Antifreeze and Pressure reducing valve / Expansion tank

[heckmab]

Hello,

We have a summer cottage in upstate New York that gets winterized every season. We just did a major remodel and had a plumber install all new PEX and a new water heater. At the same time, the town also ran a new water main and it now includes a backflow preventor.

The pressure relief valve on the water heater now drips.

*The house pressure at the outside spigot is 82psi.
*Pressure relief valve doesn't drip when the water is set to "low" (around 94F), but once I bump it up to 114F it drips (confirmed it opens at 150psi when gauge on the water heater).

Questions:
1. Is the best plan of attack to install a pressure reducing valve after the main coming into the house? In addition, also install an expansion tank (set the pressure to 65 at the PRV and pump up the expansion tank to 70 psi)?
2. Since this is a cottage, there is no crawl space or basement. The only location to install the PRV without ripping up the floors is to put it outside. Is it okay to install a PRV outside as long as it's properly winterized?
3. We typically use antifreeze for winterizing the pipes. Will there be any issues if antifreeze sits in the PRV all winter?
4. Is there anything special I need to do for winterizing the expansion tank and pressure relief valve?

Thanks for all the help!
Brandon

 

[Reach4]

PRV or not, you will need a thermal expansion tank with the air precharge set to the PRV setting, or 80 PSI if you risk not having a PRV. A plumber would have to put in a PRV. I am not a plumber, and I might risk it, selecting the next size up for the thermal expansion tank.

It is fairly normal for water pressure to rise over 100 psi with a typical thermal expansion tank.