How and why we balance a central heating system

[@hvacdesignsolutions]

The closest rad to the pump should have the most restricted balancing valve (lockshield). This ensures that the downstairs rads achieve their design flow rates on a cold winter design day. If the upstairs rads are the least restricted, the pump will just push most of the flow around the top floor rads and starve the most remote rads from the pump.

[@martinasher8705]

Very confusing as it seem you are saying hot water falls while cold water rises which we know is completely the opposite to what happens, in my experience the most common complaints are that the upstairs radiators get hot while the downstairs radiators remain cold or take a long time to get hot or do your radiators get hot at the bottom while still being cold at the top?

[@MrRawMonkey]

How I do it. Open up the TRV’s to maximum. Turn all the lock shields to off and then open up maybe half a turn or less. Turn on heating and wait for radiators to start getting warm and then quickly feel all the tops of the radiators making a note of which are still cold and which are already hot or are already warmer than the rest. Now go back and make slight adjustments to hot radiators to reduce the flow or increase the flow to cold radiators. Next day do the same, making sure all radiators are heating up at the same rate and adjust accordingly. On day three just make final adjustments and now set TRV’s to desired room temperature. Job done. Ideally there will be sufficient heat drop across the radiator to allow the boiler to condense which can only be achieved if the return is below 55C

[@NickTaylorPlumbingLtd]

MrRawMonkey good for you and thanks for sharing, it does take time to tweak it and get it right, I find my way generally works everytime and takes me about an hour which is a bonus! But it’s best to take your time with it and get it right 💪

[@milkman100001]

what about your 12degree delta across the rads? does this not matter?

[@NickTaylorPlumbingLtd]

Hi Dean, Thanks for your message, The joys of the Delta T's! Ill do a video about it over the next couple of weeks about the theory/technical side of it, generally though in a domestic setting if you follow the guidelines in this video you'll have an even spread of heat.

[@dennishumphries9406]

Hi Nick, how do you balance radiators in a bungalow (one level) thanks.

[@NickTaylorPlumbingLtd]

Dennis Humphries thanks for your messege. Its a little tricker to balance a bungalow as its prone to air locks generally due to the pipe runs being in the loft and then dropping down to each radiator. I’ll do a video and post it on the weekend to explain better. For now I would open all locksheilds 1 and a half turns, bleed any air out the rad vents and that should solve your problem. Don’t forget to like and subscribe if you haven’t already 👍

[@dennishumphries9406]

Hi Nick, thanks for your quick reply, regarding the balancing of radiators in my bungalow., I’ve got a combi boiler in the airing cupboard and all the plpe work runs under the floor boards, does that make a difference? Thanks.

[@NickTaylorPlumbingLtd]

Hi Dennis, Its better that your pipes run under the floorboards then up to your rads rather than up into the roof of your bungalow then down to the rads, It means that the air (air in central heating systems is a headache) will go to the highest point, in your case the radiators which is easily removed rather than be stuck in the pipes in the loft. Hope that helps. Thanks, Nick

[@dennishumphries9406]

Nick Taylor thanks Nick.

[@EMEL-hr4ut]

I have been diy'ing with rads for 12 years and just opened lockshields willy nilly. Thanks for thr insight as I have been making a balls of it !

[@NickTaylorPlumbingLtd]

Hi EM EL, Thanks for your message and that's great news I'm happy to help, don't forget to like and subscribe for loads more upcoming videos

[@gregorydavison3421]

What about delta T of 12 degrees? Living spaces downstairs around 20 degrees, bedrooms 12 degrees surely. Most have bedrooms upstairs....you putting most of the heat upstairs?

[@NickTaylorPlumbingLtd]

Hi Gregory, Thanks for your message, Ill do a video over the next couple of weeks about the theory/technical side of Delta Ts, heat loss and radiator sizing, in general though and keeping things simple for a domestic setting, if you follow the guidelines in the video you'll have an even spread of heat throughout the home. Hope that helps, thanks, Nick

[@corey_1111]

Would it be exactly the same concept if the boiler was downstairs? Don’t mean to sound stupid, but I’m trying to wrap my head around it. Thanks!

[@NickTaylorPlumbingLtd]

Hi Corey, thanks for your message. No problem in asking the question its better to ask and know than always be unsure. in theory it makes no difference where it is positioned. Hope that helps. If you haven't already don't forget to like and subscribe.

