Nickfromwales

And yes, the red Reliance TMVs each control the temp to the ground and 1st floor Ufh manifolds. Without them the water from the TS would go into the floor and cook Mutt n Jeff

Your Heatmiser system

Plain all round deffo.

Getting the house 'warmed through' will take a chunk of heat unless youve elected it to do so incrementally ( leaving the stat on and set to the desired temp ). Peter and I set the system to do 'summer / winter modes' where the top stat is the boss if you select DHW only ( aka summer ), and the lower stat is the boss if youve selected space heating ( aka winter ) where you will then also get DHW as a bi-product of the TS being hot. The idea was, fuelled by confusion and free beer, to only heat the upper 1/3rd of the TS during summer ( or when only hot water was required ) to reduce the volume of heated water. As there is far less volume then, the stat is set to a higher temp to get the boiler to kick in sooner, but to also have less work to do ( as at 24kw it was undersized for the system ). The lower stat is set to the lower temp as there is much more water and far less recovery for the boiler to do when the TS is full of warm water. Dont forget that the boiler also has to heat up 450L of cold water when you select the heating and water from a standstill before anything gets to the UFH. Comprendez vouz ?

Hi rusty. Welcome to the madhouse. Have a good read through as there’s a LOT of info here. ?

You should have got flexible cable, number of cores to suit, as the solid core stuff is for fixed wiring only. The Basic stuff is for wiring between the CU and the fused disconnection unit, and then you can use flexible cable, suitably protected in a trunking where practicable, which would be far easier. Also no need to earth sleeve anything as the earth will already be a PVC coated core.

@MikeGrahamT21, just glanced over this and spotted the bottle vent on the manifold laying flat. As you'll have the rads as the high points for bleeding air out I'd cap that off. They cant stay in the horizontal position or they wont work and will leak like a bugger.

Taking off the rads and blowing them through with cold mains water off the hose pipe is a good idea. I turn them upside down, and give them a few whacks with a hammer and a wooden block. Thats as good / better than a flush IMO, but If theyre over 30 years old, you'd be a heck of a lot better off changing them all to new convectors, and the heat output and reduced boiler temp will be significant. A power flush will be expensive, and you'll have to change all the radiator valves at the same time ( thus mitigating against @PeterW's point about causing multiple leak points ). If you change the rads and valves then you can get away without the expensive power flush, so you can then put that money towards the new rads. MrCentralheating online is cheap as chips and do package deals on rads and valves, but do avoid B&Q / Screwfix as the Kudox rads are garbage. If you have an old boiler I'd not recommend flushing that tbh, but it will be full of crap too. That would be better dispersed by using chemicals, over time. TBH at 60 years its time to spend some money on it as its all probably at the very end of its serviceable and reliable life. A leak could be more expensive than the system having an overhaul

TBH there wouldn't be a problem cutting rips of tiles into the gaps and just grouting and caulking. The only person who will ever look up at that is you. After its in and the room is finished and in use, you'll forget all about it.

With how fragile the vacuum insulation panels are, that would not, IMO, be a good idea. It may knacker your warranty too. I very much doubt SA would endorse that.

I remember as a schoolboy pricing a job with a mate. It was to remove a long dead, 3' dia tree stump from a 'posh lady''s garden. We went off and hired a tirfor and some strops and set about digging out and ataching to the stump and root ball. Happy with the effort we then found a huge cork tree 30' or so away to use as the anchor for the other end. We had a long pole attached to the winch and huffed and puffed away for what seemed forever. We went to check on progress, it had probably moved less than half an inch. Back to the winch we went and another tag team effort of huffing, puffing and foul language. This took us all afternoon. Nothing. The lady of the house came out and used some foul language all of her own, for all the time we'd been grafting in earnest, all we'd done was pull the cork tree out of the ground We turned around to see it at around 30 degrees with the root ball clearly visible ! We were sent packing with the hire bill coming out of our own pockets, bad backs, and a lesson learned. School boys vs tree-stump = no chance.

Which size / type of units did you got for ? 12's judging by the weight? Jesus Jeremy !!! It took 4 of us to get up a double- winder staircase with a 58/9 eHw the other day !!! How the hell did you manage that ?!? All I can say is thank god the customer was home and was a young fit chap or it would have been staying downstairs on some very long flexible hoses . Don't underestimate the weight if these things folks, and allow for mechanical handling. If going for size 12 units beware as they feel like they're bolted to the floor.

