Step-by-Step Guide to Setting Up an Underfloor Heating Manifold

#installation #underfloor #heating
In this video, I am showing you how to commission a new installation of a underfloor heating system.
We go through:
- pipe sizing
- floor out put - how to calculate it based on the heat loss
- how to calculate flow and adjust the pump
- how to calculate flow through the manifold and adjust flow meters
- how to adjust blending valve
I also give you resources for further study and reference. I share the books, courses and online resources that I personally use.
Book Heat Geek online heating mastery course though my affiliate link below:
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Contact me through my website for quotes for plumbing & heating works
www.urbanplumbers.co.uk/
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Content:
00:00 intro
00:59 heat loss
01:33 floor output calculation
02:18 TOG values
02:36 Setting pump speed introduction
03:40 flow rate calculation
04:45 pressure loss index circuit
06:31 Pump charts and flow through the manifold
08:00 Adjusting flow meters
08:32 Floor surface temperature & blending valve setting
09:32 Resources for study and reference

[@paulgilliland2992]

Short but very sweet. No one else on YT is explaining basic thermodynamics at all , at least nothing I have seen . Also this channel is criminally undersubscribed to.

[@UrbanPlumbers]

Adam (heat geek) has some good videos!

[@simonaustin1788]

Very informative- really like the way you talk through the calcs and then relate the results to UFH set up👍. More please!

[@daveblanche1]

I enjoyed this. I am not a heating engineer, but a biomechanics sort of guy, and this was good to follow. I may also have been an aircraft engineer in my past, though. My system was installed in the way you discussed…and the builders even threw the thermostats out in the skip, too… No balancing as all manifold valves were full open and a broken(stuck) blending valve so the boiler flow at full temp was blowing through our screed floor at 75c. So all those faux pas were “fixed” by me during lockdown 1, and I just managed to check it all out using logic! Awesome. Getting a priority hot water conversion and weather compensation fitted to my Viessmann boiler tomorrow (sorry about the Viessmann bit). You and heatgeek have saved me a fortune.

[@Stephenevans78]

Great video, I had all my values calculated by the company that supplied the UFH system, but I’ve installed it and really wanted to understand the technical aspects and make sure it’s working at it should be. Thank you.

[@bruceeyers9819]

Great explanation .v good explanation of what to set manifold flow rates to and I turned down my pump to 1 after checking the pump flow curve saved 30kw per year.

[@bietmirnix]

So far the best video on this topic.

[@SisterAbdullahX]

Awesome! And thanks for the reference material/training recommendations.

[@grahamwarren2893]

Excellent tutorial for anyone really interested in the subject. More please!

[@UrbanPlumbers]

more is coming soon

[@henrybartlett1986]

Excellent. Thanks for posting.

[@Loopyengineeringco]

Wow, amazing video. Great reference for the calculations. Will be checking back here at least 10 times 🤣

[@fredjennings9268]

Thanks for all you videos, informative and inspirational.

[@UrbanPlumbers]

You are welcome

[@eastmids10]

That's demystified so much, thanks man.

[@UrbanPlumbers]

No worries!

[@jamesknowles550]

Hi -- really like your videos -- i've been a plumbing + heating engineer for 47 years and now like you have my own business --your work + knowledge is secound to none -- your customers are lucky people --

[@tamz2tamz2]

The biggest problem is people don't or won't pay for knowledge hence the part at the beginning, pump on 3 and set all the flow valves to the same. It will still work fine and you will never have a complaint. A race to the bottom as they say. People want heat at the cheapest cost to install. Seldom will you come across someone who wants and is willing to pay for the best designed system. Such is the world we live in but if you can, at least try sometimes. Btw BG fkd more open systems than they fixed simply because they never taught their "engineers" to read a pump graph.

[@bradleyjames3709]

Excellent. Proper engineering.

[@markwebb6741]

Thanks so much. Just what I need - have booked myself on the course!

[@UrbanPlumbers]

well done - I am sure you will enjoy it

[@Daniyalahmad119]

Amazing.. thanks a lot for your effort... really really helpful

[@andrewmillwardwatford9410]

The heat geek course has produced a great engineer for sure. It's great to see the learning applied. I'd like to see you use WC and a variable mixer next.

