T&P Relief Valve Question

[Jb9]

Hello,

I am going to sleeve a stem wall so the T&P Relief Valve will exit a crawlspace and empty to the outside (6" above grade). I am trying to do the height calculations so that the Top Mount T&P valve will allow the 3/4" copper to pass through the sleeve. Can the T&P Valve be lengthened if I get one with an 8" thermostat probe?

I just want to make sure I hit the height I need. The tank is a Low Boy Electric.

Thanks in advance.

 

[Terry]

With water heaters changing sizes every so years, it seems a lot of trouble to adjust the hole in the wall to the height you have now.
Normally the drain in the wall is lower and you can use 90's to get down to your height. I have also raised the T&P when needed to get grade when the new water heater was a smidge higher.

 

[Sponsor]

 

[Jb9]

Good approach Terry. So can I raise the height of the T&P if necessary to hit grade and allow the 3/4" copper to have a gravity flow to daylight? AHJ is allowing me to run the sleeve at 6" above grade outside my stem wall so I want to make sure that is in place so that he is happy. Does this make sense?

I was confused by what you meant... you could raise the T&P if the new water heater was lower or higher?

 

[Jb9]

I just found that Watts makes "Extended Shank T&P Valves." I am hoping this will give me the extended height. Do most water heaters not come with T&P valves installed? Can one request that a water heater come without one?

 

[MACPLUMB]

You can request any thing that you can PAY for just like ordering a new Auto

 

[Sylvan]

Try to refrain from using more then 2 90 deg fittings on the T&P discharge and cut the end of the discharge pipe at a 45 Deg angle

If you use more then two ells increase the discharge one pipe diameter

 

[hj]

quote;
Try to refrain from using more then 2 90 deg fittings on the T&P discharge and cut the end of the discharge pipe at a 45 Deg angle
If you use more then two ells increase the discharge one pipe diameter

NONE of that has ever been a code requirement.

 

[Sylvan]

"

NONE of that has ever been a code requirement."


Sorry HJ


Please look at the ASME section IV and NBBI


Reasoning is for the 45 DEG angle on ANY safety or Relief or the T&P discharge line is simple

So no one can add a fitting on the end of the piping

The reason why we certified inspectors do not like more then 2 - 90 deg firings on SAFETY or RELIEF or T&P valves is friction may hinder the FULL Flow as required

Personally I say 2 90 DEG Watts says no more then 4

Same with excess piping on the discharge


Sylvan Tieger LMP, LMFSPC ,

Federally certified unfired pressure vessel and low pressure boiler inspector , NYC , Certified boiler inspector and installer

 

[Sylvan]

Quoted from WATTS


WARNING: To avoid water damage or scalding due to valve operation, discharge line must be connected to valve outlet and run to a safe place of disposal. Discharge line must be as short as possible and be the same size as the valve discharge connection throughout its entire length. Discharge line must pitch downward from the valve and terminate at least 6" (152mm) above a drain where any discharge will be clearly visible. The discharge line shall terminate plain, not threaded. Discharge line material must conform to local plumbing codes or ASME requirements. Excessive length over 30' (9.14m), or use of more than four elbows or reducing discharge line size will cause a restriction and reduce the discharge capacity of the valve.