when central heating running shower goes up and down in heat every few minutes.shower is mixer off hot/cold pipes .i am guessing the item that tels the central heating system to wait for hot water demand to finish is faulty but just which bit is it ? ta peter

peter dixon, November 2007

Hi, contact your local Worcester Bosch accredited company. They are CORGI registered and will carry the spares required. Go to the Worcester web site and enter the post code and this will list the engineers. The problem sounds like the diverter valve is not switching to hot water as you cannot get hot water and heating running at the same time on a combi. If the temperature dips when only the shower is on and only when the boiler is running on hot water, then it is a blockage in the plate to plate heat exchanger. This can be cleaned but by the age I would replace if this is so.

Kevin, November 2007

Hi, contact your local Worcester Bosch accredited company. They are CORGI registered and will carry the spares required. Go to the Worcester web site and enter the post code and this will list the engineers. The problem sounds like the diverter valve is not switching to hot water as you cannot get hot water and heating running at the same time on a combi. If the temperature dips when only the shower is on and only when the boiler is running on hot water, then it is a blockage in the plate to plate heat exchanger. This can be cleaned but by the age I would replace if this is so.

Kevin, November 2007