Plumbing - How Does Underfloor Heating Work

Understanding Underfloor Heating. Pump, Zone Valves, Manifold, Flow Meters, Thermostat, Wiring centre, Beneath Heat Today I've done a video on how to install under floor heating and that's a full video, a step by step guide. In this video I just wanted to do like an overview and understanding under floor heating. So what does what and what different paths you have on an under floor heating system.
So first of all, what we'll do is we'll zoom in and we'll have a look at the different components and how they would work and how they would control the heating system. And I'll give you a little sneak preview of what we've done in here as well, which I'm really pleased with to be honest. The nice, lovely warm man cave now. So yeah, let's a look about.
I've got the manifold here, but I'll come back to that shortly. What I'll do is I'll start with the boiler. So this is a Combi Boiler. I've put little labels on these because some people have said that they can't understand my accent. So what we've got with the Combi Boiler, we've got a flow that comes out of the Boiler and then back to the Boiler, we have a return. So if you look at this Boiler there, we've got this flow and on this side we've got this return and then we've got this gas in the middle. As that flow goes around there so that we can control under floor heating and the radiators on a heating system, we need to separate the system. So we've got, that's the flow from the Boiler. So that's this pipe here and that just come directly to here. And this is the first tee and it splits off both sides. And then these are called zone valves. And this zone valve, this is going to be for the under floor heating as it's labelled. And then this zone file is going to be for the utility room in the back or the washroom. And then what they do is when it goes onto the under floor heating, this goes down here and then got back down here and it goes into this floor on here.
Now the floor, this floor from this one, that goes to the other radiators. So that's the floor part of it. The return part of it is this pipe here and this return comes down here and it goes in to this mixer into the mixer valve there. We've then got the manifold here, so that's the under floor heating manifold. On the manifold ,we have flow metres, we also have a pump. We have a wiring centre and then we have a thermostat.
So how this works is first of all we turn the fuse spur on and then when we turn that fuse spur around, it would give power and then the thermostat, if we turn this thermostat up and then that would call for heat. Now there's a delay on this, so what I'll do is I'll wait until it switches on and we'll come back to that.
The wiring centre has a delay normally about between five and eight minutes, depends on the system. How this would work if we turned this thermostat on, this thermostat really all it is a link, so if you imagine a wire, if you split the wire, if you cut the wire, it wouldn't work. The thermostat joins the wire together and then it connects it back to the wiring centre and then that wire centre to then will control the zone valve which is in there, the wires for the zone valve is in there and then the zone valve there and then that will open. So this zone valve here will open and send the central heating wire from the Combi Boiler around here, which will come round into the bottom of this valve here. And then the pump that's built into your manifold, your pump, will start pumping and it'll pump it around the under floor heating system. Because we don't want the under floor heating temperature to get too high, it has a blending valve on here and this blending valve can actually be adjusted and you would set that to whatever your drawings are. On this system, we want it to be about 45 degrees. The boiler's only just turned on so it's not up to temperature yet. But that's how that would work.
You also have some flow metres and you would set them, when you first get your drawings, you would set this to whatever the flow is required for the heating system so that you get your output, what you require, and then you've got your pipes to go around for your heating system and then obviously they would hate the floor.
So that's just a very, very quick video on how under floor heating systems work. I've got full length video from start to finish, including how to pipe, how to wire, how to wire your zone valves in, how to wire your thermostat, full start to finish video. And I'm going to upload that in the next few days or so. I've just got a little bit of editing to do on it. And then I'll upload that as well.
If you've got any questions, please ask them in the comments below. And as always, I'll try my best to answer them. Thank you for taking the time to watch this video.

[@ryanseddon4800]

Your accent is perfectly understandable sir.

[@AllenHart999]

Glad to hear that

[@wakkaboi3681]

my guy was so self-aware he put labels on everything so we can understand him. Legend!

[@ricojakkakarico-che2561]

Fantastic! Best video I’ve seen on any trade based installation, your labels are actually essential no matter what the accent, and I could understand every word by the way! Well bloody done mate!

[@davidrice1272]

A very good explanation of the basic set up. Helpful.

[@MrTsonkov]

Very clear Allen.Thank you for explaining.

[@ClarVad]

By the way, I love your accent. Very informative video. Great job.

