Is there no chance of running a 3/4″ cold line off a tee after the water heater valve to an acessable area…attic or basement?
If you have NO other area where you can run a thermal expansion tank, then I can only offer you these two ideas to toss around.
You can install one of the new WATTS or CONBRACO valves for your water heater shut off valve.
They just got approved in Los Angeles so check your local codes.
all they are is a full port ball valve with a small relief valve after the ball.
They are set to 125 PSI to bleed off excess thermal expansion pressure.
They come with 3/8ths compression fittings so you can add 3/8ths tubing to run your tubing to an approved drain or outside to a planter.
(the same codes still apply as far as air gap required because it is a potable water supply and subject to backflow codes.)
I use these when there is no other way to install an expansion tank.
They relieve pressure by releasing water out of the tubing just like a regular pressure relief valve only under less pressure..(and the tubing is easier to conceal and run…although I am not sure if there is a maximum combined length you can run this tubing for drainage???????)
Besides, its a waste of water!
If your really screwed and have to do something you can add a pressure regulator with an internal bypass valve at the main water service which will allow excess pressure created by thermal expansion to go backwards to the city side of the regulator and then get trapped by the regulators diaphragm!
(this will only work if the city side pressure of the regulator is less than the static pressure combined with the thermal expansion pressure!)
Its not good practice but what the hell! If your stuck your stuck!
You can install a regulator with a bypass, adjust the house pressure to say 55 psi, and if any thermal expansion happens, the excess pressure will get pushed back to the regulator to the city side and the regulators diaphragm will keep it back!
again your city pressure must be less than your thermal expanded pressure…and as a side note…pressure regulators will restrict flow so if your already dealing with low city pressure than this can cause you more problems.
If you have higher city pressure than thermal pressure you can always add an expansion tank on the main AFTER the regulator to soak up expansion…I’m sure the neighbors will love that sight! LOL!!
Be a good guy and bring a small bush to plant in front of it!! or better yet some roses with thorns! (that is usually the houses I go to to service!…thorn bushes growing around the damn regulators, and a severe ant problem, ohh and dont forget the small dog that barks at you the whole time at the fence!)
OOPS, I’m complaining again!
heres CONBRACO’s SITE, I didnt see the combination ball valve/relief valve that is approved in my area, but I didnt look too hard!
Heres a site that shows specs. on Wilkins(ZURN) regulators that has built in bypass for thermal expansion…check out the 500 or 600 series:
anyways good luck with your system!
» This message has been edited by Bruce T on 24 July 2002