My boiler has worked fine since being fitted by BG in 99. Serviced annually. Last week it stopped continually heating the water. It just heats it for a minute then goes stone cold. Turning the hot tap off then on again makes it go hot again - for a minute. It just seems to cut out and the ignition light goes out after a few seconds. I've heard it could be the diaphragm but was also told this may not be the problem and it could cost £500+ to get to the problem via trial and error. I can't afford that! I did move a radiator a couple of weeks ago but have been replacing them individually over the last year without a problem before. When the heating is on I stand more chance of getting hot water, but when it's off it's hit and miss. Any ideas of what the problem could be and the best way to fix it would be appreciated. Thanks

Pam, March 2005

Hi there I also have a worcester 24cdi boiler and my hot water works but my heating won't come on!!! My pressure is at 1.5!!! Any idea why this is and what can be done to fix it without me being ripped off??????

Kirsty, May 2014

I have my boiler serviced every year by B.G. recently it is taking a long time to heat the hot water and i have noticed the radiator getting warm even though they are switched off at the boiler, any idea.

Brian, October 2013

Don't worry Its just the diaphragm, when you open a h/w tap the pressure from that forces the diaphragm up which makes the micro-switch which then sends the signal to the PCB to goto full gas rate. Hence the reason when you put the heating on you get a slight amount of heat through the h/w tap, it wont be the full amount of heat due to the diaphragm having a small hole in it causing it to kick in then go out.

There is a service kit available for the diverter valve which comes with everything you need to repair the valve. They are under a tenner in price too ;-)

Not something you can do yourself, you need a Gas Man like me ;-)

Graham, April 2013

Worcester Bosch 24CDi Combi - occasional hot water?

mark, December 2012

my boiler is leaking quite a lot please help

john f, November 2012

pressure was down filled it up fan is runing but bioler not runing is the pump sticking

robin, August 2012

I only get hot water from tap if the heating is on? if heating is off only get cold water!!! Any suggestions

Lindsey, March 2011

I had the banging in the boiler, thought it was going to come off the wall, boiler is 5/6 yrs old, serviced every year. I had the system power flushed and also descaled, cost £300, no more noise and generally runs alot smoother?

Bezz, February 2011

"hi i have a worchester combi boiler 24cdi everytime i turn it on the pressure needle keeps jumping up an dwn an the boiler keeps making a banging noise like its going to burst any ideas anyone"

I have the very same issue.... I also had Steam venting out the top. I have drained the system as it was putting enough pressure into the rads that they were leaking

Mark Morley, December 2010

It sounds like the secondary heat exhange (sardine tin looking device) needs cleaning as the hard water scales it up.....FERNOX has a chemical you can purchase (i think it's called the X12???? don't quote me and you put this fluid in a bucket and the heat exchange into it.....shake it a few times with the fluid and leave it for a couple of hours before refitting it.....you must be GAS SAFE to do the work otherwise you are breaking the law!!!!!! You shouldn't be paying anymore than £150 all in.

Hope this helps., December 2010

hi i have a worchester combi boiler 24cdi everytime i turn it on the pressure needle keeps jumping up an dwn an the boiler keeps making a banging noise like its going to burst any ideas anyone

yaseen, November 2009

The boiler trips out and needs to be reset by the red button, can anyone help with this? Also need to know how to increase the pressure as think this may be linked?

Liz, December 2008

Hi, I had same problem eventually went to no hot water at all.
Solution was the diverter valve, tried just replacing the diagphram at first, but eventually had to replace complete valve. Its a swine of a job. TIP -- got my parts off E Bay for a fraction of the cost.

colin Ward, April 2008

I've got the same problem, but not only with hot water,also in heating, try to by-pass your programmer if you have, this may be faulty.
my problem now is when i can't get my hot water or central heating on, i pushed the fron cover of PCB a bit and it will come on, any idea what's wrong? cheers.

alvin, June 2007

i have a worcester 24cdi combi boiler...and it is having problems...my central heating has stopped working...radiators cold....hot water gets hot then cold....help plzz

jon, May 2007

I have had the same problem and British Gas came and replaced the water divertor and the pressure relief valve but in the end it was the heat exchanger. They want to charge me £255.00 for this heat exchanger on top of the amount I pay every month to them for looking after the boiler. I have checked this on the net and they are £73.44 inc. of VAT to buy! So beware of being ripped off.

Lynne, March 2007

What if the microswitch had been tested as you said, the DHW tap running but the boiler doesn't fire? Any ideas would be appreciated.

Michael, January 2007

the best thing to do is to locate the valve where the diaphragm is in and there will be a microswitch on it which is operated when you turn on a hot tap , check to see if the pin moves out of the valve and operates this microswitch, prove it by manually operating the microswitch with a screwdriver with the hot tap on and see if you get continuous hot water if so then the diaphragm is split

steve, March 2005