Drayton Wiser Home Assistant Integration

Third party integrations
3717

As others have said, it does depend on your particular circumstances and the house construction.

However, what I will say regarding “installers” is, in my experience, most of them know bugger all about heating and thermodynamics, only being qualified to safely install a heating system, which is the only qualification they need. This is actually an industry-wide problem, as there is no formal qualification to become a “heating engineer” other than being Gas Safe Registered AFAIK.

I would suggest you find a Heat Geek near you and get them to come and take a look. They take training through the Heat Geek programme to properly understand heating, and although it is not an industry standard qualification, it does indicate they have at least got a grasp on the basics of heating. In the past I have had supposed “heating engineers” service my boiler, which I have spent time to carefully adjust the flow temperature on, crank it up to max and leave it there. It shows absolutely no undestanding of heating.

The most efficient way to heat is low and slow, with the boiler return temperature below 55C in order to recouperate as much energy as possible through condensing. This is why I said that you may want to reconsider the idea of using motion sensors as you don’t want to be constantly turning your heating on and off.

It’s true that putting smart TRVs in each room does cause more calls for heat than if you only had one central thermostat. However, the thing that you get from having smart TRVs in each room is comfort. Each room will always be at the correct temperature and you can fine tune the heating as you want to balance comfort and efficiency. The Wiser integration in Home Assistant allows you to put some TRVs into an emulated Passive Mode, to act like a dumb TRV i.e. it stops them calling for heat, unless other rooms that are actively heating are already calling for heat and you can take them in and out of Passive Mode according to your situation e.g. only passively heat a guest room unless you have guests staying.

What I can say is that we moved from a 3 bedroom house 2 years ago, before the energy prices soared, to a 5 bedroom house that is twice the size and our bills are less here than they were at the old house (even with the massive price increases since then). Granted this house is much newer and better insulated, but we have smart TRVs in every room and are not heating 3 of the bedrooms most of the time. They are placed in Passive Mode with a setback of 16C and a minimum temperature of 12C and I have spent a lot of time tweaking the setup to e.g. automatically switch off the heating in rooms where the doors and windows are open, change the heating schedule for certain rooms automatically dependent on who is at home. These are the biggest benefits of having separate room control, along with the comfort that it provides. It depends how far down the rabbit hole you want to go in tweaking everything to gain those efficiencies though.

3 Likes
3718

In addition to what I already said about so called “installers”. Even if they do know something about heating, most of them will recommend what they are comfortable and used to installing and not necessarily what is best for you.

From my fairly limited research, I believe Viessmann are widely considered to be the best boilers available and play nicely with third-party OpenTherm controllers.

Anyone that’s advising against using OpenTherm would be a red flag for me.

2 Likes
3719

@robertwigley yes agreed. Viessmann also good with 3rd party opentherm controls - probably higher end than intergas. Agreed also on installers re opentherm. Definitely suggests they don’t have much knowledge in the technicalities of heating design.

1 Like
3720

If you haven’t had the TRVs fitted to your radiators yet (the valves themselves excluding the head), instead of using regular ones, consider using auto-balancing ones.

Note, these may not be the cheapest prices, so shop around.

This prevents the need to labouriously balance the system and means that if a radiator is ever removed in future e.g. for decorating, you don’t need to rebalance. In any system where a TRV is fitted the system balance will be constantly changing dependent on which radiator valves are open. These dynamically adjust to that.

2 Likes
3721

They are talking sense, dont go to far down the micro zoning route, its not good for comfort or efficiency.

3722

I started looking at Viessmann as a top end Opentherm boiler to modulate the heat from DV trv after reading these posts, but then saw their opentherm connectivity is very limited and doesn’t allow the modulating heat curve that people tell me allows the efficiency = pointless if can’t modulate via trv.

See this post

However, when connecting on OpenTherm, you have no microcontrol on, for instance, the heating pemperature. It goes to 80 degrees (Celsius), and it stays there no matter what. I would have liked to keep it on, say, 55, and then adapting the timings as such.

Am I misunderstanding ?

3723

This made me smile.

Even in this forum, this comment shows completely opposite views - just to make sure I leave confused. lol

Although I do wonder why are on this forum if you don’t agree with TRV room zoning saving energy?

Thanks

3724

I’ve contacted 2 heat geeks so lets hope they don’t say the opposite to each other.

Off topic completely - has anyone tried Electric Water Scale Inhibitors (£70) instead of water softners (£1500 inc. labour).

The Worcestor Bosch installer swears by them in his own home and the Vaillant installer pooped on them - although he did want to install a water softner too! :slight_smile:

3725

Have a look on Heat Geek and you will read why micro zoning isnt a good idea, although a lot of people do it and are happy with the results.

I am using Wiser TRV’s but i group them so i have multiple rooms in one zone rather than every room in its own zone.

2 Likes
3726

Does Viessman actually modulate the flow temp with Wiser?

