RedSpottedSev

Thanks @JohnMo I appreciate the advantages of the 2 pipe system, as the call for heat comes off early from the Tee, particularly good for ASHP; but if I am adding additional heating into the buffer (act as future heat store) then it might not make a big difference for us. 30 is oversized for us, I think ideal would have been 24ish. But my understanding is that some of the smart controls are limited on the Worcester 4000s which come with lower heat output. Do I need a dedicated control module for the buffer tank? MM100? Does the boiler need to see it as a second cylinder acting as a heat store? As we dont have valves on the 2 circuits from the boiler, we dont need a bypass valve right? heating design v2.pdf

sorry, edited

Thank you, I have made some progress with the design and decisions. I have put the design in a file attached. I have absolutely zero experience/expertise in this so please do critique/add and modify. If there are critical safety things missing then please also do tell me. I am not fitting this myself but do want to make sure the plan is as tight as it can be. I would say that I appreciate it isn't the most efficient design as I have had to make do with some kit that I bought previously, and make future compatibility options available. - With regards to the wiring, the 8000+ has a temp sensor input for LLH. Am I correct I can use that connection for the buffer tank? This way the boiler can modulate the heatoutput to the buffer? - I would appreciate help on what settings I would then select with this set up in the 'Hydraulics' of the boiler system menu. Attached - I am still not clear/got myself in a muddle with what happens when it is 12 degrees outside vs 2degrees outside. The boiler will modulate to keep buffer at set temp. But the mixing valves on the manifold are manual. So when there is a call for heat from any sensors, the manifold will draw a set temp (mixing valve temp) to the floors. Do we then accept that if it is 2 degrees it may take much longer to heat up if flow temp is set lower, and then perhaps there will be a chance of overshooting/yo yo if the flow temp was set higher? Therefore keeping the system always on helps avoid this? Can you point me to a tutorial/guide to help me get my head around setting and adjusting the flow temp at the manifold? -- are you suggesting I remove the blending valves entirely (or set at 38 for safety), and I adjust the buffer tank temp as outside temp changes? If so, are there controls that allow me to remotely adjust buffer tank temp? Or is this where weather comp can adjust the buffer tank temp to try maintain a certain flow temp to the manifolds? I think I need to learn more about WC controls on the 8000+! Thanks again LLH sensor.pdf heating design v1.pdf

Would you advise against decoupling membrane for porcelain tiles flowing throughout over 85m2? I worry about cracking, but not sure how insulating decoupling membrane is

Thanks again @JohnMo With the buffer tank, as I will likely only heat it with a boiler or stored solar in battery stack... would it be OK for the buffer to be a Direct Unvented one with an emersion heater? Does this part of the system also need expansion vessel and pressure release safety valves too? With it being a 100L buffer, as an alternative design, would a straight up heat only boiler supplying a 300 to 400L heatstore (I've seen the advance Appliances pre plumbed multifuel, 28mm outlet for ufh https://www.advanceappliances.co.uk/product/70-multi-fuel-universal-thermal-store-sfuts/) not be an easier install? Is there a significant amount of energy saving with the previously discussed buffer and cylinder system vs one big heatstore?

I have just realised a flaw in my plan, as one Heatmeiser can't control 2 manifolds, so it is looking like the buffer tank set up.

Thank you, Great advice and I think I am getting close to my design, feedback and corrections welcome please. Greenstar 8000 plus with internal integral diverter kit, to allow for DHW priority and setting temp for cylinder and ufh with weather comp. Becomes a 4 pipe system. 2 pipes to a Telford Tempest indirect unvented heat pump cylinder 300L. Hot water feed has to travel 8m to my hotwater manifold that then supplies each outlet around the house. I am deciding if I need an electric heater/circulater as a secondary return or if there is a better set up. Other 2 pipes to Buffer tank/LLH (to be decided as I am still figuring this out) From this the pipes to my 3 ufh manifolds (2 downstairs, 1 upstairs). If I only use 2 heatmeiser UHF-RF V2 (upstairs/downstairs), I can have the downstairs heatmeiser controlling the 14 loops, as I understand each 'zone' on the heatmeiser can control 4 actuators..... Then I can link the 2 heatmeisers as primary and secondary, with the primary calling for heat direct from boiler on a switch live. So the idea being if any manifold/heatmeiser calls for heat, the boiler kicks in, and heats the LLH/buffer and the manifold pump draws the heat from there. I do like the alternative of the boiler just concentrating on keeping the buffer tank at a set temperature, and then heatmeisers just activate the manifold pump and not communicate with boiler. But if feels that in hit weather the boiler will essentially have another 100L of water to keep warm alongside the unvented cylinder, is this right? What do we gain with this instead of a large heatstore that hotwater and ufh all come out from? Which one of these set ups is more straightforward for setting up/service and wiring. Which is going to offer me more tweaking for efficency? Thanks again