[@UrbanPlumbers]

Variable mixer - what’s that? Any links please?

[@andrewmillwardwatford9410]

@@UrbanPlumbers kzbin.info/www/bejne/rqGQeKCwg71jf68

[@andrewmillwardwatford9410]

@@UrbanPlumbers your calculations are correct at design loads but almost never do we have design loads. A variable mixer with weather compensation will perfectly match the load and boiler output at all outside temperatures. Viessmann are the leaders of this technology. It's also often cheaper and always more comfortable.

[@tamz2tamz2]

@@UrbanPlumbers Andrew likes to spout his words to those willing listen. Unfortunately, as clever as he thinks he is, sometimes he talks total shyte.

[@HP-lr3xv]

Excellent!

[@maxmerton]

Truly the engineer’s engineer.

[@markgaudie80]

You lost me in the first minute haha! 🤣

[@truthwillout7909]

Great video and entertaining, brilliant.

[@UrbanPlumbers]

Glad you enjoyed it

[@danielomahony7740]

You are amazing great videos :-)

[@dlauria85]

Very nice video...glad to find competent people on the topic. One question...I've gone through the math and set the pump to max speed looking at the pump chart. Nevertheless the manifold flow meters (12) won't get to the required values. They barely reach 1 or 2 l/min. Are these rellay reliable in your experience? The system is brand new. Thanks!

[@twanakawa5551]

Thank you so much

[@lukehodges4511]

Thanks!

[@framclean7910]

I love your videos

[@UrbanPlumbers]

thank you! I love that you love my videos!

[@identitywithheld1027]

Thank you

[@ambarishsengupta4377]

Hi, Thanks for the fantastic video and guides. Can you please guide on how to connect new underfloor heating line(wet) into the existing running Manifold ? Thanks in advance

[@ershadtaymourtash2529]

Dear Expert, Thank you for the brilliant explanation. My question is whether we can install new laminate on top of old ceramics while using a wet floor heating system. Could you please guide me on whether this would prevent efficient heating conductivity, increase energy consumption, and how it might affect moisture levels? Additionally, what steps can I take to control these factors? Best regards,

[@stevec00ps]

Thanks for this video! I got underfloor heating installed a couple years ago for my kitchen (about 10m2 heated floor)/dining room (about 30m2) and checking the pump and flow rate meters it's all just set to full... I have no idea on the length of pipework but will reduce the pump right down and see if it makes any difference at all :)

[@bpdp379]

How did it go?

[@doityourselfdave]

You might be able to calculate the length of your pipework, as it's stamped on pipes at 1m intervals. So check at the manifold and follow the pipe on feed and return.

[@Deepak19833]

Wow i love how much knowledge you have about this do you cover London area? the builders have left but did not commission the UFH its cold and i don't have heating at home

[@VDB420]

Thanks so much, this is a lot easier than using heat camera's to set up the flowrates. One question: how do you determine your delta T?

[@normanboyes4983]

As usual very well explained, I realise it was just an introduction and overview and that there is a fair bit of theory underpinning the whole ‘exercise’ to understand the design concepts. I can see how installing underfloor (and Heat Pumps) will be a real challenge to a ‘box slinger’ who has been used to installing a well oversized gas boiler on the wall, doing the commissioning of the boiler and not doing very much at all at ensuring the whole system is optimum or efficient. Pretty sure that the upfront investment including lost productive time by attending the 2 day course and completing the Heat Geek programme will payback very quickly indeed, increase customer satisfaction and just as importantly improve job satisfaction.Thank you for doing this video.

[@UrbanPlumbers]

I am doing my first Heat Pump install at the moment. Boy is it a struggle. Plumbing has been easy enough (3 days of work), but wiring is just mental! Hopefully will finish tomorrow (5 and 1/2 days to swap a heat only boiler to ASHP) I am seriously struggling with it, just cant imagine combi slingers being able to even touch heat pumps. Video coming very soon.

