Vaillant 831 Ecoplus is weather compensation worth going for?

[Goinker]

Hi all.
About to go for a Vaillant 831 Ecoplus combi, and wondered if it was worth going for the weather compensation option. It's going into a 1920's 2 bed detached bungalow, with cavity insulation, full uPVC double glazing and 12" of loft insulation, so that's as good as it's going to get insulation-wise, I reckon.
System has 3 single rads, 4 double rads, 2 towel rails and a Myson kickspace heater on it, recently been chemically cleaned and inhibitor added, Spirotech and Salamander anti-scale also fitted, as I've been working towards replacing the old WB 230 RSF. Thing is, is weather compensation more trouble than it's worth, considering that I gather the kit costs around £250, so it may take a while to win that back in terms of gas savings despite recent price increases? The boiler is going on a North facing wall, so it's ideally situated for the sensor position, but is this the kind of technology that needs someone with a degree in electronics and a fancy laptop to set up, or is it simpler than that? Anyone out there with any relevant experience on weather compensation, preferably, but not necessarily on Vaillants, your help and/or comments would be appreciated.
Thanks in advance, Guys.

 

[diamondgas]

I've had experience of it on commercial installations, mainly negative; shutting down the heating prematurely. It's a bit overkill for small systems I'd personally think. However you could fit the 'intelligent' room stats that have optimum start facility! They Alter the timing according to the conditions in the room they're fitted in.

 

[bengasman]

Weather control takes 2-3% off the gasbill if the boiler is installed correctly and a bit more if the balancing is done wrong. If you add up what you spend on gas per annum and add up what the cost of supply and fit of the weather control is, you can work out for yourself if it is worth it or not.

 

[tackleburger]

Well a decent programable room stat will rush you £80 anyway manufactures ones a bit more and RF ones more again. The Vallant VRC 430f is about £180 and is plug and play and easy to set up. Some weather comp systems are a bit primitive and the savings are negligible but not with the Vaillant or the Viessman 200 series. I offer it on most jobs especially large ones where the savings will be significant. The facts are it saves money and is certainly worth having. If you have a large open plan living area you can bin the TRVs downstairs for a start and having weather comp means your boiler is vitually guaranteed to be in condensing mode for much longer that it would be otherwise due to cooler return temperatures, on smaller systems such as yours getting a return temerature below 58 degrees is difficult so weather comp will do it for you. I usually leave off as many TRVs as possible when I fit it as it is that effective. Doing so also contributes to the cost of it.

My bet is it will become part of the next set of building regs.

 

[diamondgas]

Thanks for the info tackleburger. Whether comp was around when I was installing some 15+ years ago and you needed a degree in electronics to fathom it out! As I said in my first post I've had experience of the negative side with commercial more times than I care to mention especiially around the transition from spring to summer, autumn to winter. I wonder if it'll benefit the smaller installations and also whether it'll give the same sort of grief at similar times of the year for domestic installations?

Good post though and very informative... Cheers!

 

[Goinker]

Thanks for your opinions/experience guys. I have TRV's fitted in all except 1 room, so are you saying I should remove all or most of them Tackleburger? I'll probably go for the basic system initially (intend fitting a Vaillant wireless programmable room stat anyway) then look at weather compensation as an 'add-on' when I find out the level of gas savings (if any!) over the existing WB 230 RSF. Nice to find a favourable comment for weather compensation anyway, but as I'll be retiring next year, I have to think in terms of making the pension go as far as possible, so weather compensation may be a 'speculate to accumulate' proposition rather than a wasted money 'impulse purchase'. Grateful for your input Guys.
Cheers.

 

[diamondgas]

You are welcome 'Goinker' .. enjoy retirement!

 

[Blackcatgas]

I will always try and spec it if fitting a 200 series Viessmann, the problem is that people will then ring me up and say that the rads arent getting red hot, Il then try to explain to them for the 4th time that is how it should be and if they check the temp of the room it will be for eg 21deg (depending on the heating curve set) so although the rads are not hot to the touch the actual room temp is correct.