Radiator balancing
1) Any thermometer suggestions for balancing radiators.?
2) Once you have smart TRVs is balancing still needed as they will regulate flow from the front end rather than the outlet from the rear end of the rad?
cheers
Best Answers
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1) I have a TPI 343 for flow and return (assuming that's what you want to measure).
2) Whether you have so-called smart TRVs or TRVs doesn't change anything.
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I'm no heating engineer, but it sounds like your pump might be running too fast and forcing water to flow too quickly upstairs, thus causing the noise. Opening the first two radiators might reduce the noise upstairs, by diverting the water flow, but it is not very efficient.
If there is anything you can do to reduce the pump speed, and to reduce the flow through the first two rads, I think you will save costs and have a much better installation. Maybe better heat distribution and comfort too.0 -
You can’t really balance two rads, you are balancing the whole system.
Using a TRV to do this is not really achieving it. And I won’t get started regarding so-called smart TRVs.
You have a heating system, not a pile of components. Have a look at the Heat Geek channel and see the holistic approach to heating. Or Urban Plumbers.
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Have the TRVs wide open, so that only the lockshield valves are limiting the flow. You can use Boost to open them all up for half an hour.0
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@hipponax1973
Right now it is -4C outside.
Heating has been on all night with no setback. All rooms are at their expected temperature.
Boiler flow limit is set to 55C, although the boiler typically might overshoot the limit by 3C.
Courtesy of my flow and return temp logging thermometers I know my maximum flow temp overnight has been 51C and that Tado has been firing the boiler for bursts of either 10 or 20 minutes in relay mode.
Note that early on the heating season (last October?) I requested the minimum burn time to be raised from 4 minutes to 10. So the boiler will fire for at least 10 minutes each time, but longer if needed.
It's also worth noting that my boiler is range rated down to the minimum output of 9 kW at all times. That is why a 4 minute burn (flame on time of just 3:40) was insufficient to be worthwhile and why I asked for the minimum to be increased.0 -
Sorry, the forum would not allow me to attach a picture with my reply from my phone, but I can from my tablet....
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Answers
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Experience and experimentation with my own system for over a year has convinced me that balancing is strongly recommended.
Tado regulates room temps. It does not balance the system. If the first radiator in the pipework goes wide open it will short circuit the rest of the system and return water straight back to the boiler, raising return temp, reducing efficiency and leaving the other radiators wanting for heat. It may even lead to premature boiler shutdown as the flow temp reaches the set limit quicker than it might otherwise. So now you have short cycling and the farthest rads down the line still waiting for their first sniff of hot water.
Rinse and repeat for each radiator as you move through the pipework. You need to balance each rad so that Tado cannot short circuit the flow/return by going wide open with an SRT.
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@eezytiger : this is really interesting. I have 2 radiators without smart TRV really close to the boiler (they are in the basement, next to the boiler), while all the others are relatively far. I have these 2 close to the boiler fully opened, because if they are not than other radiators in the rooms (upstairs) are quite loud (not the noise of trapped air, but just simply the water circulating). My boiler cycles a lot and I do not understand the reason, maybe that is the key what you just suggest, that the 2 radiators really close to my boiler "heat up" the return temp too quickly ?
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yes I can concur with the rads near the boiler - my flat is 1900s all on one level but spaced out with 7 rads: the one in the bathroom next to the boiler and the kitchen one are super hot and fill in seconds whilst the rest of the house takes a while UNLESS these two are shut off - I think I need to balance these two especially (or with the new TRVS on the way I can allow these two to come on for the breakfast hour and then once the kids are on the school run they will both shut off and then allow the hot water to pump around the other 5 rads.0
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@hipponax1973 Sorry, I overlooked your thermometer question. I bought several of these....
sufficient to monitor flow and return at the boiler and flow and return at each radiator. TBH you really only need to monitor the return from each rad. Flow temp into each radiator is not so important with my technique.
I use hook/loop straps to hold the thermocouple tight against the copper pipes....
My technique is not to look for a particular temperature drop across each radiator, but to check that the return temp out of each radiator is in line with the return temp at the boiler and not very much higher or lower.
If the radiator return temp is much higher than the return at the boiler then water is flowing through the radiator too quickly. It needs to be throttled (balanced). If the return from the radiator is cooler than the return at the boiler then the flow speed through that radiator is too low and the radiator needs opening up a little - or earlier radiators need closing a little more in order to pass more water along the sequence of radiators.
The aim, in my opinion, is for the return temp from each radiator to be equal and close to our just a little higher (1-2C) than the return at the boiler. It may take a few revisits to tweak things as each change at a radiator will change the balance of the system. Gradually it should be possible to home in on perfection.
