Have all work permitted and inspected. WE KEEP GOING UNTIL YOU HAVE THE INFORMATION YOU NEED. I come and go. be patient.
See if you can find a drain in the CH piping at the bottom of the boiler
If not there, you can let water out at the air vents on the radiators..highest points
Let me know how that goes, we continue until you are fixed up.
Yes, be careful not to take it out completely, turn it half a turn or so...
half a cup of water may be all you need to remove.
its only possible for the pressure to rise if the feed water valve is still open...
however anytime a boiler warms up, the water expands and runs the pressure up until the boiler cools back down again.
any time you let water out of a closed circuit, the pressure has to drop..
The boiler has a pressure relief valve fit as well... you can manually trip that, but its not the way to let water out of the boiler. it dumps way too much water way too fast.
There is one other way city water pressure can get into the closed central heat loop on a combi boiler
that happens if there is a leak in the domestic hot water heat exchanger..that allows city water to enter the CH closed loop... depending on the heat exchanger used.
we can check into that later if necessary.
Hello again, half a gallon removed should have dropped the boiler pressure...
its likely the fill valve is leaking, or that water is leaking through the DHW heat exchanger to the CH side of the boiler.
Keep an eye on it. if the pressure goes back up, that will most likely be the case.