Combi boiler problem - yes it's an Ideal Isar HE30....

Bowerleigh24 · 26 Jan 2020

Hello all

I've got a problem with my boiler and I'm skint so not currently in the market for a replacement!

It's firing fine, the boiler's warming up, but I'm not getting any heating or hot water coming through. I've checked the diverter valve head and it seems to be working (replaced not that long ago in any case). If I let it run then eventually I get a H3 (thermistor) code, but I guess that could just be indicative of the problem, rather than the problem itself.

Any thoughts please?!

TIA

JJ

CBW · 26 Jan 2020

I take it you’ve got pressure in the boiler? You said the head seems to be working, it may have failed. What happens when you call for hot water (open a tap)? Does the display show D? What happens when you call for heating? Does the display show C?

Bowerleigh24 · 26 Jan 2020

Thanks The Novice

Yes there's 1bar in the boiler.
The display doesn't get past D - presumably the pre-heat for the plate heat exchanger? When I run a tap it stays cold. Heating is on, but the system never gets as far as C...

Wondering if I should isolate the CH and see if that gives me DHW....?

ianmcd · 26 Jan 2020

Bowerleigh24 said:
Thanks The Novice

Yes there's 1bar in the boiler.
The display doesn't get past D - presumably the pre-heat for the plate heat exchanger? When I run a tap it stays cold. Heating is on, but the system never gets as far as C...

Wondering if I should isolate the CH and see if that gives me DHW....?

D is a demand for HW the HW pre-heat is a different symbol, like a capital E with no top Horizontal bar, or a capital F upside down if you like

Bowerleigh24 · 26 Jan 2020

ianmcd said:
D is a demand for HW the HW pre-heat is a different symbol, like a capital E with no top Horizontal bar, or a capital F upside down if you like

Thanks I didn't realise that. Well it's giving D, but no hot water's coming out... Can't find anything out there to give a clue, frustrating!

ianmcd · 26 Jan 2020

I have tagged @shambolic for you he will see your post and may be able to help you out, but remember we can not give gas advice as it is against site rules

CBW · 26 Jan 2020

Bowerleigh24 said:
The display doesn't get past D

It won’t go past D whilst running hot water, as you’ve learnt. What does it display whilst idol? (No demands)

Bowerleigh24 said:
Heating is on, but the system never gets as far as C...

You say the heating is on, but doesn’t get as far as C, what does it display whilst heating on?

Bowerleigh24 · 26 Jan 2020

The Novice said:
Any dripping taps?

You say the heating is on, but doesn’t get as far as C, what does it display whilst heating on?

No dripping taps.

Sorry if I misled you - the heating isn't 'on' as such - I mean that there should be demand for CH - or would be if it could get that far. Right now it fires up, sometimes shows C for a few seconds then goes to D, or goes straight to D. Heats for a minute or two (turn on hot water tap, comes out cold), burner casing gets REALLY hot, then L3 and switches off.

Pump?

Bowerleigh24 · 26 Jan 2020

Bowerleigh24 said:
No dripping taps.

Sorry if I misled you - the heating isn't 'on' as such - I mean that there should be demand for CH - or would be if it could get that far. Right now it fires up, sometimes shows C for a few seconds then goes to D, or goes straight to D. Heats for a minute or two (turn on hot water tap, comes out cold), burner casing gets REALLY hot, then L3 and switches off.

Pump?

By 'burner casing' I guess I mean the CH heat exchanger...

CBW · 26 Jan 2020

I’ve looked it up in the manual, and mentions the thermistor and pcb. My advice is to perhaps get an engineer in who is familiar with this type of boiler and get it repaired. Also Shambolic may shed some light on it @ianmcd tagged him into the post.

Bowerleigh24 · 26 Jan 2020

Thanks, yeah so that flow diagram too. Thing is, my instinct is that the thermistor is just doing it's job and cutting things off when they start to overheat. I guess PCB would be the low hassle solution, pretty cheap to get replacements too.

FWIW, the CH flow is slightly warm, return is stone cold - why does that make me think 'pump' and how do I test it?

CBW · 26 Jan 2020

Bowerleigh24 said:
why does that make me think 'pump' and how do I test it?

because you’re not an engineer or familiar. As I’ve said it still could be diverter, although you usually have heating or hot water.

Bowerleigh24 · 26 Jan 2020

The Novice said:
because you’re not an engineer or familiar. As I’ve said it still could be diverter, although you usually have heating or hot water.

Yep, that'd be a good enough reason for sure! Re diverter, I'd hoped it was that because it seemed pretty straightforward to fix, but like you say, would a faulty one not always give me one or the other?
Hope to be able to get an engineer out tomorrow.

ianmcd · 26 Jan 2020

The pump wouldnt cause the display to show D

Bowerleigh24 · 26 Jan 2020

ianmcd said:
The pump wouldnt cause the display to show D

But might a failed pump not cause the appliance to overheat, causing L3?

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Combi boiler problem - yes it's an Ideal Isar HE30....

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