SimonD

My view is that if we're going to be properly provocative with this question, we need to consider aspests that underpin the front end tech, which is unfortunately how the problem is typically viewed. The first thing that needs to be considered is the reality that whilst a heatpump may be more efficient, it also requires significantly more natural resources to make and distribute. A single heat pump installation can require up to 120kg more steel and 40kg more copper, not to mention the other requirements for various components. Shifting all boiler installs over to heatpumps would put a huge demand on mining, processing etc. of raw materials. Currently, copper mining is in decline with an insufficient number of mines going through the planning phase to come online. There is both known and unknown environmental cost to this kind of proposal. There is also an economic one as raw materials are likely to become more expensive as opposed the the incorrectly assumed reduction in price due to volume. The second is geopolitics. Chine currently controls the majority and with some materials enjoys the exclusive control of material processing for many of the materials required for heatpumps. We lost the ball on this one a couple of decades ago. For me, heatpumps are a distraction to what really needs to happen, which is a fundamental change to how we consume both natural materials and energy. The low hanging fruit of making homes more energy efficient has already been mentioned, as has behaviour change, awareness and education. The next step has to be a monumental shift in the systems in power - political, manufacturing, distribution etc. - as they've shown themselves to be incompetent in moving this forwards. In some ways, they've even gone backwards.

Usual test procedure is 1.5x working pressure or 10bar for 45 minutes for standard fittings. It's just the slimline fittings that ask for 18bar

I completely agree, I've recently had to re-wire 3 systems that were wired up incorrectly. One which was running constantly with no thermostatic control, despite the thermostat working, another new installation where the electrician had wired it all up using wagos and then shoved it all into the smallest backbox and screw it all down tight - no hot water and when I took the wires out, several live wires just fell out of the connectors. This was was even wired up incorrectly within the boiler itself. I'm just about to completely re-wire a system with combined UFD and rads where heating switched live was permanently live thanks to a dodgy 2 port valve, but when that was fixed I still had 85v at the boiler switched live together with rads heating when they shouldn't and random function of the 4 ufh zones. Weirdly all of these jobs came about because people had just bought and moved into the properties and thought things weren't quite right. I think there really should be a proper boiler/heating system training/certification coz the problems seem to be rampant out there.

This is a good candidate as someone has sensibly written 3A fuse fitted on top. The behaviour of the programmer does indicate a problem there, but looking at the wiring centre, it's difficult to establish from the photos exactly what is going where as several of the wires are hidden behind others, and some seem to disappear behind it. From looking at the labelling, it hasn't been wired up according to the labelling either- which doesn't help. As @ProDave has said, I think you really need to have the system looked at either by an electrician who understands heating systems or a heating engineer that understands heating system wiring to ensure all the components are working correctly. If you are competent using a multimeter, then it's possible to work through the system methodically and trace any problem backwards. For this you need an S-plan wiring diagram and then to understand the various switched lives within the system. I'm afraid I simply don't have the time right now to go through the steps I'd take to figure it all out, but here's my partial take on the current wiring situation on the wiring centre (based purely on the photo so worth what you've paid for it 😉). T3 - this is your switched live from room thermostat to 2 port motorised valve for heating system - bridged to T9 with yellow T5 - white from Honeywell valve - ignore T6 - Switched live from both heating and hot water valves. This goes live (orange from each valve) when either/both the valves are open. This turns on your pump and boiler. If you're having a problem with boiler running constantly then look here with multimeter and check each orange. The red from T6 looks like it connects to T12 & T13 which are what look like the supplies for pump and boiler T7 - permanent live to motorized valves (grey) coming from red originating at T11 which appears to be permanent live either from programmer or other supply. T8 - brown to hot water valve coming from blue at T14 which should be your cylinder stat T9 - bridged to T3 - presume yellow from room stat e.g. heating from programmer via stat T10 - bridged to T15 - should be swiched live from programmer for hot water but I can't determine where the connected blue comes from T11 - permanent live bridged to T7 T12 - bridged switched live from T6????? - to pump or boiler T13 - bridged swtich live from T12 and T6 ?????? - to pump or boiler T14 - switched live from cylinder stat bridged to T8 T15 - switched from programmer for hot water????? - bridged to T10 which may go to cylinder stat????? Some of these clearly have some big question marks but hopefully help in some beneficial direction. Online videos for s-plan are plenty. On Youtube plumberparts and Allen Hart have videos on the topic.