Thank you @JohnMo can you point me to a resource on how to do this properly: "I would start by looking at the longer loop and all pipes to and from that loop and look at pressure drop. Once you have that, it will set pressure drop for system, then add all the flows you need together all loops). Now you have a pump duty point. You can now make a sensible choice of system or heat only." Do you mean I calculate the distance from boiler to manifold 28/22mm and then add the longest loop which I think is 98m at 16mm. Somehow calculate the pressure drop? Then find the overall flow I would need through each zone based on my heat loss and heat output from each floor? One more thing I cant get my head around...on DHW priority, when cylinder calls for heat, boiler diverts to dhwp, then do the pumps on each manifold keep circulating water around each manifold....but what happens if the mixing valve opens to draw heat and dhwp is running. - do the manifolds not fight each other trying to draw from each other? Then do i need a directional flow control - or heatmeisers are smart enough to turn the pump off when cylinder calls for heat? - I know you said no to Low loss header, but this was why I thought it would let the pumps on each manifold to circulate at their leisure without fighting Thanks again,

Thank you @marshian and @JohnMo. I have been doing some more reading and your posts in the ufh section. That video is maths heavy, but I am working through things back to front. In that I am doing my heat loss, then using the formulas from heat geek and urban plumbers to calculate what flow I would need and use that as a starting point for each loop (work in progress). Old boiler is Worcester 430/i unknown age but on last service it was not looking good. I think at least 12 years old. New boiler: will go in loft with new cylinder (heat pump coil) to be both decided on compatability of current ufh kit i have (specifically the heatmeisers and how to get weather comp working) I will be doing my best to run each manifold as a single zone, only using actuators on the loops as on/off or very high/ low set back temperatures. The manifolds and it's pump (Grundfos upm3 auto)/mixer is from Thermrite. X2 will be downstairs in garage, supplying the downstairs area. One upstairs for bedrooms. I am assuming if I was to do the above, I would still need to change my mixer valves to ESBE electronic valves for proper weather compensation? Do they work with the heatmeisers? As each of the 3 manifolds have it's own pump on different flows, do I need to do anything special? Can I get a boiler that deals with this set up without special kit? Im confused about LLH/kimbo/closed coupled Tee... Right now I want to make sure I've pulled up all cables needed from each manifold as we are due to start plastering. Currently have 6mm and 2.5mm going up to loft for boiler and cylinder, and 5core from each manifold to future boiler position. Do I need more for ESBE? Do I need temperature monitors on each inflow for the manifolds? Thanks again for the help and education! PS the upstairs orange coloured rooms will be guest rooms which I wanted to zone off, but from what I gather it is better to continue to keep warm even when not being used?!

