Vaillant Weather Compensator

[Nightglow]

Got a Vaillant 824 combi boiler, thinking about fitting a VRC 470f Wireless Weather Compensator, only takes a few minutes to fit, as it just plugs in.
And I need to make slight change to wiring, as I'm removing old programmer.

Anybody got a weather compensator on their boiler, do they notice any benefits,or disadvantages with them.

Trying to get some idea of any additional savings you can make by fitting one.

 

[Tinders]

Im assuming this uses an outside temperature sensor? It would be interesting to see what the findings are. Ive seen outside temp sensors on commercial boilers work well, but thats a bigger boiler with a bigger burner (ie greater turndown ratio) so better modulation.

 

[Derek W]

I've specced some for new housing that we're doing (not on that type of Boiler though) and in the SAPs calculations, from memory, there is about a 1/2 kg saving of CO2 emissions per year. I know that's pretty meaningless but its the best info i can provide!

 

[Nightglow]

Im assuming this uses an outside temperature sensor? It would be interesting to see what the findings are. Ive seen outside temp sensors on commercial boilers work well, but thats a bigger boiler with a bigger burner (ie greater turndown ratio) so better modulation.

Yes it has a wireless outside temperature sensor/transmitter, no batteries, as it has a solar cell to power it.

The only problem I got, is you need to get the central heating flow return temperature set up right.

Reading through the installation manual, you can fit a second remote sensor (VR81/2), & set up a one zone or two zone heating system, plus many other options.

 

[Firestar_3x]

My Parents have just had a 937 fitted, i wanted them to fit the Weather Compensator, but after reading some forums online it seems like too much messing around for would could be little saving.

 

[Nightglow]

My Parents have just had a 937 fitted, i wanted them to fit the Weather Compensator, but after reading some forums online it seems like too much messing around for would could be little saving.

Agree a bit of initial setting up, but I still think it will be worth doing.

There are days like today, it's fairly mild, & the heating is on, could quite easily manage without the heating during the day time, but it's too much hassle changing room stat, or trv's every day to suit the weather.

I wish I can find some hard facts about savings that could be made, if I fitted one, Viessmann claim you could save up to an additional 20% on your yearly fuel bill.

 

[Firestar_3x]

There are days like today, it's fairly mild, & the heating is on, could quite easily manage without the heating during the day time, but it's too much hassle changing room stat, or trv's every day to suit the weather.

I wish I can find some hard facts about savings that could be made, if I fitted one, Viessmann claim you could save up to an additional 20% on your yearly fuel bill.

True, I'm shocked by 20%!!!!

Parents have a Vaillant engineer comming out tomorrow (new boiler has an internal leak after an hour of running) Will get them to ask about potential savings, see if engineer knows any hard facts / links.

 

[Nightglow]

True, I'm shocked by 20%!!!!

Parents have a Vaillant engineer coming out tomorrow (new boiler has an internal leak after an hour of running) Will get them to ask about potential savings, see if engineer knows any hard facts / links.

A leak!, most unusual with a Valiant.

Will be interested to know whether he anything about savings.

 

[Dangerous Dave]

I have the 470f with a Vaillant 630 boiler and unvented cylinder, the main reason was it works well controlling the hot water cylinder compared to other 3rd party controllers and I needed the zone control.

I got it all fitted at the same time so I can't give a figure on what it has saved but the installer said a realistic figure is 3-5%, this is only really in the days where the outside temperature is in double digits as this is when the system is keeping the flow temperature low allowing the boiler to remain in condensing mode for longer period where the boiler is most efficient.

It has various heating curves that can be set to control the flow temp depending on the outside temperature, I have been experimenting and down to heating curve 2.5 with good results. The whole system has knocked 30% off my gas bill compared to my old combi boiler and this is before I have even activated the summer detection function where it turns the heating off when a target outside temp is reached.

 

[Nightglow]

I have the 470f with a Vaillant 630 boiler and unvented cylinder, the main reason was it works well controlling the hot water cylinder compared to other 3rd party controllers and I needed the zone control.

I got it all fitted at the same time so I can't give a figure on what it has saved but the installer said a realistic figure is 3-5%, this is only really in the days where the outside temperature is in double digits as this is when the system is keeping the flow temperature low allowing the boiler to remain in condensing mode for longer period where the boiler is most efficient.

It has various heating curves that can be set to control the flow temp depending on the outside temperature, I have been experimenting and down to heating curve 2.5 with good results. The whole system has knocked 30% off my gas bill compared to my old combi boiler and this is before I have even activated the summer detection function where it turns the heating off when a target outside temp is reached.

30% Off your gas bill!

 

[Dangerous Dave]

30% Off your gas bill!

Yeup surprised me I expected 10-15% especially as I was moving to storing the hot water. Although my old boiler was a 23 year old Worcester Highflow 3.5 and going by the power plate on it when new only 75% efficient it also had a small water store that wasn't very well insulated making the boiler fire up once or twice a night to maintain the temperature.

