I'm a not a gas engineer, just a home owner looking to save a sheckle or two. I did buy a digital thermometer to balance mine as they're not too badly priced now. This is the first video I've seen that doesn't tell you to open all the TRV's and lockshields fully, turn the heating up full and find the order they heat up. Then when the system has cooled set the boiler temp and go round in the order of heating, altering the lockshields as required to get the temp difference.
Good vid, thanks. In ductwork systems where you can’t have control dampers, we balance the system by selecting size of pipe and number of bends etc. and calculating pressure drop in each leg but it’s more of a black art with small bore water systems.
In Denmark we NEVER do that. We have shunted two-string systems with a cirkulation pump, that lets in new hot water, and lets out used cold water to the boiler. In newer houses, each radiator even has its own circuit. Easy-peasy!
Nice video but am still unsure of when to take the temp. difference i.e. as you state, when the rads warm up then the temp. difference becomes less, just as when starting up the temp difference will be less, So, is the max temp. difference at any particular time the one I should be looking for?
Very detailed explanation Mark thanks,but it does seem like balancing is nearly impossible to do,and to achieve it means spending many hours and lots of money on new auto/smart valves, measuring kit etc,plus more gas when testing,the previous videos i have seen all say measure temperature difference across flow and return pipes when system is hot,so bit unsure how it can be done when the system is cold ?,also i have 2 new aluminium middle connection radiators in a recent extension that dont get very warm the heat isnt spread out across the entire radiator it just seems to be hot in the middle and on one side,i have been using a thermal imaging camera to identify the cause ,but not getting very far,I am liaising with the supplier at present but they don't know why,would you have any thoughts Mark.?
It's difficult to achieve a temperature difference of 12 degrees for a small radiator. Also it helps if no-one is running a bath or shower when balancing the central heating system.
I think there are two delta_T's: One is the difference between inlet and outlet, controlled by the flow valve and thermostat settings. This delta_T is the one that is optimised as suggested by Mark here to obtain 10 degrees difference. The other is the difference between the average radiator temperature and the surroundings ('the room'). Mark refers to the different delta_T's 50, 60 and 70 - I think that is the temperature of the radiator (like you would measure with one thermometer) and not the difference between the average radiator T and the room T. Delta in science normally refers to the difference between two quantities, so I'm a bit lost with Mark's definition of delta_T. The second delta_T of interest is the difference between the average radiator temperature (half way between inlet and outlet values) and the room temperature, which is proportional to the heating power supplied to the room. In turn this is connected to the flow rate and the first delta_T. Both of these delta_Ts are related, because in a steady condition the radiator has to emit the heat power it receives from the boiler. I think that for a given temperature requirement in a room, there is an optimum value of the inlet-outlet delta_T, from the viewpoint of efficiency. But of course we want the room to be the right temperature, so it is impossible to have optimum efficiency without being able to control all the variables. Mark goes on to discuss the 'smart' kit now available to be able to do this, like controlling the pump speed etc. Whatever, Mark's video really helped me get our CH system working better, and that's what matters to me!
Thank you for your help. However, I’m pretty sure I need to replace my 15 year old Vaillant Ecotec 630 system boiler now. What is your recommendation for a new boiler? I heard that Worcester Bosch has the edge over Vaillant? Thank you 😊
I have 8 rads on my system with a combi boiler. It would appear I have 3 rads that have the flow coming in through the lockshield valve, 3 where the flow coming in through the TVR and one in the bathroom next to the boiler has 2 lockshield valves. How can I balance this system? Will I need to swap them around?
@@mrwhiteno50 It appears so. My understanding is that the pipe that gets hot first in the flow and the other the return..mine are clearly muddled, so something else for me to sort .
Wish someone would explain how to balance a mini bore system with manifolds hidden above ceilings. I have 20 rads and it’s impossible to run around the house to see which rad gets hot first.
Does not matter which one gets hot first. it's just a case of balancing all of them to get that difference in temperature between the 2 pipes and yes you have to run around all the radiators.
That’s useful information. I have a similar sounding heating system with 10mm piping and hidden manifolds. I had a digital temperature gauge on each radiator flow pipe and still couldn’t tell the order they warmed up. At least 5 of the rad flow pipes heated up simultaneously. I guess this is due to being connected to a manifold. Now I know the order is not critical I can start to balance the individual radiators.
So the way I understand this is: if I have pressure modulating pump I don't need auto balancing valves. Having them installed in the system with pressure modulating pump might create conflict between two as the valves will control pressure(independently)as well. Or, am I missing something?
I've just tried balancing my system based on radiator size. The smallest (about 500 watt) radiators had the lock shield on quarter open, the intermediate (about 700W to 1 kW) had it set one turn open, and the largest (1600 watt up to 2200 watt) were left fully open. What do you think of that approach? Seems to work with the large radiators coming on more quickly, but since its August I can't properly test it out. To me it does seem logical to match the flow to the radiators ability to dissipate heat. Background - each radiator is fed by microbore, so the pipework probably limits flow rate.
I have an open vented system. The pump (Grundfos UPS2) is burner linked. If I set it to variable speed my system takes longer to heat up and the rads knock when the pump backs off. All rads, trvs & lock shields are 3 years old. Boiler is Vaillant Ecotec 415. The pump shouldnt back off because all the trvs are open and the rads tuned for 12c differential. So can i ever get my system to run in the optimised config? It seems like its not possible and the pump should just be kept in constant speed mode.
