T & P valve

[Kelti_x]

Recently had a red seal plumber install a pressure regulator valve as we discovered city pressure was close to 100 psi. We discovered it because of an ongoing issue with our T&P valve. Now it seems worse as it releases a cup of water every second night which is more than it did before the PRV and incidentally my second-floor shower has low hot water pressure now too.
Timeline:

• April 2021 replaced lower heating element due to hard water calcification - plumber 1 suggested I try and seat dripping T&P valve myself
• May 2021 plumber 2 replaces T&P valve and new dip tube
• Feb 2022 get back plumber 2 who finally checks water temperature and pressure because of on going issue
• City pressure 100 psi- recommendations for PRV
• Temperature adjusted – Kitchen tap 123F- very little action from T&P valve
• March 2022 install PRV
• PRV gauge reads a little over 55 psi
• Now instead of dripping occasionally there is a cup or two of water releasing from T&P valve every evening or every second evening.
• April 2022 plumber 2 replaces T&P valve but two days later the T&P valve giving off a cup of water again.

What should I look for when speaking with new plumber.

 

[SHEPLMBR]

Did they install an expansion tank?

 

[Twowaxhack]

Do as Sheplumber suggested, it’s the correct advice to stop the drip.

I’d ask the new plumber to first set my pressure to 75 psi. This will help restore some hot pressure to your shower.

 

[Kelti_x]

Did they install an expansion tank?

They made no mention of a thermal expansion tank. I asked if it was a closed system and if that was responsible for the T&P valve release but they said no.

 

[Kelti_x]

Do as Sheplumber suggested, it’s the correct advice to stop the drip.

I’d ask the new plumber to first set my pressure to 75 psi. This will help restore some hot pressure to your shower.

The funny thing is that low pressure was not immediately a problem. It appeared to be lower and lower after a week or so after the PRV was installed. Plus the cold water seems to be higher and it is just the hot that is low. Does that have something to do with thermal expansion?

 

[Kelti_x]

Did they install an expansion tank?

Thank you. In layman's terms why does reducing the water pressure with a PRV create a problem with thermal expansion? Ball park what is the cost of installing a thermal expansion tank? Also my hot water tank is almost 10 years old. Would this new apparatus be compatible with a new hot water heater if I kept to the same size?