mk1_man

Hi, I have just started off in the exciting world of heat pumps. I have recently completed my diy install of a Vaillant 7kW unit and 250l Vaillant cylinder. Its a very simple setup with single zone covering underfloor on ground and first floors although there is only one active circuit upstairs as we don;t like bedrooms warm. I am monitoring on OEM which gives fantastic feedback so thoroughly recommend anyone doing this on their setup be it not a cheap option. Heating has been on for a few days now and I am getting strange on off periods throughout the day, is this normal? Curve was set to 0.4 but I have dropped to 0.35 as house was almost too warm. Pump has been running at around 3.3kW output and around 590W input, flow temp steady around 30degrees.

Thanks, took a bit longer to install than I had planned, probably due to soldering all of the joints as opposed to hiring a press fit tool. I was doing in in fits and starts but all in probably 4 - 5 man days in total. Hard to see how the companies I got quotes from could quote £12k plus ( excluding BUS grant ) the parts were approximately £6k and that is including vat and purchasing as an individual, surely the bigger companies command a much better discount. In my eyes just proves that the current situation is ripping off consumers and not delivering biggest bang from government investment. My view is that it should be opened up to a much bigger market and simply install to a best practice guide but essentially make something like Open Energy monitor compulsory if you want to access BUS grant with a requirement to score at least a cop of 3 or above to qualify. This would put the onus on installers and manufacturers to deliver the goods and stop it being an MCS monopoly. Thanks for advice on cooling, I was going to look into it and have ordered the following at £11 delivered 🙂 https://www.theheatxchange.co.uk/vaillant-plug-coding-vai0020266328

Chuffed to bits, finally finished my diy install of my nice shiny 7kW Arotherm. Have only used for dhw but working a treat once I realised that my esbe diverter valve was wired back to front and I was heating the ufh ! Just need to finish off wiring the OEM stuff. Old boiler out : New unit : Primary Pro and anti-freeze valves

I have just fitted a Vaillant ashp, a window above the unit and outside of the protected zone is permitted. You can also have a window that extends to the ground as long as it is non opening or at least the element that is located within the protected zone is non opening i.e. split unit.

Also you don't want hot water heating contributing to temps in the house during summer. My view is insulate everything, gives you option then for using cooling function later on also. If I had access to a press fit tool I may have gone that route. Filled up system this very morning and touch wood no leaks as yet, once system gets some heat in i will be happier 🙂

Crikes, some of the those costs are eye watering. I am just in final stages of installing a Vaillant 7kW unit plus new uvc and headline costs have been £4k for heat pump, £1k for uvc and around £1k for sundries Granted it has been a fairly straightforward install with existing underfloor on ground and 1st floors, that said have still removed blending valves and pumps on manifolds to make fully open loop, that was quite and effort to get right. It has taken me 4 - 5 days on my own and that is doing soldered joints not press fit. Seeing quotes of 15 man days makes me think they must drink lots of coffee ... Majority of suppliers appear to use the BUS grant as a nice little bonus instead of it being the fully passed on discount that it should be.

Hi Chris, we are in final stages of build / retrofit of 250m2 house, aiming for as near passive house as we can with attention to air tightness, triple glazing throughout, removed chimney and have mvhr. Also underfloor ground and first floors with 28mm primaries etc. I approached a few MCS suppliers and was being pushed towards 11 - 12kw units. This didn't match my own calcs or how the house behaved when on gas boiler. The route I have taken is DIY install via an MCS Umbrella company. I am doing all my own plumbing and electrics. Headline costs have been £4k for 7Kw Vaillant Arotherm, £1k for Vaillant 250l cylinder and approx £1600 for Umbrella costs. ( All inclusive of vat ) This way you can still install via BUS grant but are not tied to crazy prices or forced into a heat pump that you don't want or need.

