T&P Valve leaks at times.

[derby98]

I have a water heater that leaks hot water via the overflow pipe. The overflow pipe leads to the outside of the garage so i did'nt really worry but this has been ongoing for 2 years. The overflow ONLY occurs in the fall & winer & not in Spring or summer. Any ideas?

[Plumber2000]

Could be thermo expansion taking place, if your system is a closed system, as in like you have a pressure reducer valve on the main water line, this makes a called system.

What happens is when hot water heats it expands, if the system is closed then there is no place for water to expand to, so if pressure in water heater reaches 150 psi the pop-off valve opens to release this pressure.

If this is what is happening then you will need an expansion tank installed at water heater.

[MBXB]

I posted the leak problem in my new LP gas heater a couple of weeks ago. I happened to be in the garage when the T&P popped off and burped. I had installed a pressure gauge and it was at 140. I guess this is too high.

How big an expansion tank do I need for a 50 gallon gas water heater?

Thanks in advance.

Ramon

[KField]

You can use an ST-5. I think it is made by Amtrol. It is not very bic but is made for THERMAL expansion. Not a regular expansion tank for a heating system. It should have about 100 psi in it to start. There is some debate about the precharge pressure but you don't want water in it until the pressure gets high anyway.

1/30 Checked into this (thanks Dunbar) and 85psi is the max precharge allowed by Amtrol and Watts. Sorry for the mis-information.

Ken

[DUNBAR PLUMBER]

Check your water pressure; anything over 60 is considered high.


Water Pressure (http://www.wattscanada.com/faq/regulators/main.html)

[Pendragon]

I wonder where they got those numbers from for that page, they seem way off (just compared to our usage).

nearly 8000 gallons a month?
8 gallons for a toilet flush? Maybe on some ancient fixture.
50 gallons for a load of laundry? (ealier on the page it says 35, which is probably closer to being right).

We (4) only used about 2200 gallons. That's with laundry, dishwasher, showers, even the occasional roman bath and car washing, and were not being conservative at all, that's just what gets used..

[DUNBAR PLUMBER]

Thanks for taking something positive, and finding something negative out of such useful advice. I have been submitting that link for years, and if you would think for a minute, there might of been a time that this link was produced when 3.5 gallons toilets were the norm, not the exception.


And to add to that, there are a significant amount of 3.5 gallon toilets still in use. That would prove the numbers as "not exaggerated" by any stretch since it is based on averages.


So for your information, just because 1.6 gallon toilets are the only thing on the shelves these days, that doesn't mean that every homeowner, business, commercial development removed their 3.5 gallon toilets to match into a link on the internet. :confused:



Information I post on this site along with others are to be used with the intent to help people in their situation, which pressure was is the underlying problem I am trying to convey to the thread starter.


Please make a better point to help the thread starter in their situation, not curtail general information into your specific situation and try to create doubt. Web links like that were designed on averages, and I still, still work on 5 gallon flush toilets in the Greater Cincinnati area where they put bricks in the tanks to displace the water to cut down on water usage.