[@normanboyes4983]

@@UrbanPlumbers I look forward to that - you are on top of the game. BTW I would have thought that weather compensates systems should come with less wiring - so will be good for me to learn more.😀👍

[@tphvac87]

Love the SpongeBob reference man 😂, but on a real note you really know what you’re doing man kudos to you, props, good job mate!!!

[@UrbanPlumbers]

Thanks mate !

[@mohai]

Great video, love seeing your editing skills improve from the early days! I’m in the middle of setting up my underfloor system. I’ve purged the single zone UFH pipes and pump of air but what I’m unsure of is how to remove the air from the flow and return to the boiler and then connect to the pump? Currently I’ve got the pump isolated, if I was to fill the rest of the central heating system up there would still be air between the UFH and boiler?

[@UrbanPlumbers]

The boiler pump should have an auto air vent that should take care of most air in the system. Unless you have an Intergas boiler, then you will have to bleed it manually. No matter how well you purge UFH there is always some air there anyway - so if you don't have an AAV on the manifold, then manual bleeding is also required there.

[@N_z41]

I have a older non modulating monobloc (either 100% on or off ) for my ufh and was wondering if you could advise how I should set this up most efficient? I can change the set temp and also the setback delta on the heat pump. Ie bring circulating temp up to 38c and back on at -6c / 32c. Not sure of the pay off between having lower temp / set back temps compared to cycling on/off more often.

[@zedzed1046]

When hooking up to a comination boiler that has the house on radiators are there any additional diversity factors to take into account when adding an extension with underfloor heating.

[@IM-Meacho]

Love the videos Quick question what does the 8.92 value represent is it a static value Thanks

[@aleksandarstojanovski1005]

Great educational video, thanks a lot. I'm having a question regards this. I'm having 130 m^2 floor, and I'm planning to cover it with 13 circuirts, open loops system without actuators and buffer tanks. How can I be sure that my pump can drive all od the circuits well. My pump can maintain flow 25,8 L/min for delta 5 at 35 degrees celsius and it is variable speed pump with 32/102 input / output watts. Can I go with a single manifold or I need to split the instalation on multiple manifolds?

[@izmirfication]

Thanks so much.I have an underfloor heating system.I have two separate supply manifolds for a two floor house each installed on its serving floor and they use the same circulation pump and the heating system.I'd like to know if I set one of the floor's set of flowmeters higher than the other floor's flowmeters.I mean 2l/m on the second floor's , and 1l/m on the first floor's,what will I get from this configuration,will my second floor's heating respond primarily to my rising temperature on that floor.I could not put it right here, sorry for my English..

[@experienceb4bob]

Hi. I will be installing my first under floor heating on a 6 foot ×7 foot area. Any suggestion or tip

[@christhomas6843]

With a condensing oil boiler supplying the underfloor heating manifold would you set a delta t of 20 deg C from the boiler to the underfloor manifold and a delta t of 7 for the underfloor heating loops. Thanks for any replies.

[@warriorsofwarmth]

Great video, please forgive but how did you get 11.21? ive tried every some

[@stevesmith7675]

Thanks for this video. I’d like to go with UFH in a new build project. I’ve had a couple of chats with installers. One has suggested zoning with actuators linked to room thermostats but another guy (a Heat Geek) is suggesting open loop with weather compensation as the most efficient way. I have seen Adam from heat geeks talking about not zoning. My instinct is for not zoning. Do you have any preference ?

[@meineszmf]

hi, I got a question, you mention in the beginning of the video the blending valve, later you did all the calculations for pump end flow meters, but I did not see you set the blending valve later in the video. Or is the blending valve the "dial" to adjust the flow in temperature ( in this case 33.5 degrees) maybe a silly question (I' am not a pro just a home owner with cold feet and a huge gas bill) thanks if you answers, keep up the interesting videos.

[@TheLife0025]

Hi can we use two different pipe sizes with same manifold using an adapter. I'm thinking for using a 16mm pipe for my kitchen which has a larger area and 12mm pipe in hallway with wood floor which i will take out n install 60mm insulation between 100mm joists.

[@AdydeAdy21]

Hello,do i need an automatiozation for underfloor heating? For efficiency and economy bills.thank you

[@myatix1]

This is a great video! Thanks for sharing your extensive knowledge. Can I ask how a 20m pipe run between an ASHP and the cylinder effects the ASHP output?

