Vokera Linea Boiler

[brian312]

Hi there

I have a Vokera Linea boiler. I have been having to top up the pressure now and then as it drops slowly over time.

Anyway, we had a mains water outage last night. When I came in the water pressure was way down and I thought it was just the usual, needing topped up. Low and behold when I tried to top up there was no feed due to mains water outage.

The CH was still working and due to sub-zero temps I turned it on.

When I got up this morning my boiler was making intermittent "fill" noises. I think I may have left the fill loop on when I went to bed but can't be sure. I started moving the dial before checking if it was set to fill/closed (doh).
I went outside and there was evidence of a gush from overflow but is now a constant drip.

I had very similar problems before and replaced the heat exchanger about 4 years ago which cured the problem.

So far I have checked the expansion vessel (only air coming out, not wet). So i checked radiators which had air in too, so bled the whole system to set the pressure to 0. Topped up vessel with footpump and topped up water to 1.5 bar. Turned on CH and pressure has dropped from 1.5 to about 1.3 in half an hour and still gradually dropping.

Does this sound like the heat exchanger has gone again? I had pressure loss problems before the mains water outage but this is the first time the overflow has been showing water. Still a constant drip.

Any help greatly appreciated.

 

[griggs]

Is the pressure relief pipe dripping, put a bottle or something over it, to see if it collects anything.

Quite often, after the PRV opens, it does not reseat properly.

Let us know if it is dripping.

 

[brian312]

It has stopped dripping outside now (does it sometimes take a while for the water to clear the pipe?) My pressure still seems to be gradualy lowering though whether CH is on or not but quicker when CH/hot water is on I think

 

[griggs]

Put bottle / container over pipe as suggested, leave boiler running and check later.

 

[brian312]

Ok, no further leakage from overflow but pressure still dropping too fast. What do I do now then?

 

[brian312]

Pressure still dropping slowly, any further advice greatly appreciated, thanks

 

[methaneman75]

Take the front cover off, 2 screws at front and two underneath; check the auto airvent behind pump which could be leaking. Do not attempt to take off combustion cover though mate.

 

[brian312]

Thanks for the advice I will investigate when I get home tonight. I take it I can't just see this by dropping down the panel where the dials are. I need to take the full cover off, yes? I know not to touch anything that is in the Corgi registered domain. Pressure seems to maintain longer when heating is on I've noticed, if that's any help. Cheers

 

[methaneman75]

No probs, best to take cover completely off, quite easy, two lugs at top and fins down each side which locate when going back on.

 

[brian312]

So far I haven't removed the cover as the pressure seems to have stabilised. Can't work this out. When heating is off the pressure settles to about 1-1.2 then when heating is on the pressure goes up to about 1.5. When running hot water the pressure drops by about 0.2. Is this all normal.

The only extra thing I have done since I first posted was replace a broken temp control knob and I opened the pressure release valve manually. I've heard that this can get clogged up, would opening it up have cleared a blockage?

 

[methaneman75]

sounds fairly normal, you may have reseated the prv which could have been sitting on a bit of crap, if you want anyone to look at it in the future, give me a private message as i stay in west fife, only 25-30 mins from stirling area

 

[brian312]

Thanks for the advice, much obliged