Thank you, My understanding is that the current system boiler cant provide enough flow. So I am looking at a new boiler and will upgrade cylinder as we need 250L vs the 170L currently. My priority is avoiding constant on/off yoyo switching of each room and making sure they stay as constant comfortable temperature as outside temperatures fluctuate. Efficiency gains would be a bonus. I was sold the manifolds with pump and mixer initially before I had done any research (and hadn't planned upstairs ufh and getting rid of all radiators) so I have some of the kit ie pump, mixer, manifold, heatmeiser control and thermostats. So, talking about the ideal set up (which I may have to do in stages and accept some wastage of things already ordered), I can swap out the fixed/manual mixing valve on the manifolds to ESBE. I haven't come across IVAR but will read about them. Each manifold will then have ESBE/grundfos upm3 auto as a pump station and a hestmeiser. Manifold 1 - main downstairs (can reduce to 2 zones) Manifold 2 - kitchen and extension (high heat loss - glass sliders etc.. reduce to 3 zones) Manifold 3 - upstairs (single zone but option to shut off guest room when not in use) So... can I have a set up where if and when properly balanced, the heatmeiser and actuators close/open rooms that might not be in use, and the rooms in use will just have thermostats for info only, with the esbe running weather comp? How do you decide where the call for heat comes from for each manifold? (Coldest room and then adjust other flow rates down?) Also do I need extra wiring pulling up alongside the 5 core (heatmeiser) for the ESBE valves? Which boiler and control unit is likely going to offer the easiest communication/connection set up to the heatmeisers and esbe? Thanks again, I appreciate I have a lot to learn yet..

Thank you

Hello, I started a project hastily and it has somewhat escalated. The information here has been amazing. We have a 5 bed detached farmhouse (half/half previous extension, half solid 50cm stone walls, half insulated cavity). Very exposed to winds and rain. We made the decision to put ufh downstairs and upstairs, but admittedly I really should have had a proper heat loss done and spent the extra on a heating engineer. Lack of knowledge and poor advice at the time... but here I am. Build up is 70mm hardcore/blinding, DPM, 150mm concrete slab in mesh, 150mm PIR, 16mm ufh pipes at 150mm centres clipped to insulation with 75mm sand/cement dry screed to SR2. Upstairs, removed old floorboards, leveled the joists, extra reinforced those that needed it, noggins etc... 5cm PIR between joists, soundproofing tape, routed floorboard for 16mm pipes at 150mm spacing. Primer, Perimeter 6mm expansion strip tape and then 1 to 3cm flow screed over the top to level, fill in boards. Upstairs is 6 valves for 5 bedroom zones. The bathrooms are on electric ufh mats. Downstairs is on 7 valves doing 4 zones. I am likely going to add another 5 valves for 3 zones for an extension in the future. All runs are below 100m, 16mm at 150 centres. My thought was this way I can reduce flows and wouldn't be left with a cold house (cant insulate internal or externals of the old part of the house). The 3 manifolds have a manual mixing valve and each with its own pump. Each manifold has a heatmeiser control that I am told connects to actuators that go on the valves. Then each room will have a thermostat that switches the actuators on and off when the rooms hit the set temperatures. I had assumed that my current boiler/cylinder would have been enough to supply the system. But my builder's plumber says that it is a very old boiler 10+ years and they would recommend an upgrade. Finally to my question and thanks for reading so far: My heatloss is around 15 to 18kw. I have ruled out ASHP due to only having access to cost/space and single phase electricity. If I am going to upgrade my heating system, I would like to have weather comp option and hot water priority. I have had lots of mixed messages and designs about this from different plumbers, with huge varying cost. So here I am asking for option on what people have done with wet underfloor only set ups. Current recommendation has been a heat only system with a low loss header that supplies ufh and the cylinder... In my head I was thinking a 4 pipe system boilder that has inbuilt domestic hotwater priority. Some kind of communication centre that means the heatmeisers can call for hotwater at a different temperature to the hot water cylinder. Do I need a low loss header for the 3 manifolds to connect to and blend from? Have I shot myself in the foot with the kit I already have (manual mixing valves and heatmeiser) to have weather comp? I am happy to invest time tweaking flow rates etc... to get a more stable heatoutput to stop the actuators constantly opening and closing. Sorry if you think this is better suited to the the ufh forum Thanks again

Hello forum, Just wanted to say a hello as well as thanks to all the advice on here. I am a competent DIYer, but what I have for love of buying tools, am very much lacking in time. I am 80% into my renovation which has escalated. What was supposed to be an extra bedroom for a new arrival, has turned into full rewire, re plumb, wet ufh, new window opening and sand blasting beams etc... Because it wasn't well planned there has been a lot of online reading and problem solving. I have got a little stuck now with some info and would be grateful to the forums help to get it over the line. Thanks again for all the help.