Nickfromwales

Most typically don't pressure test with any antifreeze, and it's already been discussed on here that the likelihood of the below ground pipes ever freezing is pretty much zilch. It's the pipework that's above ground that's the issue, but a simple heater and a desk fan to blow it around a bit will be ample.

Buy a.Willis heater and get the chill off . You can get some heat into the slab and it's pretty straightforward to link to the manifold, prob only a few hours work to Heath Robinson one in. Or go nuts and buy 2 .

Good tip. I often have those sharing the same space, but I always run the HRC's for customers on a timer to suit occupancy. Ooh, just had a thought. You could connect the HRC from the burglar alarm panel....HRC on when alarm disarmed. Dragons den here I come ??

That drone is the dogs danglers . And, Sooo much snow. . We got some today but too wet to stick. ?

I normally do them in 10mm. As they have a double check nrv back at the pump return, the HRC pipework cannot contribute to flow rates at the outlet. Water can only pull through the hot delivery pipe so going bigger on the HRC pipework is a complete waste of time. The flow rate should be defined by the pump, as in it only needs to be on speed 1 / lowest setting which is ample. @TerryE @SteamyTea my argument is running the HRC from say 06:30 ( everyone waking up ) to 23:00 ( everyone tucked up in bed ) vs a system that utilises pir sensors aka occupancy switches which trigger the pump when a person walks into the room. If there are a couple / few bathrooms then all the cool / cold ( ambient ) water that has gone 'dead' will be circulated back to the uvc / Other and will drop the temp according to volume / frequency. It will ALSO draw unwanted hot water into the rest of the entire DHW network, serviced by the HRC. So.......my multi-faceted argument is which is the lesser of the two 'evils' ? I for one would say do away with the complexity of the room PIR's etc and just whack the HRC pump on a simple timer. For the occupancy switched setup to be completely comprehensive it would also need to be extended to cover the cloakroom / kitchen / utility, so, afaic, that could soon see a lot of cycles of hot water being drawn into already dead legs, which will be hugely wasteful as it'll be unwanted in all areas other than the target outlet that triggered the pump, and all those dead legs will have fired all the static water back to the cylinder. Id rather it was up to temp, left on, insulated as well as practicable, and controlled by a simple timer. The additinal volume of circulating DHW is also useful as an addition to the volume of hot, stored water, thus slightly increasing the DHW capacity. Bingo.

The cost, ideally, for running a hot return loop over say 24 hours. As above and for a basis, 65oC water temp, 18oC ambient service void, 30m of 22mm pipe and 30m of 10mm pipe insulated with this stuff. Maybe the spec is here ?

Is there any merit to adding a Y strainer before these AAV's in systems that have ferrous components or part existing pipework being recommissioned ?

@TerryE, you had better concentrate on the house . Thanks for replying. ?

PIR's aka occupancy switches . @jack, I think back in the day I was SLIGHTLY more conservative with my 'suggestive nature' plus iirc you said you had a designer / installer who was reasonablely fluent with the type of system / installation that was being discussed at the time so I didn't get overly involved ? but thanks for adding this as it could reinforce the decision @divorcingjack makes now in favour of doing the 'right thing'. Fwiw, with decent insulation, id be extremely surprised if the HRC added any 'heating' to the house, even in summer.

I've argued about this ( in my head ) as I'm often suprised that someone would starve themselves of such a worthy luxury for the sake of a few pennies a day in lost latent heat and the 20-25w pump power. I fail to comprehend how, after building a low-energy, cheap to run home, there would be such concern. ? @TerryE, would you be a darling and run some numbers for us? Based on 9mm Armorflex insulation maybe with 30m of 22mm pipe and 30m of 10mm pipe, and as much as all the juicy bits in that link appeal to the boffin in me ( ?? ) could we get a real world ( aka thick plumber ) POV in pence per day estimated running / losses costs ? One for @SteamyTea too, me thinks. He loves this kind of thing, nudge nudge wink wink.

