Vaillant eRelax/vSmart app chart - "Heating operations"?

[Matthew Butt]

We've basically got to grips with the Vaillant vSmart app, but there's just one thing that puzzles us. When you view the charts, what do the "Heating Operations" bars actually represent? They're shown as percentages, but this doesn't relate to the flow temperatures on the boiler in any way. For example, the bar might show 100%, but when you look at the boiler it's running at something like 46°. There's no Vaillant documentation that we can find that discusses this. It's a shame the flow temperature can't be shown on the chart, as that would be more meaningful to us.
Here's a screenshot:

 

[Chuck]

I don't 'know' the answer because you haven't provided model numbers but my guess is that you have a TPI thermostat and a condensing boiler with a 20°C delta T limit set. If I've guessed correctly:

The black line is the system thermostat setpoint (i.e. desired) temperature.

The dark green line is the room temperature measured by the thermostat.

The green bars are the proportion of the time the thermostat is demand is 'on'.

When the system is relatively cold and the thermostat is constantly demanding heat (100%) I infer that your return temperature is 26°C, which would limit the flow temperature to be 46°C. The flow temperature will rise as the return temperature does.

As you can see, it takes a couple of hours for the system to come up to temperature but once it's there it's regulating quite nicely. It's possible that the circulation rate on the system is a bit low and/or the the radiator lockshields have been screwed down a little too far and a smaller temperature drop drop ('delta T') across the radiators would help.

Impossible to be sure without further information and measurements, but a good heating engineer should be able to sort you out without difficulty.

 

[Riley]

I’m guessing Vaillant and vsmart which is their own internet stat

 

[Matthew Butt]

Yes, Riley, you guessed correctly.

Just for completeness' sake, it's Vaillant's own vSmart thermostat, connected via the Vaillant VR66 wiring control centre to a Vaillant ecoTEC Plus 624 system boiler.

Thanks, Chuck, for taking the time to provide such a detailed reply. Our system's only been up and running with the vSmart control for just over a week, so it's in the middle of its 2-week initial learning phase. For that reason, we don't want to make any changes to system settings until the 2 weeks are up.

As I say, we're just puzzled by the "heating operations" bars on the graph, which don't appear to correspond either to the boiler temperature or the burner level (as displayed on the boiler itself)...

 

[Chuck]

As I say, we're just puzzled by the "heating operations" bars on the graph, which don't appear to correspond either to the boiler temperature or the burner level (as displayed on the boiler itself).

Like you, I can't find any (public) domentation for this value but you could try emailing Vaillant tech support:

Technical Help

to see if they'll find out for you. As I said above, based on the rather small sample of data you provided, it looks to me as though it is just the proportion of time that the boiler is 'in operation', i.e. supplying heat (burners on) to the system, which is something the vSmart controls and hence knows about. AIUI, the ECO Tech Plus 624 dates from about decade ago so I wouldn't expect it to transmit data such as flow and return termperatures or burner power back to the vSmart. You'll have to use the boiler display, or thermometers, for that sort of info.

I suggest you treat these charts as a bit of fun. However clever the 'app' is, it's not going to change the heat losses from your house or what temperature you need to feel comfortable and match your life style. Unfortunately, it's these things that need to change if you want to save energy.

 

[Matthew Butt]

Thanks, Chuck. As you say, the main thing is setting the stat so that we're comfortable. We did ask Vaillant for some clarification about something else and they were very helpful, so I can certainly go down that line. I just wanted to check with you knowledgeable folks first.

 

[DIyMark_london]

The VSmart is made by Netatmo and is functionally identical PLUS it adds in modulation of compatible Vaillant boilers