Sealed system -- increasing pressure.

[islandman]

Over the winter there has been a continual slight pressure drop needing re-pressuring about twice a week -- not much but continual.

This was traced to a very small leak at a rightangle joint which fortunately was very easy to access.

Repair was done about 3 weeks ago and to be certain this was the only leak I checked the pressure daily and for 2 weeks it was rock solid steady. Always checked cold.

This last week I've noticed a slight pressure increase at the cold reading. It was steady at 1.4 bar but had increased to 1.5 a few days ago and this morning it was at 1.6.

Boiler is Vaillant Ecotec 831 & I'm reading the digital display rather than the needle dial.

I've checked that both filling taps are firmly turned off.

With an increase in pressure I assume it can only mean that water or perhaps air is entering the system ------ the rads are all hot with no cold spots. The system was drained to effect the repair and refilled & bled adding inhibitor.

I have noticed this week that the overnight temp has been much milder resulting in the house temp being alot higher so could this just be the reason.

As yet I haven't released some pressure to see if it keeps going up and I guess this is the next step.

Any ideas welcome. Ironically, after a few months being frustrated by dropping pressure it now seems to be going the other way!!

 

[Steambod]

I'd be surprised if just the temperature change in the house was bumping the cold pressure up that much, unless you have a faulty expansion vessel, but then the relief valve'd be popping all the time. Could be the filling valve letting by I had a similar problem on my previous boiler when I topped it up and shut off the valve or so i thought. Came back in the evening to find relief valve dripping down back wall of house and system pressure up to 3bar. To check I sugest undoing the filling loop to make sure it's not coming in there.

 

[muggles]

As steambod says, remove the folling loop flexi connection and see if it drips, if it's running that may well be your problem. If it's not running the only other way water can get into your system is via the plate heat exchanger, which will be ruptured and require replacement.