@dr_dongle I think this was the announcement Tim was talking about.

Hi Tim, not sure if you have already covered this elsewhere in the forum but (separate to my continuing interest in CT meters and 200A multi supplies) I have a Vaillant Ground Source Heat Pump too that is connected to single phase supply with a SMETS2 smart meter and the announcement of HeatPump Plus has caught my eye but I have a question about eligibility requirements.  

My Vaillant ground source heat pump is a flexotherm 5kW, it was new in 2021, and (according to Vaillant website) it can have can have a myVAILLANT connect internet gateway connected to it (although it doesn’t have this at the moment).  However the eligibility requirements for HeatPumpPlus seem restricted to a single type of Vaillant air source heat pumps only, is there any possibility that my flexotherm Ground Source HP could be eligible if I had the gateway installed? 

I’ll ask internally @ruralCTsupply and get back to you 

thanks v much Emmanuelle, I have also contacted Vaillant myself as well as I am interested to hear from them if there is a technical difference (apart from the obvious) between their aroTherm air source HPs and their flexoTherm ground source HPs that makes this possible with the aroTherms but not the flexoTherms

Hey @ruralCTsupply,

The response from the team:

I believe it’s a question about Ground source heat pumps. We are currently focused on monobloc air source heat pumps at the moment but we will review any compatibility options regularly to ensure that we’re serving as many customers as possible

@Tim_OvO After a lengthy period away from this group I can say that as of yesterday I have my heat pump system going.

To summarise: It is a retrofit to a 4 bedroom 1970-1990 single storey house off-grid for gas which was formerly heated with a 23 yr old 50-70 kW oil boiler. This generated about 10 tonnes of CO2 per annum which I felt I needed to do something about.

Because of the size of the house and difficulty in insulating it past the obvious measures the new system is a hybrid - a Vaillant 12 kW ASHP as the main source but with a much smaller condensing oil boiler to provide additional heat during really cold snaps. A number of radiators were replaced with three-panel ‘K3’ radiators which are the same height, width and pipe location as the old ones but are deeper.

Of necessity I also got my supplier (OvO) to install a smart meter and my next job is to explore their variable tariff and how to use it to best effect. There is also a lot to learn about the new system which is controlled on a very different principle than the old one.

The old system was controlled by a Hive controller which I’ve left on but just to provide convenient access to some smart TRVs. in the new system these don’t have a lot to do but it does mean we can have individual room scheduling and they deal with a quirk in the old system which I’ll not bore you with. 

As of today the new system seems to be working - I don’t remotely understand it all but that will come. The pipework is a sight to behold - those of you who remember the pipes at the start of the Monty Python episodes will get the general idea.

Part of the issue was that the installers needed to bring the 1970+ pipework up to date and quite a lot has changed since then.

Anyway, I’m off on the Great Green Heating Adventure and happy to chat about it and what I’ve learned if anyone’s interested.

@dr_dongle sounds like a great system.  Where are you and who were your installers ? Have you done this through the Heat Geek arrangement with OVO ? 
It would be good to see some photos of it all !!

I don’t know much about the Hive controls but I’ve read that scheduling individual rooms lowers the efficiency.

@juliamc If this is the best forum then some photos are a must - it is actually very simple - for heating the ASHP feeds a buffer tank from one side and the oil boiler from the other and then the heat pump heats the water by itself but by the time the pipes have crawled over each other the result is a sight to behold.  I’m in the countryside near Kinross. The heat pump side was done by IMS in Perth and the oil boiler was done by a good local plumber so I have continuity. Not Heat Geek but IMS have been doing heat pumps for I think they said 18 years. For all that, I think I’m a very early adopter for this sort of system and everyone is interested and learning a lot. 

The room scheduling is really just the main bedroom - we prefer it cool at night but warmer to get up to. That’s easy with the smart TRV and one room shouldn’t affect the system too much.

