Vokera Gas Combi-Boiler

Discussion in 'DIY' started by Dennis48, Jul 23, 2010.

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  1. Have lost water pressure, have turned Filling/Inlet valve vertically down to the filling position has per instruction booklet. Says the water should be entering the boiler to bring the pressure guage up between 1 and 1.5 bar.
    But no water is entering the system, also no water coming out of the hot water tap. Any ideas on how to solve this problem?
  2. May sound like a silly question but do you still have cold water coming out of the tap? If not, and you havent turned it off at the main inlet then your water is off, probably because the company are doing work on a main.

    Next thing is you say you have lost pressure, specifically what has happened? Was it at the recommended 1.5 bar and then dropped suddenly or was it gradual? Or is it a newly installed system?

    There are a few reasons I can think of why you may not be getting pressure back up if it was gradual.

    1. Waters off
    2. System has an airlock somewhere in it (bleed rads)
    3. Somethings leaking and the water youre putting in is getting straight back out somewhere in the system.
    4. Dodgy inlet valve on boiler
    5. Blockage in pipe from mains to inlet valve

    Edited to add 4 and 5.
  3. Have no water coming out of the hot tap but the cold is working fine, the boiler is set to hot water only the heating side is turned off and has been for a while. Because there's gas involved I ain't touching it, plus I was a gunner not a plumber so the wife wont let me anywhere near it with my hammer.
  4. Sounds like your mains water is ok then. Do you definately have power to the boiler? If the fuse has gone the pumps wont be getting power, which could explain the lack of water to the hot taps, but not the fact that you arent getting the pressure up by opening the inlet valve. Based on what you have described it sounds to me like you have a blockage or air lock somewhere between the main inlet to the house and the boiler inlet valve.

    I hasten to add that although I work in Building services Im not a plumber either.
  5. If you're on British Gas' HomeCare boiler maintenance service it's dead easy to call them out to get it fixed, and there's no charge. If you're not then it's easy to sign up...
  6. And the very first thing they'll do is come to your home to inspect your system, tell you you have "gas in your radiators" and that "they need a power flush, that'll be £700 sir"
  7. PM sent. I may have a solution.
  8. my boiler has 2 valves that need turning to fill the system with pressure. A lot of new boilers will also not heat the hot water unless it is fully pressurised!
  9. Yes; the filling loop's flexible hose should be disconnected when not in use. So there should be a valve on the cold water main and an inlet valve at the other end where the hose connects. The pressure is (rule of thumb) usually 1 bar cold, but check the instructions.

    Most systems need topping up once or twice per year. If it happens regularly, the expansion vessel has probably lost it's air charge so the expanding water forces the pressure relief valve (PRV) open. The PRV can then start to leak if grit gets under the valve seat. You can clear it sometimes by manually opening the valve (and then refilling) but it's usually a new PRV.

    BTW I'd avoid British Gas like an incurable plague. They are tossers (mostly). I also work in building services and am not a plumber; my plumbing is better than any plumber I've hired so don't let them near my systems. I've avoided British gas since they made a determined effort to cause a gas explosion in my house 20+ years ago.
  10. ot, why do they say to remove the flexi hose? they're all decent quality these days, and the valves and sealing stop any accidental pressure flow/leaking so don't see why it should be removed (i haven't because it's bloddy handy when having to drain the system every couple of months after installing new rads slowly but surely).. is there a safety aspect to this?

  11. To prevent contamination of the water mains by back-siphonage. You really don't want to drink someone's old sludge, corrosion inhibitors, anti-freeze, etc..
  12. Found the flexi hose and fitted that, the instruction booklet has a line missing in how to fill up the boiler. Tells you to turn the filling/inlet valve to the south and you should be able to hear the water filling up and the pressure gauge rising. What it doesn't say that you have to turn the little stop-cock on in order to to fill the tank. Many thanks for all the tips gentleman it appears to be working now after trying to find instructions and photos of boiler on the web.
  13. fair one hadn't thought of that aspect - is it still an issue with one way valves (understand that this may sound daft..)?
  14. Don't rule out a leak in the closed loop central heating system. Make a note of the pressure and check it again in a couple of hours/after a day/after a week. Always check it at the same state, ie not running and cold first thing in the morning would be good before anyone turns on the hot tap. If there's a significant drop (Make your own mind up what looks significant) then check your radiators/valves and pipes. It wouldn't be a big deal to check them out anyway.
  15. Ok Thanks Barking