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Can't you buy a data SIM like: https://www.three.co.uk/broadband/data-sim-payg Edit: see you mention preference for O2 / EE. Look for mobile broadband or packages for tablets. EE have a whole line of Mobile Broadband offers, not sure they are sim only but if you are looking for a router too then worth a look.

The dynamic adjustment of temperature via opentherm is one of the reasons I went this route and Wiser is fully dynamic in this. If I set my system to regulate temperature in my cold room (starting from cold) it will set the water temp to maximum until the room temp is within about 0.5C of setpoint and will then moderate it down to whatever it needs for steady state. @gaz_moose I don't know how techie you are but if feel able to I thoroughly recommend setting up HomeAssistant and installing the Wiser plugin. It lets you see what's going on and understand your system better including how often your boiler cycles. I'm not sure that Wiser is great at handling cycling when using opentherm. I suspect if your heating system is well designed then it should work ok but with mine (which is badly designed) it doesn't handle things great. I'm still working through how I want to manage this but you really want to avoid frequent cycling so if that's happening in your case then you may want to take extra steps. (If Home Assistant is a step too far, then standing in front of the boiler and watching it for 20 mins while the temp is steady state will show you how much it cycles). An easy one that seems to work is to have the scheduler regularly adjust the set point up/down by 0.5C as the cycling seems to happen when very close to set point.

Their FAQs are very informative: https://buffalomachines.co.uk/pages/faqs Website says they have 30 years combined industry experience but company only incorporated in 2023: https://find-and-update.company-information.service.gov.uk/company/15271611 Looks like they are just a UK importer of Chinese machines. So whether you actually benefit from going to them IDK. Maybe warranty issues, but adding the middle man might not help much in reality

Ideas to consider: 1. Don't split any loop between areas, put separate loops. 2. For routing the pipes for the loops for the second phase, either use conduit as @Nickfromwales to allow you to install the pipes when you are doing the second phase, or look to see if you can route pipes in walls/ceilings between areas. 3. Maybe it makes sense to have two manifolds, one for phase 1 and one for phase 2. Then you just have to route 2 (bigger) pipes between the two locations.* * Some nuances here that needs careful thought but worth considering if other options difficult.

You'd need a very big PHE. The flow through pool heatpumps is huge compared to CH. If you have to upsize the domestic heatpump you may also lose out financially. Pool heatpumps are super cheap compared with domestic ones. Feels like this is something so outside your normal heat pump installers wheelhouse, that you'll either be paying them a huge amount to learn on the job and develop a bespoke solution for you or you'll scare them all off.

I thought pool heat pumps had fairly different optimisations from domestic ones so trying to mix them would not be advisable. @SBMS wants cooling anyway so I think needs a separate system on that basis.

Make the connections on the roof, run continous cable through some form of protection (trunking, kopex, etc) to the ground. Don't make connections inside the roof. If you are using the PV Ultra cable I guess you'll need a connection box on the roof which is a little more tricky to create space for but doable. Ignoring the detail about how the cable routes from roof to inverter I think you want all the solar panel MC4s to be accessible from the roof side. If a panel gets damaged or needs to be lifted for another reason, you need to be able to access the connections from the roof side to disconnect it.

Reading between the lines it sounds like you don't feel you get enough heat in the loft conversion so to get that room hot you have to turn off the other rads (either because it doesn't get hot otherwise, or by the time it does get hot the rest of the house is boiling). That sounds like something is wrong with your system. If starting from a cold house, turn up all the radiators and turn on the heating. All the radiators should get hot at roughly the same speed. If that doesn't happen then your system isn't balanced and some of the hot water might be short circuiting back to the boiler before it reaches your cold room. If this is the problem then the first step is balancing the radiators and then coming back with more info on your system if this doesn't solve things. I've just been doing similar in my place. Once you have things roughly balanced you should be able to just use normal TRVs to adjust individual rooms. Yes this still means all the rooms heat at the same time, but rooms should warm in approx the same time. If, like me, some of your rooms have woefully undersized radiators then you still might have a problem, but smart heating won't solve that.

Thought that was recommended against these days. In any case, best to keep the active electronics outside of the hot (in summer) loft if you can.

My worry would be it's 2.5mm2 copper coated aluminium. Still probably better than the 1.25mm2 copper ones mentioned earlier, but nowhere near 2.5mm2 copper.

That one makes my spidey senses tingle. As in is it a dodgy Chinesium one? It's also available at close to half the price on polybound.co.uk (the claimed manufacturer - who seem to specialise in resin bound surfaces). https://polybound.co.uk/product/tools-equipment/25m-blue-extension-cable-reel/

I wasn't thinking about CH at all. Now I remember you previously talking about it being unvented. No matter, the HW cylinder/system can be dealt with independently AFAIK so no need to link the two in a single job. So no real reason to change it from a delapidations point of view. As far as maintenance goes, I remember you saying you were aiming to get as much done as possible before retirement so that you kept your costs low in future. Retirement also brings the future potential of not being as able to DIY as much. I tend to think that both of these lean more towards the unvented solution as it's simpler* but maybe not by a lot. But the backup water during outages is a big positive of the vented option. *Yes you have the PRVs and the associated maintenance. But these are all contained in an accessible heated/controlled space, no ladders involved, no float valves or pumps to play up.

