Nickfromwales

Have a second look That setup looks to me to have a high temp probe in the head of that blending set. If the flow temp is too high the pump shuts off. Same with the Vogel & Noot setups.

@AliG ?

I’m on site in Salisbury and live in Swansea!! I DREAM of being an hour away

No stupid. It’s 45 mins for that.

Hooooooold up. What does that temp gauge read by the U/S pump

And pay for the callout

?. Yes, I know that. Get the installer back.

It might be the fuse in the manifold wiring centre. Hold fire before telling someone the fault, as the correct order of events is to get the installer back to tell YOU what’s wrong Idle thumbs etc.....

Get yourself some wet-wipes and enjoy ?

Hepworth for HRC needs to be temperature capped so a TMV is required in every instance. I’ve been using the same TMV that goes on the SA units as they’re decent reliable units. I set those to 50oC nominal and happy days. The question of how much of an arse your BCO is, whether or not they make you drop the bath to 46oC as “god intended” ( some BCO’s think they’re ‘up there’ for sure, and some are just massive bell-ends ). ??. Best to check before assuming that 50oC everywhere is acceptable.

TRV’s would take a normal actuator? Available from £5 up.

The only bit of kit needed here is the thermostatic valve, and that one is a good make and will be super-reliable. Flow control is simple to work out. Working from the biggest loop, open the gate valves 100%. For the next longest loop, close whatever % difference the difference is and keep going until the shortest loop is the least opened gate valve. Most gate valves are 13 turns so 1.3 turns = 10%. Bingo. @Gus Potter you are a pipe wizard, Potter. ?‍♂️ Love the comment about the submarine commander ?. Did you put a suitable hat on whilst frantically twisting gate valves in different directions with both hands? “She’s coming up by the stern, captain!!! Somethings gone wrong” lol. Time to start a book on how long this system will be in like this for with the door shut..... ???

You can't put colder than 12-14oC through the slab or you'll get condensation forming on the floor. Slab cooling needs to be a thing you forecast the execution of, not just switch on and it cools the house, so set it up for early prevention and not cure if you decide to include it in your design.

Fire away

You’ll need to link flow and return at source and fit a gate valve for a manual bypass adjustment. Linking the F&E will do zilch as they’re only a tiny bit apart and on the same flow pipe. ? Needs to be across where you link the PFM in ideally.

Nah, it’ll be fine. Worst part of the HWC will be the cold connection at the bottom. If that’s looking ok then the rest will hold up.

If running through the whole single pipe system as well as the boiler it’ll be fine. Have the MPV open as a bypass so the heating circuit isn’t seeing full force of the PFM. The old school boilers are pretty tough tbh. Reversing the flow is the money shot as that stirs quite a bit of crud up, as does using an SDS rubber hammer on the bottom of the rads whilst flushing. Go hard, or go home.

Seems so. Also looks to be susceptible to long runs having cooler rads at the end of the run too, vs flow and return systems.

What is the construction type? Block and brick? You'll need to parge-coat all of the internal walls and not go for dot n dab. You could just use a membrane to go from 50mm below to 50mm above the joist detail, and AT tape the hell out fo everything before covering the tape with wet plaster ( parge-coat ). This will be a bugger to detail over a whole house, but remeber that you will need MVHR or at least MV to pass building regs in an AT house.

Our hero.... LOL ?

That's its job. 24/7 The only thing required there is your absence The internal Vaillant programmable room thermostat says when and how hot, f.uck all to do with the external unit / thermometers / owt lad. Stop worrying about anything outside influencing your use of times / temps as that is done on your behalf TO COMPLIMENT the times and temps set internally. You are an END USER, not a technician. Focus on what you NEED to know, not what you'd LIKE to know. Life's too short ( yours AND ours )

The whole picture is necessary to get a full set of ( correct ) replies "Elaborate away". Yes, just a cable from the grey to the LR and you're done. That's all 230v so all good. I've never done anything less WRT earth and 230v in the same cable tbh, so someone drummed that into me somewhere! Almost every double insulated controls I've ever fitted ( and I've fitted countless number of every kind going ) have had an earth terminal for looping a continuous earth path through. That has not been connected to the equipment, but just a stray terminal set in a bit of plastic / whatever that is a junction to maintain earth continuity, should it be that a downstream bit of kit requires a reliable earth arriving at it.

Yup. Nowt lazy about that then. If you switch heating on only, you'll only get flow through the rads. Word.

Just take pictures before boarding, with a tape held up for reference measurements. Pipes are usually in the centre of the stud void so you'd have to go out of your way to strike one. Prob best to stick the foil tape to the back of the PB instead of onto the pipe.

Wont the MPV just open for heating only if the cylinder stat is satisfied? Failing that, just close the HWC gate valve until the heating is blown through. Is there a cylinder stat, or does DHW simply just get to the set temp of the boiler stat?