Are Vaillant controls worth the investment?

[windsortg]

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?

 

[CBW]

£800 for controls seems high, so in my opinion, unless you're able to recoup that I would stick to heatmiser

 

[Harry Bloomfield]

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?

It is a large investment, and will take a long time to recover the cost from what you save, but it's not just about economy - The Vaillant controls also improve the operation. There is much more use of modulation, much less temperature swing, as the boiler output becomes much more gentle, rather than on/off bursts of output. The creaking of pipes from the regular on off bursts, is much, much less.

I had a new Vaillant boiler installed, and rather than paying full price for the latest controls, with features I didn't need, I managed to track down an earlier, but still current set of controls, bought as a full set, brand new, on Ebay for a little over £100. That was the wireless controller, wireless receiver, plus the wireless outdoor sensor. I then picked up the unit to go in the airing cupboard VR65(?) for £30, complete with cylinder temperature sensor, to avoid using a mechanical cylinder stat - again new/unused. My boiler was set up to work on my old basic controls, so it was a few months later, before I switched it over to the Vaillant controls.

My initial impression of the Vaillant boiler, when first installed in the same location as my old boiler, was that it sounded noisier in operation, than my old one - when it ran, it was very noticeable. Once the old controls had been replaced with the Vaillant controls, it became so quiet, I often now have to open the boiler cupboard, in the kitchen, just to confirm it is running - whether serving HW or CH, and to check it has finished heating the cylinder of HW, via the display. It is inaudible.

 

[windsortg]

thanks @Harry Bloomfield. Yes, I got the feeling that these Vaillant controls should be considered as a method to improve the operation of the boiler, and hopefully improve the comfort level within the house. Which boiler did you have installed?

Did you deliberately wait to get the Vaillant controls so that you could see how your new boiler was behaving with your existing controls?

Since my existing Heatmiser controls are all hard-wired, I would be looking at hard-wired Vaillant controls. Do you recall which wireless controls you purchased as these may also come in a hard-wired version?

I was initially looking at:
- Vaillant sensoCOMFORT VRC720 room thermostat for programming the CH & UFH, and acting as the thermostat for the CH
- wiring centre VR71 (I believe this includes the VR10 cylinder thermostat sensor)
- VR921 internet gateway
- VR92 (for the UFH thermostat)

However, these together are proving all costly. I was on a call with the Vaillant technical team and have possibly come up with alternative Vaillant controls:
- Vaillant sensoHOME VRT380 room thermostat for programming the CH & UFH, and acting as the thermostat for the CH
- Vaillant VR 66/2 (wiring centre)
- Vaillant VR 92 (UFH thermostat)

I need to figure out the internet gateway. The Vaillant technical team suggested the Vaillant VR 904F internet gateway but I cannot find a supplier that sells them.

I have a Megaflo HW cylinder which has a cylinder stat attached. As I don't adjust the cylinder temp, I will do away with the Vaillant cylinder temperature sensor.

I may hold off from the weather compensation unless this would make a big difference?

 

[Harry Bloomfield]

Did you deliberately wait to get the Vaillant controls so that you could see how your new boiler was behaving with your existing controls?

Since my existing Heatmiser controls are all hard-wired, I would be looking at hard-wired Vaillant controls. Do you recall which wireless controls you purchased as these may also come in a hard-wired version?

Vaillant 418 Ecotfit Pure, that's the less pretty one, for installation out of sight - mine hides in a cupboard. The boiler install was a distress purchase, following my original boiler going faulty, yet again. Only after which, did I do the research and added the much better 470f controls. The only hard wiring was thee ebus, from the boiler to the unit next to the cylinder(65), and before that, I installed from the boiler to the pump, to overrun the pump. The pump was originally, only ran when the boiler fired, overrun means the boiler tells the pump when to run, and runs a while after it stops firing, to purge the heat.

My original system pre-dated wireless, wired cylinder stat, wired room stat, wired timer. All replaced by the three items 65, 470f, and the outdoor sensor. The big advantage of wireless, is that you can put the 470f in the room you are in. I never used the living room gas heater, but as gas costs increased, I could carry the 470f in the living room with me, light the fire, and the heat from that - once settled for the evening, would be enough to avoid the boiler striking up.

The 470f has two room temperature presets, a day temp, and a night setback. One weird issue I had/have, with the setup, is that if you tweak the room temperature up, without storing it - it does sometimes decide to store the temperature, as a new day temperature. What it ought to do is fall back next day on what your originally stored as the day temp, ignoring your temporary change. I never got to the bottom of why/how it does that.

 

[Elektra99]

I have spent ages trying to understand Vaillant controls and havent made much progress - Vaillant VR921 sesnoNET internet gateway as an alternative to a VR92. ?

 

[Elektra99]

The drivers behind my research is a Vaillant open vent boiler has been fitted under EC04, (PASS 2035 demands smart controls and a fully integrated systems) but they have fitted Openthem controls.

I am trying to get them to swap out the Opentherm controls for Valliant eBUS but its hard going. In simple terms I am looking for
Boiler modulation, Load balancing and if I can get it weather compensation. Cant see I will use internet access and it poses additional security risks.

As I understand it the boiler wont modulate, load or weather balance with Opentherm Controls - is this correct?

I had come up with
- Vaillant VRT350 wall mounted in the hall or VRT350F
- VR 66/2

replace the VRT350 with VRC700 to get weather compensation

Is there anything else that would be needed?

Secondly I am baffled on this
I have a question that relates to the HW temperature setting on the boiler front. Initally I thought this was the HW flow temperature but the installers tell me it cant be raised about 60c. Looking at the installer manual it looks to be HW termperature that is shown not the flow tempertaure needed to deliver, for example 60C in the HW cylinder.

So how does the boiler calculate what flow temperature is needed to deliver 60C HW when all that is fitted on an on/off stat on the HW cylinder.

At present the opentherm controls mean the CH flow temperature controls the temperature of the water being sent to heat the HW cylinder BUT the manual implies the HW flow and CH water temperatures can set independently. I could gasp this if the CH temperature setting controlled the flow but it is a capped out at 60C and 60C flow wont enable effeicient heat transfer to the HW cylinder.

I am totally baffled. The user and install manual is definately open vent boiler NOT combi

 

[Harry Bloomfield]

I have a question that relates to the HW temperature setting on the boiler front. Initally I thought this was the HW flow temperature but the installers tell me it cant be raised about 60c. Looking at the installer manual it looks to be HW termperature that is shown not the flow tempertaure needed to deliver, for example 60C in the HW cylinder.

You really need to start a separate thread, however.

From memory, the flow from a Vaillant can be set at a maximum of 80C and the HW in the cylinder to a max of 60C.

The flow temperature for CH and HW need to be different, so the boiler can only serve on item at any one time. The boiler cannot modulate when serving the cylinder, fitted only with an on/off stat - instead it uses a thermistor, which reports the actual temperature back to the controller. The display can then show the actual temperature of the water in the cylinder.

With an on/off stat, the boiler runs flat out, until it reaches it's flow temperature, then it maybe modulates. Knowing the actual temperature and how far it needs to go, it can modulate throughout it's burn cycle.

I'm not sure about modulation, but the best and most efficient modulation and control, is achieved by Vaillant's own controls, for a Vaillant boiler.

 

[Elektra99]

noted will start a new thread but can gasp how it would work with a smart stat that reported actual temperature