[@AllenHart999]

Thank you! 😃

[@chriscars3578]

Another fantastic video again Alan 👍👍👍👍

[@AllenHart999]

Chris Cars Thank you very much Chris 👍

[@Skeletoncrew46and2]

Thank for taken the time to make these videos Alan.👌

[@AllenHart999]

+jonathan shekleton Thank You for watching 👍

[@AllenHart999]

+jonathan shekleton Thank You for watching 👍

[@Ro55stw]

Great video mate. Brilliant idea with the labels I am going to use my label maker next time I fit a heating system

[@AllenHart999]

I have a new toy. 😂😂😂

[@shaks6775]

Hi Allen, really appreciate your time and effort to make these informative videos. Thank you so much. Really looking forward to watching the full video of how to do underfloor heating etc.. 👍👍👍👍👍

[@AllenHart999]

Happy to help, Thank you very much for watching.

[@AllenHart999]

Did you watch the other underfloor heating videos? Thanks

[@shaks6775]

@@AllenHart999 Hi Allen, yes I enjoyed watching the Underfloor Heating Videos. Thank you for your reply 👍🤗

[@shaks6775]

I'd really enjoy a detailed video on Unvented Cylinder Installation and the Wiring or have you already made a video for that? 🤗

[@rjkelectrical6086]

Fantastic videos, thanks mate

[@junaidrehman8258]

awesome video. very detialed and the labels are a brillinat idea!

[@AllenHart999]

Thanks so much!

[@tommyblackman7119]

Looking forward to the full video 👍

[@AllenHart999]

Tommy Blackman Thank You.

[@zulfhussain1]

Really nice the way your explained it.. thanks ..

[@keithtitley9452]

Great video mate.

[@AllenHart999]

Thank you Keith.

[@jackhoskins722]

Always a good video if you get chance my biggest issue with heating is the wiring even the way you talked about the thermostat being a link makes it a lot more easy to understand would be great to see more wiring videos looking forward to seeing the full video Alan keep up great work !

[@AllenHart999]

Hi Jack i will do one just for you today. I will mention your name in it. Thanks.

[@AllenHart999]

have a look at this one kzbin.info/www/bejne/Z56xcqKmqaaZbbc

[@jackhoskins722]

Brilliant Alan top bloke you are !

[@AllenHart999]

@@jackhoskins722 Let me know if you need any other video's. Thanks.

[@daveast01]

Thanks for doing the vids Al

[@AllenHart999]

Thank you for watching.

[@dommice]

Thanks so much. Very informative.

[@AllenHart999]

Thanks very much for your comment, please consider subscribing to support the channel 🙂

[@crazygeorgelincoln]

Indeed you look well chuffed with it. It's a visually pleasing collection of pipes and things. Saw it in the drip overflow fart blocker device video. Would make a great thumbnail for the big underfloor heating video. Now seen the image I feel compelled to watch the big one once IV finished this one.

[@AllenHart999]

Hoping to tile the floor first and add it all in one video

[@samiullahamini859]

Thank you; a well explained video :)

[@andrewchesney]

Great work - thank you.

[@AllenHart999]

Andrew Chesney Thank you for your kind words 👍

[@niloofarmirsadraee6575]

Thanks a lot! Very thorough! One question: what could cause the rotameter to bounce up & down and make this really loud rattling noise? Only one rotameter on one of the lines .....

[@pangsai17]

Hi Allen, thanks for the video. I recently had an single zone UFH installed with a motor valves to control radiators seperately. However, I noticed that when only the UFH is on, there is a annoying moaning noise coming from the boiler. Tried to do a bit of research on the reason and found some mention relating to the copper piping size. The pipe coming from the boiler is 22mm however, the pipe leading to mixing valve is 15mm which is probably about a metre from the boiler. Could this cause flow issues and also the noise when only the UFH is on? For reference, when both UFH and CH is on, there is no noise.

[@easyfix5366]

Great effort

[@nachiketkaware5453]

Great overview. Just wanted to understand, in a Hydronic system, how component constitute to cost? For instance, how much % share does following components hold in a typical UFH system: 1. Manifolds and valves- 2. Zone Valves- 3. Thermostats and sensors- 4. Wiring center - 5. Heating pipes-

[@andycallow2779]

Hi Allen - thanks for the helpful video. I have a single zone system and the lights on my Grundfos manifold stay on after I turn down the thermostat. Is that normal? Any information as to what it’s doing would be appreciated. Thanks 😊

[@georgeselkhoury8313]

Thanks Allen for the video. I was wondering what is best to do to save energy and pay less gas. I used to have the boiler dials set to max, but used to control the thermostat from the room to turn off floor heating. Would turning the boiler dial down help save some gas?