Yes, the hive receiver will just fit straight onto the existing backplate. The wiring is in the correct place with 3 for hot water and 4 for heating and presumably the initial installation put these round the right way - I obviously can't warrant that as I've not tested them! But even if after you installed the hive you found that the hot water went on when it was supposed to heat the house or it heated the house when it was supposed to heat the water, you could swap those wires around. No big deal. Your existing thermostat is basically a relay switch, it is either on or off. If it's off, then there's no voltage through that circuit. With a Hive, it controls that switching instead of the thermostat so it needs a permanent live. The easiest way to do this is by connecting the two wires connected to the thermostat and then replacing the thermostat with a blanking plate. Otherwise you need to rewire the thermostat switched live in your wiring centre which is next to the hot water cylinder - this is more complicated and by the sounds of your questions, not something you really want to be doing.

I just assumed it was the same slightly yellowed conduit in the close up shot, but maybe not?

The Hive will go straight onto the black wall plate you've shown in one of your photos. You then need to either bridge the existing thermostat behind the stat - use a simple wago connector - or rewire elsewhere if preferred. However, if you're experiencing strange behaviour it's worth getting someone in to test the system as there can sometimes be other issues causing the boiler to turn on or off when it shouldn't - for example, a faulty motorised valve can sometimes cause a permanent live to the boiler. Process is install the hub > Install the receiver > Add the Thermostat > Complete online setup through the app. Hive customer support is very good and responsive to setup queries - they have a phone number and answer it too! HTH.

Your installer should either have done a self certification for building regulations compliance (through an appropriate competent person scheme) or registered the install through your local building control to notify them of the installation - that's down to him not you so your BC will want this, not just your commissioning certificate. With just an commissioing certificate you may have to pay BC for an inspection and sign off for it.

Time suggests that this approach, especially in older buildings build with stone rarely stands up to the hype and inevitably fails - it is incredibly difficult to detail this to ensure it doesn't fail, hence why so much conservation now proposes using materials that work with moisture. Are you keeping the external cement render, or is this being removed as part of the works? Can you share the full specification of the buildup proposed by the architect and the alternative proposed by the tradesmen? Your other option, which I think works best in exposed areas is to design in a break between the elements and the interior. This could either be a rain screen to the front of the exterior or a ventilation gap between the external wall and a sheeps wool stud wall inside. That way the sheeps wool/woodfibre buildup can buffer excess moisture without the risk of getting saturated if the exposed wall does get wet to the inside.

Ah, so he was spot on then. And people questioned his theories.... Yep, I know that one, but also parallel universe. I saw myself in a video about my build and knew it wasn't me, couldn't be, it was only 2 years ago but a lifetime. Then my wife says it was 8 years ago surely....because she's waited at least 8 years even though we didn't start near 8 years ago, rather I broke ground in Jan 2019. 🤷‍♂️🤷‍♀️ (me and my wife) As for what type of screws, only on buildhub could you find a 2 page thread on needing to see and feel the screws to decide before buying and spending loads of time on time on an internet forum to decide what type of screws to buy - now that's quantum mechanics for you...

I now use ForgeFast torx screws by default. Readily available from Toolstation at a good price and in large trade tubs.

Alpha Pneumatic Supplies sell full round head annular ring stainless steel nails suitable for 34 degree framing nailers. I think they probably do them for 21 degree nailers too. Brand is normally Beck fasteners. https://nailers.co.uk/ Usually best to call them.

It's 40C for ufh on the Vortex exactly as you say to prevent corrosion of the water jacket. For normal rads they recommend 70/50.

