joth

The daily kWh is largely irrelevant, what is the peak power in watts? (Or the peak amperage) An electric cooker alone is 3kW plus, which is 100amps at 24V so fairly challenging to power on it's own.

Hi Lizzie Do you have any photos 1 more year on of how the house cladding is weathering? Has the new age gris been successful in avoiding any black spots forming? Thank you!

https://www.jtmplumbing.co.uk/central-heating-controls-valves-c436/esbe-valves-controls-solid-fuel-products-c509/mixing-valve-c511/esbe-valves-actuators-3-point-p19117/s20737?utm_source=google&utm_medium=cpc&utm_term=esbe-valves-esbe-ara652-3-point-spdt-230v-6nm-60s-actuator-esbe-valves-esbe-valves-esbe-ara652-3-point-spdt-230vac-6nm-60s-actuator-12101700&utm_campaign=product%2Blisting%2Bads&cid=GBP&gclid=EAIaIQobChMIha-U0qrw6wIVgc_tCh0Q0gfiEAQYASABEgJx4fD_BwE Noice, thank you sir. Looks like ESBE ARA662 3-Point SPDT 230v 6NM 120S Actuator is the one: mains operated and 2minute open->close run time, which is the "default" and recommended setting in the FTC5 controller. (MI Page 44: "Set the Running time according to the specifications of the actuator of each mixing valve. It is recommended to set the interval to 2 minutes that is a default value. With the interval set longer, it could take longer to warm up a room.") 👍 do update us with what you find. The FTC5 looks pretty comprehensive and well thought through. Possibly a brain-ache to setup, but I am hopeful it's going to suit us really well.

Right, the ASHP we're using (Ecodan 8.5kw) controller has an output to manage an electrically actuated mixing valve, see snippet from the MIs copied below. It has thermistors on the flow and return to the UFH so in priciple can be as good as a thermastic analog valve, failure modes excepted. This is quite a nice setup, as it means the ASHP can do the right thing to actively manage cooling as well as heating temperature for two emitters running simultaneously at different target temps, and also in principle could close off (set to bypass) the mixer valve when the zone is not being actively driven, which would allow the zone pump to overrun too (i.e. support 24/7 UFH recirculation as discussed above). Now assuming we don't trust this setup to protect our expensive floor finishes, yet would still like to have that motorized mixer valve for the fine control it gives, would it make sense to use both a blending TMV pumpset and the motorized valve? We'd put the TMV on the UFH side of the motorized valve (i.e. integrated with the pump). For this exception situation only use-case, using a standard (less expensive) TMV from wunda that only goes down to 30ºC maybe ~OK as this would only close off in error case anyway? (Still can't help it feels OTT. The alternative safety measure that comes to mind is to put an additional thermistor in the floor screed or on the UFH flow pipe, and have it trip a relay to cut out the pump if it ever exceeds a set point). Bonus question: recommend me an appropriate motorized valve? 🙂 (2L+N connections) Cheers

See @Conor comment last week:

RIP Buzby

Just found this was already discussed in depth last month over in this other thread, although I'm drawing different conclusion to there!

Thanks all! Yeah think I got that bit fine -- it's the opposite case, TMV is open (drawing in from the hot flow source rather than bypassing) but the ASHP isn't feeding the UFH zone (e.g. because it's being used to heat the UVC, or it's forced off during peak-rate price surge) that was my concern. Got it. So in summary, using a bufferless design and allowing 24/7 UFH recirculation are mutually incompatible. If we want the option of running the UFH pump when the heating is not on (e.g. to balance temperature in the very sunny south facing rooms with the cooler open plan north side of house, per JHarris's setup) we need to have a buffer tank of some sort. (And sizing it is the follow on question per OP) Final question: am I right in using "Buffer tank" and "Low loss header" interchangeably? Or is there a technical difference between them?

@ProDave do you have a separate pump for ufh circulation and a blending valve? This is the setup our ASHP installer has recommended (8.5kW ecodan, no buffer or LL header) and I'm wondering what happens when the ufh thermostat drops below setpoint so is "calling for heat" but the ASHP not on or is charging the cylinder? The ufh pump will be pushing against a closed valve?? So do you need to lock out the ufh circulation pump to only run when the ASHP is active for that zone? Put another way if we wanted to run the ufh pump all day to balance temperature of rooms (like @Jeremy Harris) we have to have a low loss header, right?

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They don't really do panels only, but they were about 1.2 £/W including inverter for a part roof RIS supply only, jumping up to almost 2 £/W for a full roof including installation (and it took some negotiation to get it down to that price). The full roof is extremely specialist as the frame and panels have to be made _exactly_ sized to fit so they're pretty reluctant to provide it supply only. Also the aluminium frame is very unforgiving of the slightest undulation in the roof. Altogether a terrible choice for a renovation as we're now finding 🤣

GB sol RIS, so no tray as such just an aluminium frame. These are only ever used together so presumably the fire test was done years ago and isn't much of a thought now.

Blimey you must be cracking on! Last I saw you had just done the ground slab pour? by contrast we started renovating in Jan, yet we still seem to be 2+ months away from the panels being installed. btw interesting question about the fire cert. I've not heard mention of this at all -- ask me in a few months if we actually get the cert.

>Cleaning dreams? Avoid the need for cleaning by designing-out sources of dirt. e.g. design an airtight house with MVHR that filters incoming air, to remove a lot of dust issues. The more urban the house the more the benefit. No open fireplace, or any combustion source in the house. Clear and easy to use storage place for shoes and outside coats, and comfortable inviting place to remove them. If you have pets, a pet-designated area without them needing to roam the whole house. Ideally in an MVHR 'extract' zone so their smells and fur doesn't travel around the rest of the house. What other sources of dirt can be designed out? then removing dirt that does get in: design floor areas to support a robotic vacuum cleaner. Carpets are sub-optimal, as are uneven thresholds between rooms. Reduce number of stepped levels. Look to industrial catering and hospitals. Stainless steel kitchen and pantry, "wet room" toilets etc designed to allow periodic deep steam cleaning. There's probably clear design guidance/standards for these, but I can't find it. Then, if you're like us and can't abide cleaning, what about design elements that simplify hiring a professional cleaner? no ideas come to mind other than clear storage for cleaning equipment and a big sink for them to use. maybe a door lock and security system (inc. a safe?) that makes it comfortable letting them in even when not at home (a distant memory, but it may yet happen again).

This maybe an overzealous interpretation of Part L https://www.intergasheating.co.uk/app/uploads/2018/06/Guidance-on-Boiler-Plus-BEIS.pdf That states every house must have 2 independent temp controlled zones, and the guidance is these are often "living area" (downstairs) and "sleeping areas" (i.e. upstairs) FWIW we had a lot of conflicting advice on if we needed upstairs heating or not (and we are going PH certified, all be it EnerPHit). So we comprimsed on putting fused spurs into each bedroom to allow a possible future infrared panel heater if needed, and plumbing into the loft to allow a possible future fancoil unit if needed