Do I need a pressure reducing valve?

[Reach4]

I agree with Jeff.

If it turns out that you did have a closed system, then I would set each tank to probably 75 psi air precharge.

 

[Jeff H Young]

yes never set pressure below incoming the bladder might fully compress effectively making the tank much smaller

 

[Sponsor]

 

[Mj23]

yes never set pressure below incoming the bladder might fully compress effectively making the tank much smaller

I guess in my case, since it is set to the factory precharge of 40 psi, and the incoming pressure is 75 psi, the tank is essentially useless right now.

 

[Jeff H Young]

I guess in my case, since it is set to the factory precharge of 40 psi, and the incoming pressure is 75 psi, the tank is essentially useless right now.

not sure but id put air in it to 75 psi. however the tank could verywell be useless if your on an open system

 

[Reach4]

I guess in my case, since it is set to the factory precharge of 40 psi, and the incoming pressure is 75 psi, the tank is essentially useless right now.

Not useless, but the diaphragm is stretching significantly in normal conditions.

The thermal expansion tanks that I have seen usually spec 80 psi max on the precharge.

 

[Jeff H Young]

I think the usefulness is questionable on a open system , because I dont think your water heater is going to raise the pressure in an open system