happy.