Hi all. Stuck on one element of the heat pump interface wiring - the cabling to the diverter valve from the interface connection UV1 : I am using an ESBE diverter that has a neutral, permanent live and switched live for switching to DHW. The interface has connections marked N (assume neutral), Auf & Zu? Anybody point me in the right direction. Thanks.

Hi all, 1/2 way through my self install of Vaillant heat pump and cylinder. I am making an effort to give the flow the best chance it can by using sweeping bends, 28mm pipe for all main runs, 1 1/4" esbe diverter valve etc. I have looked at the 28mm flexible connector pipes and I have to say not overly impressed with the internal diameter, appreciate its only a 750mm run but its a chunk smaller than 28mm copper pipe. My heat pump is 300mm away from utility cavity wall so pipe run is really short, basically straight out of the back and through wall via pair of anti freeze valves. I have read a few comments about not requiring flexi hoses on the Vaillants. What are peoples thoughts?

Thanks for the input. The thing I focus on more than maybe I should is cycling and the risk of oversizing. Currently debating whether to install a 7kW or 5kW Arotherm. The 5kW will probably suffice as majority of time it can generate 7kW My rational is that it won't cycle as much as possible the 7kW unit will. Are you saying that a degree of cycling won't harm as long as its not to often?

But it appears to affect the heat pump size required i.e. the design temp is taken as 21 degrees on both floors at same time. Generally bedrooms are cooler and also not needed during the day, at night downstairs is on setback at around 18 degrees or so. None of this appears to be taken into account. I kept trying to argue that what I see day in day out during the winter with my gas boiler doesn't marry up with what I am being told I need on paper. Also MCS forces you to have a warm house at -2 degrees, majority of time temp is not below zero but you are not allowed to factor in the possibility of a few days of the year where you may be a little down on temperature and have to pout on a jumper etc. What that means is the rest of the winter and the majority of the time you have a heat pump that is to big. Bottom line is that I am now installing a much smaller heat pump than I was originally being forced to do, time will tell who was correct 🙂

The ongoing indecision of Vaillant or Joule cylinder continues. On paper the Joule heat pump cylinder appears superior i.e. 28mm coil diameter v 22mm, 3m2 v 2.4m2 for Vaillant, immersion when required is lower down, both do 595mm diameter so shorter than normal for 250l which is what I need. Vaillant has a better insulation with a B rating. My big doubt is that feedback on Internet is very poor for Joule customer service with what appears a high failure rate after just 2 or 3 years? What are peoples thoughts / experience? Regarding the coil area etc not sure why so much emphasis is placed on this with coil capacities of 40 - 42kW being quoted. If the heat pump can only output 6 - 9 kW why does this make such a difference? Thanks all.

A couple of things I have learnt on my ongoing heat pump journey is that the heat loss calcs can vary widely. Also they all appear to factor in the heat loss for ground and 1st floors at same time but in reality you generally only need the heat downstairs during the day and possibly some heat upstairs for only a few hours a day, in our case we never have heating upstairs in what is a reasonably well insulated renovated house. Therefore real life heat loss is a lot less than majority of MCS companies tell you and hence why there are probably so many oversized heat pumps out there. Regarding installation it appears to make no difference to ease of install against cost i.e. our install is quite simple : heat pump otherside of cavity wall where boiler is already, we have existing 28mm flow and return pipes to underfloor heating manifolds, no radiators as underfloor on both, power and 2 core comms already run to where heat pump is being installed as I factored in heat pump sometime in the future so made it ready. Even with all of this quotes still came in around £8k on top of the £7.5 K grant ! I have now gone down the umbrella route of installation and am purchasing and installing heat pump myself along with friendly plumber. All of the paperwork, sign off, grant application is taken care by the MCS umbrella company. Installation of Vaillant Arotherm plus new cylinder should be cost neutral hopefully.

What part of country are you at?