Hi regarding the hot water tank what should be the temperature difference flow and return difference, when it's just DHW demand , from cold. I have a system boiler heating a tank indirectly with CH. Thanks
I’ve followed all your videos on cold radiators - took it off and flushed it, changed the thermostatic valve, then changed the lock shield valve, now I’ve balanced the rads and it’s still the same - hot pipe to the valve but radiator still cold. Any more suggestions?
If standard TRVs will potentially mess up the balancing and make the boiler less efficient, is there much point in them accept to keep your room from gettibg too hot? I remember people talking about TRVs actually saving you money but based on thus if the boiler has no idea TRV has turned off a radiator, there no savings at all
You make a very good point. If you have a thermostat in one room and it detects the heat has reached the required temp then it will reduce the heat to all rooms so really the thermostat is a mute point im going to remove mine
I just cant get all my radiators hot, new boiler and new rads, the worst rad i can get one side hot but the return pipe is cold, really need help on this.
Hi guys, I have an issue with only one rad in my system. When the CH is on this rad wants to remain cold, however I can feel that the lockshield side gets hot aswell as the pipe, but the TRV side remains cold and will only ever get lukeworm. When I remove the TRV from the rad and open the TRV, there is water gushing out. Does anyone have an idea of what may be going on?
did you solve it? i would check the trv pin is not stuck by carefully pumping the pin. if its stuck down you wont get flow either that or maybe sludge build up in which case you might need to remove it and flush it
Can you give me some advice e please, my living room radiator isn't heating up as well as all the rest, its the largest radiator.we flushed out the system, took the radiator off and run a hose through it, it was pretty mucky. We bled the radiators and it's still the same. If we switch off all the other radiators it gets hot and works. I've tried to balance the radiators and it made it worse. I'm not 100% sure if I got the right sequence. Our condenser boiler is down stairs in the kitchen and the pump and cylinder tank is in the upstairs bathroom. So not sure which is the first. All advice will be greatly appreciated. Tia
get two people to do this one upstairs one downstairs yell when you find the first rad that gets hot. what i did was this i turned on all my rads both sides. Turned on the heating and felt all the rads until i found which one heated first this should be pretty easy then i turned off the heating and fully closed off the first one then put the heating on again checking all the rads and found the next one turned it off shut down the heating waited and then did the same each time this will bypass the ones you know and force the water to the next in sequence. also unscrew your trv and push the pin up and down using pliers in case any trv pins are stuck making it impossible to find the order. maybe do this step first before you do the order
yeah he totally missed that part out which is pretty bad. you open all the valves on all rads fire the heating and hand check each to see which ones get warm in which order
All my 5 radiators are cold at the bottom but they were fine just last season. Would it be central heating pump malfunctioning or a sldge in radiators?
@@gulag8735 I got it fixed. It was not radiators and pipes that was the problem. For some problems you relay just need to suck it up and call the plumber.
A tip our plumber gave, was to leave all the TVR's open during the summer months. Otherwise the pins jam closed. Removing the TVR head and gentle tap with a hammer can get the pin moving freely again 👍
@@Trev5 in my case it was not radiators at all, it was a build up dark hard stone on the inside walls of the pipes coming out of the boiler. This stone reduced the bandwidth siginficantly so water could not properly circulate in the system. Removing the pipes and just give them few hits alowed for remving the stone and fixed the problem.
My damn pipes are made of plastic i cant measure on them. But my question is we heat the house with coal burning boiler and a 500L hot water tank if it is warm enough in the house isnt it more efficient to send as hot water as possible back to the boiler so the fire will burn less intensively and use less coal ?
The lock shield valve is the one on the return. That is the one that heats up last from a cold start. If you have two wheel valves on both ends you should replace the lock shield wheel by a plastic cap to prevent it being turned. Or you can mark the lock shield valve with some plastic tape. When balancing open the other valves fully and adjust the lock shield valves following the guidance Mark provides in this video.
Lockshield (on the return pipe) is normally fitted with a cap so it cannot be turned, to adjust you need to pop off the cap and turn the valve with an adjustable spanner. The other side (the flow pipe) is normally fitted with a thermostatic valve or a normal wheel cover that you turn to adjust. The temperature at the flow pipe coming into the radiator is hotter than the return pipe on the other side coming out. I use a digital hand trigger thermometer to measure both sides thus giving me which is flow and which is return. You can pick one of these up in Lidl for about €20
Hi, I have a modern condensing combi boiler system with a flow temperature of 60 degrees. I have currently gone with a temperature delta between the flow and return of 12 degrees on each radiator that i can, but some of the further radiators are still not getting adequate flow/warmth. Would it be okay to aim for a higher temperature delta of for example 18 to 20 degrees to help balance the system as the system is incapable of balancing with a 12 delta between flow and return on the radiators that are getting hot. Kind regards.
Useful video but do I need to go to the rad nearest the boiler or the hot water cylinder/pump first, then the second nearest one and so on? I'm assuming the hot water cylinder as that's the thing that pumps out the hot water not the boiler, so I'll try that first. No, that can't be right as the hot water in the cylinder is just used for hot water for use in showers/bath isn't it? The hot water that circulates round the rads comes from the boiler, doesn't it?? I need more knowledge on my system before I try to fix the cold rads I have! Hashtag beginner....!
Please help me I replaced 3 radiators after that, and all systems blocked 🚫 mean 10 radiators not working. I drain all systems air out from radiators still not working kindly please give me the solution what wrong 3 meter pipe next boiler very hot after that not hot aswell Please help me Thanx