Hi. Can I ask who has specified a single unit for DHW and space heating? This would have multiple issues if not sized accurately. What standard are you building to, and do you know your space heating requirements in kWh eg fabric and ventilation combined? Sizing for both to come out of one unit is a very tricky balancing act and I would not advocate that unless your seriously oversizing the unit. However, as a size 12 ( ~14 kWh ) unit is the biggest you'll get before going to a SA 'cube' then I'd every wary of following this path. A SA on its own for DHW is extremely effective as it has time to recharge between depletions ( part or full ) whereas space heating will be a constant drain with no regard for leaving capacity behind ( in a shared unit ) for your DHW needs. I would only suggest this route if the SA unit was providing preheated cold mains water to a downstream water heater. Another issue will be that in any 'e' prefix model you have an electrical immersion heater which is only 3kW. Therefore if your combined load was 3kW or > you'd not be able to offset consumption by using grid electricity to 'boost'. I have set two installations up recently, both to achieve a 'no heat pump / all electric + PV scenario, and have done the following : Eg 1; 2 x SA eDual units for space heating + DHW uplift. Hot return tees into the 2nd unit so DHW recirculation cannot deplete the 1st unit. 1 x SA eHw unit for DHW only. Its capacity is nearly tripled by receiving preheated water from the two eDuals, and its segregation means that space heating cannot ever leave you with no DHW. Eg 2; 2 x SA eDual units for combined space heating and DHW. This scenario simply sees the units oversized to allow for worst case DHW consumption, but also assumes the PH levels of space heating required will always be able to be met or exceeded by injecting up to 6kWh of electricity ( PV primarily but grid backup for 'boost' will resolve 'party mode' where very high demands are made ). That system will be set up to inject electricity at the 50% system depletion level, regardless of day or night, but that compromise was made to ensure a heat pump wasn't required. This was agreed with the client at the design stage and all caveats / pros / cons discussed at length months prior to the order and installation of the SA units. No situation is the same as the last so remits and designs vary job to job. Doubling up on the units can also be a requirement where very high DHW flow rates are required, whereas a single unit under duress may start to run warm rather than hot, say if 3 showers were running simultaneously, as the water would be passing through the heat exchangers too quickly to absorb and convey the stored heat energy. There is no 'black magic' here, just sizing correctly and understanding how things bolt together. SA need to get their support side in check as these questions seem to be going unanswered, which is a shame.

A bit late to the party i'm afraid. Looking damn fine there me old china mug @Onoff I'd 100% put a cornice not a standard cove in there. See Gyprocs 135mm S profile for eg. You could go for a smaller one, but that S profile looks the dogs bollocks when up. Its a bastard to cut and mitre, as its IIRC 92mm out and 88mm up so doesn't sit in a generic mitre box, but the results are great. Another option is a 60mm Upvc D-section.

Salus used to be ? but their new stats look ok. I’d not risk it tbh. HW or Drayton for me.

Honeywell every time for me. Danfoss second. Does your boiler do a pump overrun?

The WC pan will be fine, but it will need a fresh approach. CT1 will be your friend. You can tile perfectly but the tiles are never that perfect tbh.

Nope. That'll make it nigh on impossible to get two courses plumb as well as flat. Fine with little 100x100mm tiles etc but not the size your laying.

There I think

@AliG had some nice stuff going that route iirc.

First point is moot as single pole switching in a central heating system is always either upsteam or downstream of suitable means of double pole ( dedicated ) isolation. Your precious contactor will, in normal service, be fed by a single pole MCB and not even that will be seen as routine isolation as a well designed system will not see you going into the fuse board to isolate for servicing. MCB are fault devices NOT isolators. Most MIs will call for such equipment to have “a means of LOCAL double pole isolation with a contact separation of at least 3mm” so the solid state relay would first be fed from either a 13a DP fused spur or a 20a DP switch which would be identified as the equipments means of local isolation. Are you saying a SS relay wouldn’t do the job? Without the clunk? A brief tutorial and please see the section on Solid State Relay Output Circuit where the primary example scenario is based on switching heating loads. Game, set and match.....”New balls please” ?

You like the arc’ing and clonking of the contactors ? Electormechanical vs solid state ? ?

For reliability I’d go for a solid state relay to switch the Willis heaters. One relay per Willis.

Infinitely more problematic and complex as you’d need floor probes to stop the slab getting too hot as well as a blended manifold and room stat. The problem would be the higher w/m2 that would be required, and that can only be overcome by chucking more heat into the floor. Theres only so hot you can make the floor in a domestic dwelling so your limited. Also you’d need to put much more pipe into the floor to facilitate the higher energy input, eg more loops and bigger manifolds. Plus you’d need VERY accurate room thermostats like @JSHarris has to stop any over / under shoot. I’ve walked away from a LOT of retro fit Ufh jobs where the punter remained unconvinced that Ufh was a very bad idea a) off fossil fuel and b) in a high energy consuming dwelling. Rads are quick and cheap...... and effective too.