Vaillant ecomax 824 - pressure rising and falling/water leak

[Murdoch]

Hi

We noticed a water leak in our boiler cupboard in the kitchen last night. Probably about a half a cup fall. It potentially could have built up over the last month or so (we installed a new thermostat a mth ago and it was all fine). I took the front of the boiler off and there was water in the bottom of it. I watched it for about 30 mins when running and could not see an obvious place where it was coming from.

Right now the pressure falls while the heating is off and rises when it is on. The pipe located outside the house is leaking water (I have a jug underneath it). The pressure is falling at such a rate that I think it will get to zero and the boiler will cut out overnight when the heating is off.

I have 'tested' the valve on the expansion vessel and it leaks water.

We will be getting a local engineer in but given the time of year, they are not available until the middle of next week.

Are we ok to leave the heating on or should we turn it off?

Also I assume that the expansion vessel needs replacing. Does anything else need replacing? Any ideas what has caused the leak in the boiler?

Any help is gratefully received.

 

[petej]

If you have water coming out of the shraeder valve on the expansion vessel the diaphragm has gone, allowing water through it to the dry side.
The vessel will have to be replaced.
This would cause the system to over pressure when hot and water to escape outside through the pressure release valve, these sometimes will not reseat correctly when opened !.
As a stop gap you may get away with completely draining a reasonable sized radiator of water and leaving it full of air with the valves turned on to give the expanding water somewhere to go..
Pete