Lofty718

Are you not able to get a £7500 grant for a heat pump there? your energy costs are obscene Also on your install why is there a pipe discharging into a jerry can? lol

Identical setup to me just with a boiler instead, I have VR71 with two zones but one zone (radiators) is an unmixed circuit. I will consider in future, maybe running a hybrid system keeping the boiler for HW although you cannot get the grant with a hybrid system. I didn't fancy a heat pump initially after reading about a lot of people having issues with their installs and didn't fancy a huge unit on the patio lol I've got the whole heating setup tucked nicely in the loft. I think @JohnMo suggestion is a good one. Will result in a low temperature system and efficient system without a ridiculous outlay. I looked at the cost of the massive pump on his HW circuit and depending on the model it's at least £500ish. @Adsibob that is a grundfos magna pump right? I feel the installer has really taken advantage here with overspeccing the amount of equipment needed.

My weather compensation sensor is badly placed on the black facia on NW facing wall so it heats up in the sun lol I've been meaning to grab a ladder and move it but it is not actually much of an issue at all, mainly because when there is any meaningful sun that can tamper with the sensor the heating is off anyway Mines wireless I imagine Viessmann have a wireless version too

The gas cooker costs peanuts relatively to heating and HW so doesn't add too much. Don't have MVHR either UFH is only 45sqm of mine, the radiator circuit eats up a lot of gas (11 radiators inc bathrooms) I imagine if you can get your boiler running with modulation and low flow temperature your gas usage will be tiny. I'm quite happy with the gas usage of mine considering the comfortability and just leaving it on 24/7 Few fails on my install happened too, first being a 30kw boiler with minimum modulation of 5.8kw, where as yours is 1.9 or 2kw can't remember. Then also the UFH was 200mm centres in a big open space, which isn't so good. But lessons learnt

1930's 190m2 end terrace with solid brick in existing house and cavity wall in some parts, old suspended floors uninsulated and no ewi (should of done these) whole house heated 24/7 to 21.5 with setback to 20c at night gas bill for december worked out at £6 a day this includes cooking and hot water usage (cylinder is set to recover 24/7 too whenever hot water drops below 40c)

I have towel rads running on weather compensation flow temperatures on two different circuits. One towel rail is on the UFH circuit and the other 3 bathrooms are on the radiator circuit, my bathrooms are always very nice and warm but I did choose 1800Hx500L towel rails. Obviously this means towel rails won't be on in the summer but that's a bit wasteful regardless. I did wonder about that huge pump he has on his circuit, it looks expensive and totally uneccessary i've only seen those installed in mansions lol. @Dan F when you say you have mixed circuits do you mean you have electronic mixing valves? what curves are you running in your place? I'm on 0.4 for radiators and 0.35 for underfloor heating A mixed circuit for each of @Adsibob manifold would be too costly you could run the whole system from one mixer or even better straight from the boiler. I read back on a previous thread in April where we were discussing this and you said your house is split into 12 different zones... is this true? that's insane.. so you have 12 different thermostats?! This is how my boiler is running today, constantly on at low temp. I recently range rated the boiler down to 8kw, meaning @ 30KW It's insanely oversized.

@Adsibob Don't rush into getting an installer yet until you figure out what you want and then crucially make sure you choose someone who knows what they are talking about and knows about low temperature heating and proper controls. @SimonD can I ask why you think he needs a buffer? it's quite unusual. It's my understanding that a LLH is installed to hydraulically seperate the circuits so a multi pump heating system can run at different flow rates without the pumps fighting against eachother. since he has only UFH in his house it seems to me the most efficient way of setting up his system would be to run two different flow temperatures one on hot water priority for the DHW and then the boiler at all other times providing flow direct to the UFH circuits. This would mean boiler always condensing 100% of the time in CH mode Is it possible he could even go as far as removing every mixing valve and pump from the manifold and running all off the boiler pump? this could of potentially been a much cheaper install with much less equipment needed.