 

[FlyFifer]

I was a heating engineer on industrial size building maintenance which all had heating compensators of one sort or another plus zoning capability on the larger installs. All had balancing valves on the flow & returns to get the 11 degrees differential required to get best results from using outside temp sensor along with room/area stats & rad stats. Personally I don't think there would be a lot to gain fitting this type of control to a domestic system of average 8/9 rads plus hot water but, as in my own house, I have 16 rads plus stored hot water & may be beneficial. Have recently zoned upstairs bedrooms from downstairs living space with 2 x programmable room stats & another heating zone valve. Heating is on 24 hours at C/H clock in kitchen with all other timings & set back heating temp controlled via the room stats alongside rad stats. My gas bill has remained constant past 3 years with each year having additional controls fitted. Next year is going to be remote wireless programmable rad stats individually time & heat setting controllable from a hand held main controller with up to 12 zones available. I don't have a condensing boiler nor is it a sealed system but just having ability to zone, time & have set back temp control has saved me at least the increase to gas prices past 3-4 years. An outside temp sensor/compensator has to be installed in a location suitable for it's purpose & may not be easily achievable in a domestic dwelling hence my reluctance to go down that route though may be my final "fix" in a few years time.

 

[Firestar_3x]

A leak!, most unusual with a Valiant.

Will be interested to know whether he anything about savings.

He said it's too variable depending on the property, many people don't know how to set the system up correctly, however he quoted around 15%.

In other news the Vaillant engineer fixed the leak (badly installed washer from the factory), he replaced the whole assembly rather than just the washer, boiler worked till rads hot, engineer left, boiler started to leak internally again.

Not impressed, considering this is Vaillants best model they offer, the plumbing centre won't exchange the boiler, and Vaillant simply say they won't replace just come out as much as needed till fixed.

Bit rubbish really.

 

[Nightglow]

Crap engineer, Crap boiler.

Speechless!

I would always put ch full on & check system is fully working & leak free.


Trading standards see what they say, have you got to except a new boiler to be repaired, or can you get a new replacement, as it's unfit for it's purpose?

 

[Dangerous Dave]

Two Vaillant installers advised me the 937 is not a great boiler and you are better getting the 838 the main reason being despite quoting 20l a minute hot water flow the 937 still has a 15l/min flow restrictor (same flow rate as the 838) and to get the quoted 20l/m you need a mixer at the boiler to blend cold water in. They also advised it is not a very reliable boiler due to the internal store electronics/pipe work, a quick google search seemed to confirm this.

 

[Mickie]

I find the best way of saving money on gas, is not using it.

 

[budwozza]

I find the best way of saving money on gas, is not using it.

A good way to save electric is not to post on forums!

Did the Vaillant engineer run the boiler at max to test it? Shocking that it's still leaking, has it caused any damage (wall, floor, carpet ect)?

 

[Firestar_3x]

Second engineer sorted the problem, O rings and a plastic fitting are common problems on the 937 during commissioning, so he's replaced the plastic part with a brass fitting and went through the rest of the boiler, the first engineer did indeed stay till the heating fully warmed up.

All is well and running great, no damage due to the boiler being in a utility room, floor is tiled too.

Bit shocking when Vaillant have a good name, you really don't expect something which has gone through QC and should have been pressure tested to have this happen.

Oh well, least the warranty support is spot on.

Next thing to deal with is this boiler should have a 5 or 7year warranty depending who fits it, the card in the boiler box is only for 2 years.......

 

[Predators222]

I have the 470f with a Vaillant 630 boiler and unvented cylinder, the main reason was it works well controlling the hot water cylinder compared to other 3rd party controllers and I needed the zone control.

I got it all fitted at the same time so I can't give a figure on what it has saved but the installer said a realistic figure is 3-5%, this is only really in the days where the outside temperature is in double digits as this is when the system is keeping the flow temperature low allowing the boiler to remain in condensing mode for longer period where the boiler is most efficient.

It has various heating curves that can be set to control the flow temp depending on the outside temperature, I have been experimenting and down to heating curve 2.5 with good results. The whole system has knocked 30% off my gas bill compared to my old combi boiler and this is before I have even activated the summer detection function where it turns the heating off when a target outside temp is reached.

That’s great savings by the way.

I have found one problem with weather compensators for systems specifically to yours where hot water is demanded at the same time as heating, there is no reduced curve as your cylinder will need a minimum of 60 degrees c to heat up the water to a safe(bacteria free) temperature. Therefore it become obsolete when this happens as you cannot have 50 degrees heat leading towards radiators at the same time as the cylinder coil needing 60 degrees.
I have currently created a dual proportional zone valve to counter this by reducing two separate flows in a domestic system, so hopefully this issue can be avoided in the future .

 

[Tinders]

Blimey bit of a thread bump. Peculiar 1st post on a Computing forums