Vaillant 824E - error code S30 no heating

Hi guys,

Sorry if this topic has been already discussed (and I've certainly seen it several times) but even after reading different threads I can't get my boiler to work.

Here is the situation:

Hot water operation is fine, all other relevant functions (i.e. warmstart, etc) with HW system are working.

Heating operation only works when forced manually by pressing "+" and "-" simultanously (in SF.h mode).

The status code I'm getting is S.30 so no heating demand.
Boiler is connected to UFH heating manifold with thermostat on the pipe. In SF.h I can heat the pipes easily.


Things I've done so far:
- checked the manual and disconnected any external thermostats (now pins 3 and 4 are linked).
- both 3 and 4 have power while 5 remains neutral
- checked other boiler operations (like HW and SFH) all works ok
- checked the temperature dial setting for heating and turned it max right (open)

Now as I would really like my boiler to be a little bit more automatic and heat my radiators up without me (by doing so in SFh mode) I'm really keen to get this one down.

Did anyone seen an issue like this or can point at something I'm doing wrong?

I would really appreciate your help and advice.

S.30 means no call from external controls, ie no live on terminal 4. put a link between 3 & 4 and press the i button again.

Still S.30 displayed? - Then the CH control knob is broken in the switched off position.

Thanks Beerlover for reply.

Unfortunately still S.30. As for the knob that is an interesting idea which I shall pursuit tomorrow.

I'm going to install Heatmiser UH1 wiring centre into this boiler to see whether this will force it to work.

Simple to check turn the knob and watch the display, if it doesn't change the knob is broke

Maybe I'm missing something. What do you think I should see (apart from the temp in the system and status code) after turning the knob?

I can't see anything changing on the display by turning either of the knobs.

Hi all,

I realise this is an old thread but I've just looked at an Ecotec Plus 618 R1 that has the same issue. Live on 3 & 4 but S30 showing in the display. Sometimes the boiler will fire and sometimes it won't but always has live on 3 & 4. I'm thinking something breaking down on the PCB perhaps ?

Knappers said:

Hi all,

I realise this is an old thread but I've just looked at an Ecotec Plus 618 R1 that has the same issue. Live on 3 & 4 but S30 showing in the display. Sometimes the boiler will fire and sometimes it won't but always has live on 3 & 4. I'm thinking something breaking down on the PCB perhaps ?

Click to expand...

If the heating dial/knob on the front has been looked at and you're definitely getting a switched live return (terminal 4) then I'd say very likely the PCB, as it's not seeing the demand.

Yeah, that's my thinking. The control knob is definitely working okay as the temperature display changes when I turn it up and down. It's such an intermittent fault that I reckon it must be the PCB. I've got a SH one I can try just to prove the point before I throw a new one at it.

Knappers said:

Yeah, that's my thinking. The control knob is definitely working okay as the temperature display changes when I turn it up and down. It's such an intermittent fault that I reckon it must be the PCB. I've got a SH one I can try just to prove the point before I throw a new one at it.

Click to expand...

That’s what I would do if I had a SH one. We carry a van stock of them so would use new.