Also, if easier, with the HRC you could just run a 15mm hot to the kitchen and utility direct from the UVC and run a 10mm HRC back to the UVC for absolutely instant hot water there. No need to manifold those tbh, as a ballofix isolation valve in the kitchen unit will suffice. Note : You'll need a ballofix isolation valve on both the hot and the HRC at each point they converge for service and maintenance. Water will travel back down the HRC so just shutting the one isolation on, for eg the kitchen sink, would still see water coming out of the tap.

@divorcingjack With the time constraints and lack of space to a) get services through, and b) keep a distance between the hot and cold feeds so the hots don't warm the colds, I think you'd be better off either dropping the manifold idea all together or doing the two remote manifolds, ( if you have sensible and accessible space to locate them adjacent to the rooms ). If you go 2x remote manifolds then don't forget to size them accordingly so you can take the kitchen and utility off the one closest. Either that, or as I'm not familiar with the layout of your house vs plant location etc, mount one larger manifold centrally to the two bathrooms / kitchen / utility. What I'd do, is then run a hot return circuit ( HRC ) between the UVC and the manifolds, with the HRC pumping through each manifold therefore keeping the entire manifold and the beginning of the connected pipework hot. This is achieved by connecting the HRC to the opposite end of the manifold to which the hot water arrives from the UVC, so basically your removing almost the entire dead leg of cold water, ( bar whatever is left in the now shorter final pipe runs from manifold to outlet ). The advantage here for you with that solution is only having to run one 22mm hot pipe from UVC to each manifold, and one 15mm or even 10mm HRC pipe back alongside it. The HRC can be 10mm without any problem whatsoever and it'll help too with being smaller as it really needs to be well insulated, as will the 22mm hot supply pipework, as when the HRC pump is running they'll be constantly hot and you want to reduce the losses as much as possible. If you insulate the HRC pipework well then the losses from running it will be negligible, but there are other measures to reduce that like putting occupancy switches in the bathrooms which only trigger the pump when the bathroom is occupied. I'm personally of the opinion that you'd be better off just running the pump when the house is occupied, as I don't see the appeal of having the slugs of static cold water in the dead legs of both bathrooms pumped back to the UVC to be reheated every time someone just has a pee and washes their hands being a good thing. You could argue that the cost of reheating that water would be similar to the losses from running the HRC constantly through the day. Maybe one of the resident uber mathematicians here could crunch the numbers on that, but if there is solar Pv in the picture then it's a no-brainer, just let it run from 06:00 to 23:00 or if your creatures of habit, with occupancy. Tbh, if I had my own to do, it would deffo be a cylinder, a HRC, and ( even without MCS ) I'd put at least 2-4 Pv panels on the roof to contribute towards any household daily background consumption, such as white goods / electronics and HRC etc. Just for clarity, what exactly are the distances between the UVC and the furthest hot outlet ? Maybe helpful to see this

Can't you excavate to find the start of the 32mm section and then camera survey to get the location of the joists & the 50x32mm reducer? I'd be doing my damnest to find the leak, and if it could be fixed in a day then bingo. Camera survey should be able to give you the distance from entry to the junctions / joints so you could try and work with what you've got. Do you intend to dig / follow the existing trench pipe run and lay alongside the leaking main anyhoo? I wouldn't give up so easy TBH, how much is the new main estimated at ?

Also @AliG you need to call a site meeting. Expailn to every guy / gal on site the importance of keeping doors and windows closed and drive the point home. Assuming they will do it isn't good enough, plus they need to be doing it when your not around too.

Every day is a school day . Never knew that ! Its bottled gas or red diesel heaters then, as I doubt there is any provision to be running all these massively electric-hungry devices. A couple of big dehumidifiers will use a lot of juice, even if via a 110v tranny. Maybe get the sparky to cut a couple of chunky supplies in at the CU for temp feeds ( e.g. Stick a 32a C-form socket on each cooker feed ). Or just make sure your running them off different ring mains if the generic electrics are operational? A few cheap 12" oscillating desk fans blowing across the slab should help move air around to help the dehumidifiers out a bit too.