These are brick walls with a small infill extension having used dense blocks

It's been suggested to me to dot & dab the plasterboard over Gyproc Soundcoat plus parge coat where I'd planned battens with service void. How might I regret dot & dab versus battens as dot & dab is going to be both cheaper and quicker. Anybody else able to share some pros and cons?

I've used hardwall plus multifinish on high suction clay bricks. DIY and no cracks. The way I approached it was to liberally spray the bricks with water, let it soak in and then spray again before applying hardwall. With the hardwall, I keyed it and left to set, then wetted and applied the multifinish24 hours later. No need for pva or anything like that, just hardwall and multifinish.

Not in mine. Can hardly hear it now even when very heavy. Once we've got the final 50mm in the service void nobody will really notice. Ours is a good few hundred mm of Sheepswool insulation which is also a good acoustic insulator.

I doubt it. That's exactly what I meant in my post 😁 I studied 'proper' engineering at degree level too; aerospace engineering. I was drawn to aerospace engineering because I'd been influenced by members of a gliding club I used to fly at where they built their own planes, then got turned off aerospace engineering because it was so much about mathematical modelling and it just didn't inspire me, so I changed paths. I also worked at what used to be Foster Wheeler for about 5 years. I tend to think that a proper engineer includes those who can make, build and work on the stuff they're designing.

Engineer is quite a confusing term for a lot of people, but its formal definition from the Cambridge English dictionary does include: 1. a person whose job is to design or build machines, engines, or electrical equipment, or things such as roads, railways, or bridges, using scientific principles: - a civil engineer - a mechanical/structural engineer - a software engineer 2. a person whose job is to repair or control machines, engines, or electrical equipment: - a computer engineer - The engineer is coming to repair our phone tomorrow morning. So heating or gas engineer, for example, could technically be correct. I personally get miffed by design engineers who somehow believe they're above the engineers that work with their hands. I remember when I was taught how to use metal lathes and mills and my teacher was the head of apprenticeship programme at the AWE. He used to get looked down upon because of his dirty dungarees, until those very same engineers had a problem and were told by the senior design engineers to ask him for help to solve problems - the things he could design and make were incredible. They used to call him a technician.... Probably a little overkill, but I'm not sure I'd let a thermodynamicist anywhere near my heating system......much like how I wouldn't let a physicist anywhere near the design and building of my house.😉

@Kelvin and anyone else in Scotland - a paper that might be of interest highlighting ventilation aspects that affect both MVHR and natural ventilation performance: An assessment of environmental conditions in bedrooms of contemporary low energy houses in Scotland

I'm certainly no designer of passivhaus, but in terms of airtightness and ventilation, you need to look at them as seperate processes (while taking into consideration the ventilation in the house design of course). With airtightness you are looking to minimise as far as possible, the uncontrolled infiltration of air into and out of the house caused by a non-airtight fabric. Once you've done this, you have a more known volume of air that needs to be exchanged within the house to keep it healthy and comfortable. There are a number of calculations that can be used to predict average volumes exchanged through natural ventilation based upon localised climate and temperature differentials between exterior and interior that can then be used to understand the size and quantity of vents required. For example, a Passive Stack Vent would have a calculated diameter based on room volume and predicted pressure differences in order to make sure it neither over or under ventilates the house. Bear in mind here that because a naturally ventilated house does not have constant exchange, you need to consider the average ventilation rates, so there may be times when RH peaks above recommended levels. But this doesn't matter over short periods of time. Mitigation can then be achieved through strategic use moisture buffering materials. Another strategy is of course to supplement the natural ventilation with lets say a mechanical extract vent switched for particular peaks of RH or CO2, for example. In terms of building regulations, I'm in England and with highly airtight buidings I believe that the current regulations permit the use of natural ventilation providing there is a specialist design. In terms of Scotland, they seem to have been more prescriptive and shot themselves in the foot slightly I wonder. However, reading the document, it simply says that for low infiltration dwellings, mechanical systems should be used to "augment, complement, and/or improve natural ventilation." It then gives some examples of systems that can be used. In this instance, if a natural ventilation system is designed by a company specialising in these systems, then first have a discussion with building control and then secondly look to add a something mechanical. In any case the Sottish regs don't appear to mandate MVHR.

