Vaillant boiler doesn't respond to thermostat

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Hi there,

I have a VAILLANT EcoTec Plus VUI 246/5-5 (H-INT II) that I control with vSmart app.

The boiler reacts heats water per schedule, reacts to commands from the app - I just switched off the summer mode (as in no heating) and the summer mode icon disappeared.

The problem is that the boiler doesn't react to temperature changes. The app's front page does display the desired temperature - but that detail misses from the heating graphs. In fact, it disappeared from the history altogether.

The apps shows that the boiler is operational but it's not. I restarted the relay, the thermostat, turned the boiler off and on. No change.

I'm at my wits end.

Any advise appreciated.
 
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I have vSmart but a different boiler, I may be able to help…. Some questions:

Has it ever worked correctly?
When vSmart is requesting CH to be on, does a radiator symbol show on the boiler display?
Are any F.xxx or S.xxx codes displayed on the boiler?
Do you have one or two motorised valves? Is the one for CH moving?
 
@UpgradeME, thanks for the reply.

Yes, it did.
Yes but it does not flash - passive display = heating regime on, flashing = actual heating on.
No.
No idea.

Having said that, I disabled smart features (predictive and advanced operation) and the boiler began its CH work. So far so good.
The thing is that the heating graph is still empty and has no record of any operation today. In the past, that would be updated immediately.

At least I have heating for now.

Will try manual override tomorrow - increase the temp outside of the scheduled hours, to see if the boiler responds.
 
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The thing is that the heating graph is still empty and has no record of any operation today. In the past, that would be updated immediately.

FWIW, I’ve just checked my vSmart app and the graph shows the temperature recorded for today and a couple of small bars at the bottom for boiler use.

If you scroll left, when was the last time it was recording temps on the graph? Did anything change at that point? (I think all that data is stored on Netatmo / Legrand servers (the actual OEM for the vSmart) - re-linking your account to the thermostat may help if it’s not recording correctly!?
 
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