ProDave

No, that is what you would use if you were having lots of individual zones and individual actuators for each pipe loop. You just want to join together the two motorised valve cables, 2 thermostat cables, a cable to the pump, a flex in providing power and (still to be determined) how to connect to the RTC6. Something like this https://www.toolstation.com/drayton-wiring-centre/p56309

Good find, but THE PRICE !!!!

To make it work you need a junction box to connect it all together, I would start with a standard central heating "wiring centre" which is usually just a plastic box with a 12 way terminal block inside and lots of cable entries. I am hoping that one of the many forum members familliar with the FTC6 will answer what it's call for heat input is.

So you have one motorised valve per manifold but only ONE pump that serves both manifolds. That complicates the issue. What is the call for heat input on the FTC6? Does it have to be a volt free contact or will it accept a switched 240v ac input? The logic is: Basement thermostat energises basement motorised valve when it wants heat. Ground floor thermostat energised ground floor motorised valve when it wants heat. The feedback contacts (orange and grey wires) from both motorised valves connect in parallel and will turn on the pump when either floor is calling for heat. Where it will get complicated if the FTC6 insists on a volt free contact you will have to use a relay.

Yes you want to specify "loop at switch" Wiring regs don't specify which method to use, it is choice of the electrician or the client.

If anything I would say mine defrosts more in DHW mode as it is generally working harder then.

The worst time for icing is when the air is a few degrees above freezing, the heat exchanger will be colder and in this case below 0. Once the air gets below 0 for any length of time there is little moisture left in it, so almost counter intuitive, there is much less chance of icing. I have an older version of the monoblock ASHP and there are no user adjustable parameters relating to defrosting. And nothing published about how it decides when to defrost. I would be inclined to just let yours get on with it if nothing else to see if the defrost function works.

4 gang grid switch is your only answer with one fitted with a blank. I have never seen a 3 gang switch in a 2G wide front plate. Or if going for new dimmers, just buy any make of new dimmer and swap the modules over onto your old front plate.

My No 1 tip is do it as a warm roof or hybrid roof. So air tight layer over the top of the attic joists (roof stripped completely) external insulation over the top of the joists, then batten counter batten and tiles or do the rolls royce and an in roof PV system. Take the insulation right down to the eaves don't faff about trying to exclude the eaves space from the insulated envelope. You might want a SE to check the existing attic trusses are ok for a heavier roof tile and PV.

I thought the conversion from m3/m2 to ACH was very approximately 1:1 but there is no simple universal conversion because it depends on the geometry of the house, i.e is it single storey, 2 storey, vaulted ceilings etc. If it really was divide by 20 them my 1.4 m3/m2 would be 0.07ACH. No way is that the case.

And sometimes it can be warmer here due to the Foehn effect

I would say 15mm is pretty insignificant for a 175mm joist. The important point is drill the hole on the centreline.

Hillockhead is not far from me, on the north coast of the Moray Firth. It's one of the weather stations I use when checking if it's good sailing weather. Contrary to popular belief but sun does shine up here. The reality is the main difference in the weather up hers vs down there, is here it is colder and windier.

It's an electric fan heater. If it uses half the electricity of another heater it will take twice as long to heat the room and cost exactly the same. If you want an electric fan heater, just buy the cheapest one you can. Trying to claim it is more efficient than others is snake oil. EEK I just looked at the prices. AVOID.

You are slightly confusing the discussion by talking about a "reed relay" Those do exist but they are not what you want. you want a "reed switch" that is just a switch that closes when it gets near a magnet. You might find the contact rating a bit low for your needs so you might need to use the reed switch to switch an conventional relay to turn the lights on. My personal preference in that situation would be to reverse in. Reversing out you are putting the rear end of your car in danger before you can see if anything is coming. That is actually safer at night because you hope they would have lights on so you should see someone coming. If you were building that house now they would insist you had turning space so you could enter and then leave in forward gear.

With mine, an LG ASHP I turned off all the settings in the heat pump to automatically use the immersion heater. A well respected former member did a very good analysis that if you are on treated mains water, you can be sure there are no bugs in the water supply, and if the cylinder is unvented, no way for bugs to enter, so no need for a legionairs cycle. Different matter if you are on a private water supply or have a vented water tank fed from a header tank. I can still turn my immersion heater on manually should I need it, and in any event surplus solar PV automatically goes to the immersion heater.

Just watched this episode. I don't have a problem with the size if it. If someone can afford it and that is what they want best of luck to them. Although it took longer than their plan, there were not any major blunders with the build. But what did get me quite angry and shouting at the television was this Passive House Plus. The house has to generate 4 times the power it uses. That's a very laudable aim and one you would hope would be achievable. And it is the achievable bit that got me angry and shouting, because where I am, and in countless other places it would simply NOT be achievable. Not because I don't want to, but because the DNO would not allow it. They did touch on this in one sentence right at the end, the DNO export limit in this case is limiting them to about 2.5 times what the house uses. That is way better than what I am allowed, but still it shows the infrastructure and the red tape is holding back proper domestic scale self generation. And the £100K plus cost of the roof PV system would be another deal breaker for me. If programs like this keep on showing that domestic scale self generation is being hampered by an under funded under capacity grid, and stupid red tape, then perhaps, just perhaps the situation might improve.

These Horstman timers can be wired in a number of ways bepending if you have 1 or 2 elements and if you have a switched off peak supply. But the general principle is you want the tank heated between about midnight and 7AM during the cheap rate. The boost is only there in case you have used a lot of hot water and ran out, and will be charged at the peak rate. I would set your normal timer times from say 3AM to 7AM to get the latter part of the off peak time, and then only ever press the boost button if you have used all your hot water and need more before the next overnight charge.

I seem to be the only person who has the downstairs hall light also switched from top of stair and bottom of stair. It just seems such an omission not to do it.

Main bedroom light switched from by the door or either side of the bed. Bedside lights were 2 gang also switching a wall light. So one of them had to be a 2 way and an intermediate side by side on the same plate.

If you do more than 2 way switching, i.e. if you want the same light controlled by three switches, then the middle one has to be an intermediate switch which is different and has 4 terminals. If it then happened that the intermediate switch had to be on the same switch plate and another switch controlling a different light then with most manufacturers you have a problem. Most manufacturers only sell single intermediate switches and the traditional way around that is buy "grid switches" where you buy a mounting frame and the whatever switch modules you need. but that limits your choice. The Scolmore Click are not exactly grid switches but you can unscrew the switch mechanism with a single screw and swap them from one switch to another enabling you to mix intermediate and normal switches on one plate.

The two separating the living rooms (walls with bifold doors) I would look at aligning the walls with the pipes, so using perhaps 5 by 2 studs centred on the pipes so the pipes become completely encased in that bit of wall with no visible boxing in. That would take some carefull planning probably at foundation time if they are load bearing in any way. The air testing, buy the testing kit from somewhere like Screwfix and do it yourself. Up here BC want to witness a test so it is handy to have your own kit to save paying the plumber to come and do it when BC come.

That land will be well contaminated then.

I bet the original socket had scorch marks from the plumbers soldering.

Use common sense. Assume pipes WILL leak or drip, so avoid sockets directly under pipes. I have a socket in the sink unit for the boiling water tap. While we are at it, for dishwashers and washing machine, I fit the socket right at floor level UNDER the adjacent unit, so you don't need to pull the dishwasher or washing machine out to get to the plug, just remove a bit of kickboard. That REALLY bugs me for PAT testing when you have to heave a washing machine out just to get to the plug.