Nickfromwales

Assume those are dense concrete blocks, ergo no need for a padstone under the ends of the steel? If block on flat for those walls, where is the cavity or insulation to be placed? At the very least you'd expect to see those to have been made good with a brick and mortar infill? The drafts will be a bit of a problem if not dealt with prior to facias going on.

Not on a system that has actuators and rooms stats. That can run down to just one active loop, so would need the equivalent capacity in the buffer as 'run-off' when the heat demand is down to the minimum / house near to set temp. Nope, do NOT do that!! The mixing valves take cool water from the loops, where the water in the loops gets recirculated until cool enough to be reheated by being blended with the incoming ( available ) heated water. These are there to protect the flooring / occupants against damage / injury. If you open these manifold mixing valves to their max setting, and the 1st floor heating is not getting the house up to temp, the issue is with the design and spec / execution of install, and nothing to do with the system not working properly ( functioning at its max potential ). You can create a furnace of heat, but if the emitters cannot convey that heat to the air space in the rooms then it's a paperweight. The 6mm screed is a concern, but essentially not much difference to that vs the Wunda overlay system with a tile bonded atop so the question needs to be, what is below it? What is the floor covering upstairs? Have you opened the mixing valves to max setting ( what does the valve say that is? 1-6 etc or oC? ) and did action then show on the manifold thermometer?

PICS?

It may be best to upload some images of the manifold(s) and controllers etc, so members can correlate what they see to what they know / can find for you . That will be a much shorter route to getting some replies.

Google some images online of cables which have started fires and come back to me! None in places where they're 'moving' or 'moved frequently'.........why the hell would they be!?!? The only cables I've seen affected by this have been stitched into the fabric of a building, ergo NOT subject to mechanical manipulation in any way, shape or form. EPS manufacturer saving their products ass here IMHO. http://enviro-therm.co.uk/wp-content/uploads/2016/07/Polystyrene-melting-to-cables-e1468939790162.jpg Just a pic off the 'net, but pretty much what I discovered in my place when I boarded out the attic. Some genius had crumpled up polystyrene ceiling tiles and had filled every bloody gap in the 1st floor ceiling void with the damn stuff as insulation, encapsulating all the lighting and power cables. The state of the insulation was shocking ( no pun intended ) with the EPS and PVC seemingly becoming 'one'. This thread is an opportunity to avoid even the possibility of this happening, where is the argument to not follow such advice? Case dismissed, and fill your boots if you know better AFAIC.

It's been set up sympathetically, to stop the boiler short cycling perhaps? If you split this to run the UFH independently then the boiler will have to modulate a lot to match the lower heat demand. It's a double-edged sword, so consider if you actually need to create this divisibility before you open a can of worms.

Hi. Rads will be fine, and the cylinder similar, just the controls may need a re-work. In terms of the running the UFH, particularly if you want to do this independently, you may need a buffer tank, or you could switch the unvented cylinder to a thermal store which will give you stonking hot water plus offer up hydraulic separation between the oil ( non modulating output ) and the low heat demand of the UFH. Other than those considerations it's essentially an S-plan system boiler arrangement, so quite simple / straightforward tbh.

North of £6k for gas points to a poorly insulated home, and an in efficient system. Nothing wrong with the boiler choice here, and assume radiators are modern convector radiators? Trickle vents on windows open? What insulation is in upper floors?

Just watched the videos!! Never seen that before, something seriously wrong here. Credit to the plumber, it’s a neat conscientious installation, but maybe technical / hydraulic issues are at play. Firstly, I would not have put all these segregated heating loads ( a couple are very small ) onto a gas system boiler without proper hydraulic separation. The 4 zone valves will all be sucking water at massively different L/p/m flow rates, and the UFH pump will be getting ‘pushed’ by the pump in the boiler. It’s all very hydraulically unbalanced. Yes there’s a bypass, but it’s not designed to be used in such an adverse way imo. Your plumber will need to install, firstly, a small buffer tank or large low loss header ( LLH ) to allow the boiler to fire > pump to that hydraulic separator > return back itself without ‘seeing’ any of the heating circuits directly. That will remove the push / pull factor here which I think is the start of the issues. In the boiler installation guidelines, most will state that the appliance shouldn’t be installed; where it would be subject to / unless measures have been taken to avoid, short cycling. With the segregation you have here, you’re on the borderline or just the wrong side of it. Next thing to do is to remove all the actuators and run the system again without them fitted. With the actuators removed the loops will be free flowing. The thing causing the water hammer ( loops and pumps to ‘jump’ ) will be the actuators ( I believe ) so I’d like to see them out of the picture to see what effect that has. So, @Lurchie, please do that and run the UFH on its own and report back. Turn all UFH stats to maximum and tell us what happens.