@Adsibob no offence pal but just because something doesn't seem logical in your mind does not mean it doesn't work. plenty of people run heat pumps on boilers on pure weather compensation with no room influence at all. The only time you might have a bit of trouble is on mild days but anything can be over come. Your system is all UFH so it would be perfect for weather comp, the circuits are easy to balance on the manifolds simply provide more flow to the rooms that don't get as hot. Vaillant controls allow room influence and weather compensation at the same time which is what I use because sometimes when cooking in the open plan area it heats up a lot so it's good to have some room influence, you can do the same on Viessmann they have a stat for room influence, but using third party room stats is a mistake unless it's only as a high temperature limiter and not turning boiler on/off I think a good engineer could get you a 20% reduction in your yearly gas bill compared to the setup you have now. You spent a fortune doing up your house why settle for an outdated heating system that just 'works' Load compensation will allow your boiler to modulate down to the 1:19 ratio that it can and the burner will acheive longer burn times, some people I know with Viessmann can have single burns lasting hours. Longer burns and less cycling = constant condensing which means less gas usage, the house would also be more comfortable too. As someone mentioned previously without weather comp or load compensation your boiler is not currently doing what you think it's doing

Yes that's a common thing I've seen too some installers will assume money is no object and add loads of pumps, a low loss header sometimes even a second uneccessary boiler. My boiler is an oversized ecotec 30kw, unforunately I purchased it on advice of the installer before I learnt about the proper design practises. It's range rated to 10kw and heats the house perfectly so I could of probably had a 15kw ecotec and even that might of been oversized. The only advantage of my oversized boiler is that the coil in the cylinder is rated to 28kw so it provides quicker heating times, but the ideal setup would of been smaller boiler and a high recovery heat pump cylinder. Oversizing is less of a problem on the Viessmans since the modulation on them is so impressive. I would advise @Adsibob at a minimum to get his boiler installed with controls that can actually modulate his boiler. His house I think is fully UFH so to actually have a boiler running at 50c+ constantly in this day and age is bonkers.

Vaillant also released a 4-pipe boiler the ecotec exclusive but I don't think it's as good as the standard ecotec Most Viessmann installs I see from good installers who have done the Viessmann courses generally don't ever install their systems with room stats and the boiler is run fully on weather compensation, this is what Viessmann generally recommend unless the property is not suitable I beleive weather compensation is mandatory in Germany and Holland, it seems we are way behind when it comes to heating in this country and our installers are generally very poorly trained.

This is almost how mine is setup, I have cct's they go to 1 pump for radiators which is piped to two seperate zone valves one for radiators and one for pdhw then the other branch of the CCT goes to an esbe valve and UFH pump. All pumps and zone valves/esbe valve is wired into Vaillant wiring centre. When cylinder calls for heat the heating shuts totally off and the boiler ramps up to 75 and uses the same external pump used for the radiators to heat the cylinder. Once the cylinder is satisfied (which is very quickly) it goes back to heating mode with all zones open

This is an example of how it should be setup, 4 pipe with the mixing valves. I have the same electronic valves in the video controlling my UFH.

I've told you about this in previous threads before but you thought I was talking nonsense setting up a Viessmann like that should be a crime and the plumber is 1000% a cowboy -No weather compensation -No PDHW -Boiler sending high temperature water down to UFH manifolds (inefficient) ufh should be controlled by weather compensation and electronic mixing valves wired directly into the boiler There should also be temperature sensors on the flow pipes, one for before the low loss header and one for every other zone and another in the hot water cylinder. Viesmmann has all of this stuff built into it out of the box, I had to pay £300 extra to add this all to my boiler. With PDHW on my Vaillant I leave my hot water cylinder constantly set to 44c and whenever it drops below the boiler will ramp up to 75c to heat the cylinder, then back down to 38-45c flow temp to heat the rads/ufh. You have the best boiler on the market but the way it's been setup he might aswell have slung in a crappy baxi boiler because you are not actually using any of the tech that you paid for that makes the boiler so good. I had a similar issue with my 'plumber' who wanted to install my Vaillant ecotec with heatmiser stats zoned into tiny little bits with a nest for radiators and hot water but I stopped him in his tracks and got it done properly. In my case installing a Vaillant with anything but Vaillant controls means the boiler cannot modulate and is simply an on/off dumb stat - yours must be too if it's controlled by Tado

What's the drainage situation in your proposed extension area? relocating manholes can add quite a lot to costs For 50k and you doing a lot yourself I would say it might be acheivable if you can get someone to work on a labour only basis and you provide materials. good luck keep us updated

I highly doubt this is acheivable for 40k for someone who's not in the building industry themselves. A nice kitchen alone costs 12-15k. without fitting

I'm in a similar sized house (2100 sqft) but using 160kwh per day heating whole house to 21c 24/7 got rads upstairs rather than ufh though. I notice your pump speed is on number 3, this is a bit high try and put it on number 1 and see what happens also your flow meters are all over the place some reading very high. On the gauge on the UFH manifold what flow and return temperatures are you getting? are all the pipes evenly hot to touch? also what boiler do you have and how is it controlled?