[@UrbanPlumbers]

It depends on the output of the ASHP and pipe sizing. How big is the HP and what is the size of pipework ?

[@myatix1]

I have a 7k Vaillant aroTherm Plus and was planning on using 25 or 28mm pipe

[@myatix1]

Also with regards to ufh flow rates, how does the flow rate work when you are using multiple loops? We have a room with 262m of 16mm pipe with output of 1095W. The flow rate of that is 2.23L/min (but we have 3 loops not 1 loop at 262m) I presume we divide the flow rate by number of loops to give the flow rate/ loop?

[@torreslondon7541]

I have moved into a house where the UFH manifold appears to have been installed the wrong way around: flowmeters on return and TRVs (with thermostat actuators) on flow (hot water in). The system works, but the flow meters always show zero. I assume to make the system work at its full efficiency the manifold needs to be planned the right way round (the reverse of what mine is)?

[@RS-ei3yt]

Hi, great videos. Very informative. Qq I am thinking of having underfloor heating on the ground floor with traditional radiators upstairs using a combo boiler. Wd that be possible..?

[@RS-ei3yt]

Combi boiler*

[@harpssingh1477]

Hi I just recently completed my UFH manifold with my combi boiler and existing rads. Ive made two zones one for ufh and the other existing rads circuit. I adjusted the flow rates on the ufh manifold. When under floor heating ran with rads all is fine. When rads cut off and just UFH ran the boiler started short cycling, this later i figured out because the ufh only needed 2.5k and the boiler couldn't modulate down to that low. So i was puzzled something isnt right as for the ufh the delta T value was like 45/25 which we needed 7 or 10. Also cud never seem to get air out of the system. The Return pipes were not heating up either. So i now openned all flow rates to max and everything sorted itself out the pump ran at full speed, the delt T 7 was 45/37 and the boiler is now not short cycling and running normal, also returns are warming up. Do i need to set the flow rates as its working as it shud or was it a case of trapped air.

[@shredder9536]

Brilliant video. Just wondering is the pump on the boiler not strong enough to power the underfloor heating so it needs it's own pump?

[@UrbanPlumbers]

Flow rates on UFH are 3 x the boiler flow rates at the boiler and you need to consider pressure loss on the pipework - That’s why you usually need a manifold pump but not always

[@HuyLe-uc1um]

where did you get the number 8.92?

[@AudioJudgement]

I'm having an issue with my UFH system. I set the thermostats to 22 degrees, but it doesn't go any higher than 20 (ambient). All the valves on all the circuits are open and it basically doesn't shut off as the desired temperature is not reached. Water temp on my gas furnace is set to 45 deg and blending valve is at maximum (50 deg). I observe that the pipe which goes into the blending valve is 37-40 deg but every pipe after the blending unit is 25-27 deg. Curiously, on a hot day, the ambient temp was reached, and all the valves were closed, circuit board and pump were shut off. I experienced the exact moment when everything shut off. And when I touched the blending unit, the pump, the pipes, they were all hot (the hear didn't stop at the blending unit). This problem started out of nowhere. I didn't do anything in particular, except from increasing the pressure on the furnace from 0.9 to 1.7 bar.

[@MrDBT85]

Very informative video. Interesting that the 2 Kensa GSHPs installed at our site about 8 years ago don't have flow meters on the manifolds, only the actuator heads connected to their room stats. I can only assume that those circuits are just running at full beans from the pump they are connected to?

[@UrbanPlumbers]

HP runs at DT of 5-8c so the same as UFH so can in theory work without flow meters if all the loops have similar length and resistance

[@MrDBT85]

@@UrbanPlumbers Yeah ours runs at about DT6 and its all UFH, I'm trying to get the design documents located so I might be able to see what the loops actually come out to. We're just about managing 3:1 on the COP so naturally if we can improve that I'll be happy! Thanks again!

[@andrewriley4204]

Great, very informative. Do you get to keep a Reference Manual with the Heat Geek course or just a Work Book ?

