Are Vaillant controls worth the investment?

[windsor-tg]

I am considering replacing my existing boiler with the new 2023 Vaillant ecotec plus 625 boiler. I currently have 3 x Heatmiser neoStat thermostats that are all hard wired back to the wiring centre; one for the central heating, one for a room with UFH, and one for the HW. I use the Heatmiser smart app on my phone to control the heating. 

 

I have read conflicting opinions about Vaillant controls; some people recommend the Vaillant controls as they modulate the boiler better, maintain even temperature within the house, and this makes the boiler more efficient. Others, however, have said it is a large investment that will take several years to get your money back.  

 

I have had a look at what Vaillant controls I would potentially need, and the cost is in the region of £800

 

Is it worth investing ~£800 for Vaillant controls or just stick with my Heatmiser setup? 

[JohnMo]

Depends on how the boiler is installed. If on S or Y plan, the boiler is fixed at a set output temp for heating the cylinder and and CH. So is pretty much on or off from what I can tell.  

 

If you need to spend £800 on controls on top of the boiler cost, I would be looking at a boiler that will control all the correct things out the box - examples are Alpha, Atag, Intergas. For good efficiency you need a boiler setup to do weather compensation, you can then set a curve that gives lower output temperature based on outside temperature. If you have radiators where the controller sits, load compensation is also good.

 

None of this will fix your short cycling on UFH when that is run in isolation, without some form of buffer or volumiser.

[windsor-tg]

31 minutes ago, JohnMo said:

Depends on how the boiler is installed. If on S or Y plan, the boiler is fixed at a set output temp for heating the cylinder and and CH. So is pretty much on or off from what I can tell.  

I believe I have S plan as I have seperate zone valves for the HW, CH and UFH

 

33 minutes ago, JohnMo said:

If you need to spend £800 on controls on top of the boiler cost, I would be looking at a boiler that will control all the correct things out the box - examples are Alpha, Atag, Intergas. For good efficiency you need a boiler setup to do weather compensation, you can then set a curve that gives lower output temperature based on outside temperature. If you have radiators where the controller sits, load compensation is also good.

 Not sure what you mean by "If you have radiators where the controller sits" ?

35 minutes ago, JohnMo said:

None of this will fix your short cycling on UFH when that is run in isolation, without some form of buffer or volumiser.

 not looking at these controls to fix the short cycling

[JohnMo]

2 minutes ago, windsor-tg said:

Not sure what you mean by "If you have radiators where the controller sits" ?

If you have a controller that supports load compensation, and it is, say located in the living room (where I assume you have radiators and not UFH) if the sun is warming up the room the load compensation controller will modulate flow temperature downwards to reduce radiator output.

 

But on S plan that would most likely not work as you will have fixed output temperature.