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Andrew Smith
Andrew Smith, HVAC Technician
Category: HVAC
Satisfied Customers: 3756
Experience:  Heating and Controls engineer
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Glowworm 24hxi boiler, flashed F12, reset and boiler worked

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Glowworm 24hxi boiler, flashed F12, reset and boiler worked fine for around 24 hours then started flashing what looked like 88. Reset but boiler did not respond, even the green power-on indicator remainder off, though power is still present at the incoming terminals.

And ideas what the problem could be?

What other checks need to be made?

I am a retired control engineer.


Joseph Moore


Its a tricky fault to get to the bottom off. I'd recommend calling Glowworm for a fixed price repair. Last 2 I had needed pcb but can also be harness or display pcb and not very easy to check.

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We have had a similar thing in the past on these boilers where it has shown f12 but has actually masked a dhw plate to plate exchanger fault, expensive because the changing of the user interface (display) board proved to be not needed but was what glowworm suggested.

JACUSTOMER-14hvzfxl- : Oh dear. Not good news is it? Any idea what the pubs cost?
JACUSTOMER-14hvzfxl- : The Glowworm fixed price repair is around £250 or so isn't it?
JACUSTOMER-14hvzfxl- : Does that cover whatever parts are required to fix the problem?
JACUSTOMER-14hvzfxl- : thanks
JACUSTOMER-14hvzfxl- : Oops! I don't know what happened to my previous reply, so I'll try again.
JACUSTOMER-14hvzfxl- : Have we lost contact?
JACUSTOMER-14hvzfxl- : We seem to have lost contact.
JACUSTOMER-14hvzfxl- : What is going on?
Customer: Maybe I'd better leave this open in the hope that my response is addressed later?

Glowworm guarantee to fix your boiler for a fixed fee of under £200



The PCB is £183+VAT


Customer: Thanks Andrew. I have now arranged for a Glowworm technician fixed fee repair, as you outlined.
Customer: i have also opted for a boiler service too, at the same time.
Customer: Hopefully this will resolve our heating problems, even though it is rather costly.
Customer: thanks for your help.

I think it will give you the best outcome as they will keep putting parts on it until completely fixed

Andrew Smith and other HVAC Specialists are ready to help you
Customer: replied 4 years ago.
Out of interest - the repair took all of five minutes. The Glow-worm engineer replace the main PCB, SYMS17.0, and switched on again - whalla! Everything back to normal (except my bank balance).

Cheers !
Glad it is sorted, it will have cost you less than another engineer fixing it - parts and materials.
And if you have problems in the next 12 months you can call them back for free.