Something seems very wrong here, UFH shouldn't need to be run at 50c what is your downstairs UFH running at? Mine is running at 38c in this current weather Post a picture of your manifold setup. How many kwh of gas are you using a day?

An electronic mixing valve does not need to be wired from manifold, it goes only from the mixing valve to the wiring centre, my mixing valve is next to the boiler. I've not heard anyone say their house is cold from using Vaillant controls,on the contrary mine is very comfortable with the low and slow form of heating. The reason I say you don't want sensohome is that it does not come with weather compensation out of the box and it also has quite a few other limitations. Weather comp will make the boiler more efficient and house nice and comfortable. The heating will be controlled by the weather on a curve which you set that suits your property, this is why you need an electronic mixing valve as heatmiser and standard UFH mixing valve will not work. Your setup could still be wired into the Vaillant wiring centre relay but it would only work as an on/off type of control which is pointless Also the setup allows hot water priority, so you can run your boiler at 3 different flow temperatures like urban plumbers video, currently mine is running at boiler 42c flow temp, ufh 38c and radiators 36c and keeping the house nice and warm 24/7, when cylinder calls for heat heating shuts off and boiler ramps up to 70c to heat the cylinder. Another cost you would need to consider is an extra pump needed for the radiator circuit. I have two external pumps one for ufh and one for radiators costs were esbe actuator -£90 esbe mixing valve - £110 vr71 - £150 vrc720f - £235 vr92f - £120 extra pump - £100

I watched that video and bought the same setup 15 a day is a lot but it doesn't surprise me on a poorly controlled setup. Is your boiler the new ecotec with the digital controller on the front? if so you are hugely missing a trick by not using the proper controls. sensohome won't work for your setup and you could use a vr70 rather than vr71. I picked up a vr71 on ebay for 150 pounds, also you would need an electronic mixing valve to control the ufh which is wired into the vr70/71. the kit is quite expensive but it's an investment, my boiler runs at 45c on these cold days and is heating 24/7. how big is your house? @marshian I've watched that video a few times, it's one of the reasons I bought the same setup

Nice setup John, I also have an esbe mixer wired directly into my Vaillant wiring centre working on weather compensation. Best way to control UFH

You are wasting the modulating tech of your boiler by not using the ebus system from vaillant to control the boiler, this is why your system it not running properly and probably wasting loads of gas. Get yourself sensocomfort vrc720f controller and scrap the heatmiser.

This is the issue with poorly controlled UFH, on on/off controls. UFH is best installed open loop and with an electronic mixing valve on weather compensation rather than the old tech mixing valve at the manifold receiving high temperature from the boiler and trying to blend it down. Also what speed is your pump on? some installers leave it on too high. Fiddle around with the flow rates on the manifold start by giving less flow to the smaller loops and see how it reacts

R7/8 9/10 and 11/12 are for electronic mixing valves/pump mixing groups R6 is I beleive a switched live that can turn a pump on and off. I have two pumps wired into the VR71 on my system R6 and I can't remember which other one so I'd assume R5

Nice, low temperature heating is definitely the way forward. My system boiler runs at 36c flow temp and is keeping the house at 21.5 24/7

There is barely any documentation on the Vaillant wiring centres and like you I got my information from schematics/reading forums With the VR71 it's a case of wiring your auxillary inputs into it, mine being UFH pump, radiator circuit pump and an electronic mixing valve (esbe) Then the corresponding sensors need to be fitted to the pipework one for each zone, then another sensor before low loss header if you have one and also one sensor sits in the cylinder pocket and all of this combined with the outdoor weather sensor allows amazing control of your heat source.