electric water heater no pressue & temp relief valve


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Old 10-05-14, 01:09 AM
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electric water heater no pressue & temp relief valve

hi


electric water heater require a pressure temp relief valve
due to hi press and temp that occur and may lead to damage the heater
here in Iraq
due to lack of a good quality relief valve
most of plumber don't add a relief valve
instead of that
and form water line that go to house
they add a pipe higher than the heater (above house water tank)
by this way any extended pressure and temp
then it will released via the extended pipe to outside

so what are the advantage and disadvantage of such method

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Old 10-05-14, 03:10 AM
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Install a T&P valve, install a PRV to regulate the incoming pressure, and set the temperature lower. I have no idea what the extended pipe would do for you. You have to remember this is primarily a North American site. Our codes differ from yours considerably.
 
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Old 10-05-14, 04:18 AM
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thank u for your kindly reply

the utilty of pipe
is
when preesure and temp reached hi value
it will be released through this pipe to outside air
by this way any over press an temperature is prevented

u get the idea or not (sorry for my broken english)

i know that i must install T&P valve

but my question about the pipe

what u think about it
it wrong or correct
 
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Old 10-05-14, 01:14 PM
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For a fully gravity fed system with vented water storage tank (cold water supply) in the attic or on the roof, the vertical pipe open at the top as you have shown will substitute for a temperature & pressure relief valve on your water heater.

Some energy inefficiency/loss will occur due to tiny eddy currents of water up and down within that vertical pipe but that can be corrected by building a loop-the-loop just above the water heater using four elbows.

Gravity systems are rare in the U.S. With a sealed pressurized system the vertical pipe will not work unless you put a pressure relief valve at the top. The T&P valve on the heater itself works better because it provides overtemperature protection as well as overpressure protection.
 

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Old 10-05-14, 04:46 PM
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For a fully gravity fed system with vented water storage tank (cold water supply) in the attic or on the roof, the vertical pipe open at the top as you have shown will substitute for a temperature & pressure relief valve on your water heater.


that exactly system what most of us have here


Some energy inefficiency/loss will occur due to tiny eddy currents of water up and down within that vertical pipe but that can be corrected by building a loop-the-loop just above the water heater using four elbows.
u mean instal it like square

The T&P valve on the heater itself works better because it provides overtemperature protection as well as overpressure protection.


u mean the vertical provide either temperature or pressure protection but not both???
 
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Old 10-06-14, 01:28 PM
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You stated in your first post you have high pressures, so I took it to mean you had a pressurized system. If you only have gravity feed, as long as the pipe is above the water tank, it will serve as a temperature and pressure relief member. Yes, you can install it in a square or round loop, which ever you can accomplish. There will be water leaking from the top of the pipe on occasion due to the natural forces of heat and convection.
 
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Old 10-06-14, 01:36 PM
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im sorry for my broken english

If you only have gravity feed, as long as the pipe is above the water tank, it will serve as a temperature and pressure relief member. Yes, you can install it in a square or round loop, which ever you can accomplish. There will be water leaking from the top of the pipe on occasion due to the natural forces of heat and convection.

ok
what are advantage and disadvantages
only water leaking or another thing
 
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Old 10-06-14, 02:27 PM
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None that I know of. We don't use that type system in the US, so experience is limited. We use about 65 psi for supply pressure. The water heater will handle more, but we use a T&P valve to vent off excess pressure or temperature to a controlled atmosphere, usually a floor drain.
 
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Old 10-07-14, 03:56 PM
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A vented gravity fed system with the open pipe above the water heater as shown will never develop hazardous pressures inside.

Each new tankful of water expands a little when heated. This may cause a small quantity of water to overflow out of the top of the vertical pipe.
 
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Old 10-07-14, 04:16 PM
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thank u for your kindly reply
if the method was correct
why it doesn't used in USA
then its disadvantage or not
 
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Old 10-07-14, 04:47 PM
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We don't use gravity fed systems here as a general rule. We have pressure systems as indicated in post 8. This is for public water systems as well as private well systems. Gravity is what you have, and you have to do what you can to achieve pressure and temperature. Our water is generally pumped into tremendous tanks above ground about 100' or so. From that, gravity creates a great deal of pressure where it is distributed throughout a geographic area. Our well systems rely on pumps and pressure holding tanks so pressure is constant.
 
 

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