[@corey_1111]

@@NickTaylorPlumbingLtd awesome thank you mate

[@rogerkirby6586]

Balancing radiators, I have seen so many you tube videos on this subject that are wrong so thought I would correct. This applies to combi boiler systems Why have a boiler and radiators in the first place, it is to heat every rooms air that has a radiator to a desired temperature to make it comfortable to live in, modern radiator have a (TRV) Thermostatic Radiator Valves which allows the air temperature to be set. The valve at the other end of the radiator needs to be fully open to allow TRV full control. The combi boiler has two pipes connected to the rad circuit, flow and return. When working the boiler heats the flow water to the temperature set by the rad temp control on the boiler. At the same time it monitors the return temp, as the return temp nears the flow temp the flame is reduced, when nearly the same the flame is turn off only turning on again when over certain difference is monitored. Always monitor air temp in a room not radiator temp because that is what we feel. If the room is too cold turn up the TRV, if too hot turn down. The TRV should control to this setting. If you think radiators are getting too hot there may be a cold draft entering the room needing more heat to be used to heat to your temp. If the room air is not hot enough and you have the TRV fully open there maybe not enough water flowing in the rad i.e. a blockage or simply the boiler is set too low. I know there are many and various more faults but this is the basics.

[@millomweb]

I'll take your word for it that this video is bollox - as I can't hear what he's saying - as the volume level is 2 out of 11. I never did any rad balancing on my system as it doesn't need it. Systems with TRVs don't.

[@hvacdesignsolutions]

Wrong.

[@millomweb]

Some volume on the sound would be good for videos.

[@NickTaylorPlumbingLtd]

Hi pmailkeey, thanks for taking the time to comment and letting me know of this. If you haven't already please like and subscribe to my page as it really helps.

[@johnf3326]

I use digital thermometers with remote probes from ebay, inlet and outlet, to set a temperature loss between 10 and 15c. Lockshield valves are non linear. Once they are opened 1 turn its virtually full flow.

[@ianbirch5811]

Great video 👍 just a quick question , my downstairs rads are 62degrees & my upstairs range from 58 to 63 degrees , all heat up around the same time , would you say those temps are acceptable ? Cheers

[@rodgerq]

I'm a competent DIYer and this is something I've only just come across having moved into a 4 floor home with the boiler on the 2nd, and finding the rads are not very well balanced. I checked all the lock shield valves are they are all open fully so I throttled back the lowest floor ones(funnily enough they were colder?), My thinking being that the water was flowing through too fast. Clearly my theory is wrong so I will start again and do as you say. Is it worth while using a temperature laser to monitor the input and output pipes to get the same temperature drop across each rad? Or am I just overthinking this? We also have a TADO smart thermostat and smart TRVs across the house, I don't know if that makes any difference? Thanks for the video

[@NickTaylorPlumbingLtd]

Hi Roger, Thanks for the question, If your having issues with nearly all of your radiators it sounds as though it could be your central heating pump which is broken, therefore not circulating the water properly around your system, this means that adjusting the lock shields wouldnt matter as there is not water circulating from the pump. It also sounds like you've tried to adjust the locksheild and had no luck so you've already tried the simple and most common fault which again points in the direction of the central heating pump. Hope that helps

[@rodgerq]

@@NickTaylorPlumbingLtd hi thanks for the reply. The radiators aren't not heating up, just that they all seemed to be different temps. I have since played around with the balancing and somewhat improved them. As I mentioned above the lower floor(45 sqm living room which is heated by 2 radiators) seemed to be the worst but having played around they are now better. I am considering an ASHP and underfloor heating for that room. It appears there are grants to have one fitted.

[@millomweb]

@@NickTaylorPlumbingLtd Sounds like you need assistance to understand how to use your heating system.

[@nw5835]

could only do 20 seconds due to the muffled low audio, I'm sure the video was good.

[@largesmallgarden7648]

I'm assuming if the boiler is on the ground floor it's the same but in reverse

[@alanwilkinson2789]

Hi Nick. Would the pipe diameter on the system rads have any bearing on the amount of opening on the lockshield valve as my pipework is a mix of 10mm and microbore so I assume not as good flow as 15mm pipe, and would have a reduction in flow to start? Thanks, Alan

[@weementaldavy5987]

You're describing it as if the boiler is downstairs ( opposite to your diagram ) very confusing , all other videos say that the radiator nearest the boiler is the one that should be almost closed down then eachother thereafter should be opened up slightly more till the last one in the chain is fully open , that one being the furthest from the boiler .

[@NickTaylorPlumbingLtd]

Hi Wee Mental Davy thanks for taking the time to comment, welcome to the world of plumbing! If you listen to what I say dispite the boiler location you will have a perfectly balanced system. There is some truth is what you say about turning the radiator closest to the boiler down, I find this works but does not balance your system as well as it should be, every house is different and the way I explain it is the simplest and, in my years of experience in the industry works the best and most efficiently. Hope that’s of some help and you’ve managed to resolve your issue 🤞👍

[@alannicholson4904]

How would you balance the following type of system? Bungalow, 10 rads all with TRV’s, combi boiler in loft, all pipe work downstairs under floors but it’s a one pipe system with bypasses at each rad.

[@millomweb]

With that system, just ensure all lockshields are fully open.