It's getting heated from scratch for the first time, you dont have a front door, you don't have the mvhr running, and the doors which are there are like saloon doors ? Your going to chew through a lot of gas, not exactly a game changer ? Turning up the flow temp by 2-3oC should make a big difference so give that a whirl first and see what difference that makes over 24 hrs. To reinforce this I'd get some paraffin space heaters in on hire and blast some hot air through at the same time to get things moving. If you have deadlines then don't hang about, get the place warmed through by whatever means necessary. If there is a little cracking of joins in the plaster etc then so be it, it'll happen anyhoo to some degree so just bite the bullet and get the process shoved along a bit, even if it is against its will and a bit expensive on fuel. It's not going to happen any other way tbh.

? looks different to me as there is a spindle. The single levers usually go onto a square or rectangular shaft. I'd say not.

Ok, happy days. If I seem ? mph it's because I am . Good that you can fit large radiators in, as that'll work well with the ASHP. The bigger the better and that'll allow the flow temp for heating to stay low. Good that the stove air supply comes from outside, just make sure the stove is airtight as possible / good door seal etc. The reason I asked about how long your keeping it / how close is it was that I was going to suggest a single communal system which would reside at the main dwelling and feed the cottage via an umbilical supply trench. That's out the window as your too far away. Your having mvhr, so get the place as airtight as a drum. Hire / borrow a smoke machine and do a blower test. You can watch where the smoke goes and just keep going around until you've got it as good as you can. Using a torch outside on a still evening will show smoke outside. Also, be VERY mindful of where the intake for the mvhr is placed, as @JSHarris has had recent issues with neighbours wood burners stinking his house out. More on DHW in a bit.

There are 2 types of 3-way valve. One is a mid-position and one is a diverter. This one, following the link from the part number, is a diverter so can actually only give fliw to one port or t'other For mixed / combined flow ( true Y plan where a single flow temp can serve the rads and the dhw cylinder simultaneously ) the mid-position valve is the kiddy.

I argued against the single lever SEQUENTIAL valves ( because they have no flow control ? only temp ). The one you linked has both, but I'd really endeavour to find a thermostatic one TBH. Id rethink this if I were you.

Take your time, it's not a race ? I / we put a lot into one post as I am posting between merchants visits / working etc ?

Oh and are the properties detached ? If so what's the distance between the two ?

@Cpd Ok. Some observations . Why bother with an ASHP at all ? If it's only running a couple rads upstairs you'll be far better off going all electric. If you do go for the ASHP I'd deffo be utilising it to provide 100% of the space heating and at the least preheat ( via a small buffer with DHW coil ) for the electric instants. That all takes room and capital, and I assume you want a reasonable cost vs return. This sounds increasingly complex and TBH just screams gas combi boiler very very loudly. Can't recall if you have mains gas or not ? Also, a room sealed stove is a nice feature but kind of mucks up your airtighthess for effective use of the mvhr. I'd go 'outside air fed' for that at the very least. For space hesting with a ASHP you'll need oversized radiators to run at the lower flow temp, you don't really want to exceed 40oC or you'll end up defrosting on grid electricity and a higher flow temp will drop the CoP so you'll also be burning more grid electricity to reinforce the ASHP operation. You may be happy with an instant wall-wart over sink water heater but renting a house with one ? It'll look less than appealing and the flow rates from them is pitiful on a good day ? Before i go on to make some suggestions can you clarify..... 1) gas yes/no ? 2) are you holding onto BOTH properties for the foreseeable future eg 15+ years? 3) can you get large radiators in downstairs?

Combined with a smoke machine will soon identify where the bad air leaks are so they can be plugged.