No figures as yet. Still to organise a test as I'm really, desperately hoping to actually finish the house this year. However, given the number of hours spent with airtight foam, tapes, sealants, liquid membrane, parge coating, airtight caulk and all the other myriad of products in this space I'm secretly expecting the result to be okay, but we'll see. It's one of the little projects on my list to build my own fan and test rig, so I might soon be on here asking for some help to do this.

I got mine from Rytons: https://rts.vents.co.uk/blog/products/acoustic-aircore-and-airliner-sets-background/

The CIBSE Domestic Heating Design Guide gives the environmental design temp of bathrooms as 20-22C so my assumption has been that 26-27C is an in use figure.

I personally don't give two hoots about whether someone chooses to install MVHR in a development and everybody is different in terms of what they desire and feel comfortable with in terms of temperature variation throughout their house. I respect your experience of your home, but what troubles me is the use of limited data to come to conclusions that are then stated as fact about how these systems work more generally, without backup from larger scale research. This often feeds into what I think is becoming a bit of a MVHR evangelism that assumes MVHR is the only benign solution whereas it's actually more of a marketplace with vendors trying to sell us more technical kit which may often be unnecessary and costly over the long term, - this is even the case with the utterly poor paper published by the passivhaus trust which @Kelvinlinked to earlier in the thread. So forgive me for a minute if I geek out for a while 😉 If you look at temperature variation in the Chartered Institute of Building Services Engineers, for example, the indoor temperature range between rooms can be as much a 10C. As I quoted above it looks like this: Bathrooms 26–27 °C; Bedrooms 17–19 °C; Hall stairs landing 19–24 °C; Kitchen 17–19 °C; Living rooms 20–23 °C; Toilets 19–21 °C Whatever your beliefs about the extent of temperature equalization in homes, the wider research shows that this kind of variation cannot be provided by MVHR systems and this is found to be an issue for occupant comfort (and control). So, in addition to the limited phrase you chose to hang your coat on in the research I quoted above it says: "Research into thermal comfort supports the view that occupants of free-running buildings experience a comfort band, which relates to external temperatures and is wider than that experienced in mechanically ventilated buildings [15,16,17,18,19,20]." (bold is my emphasis). But to take some quotes from other research: Title: Ventilation Performance and Hygrothermal Conditions in New-build UK Housing (link: https://core.ac.uk/reader/159923279) "Significantly less variation of temperature and relative humidity levels were observed in homes with balanced mechanical ventilation with heat recovery systems (p=<0.001)" Title: Thermal comfort and IAQ in super-insulated housing with natural and decentralized ventilation systems in the south of the United Kingdom. (Link: https://core.ac.uk/reader/220155974) "Achieving thermal comfort in winter is as dependent on the heating system as the ventilation strategy. Decentralized systems tend to create thermal zones with different temperate within a building, while centralized systems tend to provide uniform temperatures in all rooms. " Title: On the oversupply of heat to bedrooms during winter in highly insulated dwellings with heat recovery ventilation (Link: https://www.sciencedirect.com/science/article/abs/pii/S0360132316302657) "The results clearly illustrates that the supply-air temperature and the temperatures in the living room and bathroom have substantial effects on the thermal conditions in the bedrooms. A one-zone MVHR solution, with approximately the same the supply-air temperature to all rooms, has clear limitations regarding the provision of thermal comfort in bedrooms." With the last quote, just wait for the next iteration of MVHR which would unsurprisingly be multi-zone to squeeze even more money out of us, add yet more complexity to the system, and be much harder to commission, run and maintain properly. If you're still tuned in, I could go on because I have plenty more papers I could dig out, but then it would get a bit silly, if it isn't already. 😉 So I'll go back to my original claim with some more specificity in that MVHR (centralised) will provide more uniform temperature through the house than a decentralised natural ventilation system.