Vaillant EcoTEC pro 24 - S0: No heat demand?

[techno12]

Hi.

So, I've fired up my 15-month old Vaillant yesterday, as it's getting a bit cold. First time since March that I've had the heating on.

However, it doesn't really do anything.

It makes the usual noises when I manually switch the CH on (via the attached Nest heatlink's button - just to eliminate any issues with the Nest wireless thermostat itself), then goes silent and there's no heat coming from any of the pipes exiting the boiler. DHW is fine.

Looking at Live Stats the sequence is

S2 (pump running)
S3 (ignition)
S4 (burner ignited)

the above takes 30 secs, and the boiler is making noises.

Then it goes to

S7 (pump overrun) for five minutes, and finally

S0 (no heat demand) forever.

Any ideas? As predicted, the original installer doesn't seem to be interested (can't get in touch with him, he's not answering) so I guess I'll have to phone groupservice.

PS When I switch off the thermostat it reverts to S30 (no heat demand: controller) which I assume is normal?

Many thanks!
Tony

 

[techno12]

Just a follow up in case anyone has a similar issue.

The valves were closed on my Adey Magnaclean! (I'd had the boiler serviced and Magnaclean cleaned a couple of months ago. I guess the guy forgot to turn the valves back on. Doh!)

Good job Vaillant were slow answering the phone earlier, as I gave up and had a little think "what's changed since I last switched the heating on in March"