Potterton Suprima - No hot water but Central Heating ok

A long shot I know but is anyone out there knowledgeable about these boilers? It is a Potterton Suprima 40L

My problem is that the central heating works fine but the hot water, however, doesn't heat up at all. When I turn it on using the wall panel, the red light stays (not a lock out) on and nothing happens, no noise, no anything. It's like the temperature is already what it should be.

What's confused me more though is that the small temperature knob on the boiler unit it turned up and when I turn it down I hear the "click" noise which indicates the current temperature - very low!

As you may have guesed I have the technical know-how of, well, a cabbage so if it is something like the thermister then a point to the right direction to help replace and fit would be massively appreciated!

Thanks in advance!

More info:
System and House is approx 6 years old
Water tank upstairs is a Santon Premier

This is not a boiler problem, but a fault in the control system.
Either the programmer, tank-stat, motorised valve or the wiring.
No. 1 suspect would be the motorised valve.

grahamderek said:

This is not a boiler problem, but a fault in the control system.
Either the programmer, tank-stat, motorised valve or the wiring.
No. 1 suspect would be the motorised valve.

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Are these componants contained within the Potterton unit? re they only replaceable by a certified engineer? British Gas want a £168 call out charge

All external controls.
Treble check the fine print if you deal with B.G.

grahamderek said:

All external controls.
Treble check the fine print if you deal with B.G.

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Sorry for being such a dunce, do you mean on the Suprima upstairs or under the white box of the Potterton unit.

BG seemed bizarre - it was an indian call centre and she was saying all parts, no matter what, was included. I strongly doubt that! Then she said it it was going to be prohibitively expensive, or couldnt fix, then there would be no call out fee. Contradictions aplently!

All that will need replacing is the motor in the dhw zone valve BG offer a pixed price repair as stated inc call out parts & labour. The call centre is not in india more likely the leeds or leicester one with asian staff

weareleeds said:

All that will need replacing is the motor in the dhw zone valve BG offer a pixed price repair as stated inc call out parts & labour. The call centre is not in india more likely the leeds or leicester one with asian staff

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I had the same problem a few years ago. Bought a new sychron motor from Wickes I think (about £14), fitted it in about 10 mins. Just a case of removing the cover from the zone valve and replacing ther motor - just make sure you turn power of first!!!)

weareleeds said:

All that will need replacing is the motor in the dhw zone valve BG offer a pixed price repair as stated inc call out parts & labour. The call centre is not in india more likely the leeds or leicester one with asian staff

Click to expand...

Same effect if you cannot understand them and they dont give you the right information!

This is likely to be a very simple repair which an independent should do much cheaper than BG. In our local area we would charge about £118 if it only needs a new motor and that includes a basic boiler check.

Tony