[@skpropertymaintenance7432]

Thanks Allan. Got a question. When the underfloor heating calls for and then sends power to the boiler via the switched live what happens with the pump in the combi if the underfloor heating has got its own pump. Thank you Wayne

[@adamharley1384]

Hi alan, I have the beneath heat system... What settings does the pump need to be on? Mine seems to be both set on the third setting? I can't find the instructions of what it should be set to? The thermostats seem to continuously click on and off when heating, would you expect the thermostats to stay on untill temperature has been reached?

[@apgx6032]

At Christmas I had to have an old Drayton actuator valve replaced on my wet UFH manifold and also the three port valve changed. I’m finding when the underfloor heating is on the pipes running into the radiator and hot water motorised valves in the boiler cupboard are roaring hot. Both valves sound to be running although the indicator lights are not ignited as they would be had I turned the rads and hot water on. Any ideas?

[@andyyork6763]

Thanks, can you explain how to bleed the system once installed to remove any residual air?

[@goodbyetothepeople92]

Hi. What setting should my Grundfos UPM pump be on for UFH? It is currently on Constant Curve 1

[@harpssingh1477]

Hi Alan, if i have the same setup a combi with rads and an ufh, will i need a by pass if the boiler already comes with a built in bypass

[@amd3411]

Hiya! Any tips for getting troubleshooting error message on Danfoss Termix VVX B? Online suggests the error to be “power low” (E9) but not sure what that means or how to reset!

[@jamesfitzpatrick1779]

How wud isolate zones as i had to rip out some rooms under floor heating but need some to keep working on that manifold

[@zaksystems]

That particular UFH pump where is the on/off switch located on the pump?

[@RajeeTharan]

Hi Allen, I have similar system for my home. Each floor has one system like this. How to I make one floor totally off. Motor or flow knops?

[@aprendiendoaconstruirrizoh8130]

Very nice

[@AllenHart999]

Thanks very much for your comment, please consider subscribing to support the channel 🙂

[@wayneh150]

Hello there ! Have you seen heating controls with a stat on flow and return of the manifold a floor sensor and a 2..10 belimo 3 port mixing valve? I can't seem to find any information on that sort of setup

[@Tangobaldy]

I can't read the labels as they have a strange accent ;). But seriously the labels are awesome. Your accent is easy for me to understand as your bed clear and pronounce your words correctly. Somemeone pronounced my name tangoboldy...

[@AllenHart999]

I did a video as the tango man for a charity event i did, Every time you comment it reminds me of a great day. Thank you.

[@bagheadbaby]

spot on that pal

[@AllenHart999]

Thank You.

[@andrewmcgovan5866]

Great video Allen. Im trying to sort out a new install cock up UFH. Too complicated and pointless to go back to the installer and I have the desire to understand my own system. A question for you please. I have discovered faulty actuators and considering replacing them with automatic balancing actuators as an improvement replacement for the faulty ones. Ive noticed that when heat is called from Zone 1 stat the top section of the manifold and outward flow pipes fills with hot water and all the flow meters are activated even though the return actuators with the exception of zone 1 are closed. This doesnt make sense to me. Those curcuits should remain cold ??? Sorry about being so long winded

[@StylesP321]

Thank you for your video, love the content! Try a fixed tripod with your camera mounted on it - would help us understand a bit better :)

[@istehazebacchus3816]

Question … when underfloor heating thermostat is turned up, will combl boiler fire up / call for heat ?

[@sajidlunat]

Hi. Allen. 1.Can I connect ufh to 22mm ch flow and return without 2 port valve 2. I have a combi boiler and radiators 3. Or do I need 2 two port valves 4

[@jamescoburn1982]

Great video,my question is can i use a solar panel instead of gas, i live in Macedonia and we have 300 sunny days per year. Thank you for your time.

[@MartaMarta94.]

I have an question about Flow meters. On the video they are both up to the top, I have the same system and none of them reaching top in fact 3 of them are in different positions. Is that normal?

[@garethgordon9141]

Good video, no mention of actuators though, is this because there is only one loop?

[@rashadkhawaja3185]

Really helpful

[@AllenHart999]

Glad it helped

[@luizfelipemartino6804]

Do you know any company in London that do maintenance on this kind of heater?

[@daveast01]

Excellent

[@AllenHart999]

daveast01 Thank You

[@hamididrees8428]

How do I check my under floor heating zone valve workings and how to change pls

[@gersher1266]

Hi Alan. Why is there a delay of 5 to 8 minutes in the wiring centre.

[@stephenhamnett6757]

Good video, thanks for posting, and I love the accent, you from around Hull?

