Pressure rise expansion tank?

RobertHVACPro

I was doing a boiler start up and set the system static pressure at 12 psi and the expansion tank pressure at 12 psi. After the system came up to temperature (180°F) the pressure was at 14.5 psi. I checked the sizing of my tank and its sized properly per amtrols sizing chart for a 125k btu CGi-5. Is this normal or is there a problem?

RobertHVACPro

Pic of install

JUGHNE

Are you pumping towards the tank or away from it?

hot_rod

2 psi increase is not an issue.

RobertHVACPro

I’m “ pumping away” 😎

EBEBRATT-Ed

@RobertHVACPro

2 psi rise is fine. In fact a lot of systems will go to 20psi or more when hot. It's not an issue unless you get over 24psi or so. 80% of the releif valve set point shouldn't be an issue. The larger the expansion tank the less pressure rise you get.