Condenser boiler topping up water pressure

iainBB

Hi
I hope someone can help me, My dad has a pretty new condenser boiler that every once in a while the pressure drops down to below working pressure. Around 0.5 bar it stops working and the then working pressure is about 1.4 bar.
It was .7 bar at the weekend so we tried to replace the water and up the pressure in the closed system by attaching it to the mains and then opening the valves.
Our issue is the connection to do the above is in the attic of a 2 story house. So the connection is about 5 to 7 meters of the ground. When we try and up the pressure in the system it only goes up to 1.1 bar or so. And can take up to 20 min to do this.

My thinking is the pressure in the mains water in the attic is too low to up the pressure to 1.5 bars. If the connection was on the ground floor or the second floor this would not be a problem. But because the connection is in the attic and the height of the mains water has dropped the mains water pressure to 1.1 so we can never get the water in the boiler pressure to the 1.5 working pressure.

Any thoughts ?

Pete67

Top it up when the everything is cold - 1.1 bar cold is plenty. The pressure will increase when the system heats up, but should not rise above 2 bar approx. If it does there is a problem with the expansion vessel. He should get the heating system checked out, as continuous topping up will lead to corrosion and sludge build up.

iainBB

the drop in pressure is due to a small internal cylinder leak. and only has to be topped twice a year.

Wearb

If it is leaking heating water into the domestic water, it should be something to be concerned about.