Vaillant Ecotec plus 630 system boiler random heating coming on

[j_s]

Current and very new setup is Vaillant EcoTEC Plus 630 System Boiler

Controls

Vaillant Senso Comfort RF Pack (10036826)

Vaillant VR940F / MyVaillant Connect (10037346)

Vaillant weather comp module

 

Had some weird teething issues with it in that a while back when we had a cold day or 2 in September the heating came on when the wireless Sensocomfort control had heating set to off. It didn't do it after the outside temps went up again so I thought nothing of it, did mention it to installer but he has assured me it's all fitted as per instructions. 

Fast forward to the last couple of weeks and now it's more heating season, the heating is overshooting the set temperature by up to 4c and heating is still on and off after that. Heating goes off when it reaches the end of the schedule at night and appears to be off over night, rads are cold when I go to bed late anyway and I have randomly checked the boiler if it's on or not.

 

I spoke to Vaillant today and they don't seem to know why apart from told me to get installer back but he is adamant it is set up correctly, Vaillant told me to change the external temperature switch off to 99c which makes no sense to me so doesn't fill me with confidence. It did seem to stop the heating within seconds of that but then came on a while later. I've then switched heating to off via the Sensocomfort which turned it off for the last 5 hours but it's come on again just now and internal temperature is still 3.5c above the desired set temperature.

 

I've got a 0.7 heat curve on it and the flow temps are inline with the curve. 

 

There doesn't seem to be a way of seeing what triggers the boiler and it is in heating mode. All settings seem to be as they should be but something is triggering the heating and I'm at a loss as to working out what is. If I go in to the installation menu on the boiler itself there is nothing there in terms of settings without triggering a setup wizard which I'm staying away from.

 

Don't get me wrong it's a nice very warm house but it's a complete waste of energy and money, I prefer it cooler then dial it up if needed.

 

Thank you.

 

 

 

Edited November 19 by j_s

[Lofty718]

I have the same boiler and controls and know them like the back of my hand. Many installers don't understand them very well they just bodge it and scarper

Post your installer menu settings. I run a curve or 0.3 for radiators

 

What is your setup like, radiators only? UFH? Unvented cylinder? Is it running on PDHW?

[j_s]

Hi Lofty. thanks for getting back to me. I've figured it out now thanks to a follow up call with Vaillant. Room temp mod was set to inactive. From what I understand this will ignore the scheduled desired temp completely when reached, this seems to be the case as per reading

 

https://protonsforbreakfast.wordpress.com/2024/10/18/vaillant-heat-pump-controls-part-2-room-temperature-modulation/

 

I have radiators throughout in 1 zone only for whole house. 

 

Unvented Newark "Heatgeek" cylinder set to priority I believe, that is scheduled for 5pm daily to 48c with a legionella cycle every Friday at 5am.

 

I have now set room temp mod to expanded and this has got the system running to how I want. I've notified the installer of this.

 

I have the setback temp higher now at night and leave the daytime time set to what I want for the entire day.

 

The house is never going to be super efficient unfortunately, but a lot of time and effort has been made by me to get it performing to the best it can, Triple glazing, mvhr, airtight in most places with 2 rooms remaining to be worked on but both have the window reveals properly sorted now so thermal bridging is much reduced.