Vaillant Arotherm+ DHW Eco mode?

Hardware
1

Hi new Vaillant Arotherm+ 5kW owner.

I was reading Mick Wall’s energy-stats article about DHW modes.

I think my system is already using DHW Eco mode as there is an E on the default display of the

VWZ-AI controller. Is that the case ? Anyone confirm ?

Will save me mucking around in installer mode if so.

Also Flow rate shows 860l/hour which is the maximum I think.

Does the internal pump stay on this all the time when system is working ?

Thanks,

Nick

3

Fixed it for you, Nick.

4

Bill. Sorry, you fixed what ?

Nick

5

Ah I see you changed min to hour.

Thanks,

Nick

1 Like
6

860 isn’t the maximum, it’s the optimum flow rate for 5kW and DT5.

Just head into installer menu and be 100% sure looking at DHW Mode config.

7

Thanks Mick. Yes eco mode.

Whenever I look at the Live Monitor in VWZ-AI it reports building flow rate as 860l/hr.

In the Vaillant Spec sheet for 5kW (March 2025) it says:

Maximum volume flow l/h 860

I thought you only get DT5 at design conditions? Maybe I misunderstood ?

It is cold, but nowhere near that yet.

I was sure I saw Szymon on Urban Plumbers video a while ago talking about not having the

circulation pump maxed out for wear and tear issues.

We have a 4 port 30l buffer tank here, so maybe commissioned different to yours.

Cheers,

Nick

8

Ha ha. After some reading I think I was misunderstanding.

When heating Arotherm Plus runs at constant flow rate (860l/hr) and adjusts the flow temperature according to the compensation curve (if set correctly) to match the heat loss at a given outdoor temperature ?

No feedback for Room temp mod = Inactive so you need to set the curve correctly.

Now it makes sense.

Nick