[@katemackenzy5296]

Can you say if the lock valve goes on the return and thermo valve is on the flow side.

[@nrg-5003]

Doesn't matter

[@easyfix5366]

How can I fix if central heating is not working upstairs at all

[@millomweb]

Any cold rads, make sure lockshield valve isn't completely shut ! Do radiators need the air bleeding out of them ?

[@timdaly8057]

Excellent video ….. pity about sound. Well done!

[@millomweb]

What sound ?

[@pistopit7142]

Hi, good video. Do you kow how can I balance the system if some of the radiators have TRVs mounted on return pipe?

[@nrg-5003]

Most trvs nowadays are bi directional so it doesn't matter.

[@pistopit7142]

@@nrg-5003 thanks. It came up in my case it was not a matter of rebalancing but clearing the sludge from boiler pipes. The flow is now perfect.

[@grahamshillingford8229]

All the other you tube plumbers say hot water wants to stay upstairs as water is 'lazy' and wants the easiest route. Which I must agree to some extent as after my heating switches off the upstairs rads stay warmest for much longer... the downstairs rads also take longer to heat up...

[@millomweb]

If you've not got TRVs, fit them to all rads. This'll ensure water only goes where it's needed. If it's a 3 speed pump, set it to the fastest speed.

[@hvacdesignsolutions]

@@millomweb Wrong

[@mickwhelan7074]

Excellent vid. The other vids don’t make it so obvious that heat as a gas rises up but heat in a liquid is pulled down. Thanks mate, as a instructor your first class. Off I go this time balancing me rads the right way round. Down to up and not up to down...😀

[@TheZippyMark]

That bit totally lost me, heat in water does not go down, what's he talking about?!?

[@ianclarke6830]

Great video, can I ask a question, bungalow, 8 rads including towel rail, pipes go into loft, would you turn all lock shields 1.5 turns, I’ve been trying to work out the closest to furthest rad, but pipework can feed two rads from loft, comes down into one room and back enters into 2nd rad. Also if all set to 1.5 on lock shields, what happens if some rads have trv on 3 but some on 1 or 2, or would you set all trv the same ?

[@NickTaylorPlumbingLtd]

Hi Ian, thanks for your message, couple of things there; 1 - Pipes from loft that feeds to 2 radiators, treat them as 1 big radiator when balancing the whole house, once you've balanced the house and your happy the 2 radiators in question will fight each other for heat so then you balance them two after the whole house has been balanced. 2 - TRV settings. When balancing set all TRVs to number 3. This then give the homeowner control to increase and decrease the temperature slightly. However sometimes TRVs are more sensitive than others, (old / new / different manufacture etc) so if in doubt turn up to 5 or max setting. 3 - Lock shield settings, I would start off putting them on 1.5 then any rads which are cold after your heating has had enough time to heat turn the hottest rad down to 1.2 / 1. In theory that should then push the heat to the other radiators. If that doesn't work start again on all rads 1.5, then find the coldest rad and increase the lock shield to 1.8 / 2. If your still having trouble this could mean there an airlock (see my other videos) or your central heating pump needs turning up or needs replacing. Hope that helps. If you haven't already don't forget to like and subscribe.

[@ianclarke2862]

@@NickTaylorPlumbingLtd I ended up leaving all on 1.5 turns as seemed to work the best, closest rad was on its own but the others to each room where all back to back, basically pipework from loft into one room feed 2 rads, and had 3 lots like this, for example, bed 1 and hall fed from 1 downfeed, kitchen and bathroom fed from another downfeed, bed 2 and dining room from another downfeed, so to get each rad to 12degree difference found too hard. having said that the 1.5 turn on each. boiler displays flow and return and if boiler pushing out 70, return diff around 17, if pushing out 40/50 return around the 8 to 10.. i assume return would be variable like that

[@ianclarke6830]

Hi Nick, Can you also tell me what you would by default set the flow temp too when setting up a boiler and also do you think would get much benefit from weather compensation units against load modulation units

[@millomweb]

All rads with TRVs, set the lockshields fully open. If towel rail hasn't a TRV, turn it off at the lockshield then the day after, crack the lockshield open 1/4 of a turn. Repeat the following day if the rail is still cold. The day you find it hot, leave it set at that.

[@gmailalan]

On the ground floor where the boiler is all the radiators are cold, and on the first and second floors all the radiators are hot. No one has touched the lockshield valve. So why have they become cold? When I get access to the property, I'll try to balance them. What is confusing for me is that other videos make the point of adjusting the lockshield on each radiator in the order they are from the boiler. The first radiator being adjusted a 0.5-turn, the 1-turn, the next 1.5-turns, and so on until the last radiator is adjusted. So which is correct?

[@millomweb]

Fit TRVs to all rads and leave the lockshields fully open.