Occasional no hot water from combi boiler

[h1spm]

Hi,
I have a Worcester combi 350 approx 14 years old. The heating and hot water are normally fine, however, recently I occasionally get no hot water. This is at low and high flows and does not change if I leave the water running for 5 mins plus. At present if I turn the tap of and try again a while later it delivers hot water. The most recent time it failed to deliver hot water I turned down the temperature on the boiler fixed control panel and hot water was restored immediately (coincidence?).
Does anybody have any idea what may be the problem?

[gucciman]

have you checked to see if the heating is stil working ok? if it is then most probably your diverter valve is on the way out and needs replacing, sounds as though it is starting to stick and working intermittenty. this is a very common fault and easy to fix, although not cheap, its caused by a build up of sludge in the system which then jams up the valve.
could be the hot water thermistor but most likely the diverter valve.
the burner should fire within a few seconds of the hot tap being opened so leaving it running for 5 mins will do nothing to help.
and yes i would guess that turning the thermostat on the control panel was probably a coincidence.

[gucciman]

forgot to say, if your in the south birmingham or surrounding areas then give me a shout if you want it repaired.

[h1spm]

Thanks Gucciman, i'm in Leeds but thanks anayway. Do you know much about this particular boiler, is it worth fixing or should I replace it with a new condensing boiler? Are they a lot more efficient (I'm on a water meter), are the new boilers likely to be as trouble free as this has been (until now at least).

[gucciman]

your boiler is getting on a bit now but saying that along with vaillants worcesters are the best boilers on the market, theres plenty of gas engineers out there who can repair them and as long as the spare parts are still available it should give you a few more years of service while you save up your pennies for its eventual replacement.
the one thing you need to remember when or if you do replace it, if your system is sludged up then the new boiler will get sludged up too, so it will need a thorough flushing, thats the installers responsibility though.for a new diverter valve fitted your loking at around the 150 mark.
condensing boilers only save you on gas, not really going to save you on water useage.

cant guarantee that the new boilers will be trouble free as they are getting more and more complex and technical all the time, so more things to go wrong, but with any combi boiler you should get it serviced annually and expect to need a repair every couple of years, just like you would with a car.
your going to be looking around the 1500 to 2000 mark for a replacement boiler, dependant on what make and model you opt for and also if your valves or controls need replacing to comply with the energy efficiency regulations.
it may be worth contacting your council and see if there are any grants available in your area to upgrade to a more energy efficient boiler as there often is.