Alternative to thermal expansion tank

I was looking at the Watts web site for their selection of thermal expansion tanks and ran accross this. It's a toilet ballcock which also serves as an expansion valve:

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QUOTE:
Series Governor 80-M1 Ball Cock and Thermal Expansion Relief Valves are triple-function devices: a toilet tank ball cock, an anti-siphon backflow preventer and a thermal expansion pressure relief valve. The Governor 80-M1 limits the domestic water system's preset static pressure, protects the temperature and pressure relief valve on the water heater, reduces the requirement for a thermal expansion tank or an auxiliary relief valve and prevents backflow from water closets. Relief Valve Set At: 80psi.
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http://www.wattsreg.com/pdf/S-GOV80.pdf

Interesting idea -- obviously it'll waste a bit of water from time to time, compared to an expansion tank, but for some applicatons might be a nice option. Had not heard of this before.

Steve

When it fails, the homeowner will go to HD, buy a standard replacement valve for the toilet, and PRESTO, no more relief valve.

The principle could as easily be accomplished with a 1/2" relief valve like those used on small submersible pump systems, as long as the relief pressure is above the municipal supply pressure.

Bob NH said:

When it fails, the homeowner will go to HD, buy a standard replacement valve for the toilet, and PRESTO, no more relief valve.

Click to expand...

True! If I were to install one, I'd be tempted to use a nylon wire tie to attach a red plastic tag to it, instructing anyone working on it to replace with a like unit.