The hybrid system is complicated and expensive but there was really no other way of guaranteeing heat all year round - two heat pumps or a much bigger one could have needed a three phase supply. There are advantages in redundancy and if power cuts became a problem (we do get them) then the oil system could in theory be run off a generator.

@juliamc 

As promised! The ASHP is behind the wall to the right. The hot water tank and the house proper is off to the left. The tub is the buffer tank. The boxes on the wall are (L-R) an electricity meter, the main heat control and a wiring centre. At bottom is a pump taking boiler condensate into the house grey-water pipes. Yet to go in is the pipe insulation and the Internet interface.

@dr_dongle Thats tremendous. Great to see all that pipework and totally Monty Pythonesque - I can almost see a giant foot coming through the ceiling…

Does the Vaillant give you a figure for COP on the controller screen ?

Definitely! 

This week and until the installers are away I’m being good and resisting the temptation to push all the buttons. Once I’ve let it do its thing for a week or so then trust me, I’ll be all over it but till then I’m relying on the controller manual. It tells me that the controller displays a heat yield but not the COP.  I guess that that can be worked out by taking the yield along with the electricity usage from the meter.  The manual points out that the yield is affected by a variety of operating factors and is only accurate to 20% or so.  There are other sources of information such as the User controller which is in the house and the app.   I’ll also see what the HomeAssistant community has managed to winkle out of it.  Somewhere there’ll be an engineering screen for sure.

That is truly a work of art @dr_dongle! Please keep us updated with your findings 

@ChristopherS_OVO  Happy to oblige! so, before I forget it all here is what I have learned so far, misconceptions and all. Some of this I have posted before but this puts it all in one place.

I was told "your house will need to be really well insulated and you'll need bigger radiators" Also, "The biggest heat pump has a third of the output of your current boiler and will struggle". "It'll be noisy". "It'll be expensive". These seem to be mostly myths.

A conventional central heating system cuts off in the evening then comes on again first thing and has to drag your house from cold to liveable-in in a short time.  A heat pump system will constantly vary its output and pump speed but is on 24x7. You never turn it off so you never have to run it hard and so you can get away with a smaller output. There is clearly some penalty in having rooms that bit warmer when not in use so good insulation helps. There is an "away" setting and a scheduler for longer absences.

The circulation temperature is well below what a gas or oil boiler can deliver but again if you're not having to heat everything quickly then this is less of an issue. Your installer should do heat calculations which will show which radiators will struggle to heat the room and these will need to be replaced. We found radiators which were the same size as the originals and had pipe entries in the same place so they were just thicker so there was no impact on decorations. This worked since my radiators had 15mm pipes at both ends. If you have microbore then this probably won't work and you may need to replace pipes as well. 

Older houses are not designed for current levels of insulation so once you have loft insulation, cavity wall insulation, double glazing and plug draughts then it can get really hard. I have only a 50 cm void under my suspended floors and under-floor insulation would be a nightmare. There is only so much you can do.

For a big heat pump you may need a new spur from your main consumer unit and your supply should be rated at 100 amp.

If you haven't had work done on wiring or plumbing for a while then you may find that your installer will want to upgrade it to current standards. We needed some RCBs, earthing straps, a pressure relief overflow and two filters in the pipework.

My heat pump is no noisier than the oil boiler it replaces though it may get noisier with age. The main thing I notice is the blast of cold air as I walk past it. It is a thought that when a breeze blows past your house that every square metre of it contains up to 10 kW of extractable energy.

Vaillant seem determined to dumb down customer access to controls and to information about the system and I just have one number that I can change (the relationship between circulation temperature and outdoors). It is the same for a conventional central heating system but changing the temperature seems a bit more intuitive.  Your main control will be via TRVs on individual radiators - certainly with the Vaillant ASHP it has no temperature sensor in the house and apparently the algorithm monitors outside conditions and the flow and return temperatures instead.

Calculations indicated that the ASHP could struggle on the coldest days so I included the small oil boiler which the system can call on if needed. I have left my Hive system on for now but it has no connection to the boiler or pump and just manages some smart TRVs.