[@UrbanPlumbers]

Just the work book. To be fair 90% of what in the course comes from CIBSE books

[@andrewriley4204]

@@UrbanPlumbers Thanks for this 🙂 Just thinking that, having done Kimbos course, for future reference the spiral Reference booklet that Kimbo gives out is really useful. But with Adam's course I'd have nothing to look back at to help me ! To make an analogy:- If I chose to do A-Level Physics at the local college I'd get reference books to regularly refer to. Thus, seems quite tough to pay a big sum but have no future reference books 🤔

[@UrbanPlumbers]

@@andrewriley4204 that is very true. I actually prefer what Kim is doing for a simple reason - it is done very simply and allows you to apply the knowledge directly to your work. What Adam is doing is also great, but requires more effort and actually mastering the concepts. There should be a manual or at least a book with large number of exercises or online resources. Adam will figure it out. He is a smart chap.

[@lukeobrien1]

I just moved to a small country town in the United States, there's a very old Wirsbo system here. The manifold has a lot of verdigris on it. I'm not sure I trust the local plumbers having watched your video! Any advice for how to update the system without having to remove the flooring etc? Can we just replace the manifold? Thanks, even for a non-heating technician that was really informative.

[@arryrooker3079]

A Master Maths Brainbox Man Most Plumbers just lay the pipes 😆 🤣

[@terrykeeler4416]

What about the correct setting for the blending valve?

[@tsw4437]

Hello I am in process of installing water underfloor heating. As part of the project the contractor is also moving the boiler from kichen to garage. My question is when the project completed what kind of certificate and documentation should I get for the underfloor heating installation and for moving the boiler for my future record. Can you please list out what should I get from the company on completion please. Thanks,

[@Welton_Family]

Great Video and perfect for a new install with known UHF Circuit Lengths, but what about recommissioning and existing install with unknown circuit lengths ? Any tips for that ?

[@UrbanPlumbers]

Thermal camera to inspect pipe centers and pipe runs

[@Welton_Family]

@@UrbanPlumbers yes, I’ve mapped them similarly for the runouts to room but have not tried to back calculate the lengths of Serpentine laid rooms or Spiral Counterflow Snail laid rooms. I guess there equations for that and you could use an assumed Circuit Spacing of 150mm. I’m not sure how big the margin of error would be or indeed how significant that would be for overall calculations. Perhaps just using UHF Room sizes in SqM could be roughly converted to lengths ?

[@UrbanPlumbers]

@@Welton_Family yes you can calculate length knowing area in m2 and pipe spacing

[@tomggroup1230]

CZESC Szymon , czy do podlaczenia UFH tylko do lazieni potrzebuje pompy z manifoldem czy piec da rady 2m kwadratowe.

[@UrbanPlumbers]

Zazwyczaj manifold bez pompy wystarczy

[@andrewcunningham1]

Hi Szymon. Loving the videos. Do you mean that a mean water temp of 30C will produce a 30C floor temp? Worth a look?

[@UrbanPlumbers]

did I say that? Obviously wrong if I did.

[@jedherman7450]

Yes I think you did - you said a room surface temp of 30degC and a mean flow temp of 30degC (but adjust for tog).

[@timbotrucker]

Hi what control setting should my underfloor heating manifold pump be on - Differential Pressure Variable, Constant Differential Pressure or Constant Speed. It’s a Wilo Para on a 6 zone system with actuators controlled by room thermostats. Thanks Tim

[@UrbanPlumbers]

constant pressure

[@eltonolldashi8349]

👍🏼

[@kristofermed1f]

mate! i have a problem, i want to install a new monoblock heat pump but the saying is that i need tank for the flow to be better because the hp need this..? is that true? i hqve 250 square floor heat and plan a 10-15 kw is enough for heatpump, but dont have space for big tank, how big do i need

[@UrbanPlumbers]

You need to check minimum volume th HP required, then check the volume of your smallest zone and add a buffer to make up the difference

[@Biker_DL]

Great video! Any tips on balancing/setting flow when you don’t know pipe lengths?

[@UrbanPlumbers]

Yes, just use temp clamps to set it to DT 5-9

[@dmas3748]

I have a vaillant heat pump with underfloor heating in 50mm screed and radiators upstairs. Would you recommend fitting a blending valve at the manifold to be able to run the rads at 50degrees?

