Is This a Modulating Boiler? etc.

[Mottie]

Can anyone tell me, with certainty, whether this boiler will self-modulate even if I keep my Honeywell timer/thermostat, and don't use additional controls sold by Vaillant?

"The ecoTEC plus is smart: when it knows you don’t need as much heating power, it can drop to using 16% of its maximum power saving on fuel and money".

I'd be very surprised if it didn’t self-modulate with non-Vaillant controls. My 5 year old EcoTEC plus boiler does and I don’t have any Vaillant controls.

If in doubt, contact Vaillant.

 

[Harry Bloomfield]

The contribution above, by Madrab, seems to be a good point at which to come in on this conversation once again. After obtaining an answer to a question about the Vaillant EcoTech Plus 826 26kW boiler, I asked the people that told me (see a little earlier in this thread) that that boiler is self-modulating, another question — one that occurred to me later. I asked them whether that boiler is self-modulating in its own right, or whether it can self-modulate only with an additional Vaillant control. They diplomatically declined to answer. So, I now put the same question (which is very important to me) to this forum. Can anyone tell me, with certainty, whether this boiler will self-modulate even if I keep my Honeywell timer/thermostat, and don't use additional controls sold by Vaillant?

I hope someone can tell me!
L.L.

As I explained above, YES it will modulate, but only do so blind, based upon flow temperature, and to a very limited extent....

Once the flow temperature approaches the preset flow temperature, then it will begin to modulate. All your boiler knows, is a demand, or no demand for heat.

With Vaillant controls, in addition - it will know the room temperature, the desired/preset temperature, it can modulate its heat output much sooner, or even from when the boiler is first run. It knows the heat curve, needed for the house. Once the house is up to temperature, the boiler will then run at what ever modulated level, just to maintain the temperature - no regular creaking of pipes, as the heating cuts on and off. The more you modulate, the more fuel you can save.

It's rather like tearing up to traffic lights blind, versus being able to see the lights are red, so you approach more gently.

 

[Madrab]

Modulating is when the boiler's system temp reaches is set point, the burner will modulate (turns) down and maintains that set heat - most, if not all modern boilers will modulate. Your boiler has a modulation ratio of 1:10 therefore it can modulate down to 10% of the CH standard output

This is true of most modern boilers, this is regardless of whether it has controls fitted or not.

 

[Lucky Luke]

As I explained above, YES it will modulate, but only do so blind, based upon flow temperature, and to a very limited extent....

Once the flow temperature approaches the preset flow temperature, then it will begin to modulate. All your boiler knows, is a demand, or no demand for heat.

With Vaillant controls, in addition - it will know the room temperature, the desired/preset temperature, it can modulate its heat output much sooner, or even from when the boiler is first run. It knows the heat curve, needed for the house. Once the house is up to temperature, the boiler will then run at what ever modulated level, just to maintain the temperature - no regular creaking of pipes, as the heating cuts on and off. The more you modulate, the more fuel you can save.

It's rather like tearing up to traffic lights blind, versus being able to see the lights are red, so you approach more gently.

I read the contributions by Mottie and Madrab with interest (also, with some relief), and I thank them. However, you have explained things more fully, Harry, and I thank you for that. (C.H. is a very arcane subject to me.) On the basis of what this forum has told me, I shall buy the EcoTEC Plus 826 and retain the Honeywell control panel. Apart from the expense of buying Vaillant controls, I feel that I am too old, at 90, to be struggling to learn all the tricks that a new control panel would demand. Yes, I am sure that, technically speaking, a Vailant control ought to be fitted, but as long as the boiler is good enough to see us out, and gives no trouble, I shall be content.

Thanks again for all the advice, folks!
L.L.

 

[DIY_Doctor]

There you go, every day's a school day, I don't know why these manufacturers don't get on the same page, pain in the a$$ - shows how many Vaillants I install

Same a WB which is even stranger as I believe they were right at the forefront when the OT interface and protocol was being developed, pure money grab so people have to use their own overpriced controls and then invalidate their warranty's when using 3rd party OT adapters.

Don't see the point

I think you've got this upside down. OpenTherm was developed specifically to be an 'open' protocol, so its not proprietary and can be used by any manufacturer. So anything but a money grab. Valliant (and therefore Glow Worm) use their own eBUS interface but I believe most of the other manufacturers use OT.

To OP, I've had to find this out the hard way trying to install Tado with my Glow Worm Energy combi (essentially the same boiler as your Valliant as Valliant own Glow Worm). It is modulating if using the appropriate controls to take advantage of the eBUS interface, otherwise it isn't. I mistakenly bought the non-modulating Tado controls thinking my boiler wasn't modulating just because it wasn't OT, and now the boiler doesn't show any meaningful modulating operation - when CH is on, it fires up excessively and for prolonged periods which can't be good for its longevity. This never happened before I installed Tado when I was using Glow Worms own controller.

As an aside, whats the warranty on your boiler? With Glow Worm it can be extended to 10 years if installed by a Glow Worm/Valliant accredited installer, and likely to be similar or same for Valliant.

 

[Madrab]

So anything but a money grab. Valliant (and therefore Glow Worm) use their own eBUS interface but I believe most of the other manufacturers use OT.

Of course it is, I am talking about Vaillant (Ebus) and (i believe) WB (EMS) saying that their boilers must use their own controls and will void their warranty if you use another OT adapter and smart control. Therefore they are forcing customers to use their controls exclusively if they want advanced controls, that's the money grab, my comment had was nothing to do with a money grab around the free/open source protocol that is OT, I think it's you that's got my comments upside down.

 

[Harry Bloomfield]

I read the contributions by Mottie and Madrab with interest (also, with some relief), and I thank them. However, you have explained things more fully, Harry, and I thank you for that. (C.H. is a very arcane subject to me.) On the basis of what this forum has told me, I shall buy the EcoTEC Plus 826 and retain the Honeywell control panel. Apart from the expense of buying Vaillant controls, I feel that I am too old, at 90, to be struggling to learn all the tricks that a new control panel would demand. Yes, I am sure that, technically speaking, a Vailant control ought to be fitted, but as long as the boiler is good enough to see us out, and gives no trouble, I shall be content.

I do think you are maybe missing a trick, not adding the Vaillant controls. They are incredibly easy to install, and very straight forward for the user to set up. The complexity, is all in the configuration of the setting for the boiler itself, which should be sorted by the installer.

Thanks again for all the advice, folks!
L.L.

You are welcome.