Amtrol Therm-X-Trol expansion tank on incoming main line...

[Twodose]

On a Therm-X-Trol ST-12 expansion tank. Installed on the main 2” Incoming line at the Carwash.

The incoming pressure is 70psi. Max pressure on st-12 is 150 psi.

It Says in the instruction’s to Adjust pre-charge to equal incoming pressure.

Would it be correct to pr-charge the expansion tank to 70 psi? Seems to me it would.

We are required to have a backflow preventer on the main line, reduced pressure principle.

 

[MEP001]

Would it be correct to pr-charge the expansion tank to 70 psi? Seems to me it would.

Yes it would. At 150 psi the expansion tank won't do anything until the pressure in the water line exceeds 150 psi. If it's set at the maximum incoming water pressure it won't come into play until that pressure is exceeded.