Looking at this post which says:

I have a Viessman 100, allegedly Opentherm compatible and a Drayton Wiser also allegedly Opentherm compatible. They don’t talk to each other.

3727

As I said before, I personally wouldn’t use wiser for a newly installed modulating boiler, especially if you’re not going to be zoning. I would either use the manufacturer controls if they’re good or a nest as I believe nest does opentherm well as it doesn’t tend to request higher flow temps if it doesn’t need them. You would need to clarify that nest would work well with whichever boiler you end up choosing. I remember some posts on this forum saying that wiser often calculates the demand at 100% especially in the morning and hence the flow temperatures requested are unnecessarily high.

I personally use wiser in my situation and it’s great. This is because I have an oil boiler in a very old house and a modern extension - oil boilers don’t modulate. I have setup my system using the integration’s passive mode which has essentially allowed me to zone my house into 2 zones (old part and extension) and the use TRVs as temperature limiters in unused rooms.

Unfortunately, it is a very difficult topic with many differing views and a fairly poorly trained workforce. If I were in your shoes, I would try to find a really knowledgeable installer, which can be challenging, and go down the opentherm, less zoning route. In this situation, you can still use some manual TRVs to limit the temperatures in less used rooms.

What I would definitely avoid is extreme micro zoning with itrvs. I originally did this and it just leads to less comfort. By switching my system to use the passive mode in this integration and by using larger zones and temperature limits I have a much more comfortable house for exactly the same oil usage. Having said this I have reduced oil usage by 40% using Wiser compared to the terrible controls and programmer that the house had previously

3728

SEPARATE FLOW TEMPS FROM ONE BOILER

Thanks all. Really learning a lot.

I’m steering towards zone per floor, but that still requires Wiser TRV for me. But unclear which boiler speaks well to Wiser modulation and how effective it really is. Veissman seems to not speak well to Wiser from above post. All the installers shun baxi/main when I suggest it.

I have a separate consideration regarding more efficient flow temp for ufh.

Is there a combi boiler which can provide lower flow temp for wet ufh (30C?) and higher flow temp for radiators (40-50c?) - rather than a high flow temp which the ufh manifold mixer valve puts colder water into to reduce temp.

That seems really inefficient and defeats the purpose of having low flow temp for ufh.

3729

Take a look at this: https://youtu.be/LL6YhT_HkIY?si=kZOLkprFE3cYPpCb

Tldr Vaillant can and I’m sure others as well (probably viessmann) using the proprietary controls. Electronic blending valves used instead of traditional fixed ones.

3730

thanks for starting this conversation,

i agree, microzoning isnt a good idea, i think you should deffo have some non wiser trvs (or passive mode) in common areas and larger zones!

Great conversation, I wish my boiler was opentherm…

1 Like
3731

I’m another ‘It depends’ believer.
My experience:-

We had a new gas boiler fitted 18 months ago to replace an original 25 year old unit.
It’s a Heat only boiler, not a combi.
Since all new installs have to be a condensing type, that alone should provide some improvement in efficiency.

I tried changing the system setup to get the best efficiency.
At the time, the house was not occupied during the day so it was set up to be off between 9 to 3pm.
This also sort of lead to installing the Wiser system.

Low temperature, low flow just did not work for this house.

The radiators are piped in micro-bore, some 8mm, some 10mm.
The radiators did not provide enough heat output using low water temperature. (60C I think).
The rooms could not achieve their target temperatures at times.
Low flow also increased the boiler cycling activity as it could not modulate to a sufficiently low output.
(Boiler cycling results in poor efficiency).

Boiler cycling will also happen if you have micro-zoning. Radiators demand heat at random times. A radiator is likely rated at 2 or 3kW so the boiler shoves out 20kW -or whatever it’s rated at- for a short time and then has to throttle back or cycle off/on. Just think. If a room is up to temperature, it may only need a few hundred watts or so to keep there. OpenTherm may help here.
The good news under these conditions is, the return temperature is nearly always below 55C so the boiler condensing feature is always active.

Conclusion:
Low flow, low temperature needs big bore piping and huge radiators.
A boiler with a large modulation ratio (10:1 ?) is good.
Don’t over-size the boiler - it will likely result in more cycling than necessary.
With a room heating controller set to ‘Gas’, it is on a 10 minute heating cycle. Best to select ‘Oil’, which is on a 20 minute cycle, potentially doubling the gas valve MTBF.
The original CH system boiler was set at 70C, which is probably what the CH system was designed for.
It is also what it has ended up being set to without making major changes to the rest of the system.
OpenTherm would probably not have helped one jot here.

A new house design is whole different story.

3 Likes
3732

Just spoke to Veismann tech support.

They confirmed all their combi boilers:

  1. Speak opentherm (but couldn’t confirm to Wiser specificall) so this info could only come if somebody here has Veismann and its worked.

  2. Can do 2 flow temps for ufh and radiators using a heating mixer extension. They said if using a manifold mixing valve the boiler would only do the highest flow temp, but if using their own mixer it could heat to lower flow temp channel only if that was the only one being used at that time.