I have a grant but it only covers about half the cost of the project. I don't know about running costs yet though the new variable tariffs look hopeful. I did this to cut my CO2 output not my costs though I did have one eye on the eventual saleability and value of the house. I had to have an EPC done as part of the grant conditions and my house has gone from Band 'E' to band 'C', almost entirely because of the ASHP. That feels significant in that a buyer looking at 'E' might feel there could be cost issues whereas 'C' says 'OK'. Hopefully it will be MANY years before I have to sell.  

My next tasks are to see what I can get the system to tell me and to get it talking to OvO to benefit from the variable tariffs.

To be continued…   

I was in agreement with you until the bit where you’ve said your control is through the TRVs on the radiators. They will reduce the efficiency of the heat pump, which is happiest when the radiator water is flowing unrestricted around the system. If the weather curve is set correctly you don’t need any other controls. Room temperature should be steady throughout the house rather than shutting off individual radiators. The temperature of each room should be defined purely by the size and output of the radiator.

@ChristopherS_OVO  

onwards and upwards ...

​The ASHP is now networked with a MyVaillant CONNECT interface. Both the installer and I had expected this to have an RJ45 socket so it could be patched into the Gigabit switch three feet away but no, it is WiFi only and the boiler room is in a WiFi dead spot. One network extender later it is now talking to the Vaillant app on my phone but that is telling me pretty much nothing despite some useful looking graphs on the App web site. 

The App has a page for “EEBUS” and a slider which doesn't seem to do anything. EEBUS seems to have been developed by an industry consortium for "energy management devices in buildings to connect and interact with each other and with grid and market operators". It seems a prime contender for devices and apps to read information from the ASHP and for it to talk to a smart meter. I'm still researching this.  The crowd-developed HomeAssistant software has an EEBUS plug-in which I have loaded and used to interrogate the ASHP but which also tells me very little.  The plug-in developer tested the software with a heat pump and a different interface - the Vaillant Sensonet VR921 - which *does* have RJ45 and EEBUS sockets. The developer was able to get a lot more out of the ASHP than I could so it is possible that I need this other interface. Also being researched. Somehow we need to communicate the OvO cheap-rate timetable to the ASHP and then there is the electricity meter (in the picture), so far function unknown.

I filled in the on-line form at OvO indicating interest and assuring them that I had a valid setup. They have yet to get back to me except to point me at this forum.

There's a whole lot here I don't know and a lot is very new so I suspect that others are only beginning to feel their way around as well.

@juliamc I take your point about unnecessary restrictions to the point that I’ll be ripping up carpet to remove a redundant motorised valve as soon as I can . The sole use of a smart TRV that I have in mind is that we like a cool bedroom at night, something I can’t think of any other way of doing.

@juliamc sorry, re-reading your post .. you advise against *any* TRVs.? Without challenging your assertion about keeping the flow open it seems very inflexible and I’m struggling to see how that would work. Our use of this house is totally different in summer from winter or if we have guests. Also some rooms are weather-dependent, hot when the sun shines and cooler when up to three walls are exposed to a cold wind.  The ASHP only knows about the outside temperature and the temperature of the circulation return. I don’t see how it can compensate for the state of one or two rooms. I also realise now that the location of the outside temperature sensor is not optimal but that’s a different issue.  

I’m new to this though and happy to be talked out of old-school misconceptions :-)

Yes you’re right - I was oversimplifying. We also have solar gain as our large sitting room windows catch the sun all morning (when there is any). I have a Daikin with their Madoka controller which is set to modulate by 2 degrees C, so helps balance that out. I can see that if the Vaillant doesn’t have that you would be overheating there. Our bedroom radiator is sized to only get the room to 18 deg.

From what I’ve read though any guest rooms should be heated even if not used.

It’s a question of balancing the efficiency with comfort.

@juliamc so, deprecated but sometimes unavoidable?

