Hi Macplumb 777
About Installing Water Heaters
#1 What Is A P.r.v. And When And Why Is It Used ?
#2 What Is A Thermal Expansion Tank And When And Why Is It Used ?
#3 What Doe's All This Have To Do With Installing A Water Heater
#4 What Is A T&p Valve And Why Is It Used.
To add to Gary's answers.
1. Pressure release /relief valve is to prevent backflow of heated pressurized water from going back to the city's water source. Mainly a problem if the new housing developments are highly crowded and the city need to increase the water pressure to feed the development's water pressure needs. I doubt that my existing water source in this community modified the water pressure, they would have notified the home owners to install or retrofit PRVs into their water heaters. But to make sure, I'll ask my water department tomorrow.
IF the PRV is installed, the released water (very hot at this point, would drain to a plumbed drainage.
2. The thermal expansion tank is pressurized tank with a rubber bladder installed between the PRV and the heater. it just collects the backflow from the water heater thereby helping the PRV and protecting seals and valves.
3. number 1 and 2 are mainly to protect the city's water valves and safety of the house lines and helps prevent the collapse of the inner flue vent and prevents carbon monoxide being released into the home.
4. T/P (temperature and Pressure release valve) comes into play to relieve the pressure build up in the heater. normally set at 150 psi.
and yes, the T/P valve has to be plumbed to a drain as well.
In addition, California requires two sesmic straps, with the lower one being at least 4 inches from the thermostat. and a drip pan is recommended. The heater has to be raised 18 inches above the floor.
Short of buying a $135 2007 CPC book, I think I covered the important things.
and I'll call the local water utilities to inquire about the city's water pressure. If it's above 80 psi, i'll install a pvr and an expansion tank too.
So how about telling me where to buy a highly regarded Bradford White 40 gallon natural heater with FVIR, low NOX and at least 40000 btu in San Diego so that I can install one myself?
Thanks