I did smile as their support wasn’t as great as Wiser or other companies, just like Urban Plumber said it would be.

They didn’t fill me with confidence, but their boilers do seem to have features many others don’t including:

  1. the heating mixer extension for 2 channels

  2. combi 46L storage boiler removing need for a separate cylinder and heat geeks say it can supply about 7 showers at the same tim with such a small storage section as it uses heating plates instead of smaller coils.

Then the other issue is that I’ve never met anyone thats had these, and I guess most installers wouldn’t know how to use them properly?

Regardless, Wiser and Heatmesier both told me their underfloor heating solutions are only on/off and modulate via opentherm.

Does anyone here have experience with Veismann or do you recommend Baxi/Main or another opentherm one?

Thanks

1 Like
3733

See my linked post for some experience with a Viessmann Vitodens 100-W and a Wiser on OpenTherm, I was perfectly happy with how it worked, my only grumble was that the Viessmann was fairly limited in the data points it supplied (setpoint, flow temp, modulation % IIRC, but not return temp for example). The opentherm gateway was only there for inspection and overriding Wiser occasionally (I can’t remember what hacking I was doing), but it worked fine without it too.

1 Like
3734

Admin - sorry for this long post and topic has perhaps also steered slightly away from Wiser specifically, but hoping its still relevant to most here as more about wiser heating zone integration with the opentherm boilers and heating theories.

…So the story continues…

I had a long 2 hour session with my local heat geek. Turns out his boss Andrew is also the guy that originally trained Adam from Heat Geeks - he showed me snapshots of Adam saying that.

They want to put a Veismann 200W-32kw Combi boiler due to lack of space for cylinder or even a combi storage unit like 222W.

ZONING

The alarming thing is they want me to get rid of all zoning completely. No Heatmeiser for UFH. No Wiser for TRVs.

They want me to forget about the room zoning and the floor zoning too, and just treat the house as one envelope.

The ViCare app from Veismann will let me control the heating directly from the Veismann without asking 3rd party apps to do this - which will remove need for opentherm modulation as it does all the modulation automatically + greater data.

The boiler will allow me to (if I want) have 2 zones in the house. The UFH zone and radiator zone which I can turn off/on if needed.

As nobody is at home during day 80% of the time, I might turn off the rad circuit until evening - but they are against this.

However, their plan is to keep both on 247 with a setback at night and only turn off if going away.

The system only measures the weather temp externally, then calculates how much to modulate the boiler from 32Kw down to 1.x?W as required to keep the heat at the desired eg. 20C temp internally.

It uses the temp of the outgoing water vs return water temp to calculate how much heat loss is happening I think?

UFH SPACING

Although they wanted me to do a heat loss calculation at £400 this would only serve to tell me how wide the UFH pipes should be and size of radiators (which I’m not changing). As such its pointless for me. The ideal UFH pipe spacing they wanted was 100MM or 125MM to increase the surface area and allow lower water temp to flow through. (My builder is moaning as he only wants 150MM for bending issues so a bit of a conflict there - I’ve asked him to do counterflow layout instead of serpentine but i’ll need a laying plan to guide him i think).

On the heat loss issue they said its not a major issue if I don’t do that with them as the boiler will gather the data and after 12 months be able to confirm the ‘exact’ heat loss rather than the ‘estimates’ they would do.

PROBLEM

The only thing thats not making sense to me and I couldn’t get a straight answer is how their system will know when the ideal temp internally has been reached without room stats - as House A could have great insulation and House B crap insulation.

Without this information, it all seems theoretical to me although the return water temp could perhaps help somewhere but only to confirm how much heat is lost rather than how much retained in the rooms and if its the ideal temp or not.

In addition different rooms could have different insulation = different end result competely.

This is really concerning me, so I might layout the heatmeiser wiring at a minimum, incase I decide to zone again in the future. Will also lay out extra radiator piping will developing, incase rads are needed in future (although hopefully not).

Is anyone that has experience with Weather Comp (and even Veismann 200W perhaps) able to advise me on the question which remains unanswered on 0 internal stats?

Thanks

ps. They said although it sounds crazy, even ‘skill builder’ from youtube who was always disagreeing with heat geeks Adam about this has now agreed this approach and that this is better than zoning floors/turning off etc. Not been able to check this incase anyone has seen it?

3735

James - so this means that the Wiser hub can’t speak opentherm directly to a boiler for modulation without this gateway device??

3736

I would go with the advice. I’ve been watching them for a while now and also the recent skill builder videos and if I was installing a new gas system I would be doing this. Instead of having an internal thermostat, weather comp can be used purely along with balancing to achieve constant stable temps. It might take a little adjustment in the first few weeks to dial in the correct weather comp curve but then it should be pretty set and forget. The only thing that you might end up adding if you find a few radiator rooms get too warm such as bedrooms is you might add a few manual TRVs just to act as temperature limiters but most of this can be achieved through balancing anyway.