There is also ideal versus reality - when I bought this house I inherited radiators where output-over-demand ranged from 0.6 to 4.3 (!) and though I replaced 8 out of 20 radiators, tuning the rest by replacing them would be just a tad expensive ...

PS thanks to whoever awarded me the little “I’ve got a heat pump” tag :-)

Looks like a Forum Moderator discovered your discussion @dr_dongle . It’ll have been one of them who awarded the Badge. :)

Hi @dr_dongle, 

We will continually update your profile with a lovely badge to let others know what green tech you have! If you have any other tech you want us to know about, just leave it in a comment, and if it falls under one of the categories, we will add it for you!

I’m enjoying the discussion on the thread and think anyone interested in investing in a heat pump system is going to benefit from seeing your journey and decision process! @juliamc has also made some fantastic contributions, which leads to some fascinating comparisons between how you can set this up in a way to benefit you.

@ChristopherS_OVO lol it’s a journey all right and for the time being this is quite enough green technology to be going on with.

First off the SensoNET VR921 was a red herring since it is unsupported and using it will probably drive my ASHP into a state of deep depression and trigger plagues of locusts.

The electricity meter in the installation appears to be a wall ornament. It doesn’t connect to anything else and my electricity supplier will talk to the heat pump controller and not it.  I think it is there as a validated check on the figures provided by the heat pump controller in the event of a dispute. 

The system has been working in hybrid mode. There is a parameter - the bivalent point - which is the outside temperature below which the ASHP reckons that it can’t heat the house by itself. By setting this a bit high we forced the little oil boiler to cut in. I’d quite like to be able to monitor when that happens but there’s no obvious way except DIY - I’ve strapped a WiFi thermometer to the boiler flow pipe and I can log that.

Right now I’m still battling the myVaillant app or the MyVaillant gateway, take your pick. 

To recap: Vaillant provide a wall unit to control basic functions such as the desired temperature and heat curve and display some key parameters. They also provide a WiFi Internet gateway and a phone app. This does everything the wall unit does but also displays useful performance figures and graphs over time.  Except that my app doesn’t. It should, but it and the gateway aren’t talking properly (which is why I thought the app was dumb). My worry is that if they aren’t talking properly then what chance does OvO have of talking to the system?  The issues may be unrelated but if not then I could be in for a very frustrating 4-way discussion between OvO, Vaillant, the installer (potentially) and myself. Until then I just have to put with the Electricity Bills From Hell.

That’s it for now I think. Let’s see if I can get OvO’s Heat Pump Plus sales team’s attention.

@ChristopherS_OVO This is for anyone setting up a Vaillant ASHP app from Android. I think I found what caused me a frustrating couple of days.

When it is flashing blue the gateway broadcasts a temporary network. During setup the app connects to that, initialises the gateway then connects back to the house network.
The gateway then drops the temporary network and connects to the house network itself. The app prompts you to make the necessary changes *but* at the same time Android puts up dialogue boxes saying “Connect”. Those dialogue boxes should be IGNORED and instead the network changes should be made via WiFi Setup within Android.

My setup looks more hopeful now.
 

It sounds like you’re getting quite good at investigating these issues, @dr_dongle. I’m thrilled to hear you made progress and got to the bottom of what was causing it. 

I imagine the controller doesn’t have Bluetooth capability, so instead, it creates a temporary network to establish new connections. Your device prompts you to join this network, but this should be done through the system settings, as the prompts aren’t familiar with the connection type and are hitting a dead end. That’s handy information for anyone on Android who is going through the setup for themselves. 

Let us know how this impacts your setup and what improvements you find.

@ChristopherS_OVO lol I wish. Vaillant app support have come back with a little more detail about the process but reckon that if I gave the app the correct permissions (which I thought I had) it should have been seamless. This sort of thing can depend on all kinds of factors so it could go either way for others. Apparently iPhones manage it better.

OvO tell me they are sorting some technical details about Heat Pump Plus but hope to take me forward very soon.