Proper expansion tank water pressure

[Tim Morrison]

I have a new water heater expansion tank. My static water pressure is 52. When the water heats I am getting a water pressure rise to 61. I have read that the pressure should stay the same or rise very little. What might be considered very little? Should the tank pressure be re-adjusted?

[Bill Chinook]

The air pressure in the tank should be set for you average static water pressure and let sit 24 hours before connecting it to your water supply.

I installed a pressure tank in my home, but unfortunately while my static pressure is usually 55 PSI, I get spikes in the pressure during the night from my water company up to 80 PSI and as low as 45 PSI drops. I do not expect my expansion tank to last very long due to these circumstances.

[Mark Reinmiller]

Most tanks are shipped with about 40 psi of pressure. The set pressure should match the water inlet pressure, so your may have been low. Also, too much of a change in pressure could indicate that the expansion tank is too small. Refer to the manufacturer's sizing chart.