Vaillant controller vSMART vs sensoHOME RF vs sensoCOMFORT RF for replacement boiler

[DundeeDancer]

I’m starting to plan on replacing the aging boiler in my 98m2 apartment, which is a Worcester Bosch 35CDi commissioned in about year 2000. The Bosch is around 80% efficient even though it is not a condensing boiler. I’m not sure if that efficiency drops with age but the water pressure within the system is getting a bit erratic, when the CH is on it goes from 1.1 bar up to 2.3 bar and when the system cools down the water pressure drops down by 0.5 a bar over a week, so I need to keep topping up from mains feed. Over the summer the water pressure has been fairly constant when only using the shower but now the CH is coming on more the pressure is dropping more, hence the research into getting a new boiler.

 

Currently need a big boiler as apartment only has 25mm of Polystyrene sheeting for insulation in the cavity and brickwork seems fairly porous which lets the wind chill the walls.  Planning on getting the other 18 residence to sign up to filling the rest of the cavity with Polystyrene beads but when we get around to it is anyone’s guess.

 

So I'm currently thinking on a Vaillant ECOTEC PLUS 832, seems a really nice boiler. I like that it's a bit quieter than others, seems to have good modulation and the stainless steel heat exchanger will likely last a long time.  The ecoTEC 835 exclusive Green iQ also loks good but not sure why it is approx. £300 more expensive and what real benefits it would bring.

 

I’m also confused on what controller would give me the best efficiencies and how they really stack up in price comparison once all the separate components, hence the question around:-

“Vaillant controller vSMART vs sensoHOME RF vs sensoCOMFORT RF”. My gut feel is that vSMART gives most bang for buck but it doesn’t look as pretty as new senso controllers. 

 

I have a pipe dream to one day put underfloor heating into this apartment run from this replacement boiler so the sensoCOMFORT controller may be best for that plan but with the insulation in the flat being so poor, underfloor heating seems a lifetime away at the moment.

 

Also feels strange to be thinking about a replacement gas boiler when there is so much talk about heat pumps or hydrogen boilers these days but the reality is I need a good boiler for the next few winters until the insulation gets sorted out. So a good gas boiler with good modulation seems the best answer for the moment. Mind you the installation quotes are coming in at around £3K which seems high for fitting a £1,200 boiler but that might just be the going rate these days.

 

Any comments appreciated. Esp from Boiler super hero @ Nickfromwales

 

Thanks DD ?

Edited September 1, 2021 by DundeeDancer

[ProDave]

The erratic pressure is probably a sign of the expansion vessel bladder having failed or needs pumping up.  When was the last time a plumber serviced the system including checking the expansion vessel?  It seems you are choosing the wrong reason to replace a boiler that probably has a simple fix?

[Dan F]

Vaillant top of the range controller is the "sensoCOMFORT" (VRC720).  There is a wired version and a wireless version.  The wireless version allow for outside temperature sensor, main control panel and remote thermostats to located more freely.  For remote control from Vaillant app, or for integration via EEBus, you need to also add the sensoNet unit.

 

The sensoHOME is a slimmed down version of the sensoCOMFORT which has the core functionality, but doesn't support as many heating circuits or weather compensation with more than one circuit etc.

 

If you want to ensure you get best efficiencies out of the system, I'd recommend you use a Vaillant wiring center (e.g. VR71) which allows you to setup mixed circuits meaning Vailant can use a configured heating curves and weather compensation to automatically adjust the flow temperature to optimize efficiency.

 

You can play with the controllers here:

https://simulator.vaillant.com/vrt380/gb/#/setup

https://simulator.vaillant.com/vrc720/gb/#/setup

Edited September 1, 2021 by Dan F

[DundeeDancer]

14 hours ago, ProDave said:

The erratic pressure is probably a sign of the expansion vessel bladder having failed or needs pumping up.  When was the last time a plumber serviced the system including checking the expansion vessel?  It seems you are choosing the wrong reason to replace a boiler that probably has a simple fix?

 

Yes I’m coming to the same conclusion that it is the expansion vessel that is playing up. The boiler is serviced by British Gas at £240 a year with a £99 excess charge for any required fixes. BG did a good service just over 2 years ago but the last service about 2 months ago was a contractor brought in due to covid absentees, by the time I got off my work call he was all packed up and when I mentioned the changes in water pressure he said he couldn’t see anything but if it worried me then to raise an investigation call…hhhmmmm

 

The Expansion Vessel part number 87161425060 is obsolete on heatingspareparts.com  but available at plumbase for £82. So stock for this model of boiler seems on the way out so that’s another consideration on replacing the whole boiler.

 

We seem to go through 20,000 kWh of gas each year, a new boiler with smarter controls and thermal values attached to all radiators we might be able to save 20% on gas use, which would currently be a yearly saving of £153. Couple that with reduced maintenance cost of having boiler serviced by an independent with Vaillant 10 year warranty that is another £176 saving a year. So the £3,500 installation would pay for itself in just over 10 years.

 

I had hoped to get in front of the cold weather rush for replacement boilers but I’m getting the feeling there is a big demand for boilers now as it took my trusted installer much longer to respond. Previously I had installed in 2018 a Vaillant with vSMART controller in a flat I let out and it seems a nice set-up but this time the installer hasn’t yet given me options on different boiler makes and controllers like they did last time so doing a bit more of my own research now.

 

I’m going away on holiday for a long weekend this coming weekend to Sunny Stonehaven, that will give me a bit of thinking time. After that I’ll probably just get BG in to fix the Expansion Vessel and live with the boiler for another year or 2 and then get one fitted outside of the busy months so I get a good installation completed.

Edited September 2, 2021 by DundeeDancer