[@UrbanPlumbers]

No, no blending valves or additional pumps on manifolds for UFH on heat pumps

[@dmas3748]

@@UrbanPlumbers thanks for the reply 👍🔧

[@jockster5525]

Great video for refresh of this work ..much appreciated 👍 You play guitar ? Let's hear it ...I'll let you hear my guitar too 🙂

[@stevepettifer4896]

I'd love to see what you make of the near on 20 year old system someone installed in my house. 6kW electric flow boiler, 7 loops in 6 zones but one has no thermostat and is labelled as 'bypass', no flow meters and a house that loses heat for fun. I just cannot seem to find anyone local to me who has a clue. The circuit in the master bedroom is two loops and never seems to work at all well, and god forbid we need to heat more than one or two rooms at a time because it seems like the boiler isn't man enough, but then I'm not wealthy enough to run 9kW of electric boiler!

[@conradallison2819]

Hi Mate I have a question. I have a room of (3.4 x 4.8) 16,32M2 and it has a 16mm pipe total of 84.5m in a floating rib raft concrete floor. Using your calculations, it needs a flow rate of 3.26, but my supplier has indicated 1.32 l/m at 11 Deg C . Have i missed something

[@UrbanPlumbers]

What’s the room heat loss?

[@conradallison2819]

@@UrbanPlumbers Room loss of 816W and air loss of 232w , total of 1,049kW = 64.28w/sqm

[@Horizonspace]

how did you get a Delta T of 7deg? where has this come from?

[@UrbanPlumbers]

Flow rate

[@beavercud]

Where is the 8.92 coming from?

[@mgbroadsterJ]

An average installer would not understand all these calculations .

[@loveofkemet]

The average installer needs upskill or bring in assistance. Costs will have to be passed onto clients - if they want well designed low temp systems there will have to be a cost, the days of rolling up and slinging in an oversized boiler and oversized rads are coming to an end

[@jerryz673]

Do you take apprenticeship?:)

[@koningbolo4700]

If I may, I like to pick your brain for a bit. I am looking for a vale which operates without electricity and is capable to control the flow to a indirectly heated boiler (from an ATAG combination heating system) which I like to heat using heat from a campervan coolingsystem. I like to be able to cut off water flow to the coil in the boiler as soon as the water in the boiler has reached 75-80 degrees C.

[@01genics]

The start of this video was the way mine was installed, manual chucked in the bin and everything set to maximum, even temperature set at 60 One question thought, what could be the cause of the pressure dropping on the manifold, set it to 1.5bar but after 4-5 weeks is gone down to almost 0

[@UrbanPlumbers]

a leak obviously

[@01genics]

Terrific

[@01genics]

Also should the pump on the UFH manifold come on when the UFH is off but the hot water and/or central heating is on? And the flow rate is set to 3 so I'm guessing they didn't do any calculations

[@antlet]

@@01genics the UFH pump should only come on when the ufh is called for via your thermostat

[@doityourselfdave]

It's very interesting, but the flow meter gauges are that small, that you can't accurately set them anyway. You said it yourself and set them to just over 2l/m. Which begs the question, all these formulas providing accuracy to 2 decimal places is a bit of a waste if you can only roughly set it anyway - seems like the manifold/flow meter is designed for a rough gauge of flow and then tweak it as necessary.

[@UrbanPlumbers]

It’s accurate enough to set it 0.5l - better than not calculating it at all

[@BriaCroTex]

Hahahah that's mad i just recognizing myself at the beginning, pump to max, min flow 1-2l/min and thats it UF fixed if they complain about room temperature then increase flow temperature to max of 40c 😂😂

[@xxwookey]

When you give us a pressure drop in metres, what do you mean? Pressure is not measured in metres, it's measured in pascal or bar (or psi). Is that metres of mercury?, metres of water? Ah OK, it's later equated to 'pump head' so that's 'metres of water' or more or less bar/10.

[@UrbanPlumbers]

correct m h2o - as pumps are rated for head in m h20 or bar or convert to psi or pascal