Vokera Excell 80 SP?

How much air to do need to fill expansion vessel in boiler

Vicky King
November 2008

Or it could just be because the system pressure is zero :-).

I didnt read the replies properly!, a bit like saying my mondeo cut out on the motorway, and then going on about crank position/oxygen sensors in a reply without asking for a fuel guage reading...

(Why should the system pressure be zero so soon after the repair man visited (he would have topped it up)?, does the system presure change a lot when the central heating in hot?.)

You can get Fernox leak sealer concentrate to go along with the system protector...

cd
March 2007

Do a google search for vokera flue venturi. Your boiler needs servicing by a Corgi man approved by Vokera (phone Vokera for someone local), or at by one VERY familiar with the model, they will do more than just vacuum insects from the bottom of the sealed box, the will fit kit t0019, and correct various operating pressures (cost perhaps 100-150 pounds, get an estimate beforehand, make sure they have heard of kit t0019 and flue venturi...there are some clueless (& hence expensive) corgi men out there).

It sounds as if your fan, heat exchanger and venturi have become progressively more dirty, and now the venturi does not register enough flow for it to be safe to turn on the main burner.
Or it could be that your fan or pump have packed in, or it could be the boiler flow switch isnt operating; it could be many things. I assume the system pressure is in the 'green zone' on the pressure guage.


I would suggest you dont try fixing this yourself, as involves opening the sealed case, but if you do, you need to remove the fan, hood and venturi from the boiler, clean them and the primary heat exchanger, and re-assemble.

You need to verify pump and fan operation (look for boiler flow switch movement, listen for fan). Your domestic hot water diaphram will probably be due replacement and the expansion vessel due pumping up (google it, you have to keep the system depressurised when pumping up the expasion vessel and it can take a long time before it fills enough to register any air pressure, see uk.diy newsgroup combi FAQ). The 80 sp manual can be downloaded from Vokera if you have lost your copy.

Done by someone who does a few of these a week the job should take two or three hours and be done in one visit. After a proper service it should be some time before it causes trouble again. This is not a bad boiler.

If your system is gassy you may consider injecting some Fernox system protector concentrate in through one of the radiator bleed valves using a caulking gun. You can safely do it yourself.

cd
March 2007

you won't get anything with a pressure at 0 it needs to be approx 1.5 bar no less than 0.7 bar.

hi-spec plumbing
March 2007

It's hovering at about 0 bar, and has been like that (as far as I can remember) for ages, even when the heating worked. Having said that, I don't remember checking it while the heat was on...

Gareth
March 2007

whats the pressure gauge read

hi-spec plumbing
March 2007