Pressure reducing valve advice

[PlumbNuts]

We can disagree on that. A tank near the irrigation tee would be similar to a well with a pressure tank. Would you propose that somebody with a well and pressure tank also have a thermal at the WH -- presuming no check valve is between the pressure tank and the WH?
You have experience with PRVs, and I don't have any. I think them as a potential PITA maintenance/failure thing.

Not trying to argue here..... His issues (multiple) are being reported to show at the water heater which is the most common place for the expansion tank to be installed.
A PRV can last over 20 years without having to be touched.

 

[CallmeJake]

Thanks for the input, I appreciate the help.

My goal in all of this is to get the pressure valve on the water heater to stop dumping water. The sprinklers seem to be the main cause of this, flushing the radiant loop also caused it but out of the two the sprinklers run a lot more often then I plan to flush the floor.

It sounds like the PRV is recommended way to solve the problem, I plan to add a tank as well, though it may not be required by code. It seems the tank should be able to help with the pressure spike that is causing the water heater valve to blow off.

I see the posts here that say the tank is for thermal expansion only, that doesn't make sense to me. Thermal expansion causes pressure to rise, the tank gives the pressure somewhere to go. How does the tank know the difference between a pressure rise due to thermal expansion vs pressure rise due to a valve closing?

In any case, the meter and tee to the irrigation are about 45' from the tankless water heater. My understanding is the tank should work anywhere on that line as long as it's downstream of the PRV. Is that right?

Does anyone have an opinion on flow-through tanks? Getting fairly far down the expansion tank selection rabbit hole....

 

[Sponsor]

 

[PlumbNuts]

Thanks for the input, I appreciate the help.

My goal in all of this is to get the pressure valve on the water heater to stop dumping water. The sprinklers seem to be the main cause of this, flushing the radiant loop also caused it but out of the two the sprinklers run a lot more often then I plan to flush the floor.

It sounds like the PRV is recommended way to solve the problem, I plan to add a tank as well, though it may not be required by code. It seems the tank should be able to help with the pressure spike that is causing the water heater valve to blow off.

I see the posts here that say the tank is for thermal expansion only, that doesn't make sense to me. Thermal expansion causes pressure to rise, the tank gives the pressure somewhere to go. How does the tank know the difference between a pressure rise due to thermal expansion vs pressure rise due to a valve closing?

In any case, the meter and tee to the irrigation are about 45' from the tankless water heater. My understanding is the tank should work anywhere on that line as long as it's downstream of the PRV. Is that right?

Does anyone have an opinion on flow-through tanks? Getting fairly far down the expansion tank selection rabbit hole....

Codes and requirements are different throughout the country and even vary within individual states and different municipalities.

Here if there is an irrigation system installed it is required to protect the domestic water by way of a backflow protection assembly, if you have one installed I don't understand how the sprinklers switching off would cause that,,, Maybe it is not required in your area. JTOL.

To me it sounds as if your issues would be resolved by adding the PRV to lower your water pressure. But again, here if I install a PRV I have created what is called a "closed loop system" and I would be required to add the thermal expansion tank. The most common location for the thermal expansion tank is at the water heater but it can be installed anywhere on the cold main line after the PRV.

As I stated earlier it may be neccesary to replace the T&P valve since the spring may have weakened due to continues openings but you can determine that after you install the PRV.

Check your local codes and see what is required in your area; maybe you can call a local plumber to give you an estimate for installing a PRV and then he would tell you if there are any other requirements.

Here is a link to a thermal expansion tank that is available at Home Depot (not a recommendation, just a picture):
https://www.homedepot.com/p/Everbil...ugGVD9u4ILIZ6JwRRskaAi4iEALw_wcB&gclsrc=aw.ds

This type of expansion tank is all you would need.

 

[CallmeJake]

I have a vacuum breaker/backflow on the irrigation. We just finished the house last spring and everything was inspected/passed by the city. The only issue they had was making sure I didn't break the wireless transmitter for the meter, apparently people do that.

The system is 1" pvc mainline with 1" poly laterals up to the funny pipe. When it's running the water gets moving pretty fast and then stops fairly quick when the zone valve closes.

I am going to take your advice on replacing the t&p and I will have the expansion tank. Just verifying the location.

Appreciate the link to the expansion tank, I asked about the flow-through tanks because I read something about water possibly stagnating in a traditional tank.

 

[PlumbNuts]

I have a vacuum breaker/backflow on the irrigation. We just finished the house last spring and everything was inspected/passed by the city. The only issue they had was making sure I didn't break the wireless transmitter for the meter, apparently people do that.

The system is 1" pvc mainline with 1" poly laterals up to the funny pipe. When it's running the water gets moving pretty fast and then stops fairly quick when the zone valve closes.

I am going to take your advice on replacing the t&p and I will have the expansion tank. Just verifying the location.

Appreciate the link to the expansion tank, I asked about the flow-through tanks because I read something about water possibly stagnating in a traditional tank.

If the expansion tank is properly charged with air then it will not continuously hold water and therefore will not stagnate.