Worchester 24cdi dhw problem

[wobble2]

I have been reading the forum and this problem seems a little different.
The central heating works okay. The dhw is only luke warm when the central heating is off. When the hot tap is turned on the led above the water dial comes on, then the flame light comes on when the burner is lit. When the central heating is on the dhw is pipping hot. The dhw dial is set to 3 . Can anybody help me please.

 

[nickso]

hmm tough one to diagnose form a computer chair.

the fact the dhw light comes on rules out one half of the diverter. the fact the water is hot when CH is on should rule out DHW heatex.

i would be looking at the other half of the diverter or perhaps a thermistor fault.

your best course of action IMO would be to get worcester out to it. they have all the bits they need and you will likely get it fixed first visit with minimum arsing around.

 

[Agile]

I expect the manifold section of the diverter valve is not following the hydraulic actuator.

A simple test is to leave the heating off for two hours to cool down and run hot water for five minutes and see if rads heat up.

If so then the diverter valve needs replacing. Nasty job to do so best to get British Gas to do it as they deserve jobs like that. Its your cheapest option too as their fixed price repair is about £190. If you live in the right place you might even get Nickso!

Tony

 

[jackecole]

Agile - how is the hot water temp OK when CH is on then? I know you're a boiler engineer so was just curious as reading this post?

 

[Agile]

It is not really but just appears to be!

What happens is that when the diverter valve is leaking the boiler heat output is devided between the plate heat exchanger which warms the hot water and the heating system radiators.

The part going to the rads is returned COLD and thus reduces the temperature of the hot water from the primary heat exchanger as only a limited heat is added so the output temperature is not so hot.

When the CH has been on for a while, the returning system water is hot and has little effect on the hot water on the DHW.

Tony

 

[jackecole]

I see. That's very interesting. Thanks for explaining.


How comes they are hard to change then? Very tight/limited space and fiddly?

 

[wobble2]

Agile - how is the hot water temp OK when CH is on then? I know you're a boiler engineer so was just curious as reading this post?

it is as normal

 

[nickso]

If so then the diverter valve needs replacing. Nasty job to do so best to get British Gas to do it as they deserve jobs like that.

wow, bullshit bait.

If you live in the right place you might even get Nickso!

few BG customers are that lucky.

 

[hym]

Agile you really like giving BG a hard time. Suspect you are perfect of course. Do not usually rise to comments but resent being labelled as a poor engineer. Keep your comments to the subject