[@MrAnjumAnwar]

Hi Alan, well explained video thanks. I understand now how to wire the underfloor heating zone valve but how about the 2nd zone valve, how would you wire that and where the wires will go for the other zone valve? Thanks buddy

[@AllenHart999]

I will do an updated video soon. Thanks.

[@Mad4plumbing-ltd]

Love you vids Nothing wrong with your accent 👍

[@D_pawson]

Do you recon you need an auto bypass or would the secondary heatexchanger act as a by pass with it been a combi. What are advantages/disadvantages for using an auto bypass valve verse a low loss header and incorporating another pump that does not have overrun ?

[@AllenHart999]

D P The boiler has a built in bypass but it’s definitely better to have an auto bypass in my opinion. Thanks.

[@seppy6851]

Another great vid Allen, good accent too. About to start offering underfloor heating myself so was a good introduction for me. I'll watch the full install next. Is it worth attending a training course and if so do you recommend anyone? Cheers Rich

[@AllenHart999]

The manufacturer will work it all out for you and provide plans. I am going to do quite a few different video's to help as well. Thanks.

[@MrGlenfraser]

Top work Allen, what size are the boards and the pipe that goes in them? I think the ones i was looking at from another company based in the same area were 18mm board and 12m pipe...

[@AllenHart999]

Glen Fraser They do lots of different systems. Give them a call and I am sure they will give you some good advice on what suits you best. Thanks 👍

[@alandodge8911]

Hi you haven't shown where the other zone valve is wired to the combi boiler

[@hamidrezadehghan2214]

Hello mate. Thank you for this video. I am looking for map wayering controller heating please. Could you send to me?thanks

[@mrv8788]

Allen, excellent videos!!! I would like your advice about a boiler. I am going to be building a 4 bedroom, 3 bathroom house and would like underfloor heating in the whole of the ground floor. I would like an unvented hot water cylinder . What would be the best boiler to cope with this. Your advice would be very much appreciated

[@AllenHart999]

George Vella What area do you live? Thanks

[@mrv8788]

Allen Hart Kingston, surrey

[@The-Marshmallow-Cookie]

So in theory, could a heat only boiler operate UFH? My house has 8 radiators and a 150litre HWC, my boiler is an Ideal Logic Heat 15, could that run underfloor heating or would you advise a combi only?

[@AllenHart999]

Any heat source would work really. Your boiler would definitely be ok 👍

[@yannisvelegrakis7598]

Very nice video. Thank you. I have some rooms with normal radiators and 1 with underfloor heating, The thermostat is connected to the the central pump that starts circulating water all over the house. There is a second pump (after the first one) only for the underfloor heating room exactly like yours (Wilo). However, that pump is plugged to the normal electricity socket (~220V) and as a consequence it is always on. (when the thermostat is off, it is simply that no hot water arrives to the pump. But the pump is on). Is this normal? I see that in your system you have the pump connected to the thermostat.

[@AllenHart999]

I will try and do an updated video, If you would like to send me some videos

[@yannisvelegrakis7598]

@@AllenHart999 Sure. Here is a video description of the situation I was talking about. kzbin.info/www/bejne/a2OTaoFmfrV9hZI

[@haroondalal800]

Hi I have an open vented boiler syatem. After 4 hours of underfloor heating the tempreature only increases by 1 degree. Do i need a sealed system

[@AllenHart999]

Ask your plumber to come and check it. Thanks.

[@AllenHart999]

Merry Christmas

[@rodknee87]

Good video, would you say UFH is more efficient/effective at heating up a room than rads? Would have thought a lot of heat gets lost in concrete etc

[@AllenHart999]

Underflloor heating is miles better. No question about it. Thanks.

[@circuitbreaker1434]

@@AllenHart999 the main advantage is the huge surface for heat transfer wich makes it possible to use a lower water temperature wich increases the efficiency of the boiler.

[@DavideCauso]

Thanks

[@AllenHart999]

Davide Zeta Thanks for watching 👍

[@liamhainsworth26]

Sir. I have a technical question.. I am installing underfloor heating into a narrowboat. The heating is powered by a webasto (Similar to a boiler) but it has two functions; on and off... It isnt quite as techincal as the house boiler. Now; at the opposite side of the boat is my manifold (with no wiring between the two)... Is there a way; to have the pump detect hot water in the line; and automatically start?... I need to find a way to get the pump working; when the heating system is switched to ON? Any help...

[@AllenHart999]

Not really sure. Please contact the manufacturer for advice. Thanks.