I am doing install myself under the umbrella of MCS. Waiting on schematics but in the meantime looking at all options that may optimise the system and hopefully input from others. Things that work well and not so well etc. Cheers

Hi, planning on using Vaillant control, not sure what combination I need. I would like to have two wireless controllers / thermostats as part of the setup, zone 1 - whole ground floor, then one on top floor as separate zone. Plan is run open loop for whole ground floor with no buffer etc, approx 150m2 and then run single zone on 1st floor but with room stats which I have on old system to limit each bedroom temp in case they get to hot.

We have a nice 800mm entry to loft room with stairs - use it as a den for my lad, door off that to ' plant room '

Again something that has probably been discussed so apologies. I have gone to a lot of effort to make sure I have primaries in 28mm, swept bends, minimal restriction etc but now I have come to sourcing the 3 way diverter and the traditional Honeywell type appears very restrictive. Just wondering what peoples thoughts were and what others had installed. I am biased towards the ESBE VRG131 at the moment, probably in the 1 1/2" size.

Thanks for the input re the cylinder. I have decided to bite the bullet and go with a Joule Cyclone high gain, 3m2 coil, 28mm fittings, bonus is that they do the 250l in a 'short' 600mm diameter so height is only 1400mm, this is beneficial as my small plant room is in the loft (warm roof) with restricted headroom.

Thanks all for the advice. It is frustrating as my existing cylinder is a Warmflow solar 250l with twin coils, I currently have these plumbed in series on my gas boiler and the re-heat time is very quick however all of the MCS installers are saying that I must upgrade to a ' heat pump ' cylinder. I am hoping I can convince them that my existing cylinder is fine and swap it out afterwards if proven not. The Vaillant R290 shows good efficiency even at 65 - 75 degrees, if that is the case I don't see why anyone would have to swap out their cylinders. I guess an option is to upgrade the existing by running an external heat exchanger connected to secondary input running in series / parallel with the coil ?

Hi, apologies if this topic has been covered previously. We are just in process of installing a Vaillant Arotherm 7.0kW and need to change existing cylinder. My default go to option was the Vaillant Unistor 250l cylinder but having checked the specs it only has a 2.2m2 coil and also uses 22mm pipe as opposed to other dedicated heat pump cylinders such as Joule that have 3m2 coil and 28mm connections. I like the fact that the Vaillant is a shorter (600mm wide) tank which is beneficial as it is going into a place with restricted height and they are a neat looking unit with hidden wiring etc. Am I worrying to much about the smaller coil dimensions, surely they wouldn't sell a product not up to speed? I understand that regardless of coil size if the heat pump only outputs x amount then the coil can only transfer so much heat so a bigger coil doesn't necessarily mean faster heat recovery, also it is better to run cooler and longer to improve COP so again bigger coil not such a benefit? Thanks 🙂

if you are happy to install yourself or get your local plumber to install try AltoEnergy - they do the MCS umbrella scheme where you can claim BUS grant, install yourself but you still get mcs certificate and manufacturers warranty etc. They supply Mitsubishi and Samsung systems. Price after grant is approx £1000 - £1500 I have been very impressed with them and their feedback on Trust Pilot is great

AltoEnergy openly promote the self builder to install heat pump and go on training course. The only thing that would need assistance is a plumber with g3 to install cylinder.

The problem I have been fighting is the insistence of what i consider to be an overly large heat pump. The solution currently proposed is an 8.5kW Ecodan plus their 210 cylinder with heat exchanger. From what I have read the re-heat time doesn't appear that different to a normal cylinder with 3m2 coil. As cylinder is in loft concerned about now having three pumps going and noise issues etc. I would prefer single system pump within the monoblock so as to keep pump noise external. If using an external heat exchanger was so good / efficient why are there not more solutions like this?

Looking at the 210L and that's a full 210L as there is no large coil inside taking up space. On a standard 250l cylinder with 3m2 coil how much usable water is left? We have a 250l non heat pump compatible cylinder at mo and am a little concerned about dropping down to 210 litre