Pressure too low on boiler

jennypeny

Hi, just wondering if someone on her might be able to assist me with an issue I’m having with my sealed gas boiler system:
It broke down last week and we were told we needed to get a new heat exchanger, which we did. Then when we turned on the system again, bled the radiators etc. and they started to heat up. The pressure on the boiler started to drop so we opened the valve in the hot water tank upstairs to increase the pressure which worked but everytime the valve is turned off again the pressure drops. back down to .3 / 0.
If the valve is left on, the pressure in the boiler remains around a safe one, but then the water tank in the attic starts to spill water from the pipe at the top of the house.
Usually low pressure means there is a leak, but we have checked the boiler is dry, all the radiators valves are closed and the radiators fully on, there is no air in any of them. One radiator does not seem to be getting hot, so we turned it off to try and stop it effecting the others.
Any ideas of anything else to do?
Money is tight and I can’t really afford to get a plumber around to charge me just to come here and then to just check the same things we have already done. It really needs to be a last resort.
Any assistance would be appreciated.

Joey the lips

I am very sorry Jenny. I understand that money is tight but you are asking questions you should not be. While its not illegal for any one to touch there own boiler it is illegal for someone to advise you how to do it.

I am gathering you changed the heat exchanger yourself and on this note i need to close the thread. If you paid a plumber get the plumber back.

If you cannot afford on board gais may put one on your bill.

again my apologies.