🫣 Assume the HW pipes flow through these rooms to the kitchen/bathroom? Changing the HW tank shouldn't affect CH pressure unless I've misunderstood something. That is an advantage. My experience of cold water tanks in lofts is they end up with unpleasant things in them and are located in a diffcult spot for maintenance. Having said that you are not my relatives and are likely taking much more care of the system than the average person.

Without knowing about the extent of the pipework you are worried about leaking this would be my strong preference. Getting rid of shower pumps, cold water tank, etc, and if the pipework is fragile enough to break under mains pressure then chances it fails anyway at some point? (replace with point to point plastic with no joins if access isn't too bad?) Obviously, need to worry about the G3 stuff so you have less scope for DIY but overall I think you end up with less to go wrong in future.

Failing that, can you temporarily store it over winter and get rid of it after it drys out (potentially leaving time to co-ordinate removal to happen on a lorry that was coming to site to deliver something)? Double handling might make this a non-starter. But if you are doing the moving with your own equipment then maybe makes sense.

Saw something the other day. The BBC has cut its news budget by 40% in real terms in recent years. Given the big names command high salaries it seems likely that they are consuming a greater and greater amount of the budget with back ground research/beat journalists getting massively cut. Papers are similar. Their business model is crippled by social media and the lack of money in adverts these days.

Theres another benefit to starting now, even if you initially see minimal gain. It chips away at a bigger project, getting you closer to the goal. Once this is up and running, your list of things to do will be less daunting and more approachable. Plus theres always the chance that once the inverter is generating it provides you the data to justify more upgrades.

Some areas worse than others but yes. My feeling is they copied a lot of their workings from other flats that have 1-2m2 windows and applied it to my flat which has those windows replaced with sliding doors that occupy most of the external wall, then on top of that late in the design they changed the sizes of the rooms making one in particular 6+m2 bigger. The change in design for my flat means that they have got some other thermal bridging details wrong. The concrete floor extends without break onto the balcony for example.

Current ones all K1 except one

Not sure the manufacturer but the current ones are along the lines of these: https://www.stelrad.com/radiators/designer-radiators/white-radiators/flat/ £166 for K1 600x800, white £250 for K2 600x800, white If you upgraded to K2 600x1200, white, then £350 Existing are powder coated colour matched. Finding that option adds a lot to the price (looked at various brands all similar) Type 22 800x1200 white Flomasta is £58 from Screwfix https://www.screwfix.com/p/flomasta-600mm-x-1200mm-6998btu-white-type-22-convector-radiator/612xp#product_additional_details_container

Yep, lots of options, but I doubt I could manipulate the tails easily to do that and adjusting things behind the plasterboard would be the better looking option. I expect to repaint before selling anyway. New option occurred to me last night. I could replace all the radiators with Flomasta ones for not much more than the price of one new one matching existing and maybe even get some of my money back selling the old ones (though that seems questionable). It's a lot of work though and more than I signed up for when buying the wiser. Might meet payback though (especially if I can sell the existing rads). Still not sure if the style downgrade makes sense, but it's an easier sell if everything is consistent. Every room is different and it's good to have options!

Be funny if me linking to something that didn't do what I initially thought ends up being something you use! I do like the idea of using this in parallel to the Shelly, rather than programming the Shelly to do the boost itself, as you get the redunancy. But I'm pretty sure you could do with all within the Shelly and wiring a retractive switch to it.

If I decided I wanted to target full low temp system (ie, support low temps year round) I expect I would look to install wider radiators rather than go to triples. Triples will eat into the room in a negative way, longer rads not so much. But would involve redoing the pipework around the rads (and breaking into the plasterboard to do it). Having said that at this stage I think it's very unlikely I'd go that route. Sounds like a recipe for harmony!

They have put bigger radiators in the kitchen area which also has high heat loss. I suspect it's more of a screw up than deliberate undersizing. When I bought there was a big delay because the plans on the lease didn't reflect reality so had to be amended. So I think the design of my flat was changed at a rather late stage and I'd guess heating not reviewed after. Yeh, I don't think I'm going to be making the changes necessary to run at low temp all the time. If I change the rads I'd be aiming for it to be enough for low temp heating a large chunk of the time but require high temps during the coldest. 800 wide, 600 tall.

I expect so and that is one of the things I will try. I've also thought about just using the wiser scheduler to increase decrease the set point by 0.5C very frequently to keep the wiser outside the oscillation area. I don't believe thats possible. The boiler is pretty basic.