Why has a combi boiler been installed instead of the system version?

Not if it's on 22mm pipework and it's in the attic? It'll take much longer to arrive from there. Is there just an unused pipe left at the underside of the boiler?

👎 Prior to 2014??

Looks different to the one I removed, but may be un upgraded replacement part?

It won't be wasted heat It'll be advantageous heat input within the heated envelope, and the sum of all inputs = your required heat demand met via whatever source ( albeit slightly indirectly from the buffer ). Lose the buffer into an airing cupboard and keep your under-crackers fresh.

Much higher flow temps. Problem being, is you’ll need to raise this incrementally in 2°C lifts until you’re at or around the max permitted temp stated by the flooring manufacturer. That’s usually 27°C. Beyond that, it’s failed by poor design / implementation.

This will be down to a lack of physical contact between the diffuser and the upper floor. I see this christ knows how many times. Did you witness this being installed, and do you know if the deck boards are sitting snugly against the UFH system? If there's even a couple of mm gap the results ( unless it was a passive style dwelling ) would be dramatically reduced.

I've just been called to a clients build where the Ivar blending valve is not letting the toasty hot water in the flow pipe to it, through to the loops ( even with the white TRV style head removed from the mixing valve. I drained down and removed the cartridge and it was firmly stuck, but in the fully open position!! I serviced the valve, proving free movement and that the pin returned to its "sticky-outy" position ( returned to that position by the spring ) and reinstalled it all. Set it to work, and fark all, still just a steady 20oC of heat which was keeping the dwelling at too low a temp. This setup has the ASHP pumping into a LLH and that is immediately adjacent to the UFH manifold / pump etc, so never needed a secondary pump to get from the LLH to the manifold. Conclusion, possible knackered mixing valve. I'm going to order a brand new one and install it as this is an inconvenience to my client, but this worked very well the first 2 winters, and I'm flummoxed as to why this has given up the ghost ( where others have been in elsewhere, longer, and are still working perfectly!?! Some houses I've fitted with 2x Ivar manifolds and still zero issues on those projects....... Could this be a few stray "Friday afternoon" valves perhaps?

Thanks. Do you know if the upper side of the insulated foil panels are in direct contact ( under slight compression ) with or are bonded to the underside of the wooden deck? If not, the heat transfer characteristics of this build-up will be poor.

Nope. The drips / bells on the render are set correctly, a tile would block them.

Are the pipes in aluminium spreader plates / screed / other? Can you give us more info please?

Yup. UFH is done badly more often than it’s done well, particularly when a general builder just comes up with a ‘good idea’. Look at the overlay system from Wunda, that may be your best option. If it was my house I would break out the existing floor and do it properly, as retro fit UFH done anything less than immaculately will likely not heat the room unless left on pretty much 24/7 with massive running costs to boot. Original question; yes no issues there. You can cut the up-stand back by 20mm if you’re worried, and bond a strip of Compacfoam ( 400kpa ) on top just where there’s going to be traffic etc.

Why aren’t you putting the pipes in the slab? Add 50mm more insulation ( EPS ) and reduce concrete. Lose the UFH panels and save some money. You’ll end up heating the slab regardless, so will have slow reaction times to shift room temp, so why this choice of floor arrangement?

Same size as I built. I just did 10x concrete pads, rubble full as a foot and concrete on top, then timber ‘legs’ holding a sistered 5x2 ring about 2-7” off the ground ( sloping plot as per yours ). Been there a couple of years now, and a little evidence of settlement ( it was on made up ground ) but the 2x 900mm wide fire door blanks I used to make an 1800mm barn door one end still open and close without a whiff of bother, which I’m surprised at tbh. Biggest regret is a non-insulated roof panel ( powder coated metal clad roof ) and not insulating walls / floors ( as this has a life of 6 years or so before the ground hopefully gets built on ) so didn’t think it worth the expense. As it’s now my office, I regret not making it much better regardless. It just gets heated by warm air blowers ( fan heaters ) which does heat it quickly, just not cheap! Screw pile option sounds good tbh, and if you want this there for a long time do NOT have any timber in contact with the ground / exposed at that level is my advice.

I'd mask up and inject with a closed cell foam such as Illbruck and then fit a strip of 25mm PVC D-section LINK from cill to frame to cover it over.

In the bedrooms I go a bit OTT, as once this is in it is in for good. So I would do 1x duct to 1x terminal ( x2 ) in there. Sleep is precious, so is sanity. I would not bust this down to 2x ducts to 1x terminal ( x1 ) in there as the flow rates will be a bit higher in there due to the volume of the room.