Worcester 28CDi Combi Boiler - No Hot water takes for ages!

Graycope1983

[FONT=&quot]Hi,

I have recently not been able to get hot water out of the taps for 5 mins or so. The pressure has been at 0 for over a month and would not go up when turning key.

I have had a gas man come out yesterday who had to add a new filler pipe to the bottom of the combi boiler. This one has two black mini levers that you turn to let flow through.

The pressure now increases when you turn these. The heating is working fine, however we still have the same issue with the hot water taking ages to heat up. For some reason it seems to come out quicker if i turn the heating on, which is silly.

Also, there is no LED light showing near the tap icon on the boiler either.

The gas man did mention that the large red cylinder had water at the back (which was dripping at times), but said he would be reluctant to touch this unless it gets worse as due to the pressure being low for a long time i might have an effect on it.

Any advice on why I am still not getting hot water as quickly as thought would be appreciated. From your posts it sounds like it could be Diverter Valve, but I am by no means familiar with heating/plumbing.[/FONT]

Lgas

Hi, this is just my opinion, as a Gas safe registered engineer. It does sound like the diverter valve, possibly just the diaphragm inside, if you can only get hot water whilst your heating is running.

As for the dropping pressure and dripping 'red cylinder', this is the expansion vessel, and as an engineer I would immediately check that it is correctly charged with air and/or the rubber diaphragm in the middle hasn't split. The expansion vessel is designed to take up the extra volume of water, which expands when heated. One side is full of water, the other is pressurised with air (we use a foot pump to do this) to 1 bar. If there is no charge in the vessel, or the diaphragm has split, the heated water has nowhere to expand, and so the pressure shoots up. When the pressure in the boiler gets to around 3 bars, the pressure relief valve will automatically discharge this outside (check for drips at the pipe outside), and the pressure will go right back down again.

This will keep happening unless it is seen to, so I would get someone out asap. As for 'not touching it' due to the pressure getting low, that is ridiculous, it is more than likely the reason for the low pressure! I would check it on a service call if it believed it to be suspect, it doesn't take long to check.

I would get a different engineer out, personally, and make sure he/she checks the expansion vessel. Good luck!

ollski

Above post is spot on but both the diverter valve diaphragm and expansion vessels are pigs of jobs on the 24 / 28 cdi and you may find it tricky to find someone to work on them. I would call Worcester out on a fixed price repair.

gas4you

As above. I always advise getting Worcester in on these boilers for the diverter valve/diaphragm.

roddydogs

This is apparantly a known fault with WB Combis-it happens on mine if the boiler is cold... sometimes you cannot get hot water even if you leave it running for ages, all you can do is turn the water flow off, wait a few minuits and try again. the applaince then "Re sets itself" The really strange thing is that while you are not getting hot water, the boiler is firing!.. Perhaps someone in the know can explain as a gas safe fitter did to me.