How to size a T&P relief valve?

[mechth]

I'm looking for sizing method for a temperature and pressure relief valve installed a domestic hot water storage tank. For normal operation, the pressure in the tank is about 80 psi and temperature is about 145F.

Many thanks.

 

[mechth]

The tank volume is about 750 US gal and the water is heated by 2 750 MBH input boilers.

 

[BPLBPL]

Hi, assuming yours is a typical residential DHW tank, I would suggest a 210F limit for temp. and 150psig for pressure. Please make sure all components in the system can withstand the above limits.

Take a look at this valve:

http://www.drillspot.com/products/326591/Watts_LLL100XL_TandP_Valve