Regulators instead of expansion tanks on water heaters

It has nothing to do with it being a hybrid heater. In Florida, for unknown reason to me, you guys often use an adjustable pressure relief valve instead of an expansion tank. That is the only difference. The vacuum breaker is code in some locales. BTW, a pressure reducing valve is not the same as pressure relief valve. The AOS recommends the tank be exposed to no more than 50-60PSI by installing a pressure reducing valve, if the street pressure is higher. The pressure relief valve (or an expansion tank) to control thermal expansion is still required. The TPRV is a safety device, not designed to control thermal expansion and is also required. Hopefully no more confusion :slight_smile:

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Haha, confusion will still exist :wink:
I know the difference between pressure relief and pressure reducing valve, I mistyped on the first comment regarding hybrid heaters.
However, the only thing that is required in Florida is the TPRV, obviously. Many homes have nothing else installed. Newer homes typically have a pressure relief at the exterior, right next to the main shut off, and occasionally they will be at the water heater, but not required. But even then, it has nothing to do with the water heater, but rather for the whole house. Rarely I will see an expansion tank, but there is no rhyme or reason. (Had one today on a brand new home, but not at most of my new homes)
My comment was regarding hybrid heaters, because that is the only time that I consistently see the pressure relief at the heater, and sometimes, like pictured, it will have the vacuum as well. And again, a hybrid heater is the ONLY time I ever see a vacuum valve. (I only see hybrid heaters about 5% of the time)

What do you base this on? a device to control thermal expansion is required by IRC 2018 adopted by state of Florida (when it’s a closed system). I doubt your AHJ overrides these requirements. Of course this does not apply to old houses, however, a plumber with a brain will always install one because, for example, a lack of thermal expansion control device will defeat the purpose of a pressure reducing valve. Even though the code (which is minimum) only requires a pressure reducing valve when pressure exceeds 80 PSI, as you saw, AOS recommends it even when the pressure exceeds 60-65PSI, lower than the code.

If a pressure reducing, a check or a backflow prevention device is installed, it is required, this is from your state’s code:


As far as a vacuum breaker, I only know of one state, Massachusetts, where it is required, regardless if it’s a hybrid or regular WH.

Because down here, nobody installs a closed system. From water meter, to shut off, to home. And water pressure is consistently between 40-65 psi

Do you check static pressure when you inspect?

Do you guys have hills? it’s hard (almost impossible) to believe that every area of Florida has no higher pressure than 80 PSI at the street. Every foot higher (water supply) is increase of 0.433PSI, 23 feet downhill and your pressure is 10PSI higher. Here I see pressure 80-100PSI often. Some water districts will install a check valve at the meter. In both cases a thermal control device is needed.

Just use my pressure gauge at the hose bib.

haha, not in my area. We moved here from CO about 3 years ago, and vastly different. (motorcycle cruising is not nearly as fun) About 2 months ago we were driving, and my 8 year old son goes “what’s that?!”. I said "that’s a landfill…:sweat_smile:

Elevation around Tampa/St Petersburg area is roughly 25-85’ above sea level. Pretty consistent.

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