[@liamhainsworth26]

@@AllenHart999 Thanks Allen. Tried to talk with them, but they ask me to direct the question to the plumber, who in turn tells me its the electrician... The electrician then goes; i dont know, im not a plumber! Its like smashing your head against a wall haha

[@johnsloan8019]

Hi Allen, Thank you for explaining underfloor heating. My question is, can the manifold & pump be sited in the loft, as i am renovating a bungalow, room by room & i was planning to fit the pipe into the floor & bring the flow & return into the loft. As i can only do one room at a time due to living in the bungalow. The existing radiator flow & return run down from the loft - my plan is to join the manifold to the flow & return pipes from the boiler in the loft & run down to each room from there, i will insulate the pipes running down from the loft. My worry is will there be an air issue & will there need to be a drain off or bleed valve etc at floor level. Thank you again for your videos.

[@guillermoangelo9096]

I guess Im asking randomly but does any of you know a way to get back into an instagram account?? I was dumb lost my login password. I appreciate any assistance you can offer me!

[@phillipjaxson4710]

@Guillermo Angelo Instablaster ;)

[@guillermoangelo9096]

@Phillip Jaxson i really appreciate your reply. I found the site through google and Im trying it out atm. Looks like it's gonna take a while so I will reply here later with my results.

[@guillermoangelo9096]

@Phillip Jaxson It worked and I now got access to my account again. Im so happy! Thank you so much you saved my ass !

[@phillipjaxson4710]

@Guillermo Angelo Happy to help xD

[@quadrantheatingelectricspl2907]

Hi Alen, where do you buy your press fit from, thanks

[@AllenHart999]

Any merchant really. Plumb centre at the moment.

[@quadrantheatingelectricspl2907]

Fittings are expensive

[@AllenHart999]

@@quadrantheatingelectricspl2907 Yes they are about the same as push fit.

[@bbclive3544]

Could you explain all wiring including radiators

[@AllenHart999]

Yes i sure will. I will try and do a video. Thanks.

[@user-lh1vw2tu7r]

I want to shut off my home's water main while I'm away for an extended time. Will the heating still work properly?

[@AllenHart999]

yes

[@AllenHart999]

Thanks very much for your comment, please consider subscribing to support the channel 🙂

[@daveloz1]

Hi great video I have a question we recently had someone in to sort our ground source heating system out as it was using too much electricity.... We noticed the floors in 2 rooms were not getting warm enough as they used to I noticed the blending valve was a minimum would this effect the warmth? The other rooms ok and I noticed a different blending valve was at 45 degrees. Thanks

[@AllenHart999]

You need someone on the job to advise on that. Too many variables. Thanks.

[@AllenHart999]

Thanks very much for your comment, please consider subscribing to support the channel 🙂

[@daveloz1]

@@AllenHart999 Ok thanks Allen.

[@0792matt]

AAV ?

[@phillipbull3673]

Why do underfloor heating manifolds have their own pumps and not use pump in combi?

[@AllenHart999]

They need to blend the water down to lower the temp. Hence needing its own pump. Also you need to control the flow rate through the floor.

[@phillipbull3673]

@@AllenHart999 thanks ... Also how du bleed air out of underfloor circuit as iv hit one in the past with drill and struggle d to get air out and had to have it pumped

[@AllenHart999]

@@phillipbull3673 I will upload a video to show you. Thanks

[@TheAmario982]

Hi mate good video but you forgot to explain the 8 minutes delay on wiring centre thanks

[@AllenHart999]

amario anas When you first turn the power on it has a delay. Doesn’t do it in normal use. Much more about it in the full length video. Also how to wire. Thanks 👍

[@lemmykilmister450]

Ee ba gum, what are thee talking about? Nice vid mate.

[@AllenHart999]

Thank You 😂😂😂

[@percyadler4318]

Keep to radiators and Diesel Boilers as they work, because the other systems you will be hijacked by electrical quangos trying to repair the systems. Mr P. Adler

[@ahmedadam1699]

Thank you for all usefull video Allen who does not understand your accent is hard to understand English

[@frazer26]

I assume Joanne’s your wife, love how the wash room has her name on. 🤣

[@AllenHart999]

😂😂😂😂😂😂😂😂She hasn't seen this 🙀😂

[@lextrombas]

Oh this is way too complicated for me. I will have to work another plan.

[@geoffreywilliams7705]

we're really only interested in how it works man . .

[@ericmarshall8133]

🤔Looks like a Dogs Breakfast