This is why it is so useful to have each radiator monitored at once. It is a very quick process to check temps in quick succession and make small adjustments. If you only have one thermometer, or a pair, then it is time consuming to detach/attach from and to each radiator and wait for temp equilibrium. Then you can't quickly review all temps at once for complete system balance.
Here are my thermometers at the boiler flow and return. The top two log temperatures every minute, day and night, and can be reviewed with an app. Because they only sample once per minute they are not always bang up to date, but they serve their purpose.
The bottom two are the ones I linked to earlier. They update quickly, but no logging or app. They are perfect for checking Delta T at the boiler and for quickly comparing boiler return temp with the radiator return temps.
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Brilliant solution thank you - do i assume when i test all the TRVs are wide open? or doesnt it matter? Also if a radiator appears to be much further away than the others do i allow a bigger temperature drop?
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@eezytiger - I have four of those temperature sensors fairly recently - possibly from an earlier link of yours.
However your suggestion of the velcro strap works a treat (had some velcro spare on a might come handy shelf that i have just tried) These work great on chrome pipe too. Last year I tried using in infra red spot thermometer but it only works on painted pipes and sticking tape on although helps took effort to clean the sticky residue off afterwards.
Ordered another set of four of those so I can use your great suggestion of only checking the return side of 7 radiators against the return temp at the boiler. Previously had two of these on boiler flow and return to see the difference also what the flow reported compared to the boiler flow on its display but hadn't got around to how to use on radiators themselves but had stuck behind flow and return pipe of furthest radiator away that is in spare bedroom oldstyle manual trv set at 1 above living room with pipes fed from downstairs so I could easily see from living room as a starter.
Recently had a new bathroom fitted into what used to be the kitchen in a 1920s house we moved into about 2 years ago. The old tiny bathroom turned into a utility room, also upgraded an old rad for new type 22 in hallway and I suspect as a result that something is now unbalanced as a result and I think it's one of the three permanently fixed towel radiators that might be the culprit.
Sticking a few of these sensors around I should be able to see how the return temps of all the uncontrolled chrome towel type rads interact with a number of other rads which I plan to observe early morning when tado shows most trv on 100%. Have four more now on order arriving tomorrow...
Also I can then see how during the day how they perform when there is only a room or two heating request at high % but heating effectively low possibly short cycling unless it's tado doing the modulation opentherm type thing.
I have one last large old double panel radiator of 70s era left to upgrade to a modern type 22 in living room just need to consider if I can afford to at present (would be ideal as i have yet to decorate that wall) or leave until next year.1 -
what sort of flow temps do you expect with all the trvs open? i think my boiler is fighting TADO and refuses to flame for more than a few mins and the return flow temp even during boost is barely above 40 for more than 2 mins before dropping back to 30 again-my max flow temp is set to 60
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@eezytiger will i get any abberation of temp given my in and outflow pipes are vertically mounted and next to each other? where would i best place each probe? still on the pipes or just top and bottom of radiator? cheers:)
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@hipponax1973 If you use the thermometers I suggested and attach with hook and loop straps or electrical tape then there will be no aberration.
You should place the thermocouple against the return pipe, as close as you can to the radiator and squeezed and secured as tightly as you can against the pipe.
Heat will be transferred by physical conduction from the return pipe and the strap or tape will insulate to keep the heat from that pipe in and to limit interference from the flow pipe.1 -
the hottest part of the in pipe is next to the TRV, the coldest is as the bottom ail place then there thanks:)0
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is there anychance you can upload pics of how you run your tests with the devices fitted to the pipes please, just need a dummies guide :-)
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I think it is difficult to show the process with pictures, so I've shot a video, which I hope demonstrates how I compare the return temperatures quite quickly throughout the house. Of course, adjusting lockshields (if required) would add to the time taken as it's somewhat a trial and error process since lockshield valves are so vague in their operation.
However, my system is already balanced to my satisfaction, so no adjustments required. If I did want to make the balancing even more equal between rooms I would need to slightly close down the rads with the highest return temps in order to divert more water to the cooler radiators, but since I want bedrooms cooler than other rooms I'm happy as things stand.
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@eezytiger thanks alot, that really helps. i will need to go through this process aswell.
had a garage room converted few months ago, and that is really struggling to get to a reasonable temp. (i've set it to independent mode). its by far the coldest room in the house, furthest rad from the boiler aswell.
if i set it with a zone controller, then the water temps required to heat that room are max and then it just messes with the temps in the other rooms as all but one trv's are set to independent and ofcourse, uses alot more gas aswell :-) lol
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@Ervcrt100 @eezytiger - lovely setup -
I had already set my fastest and nearest rads to a lower TRV setting (manual) in order to reach the living room (slowest and furthest) and when the thermometers arrive ill see how much out of whack everything is before I add another 4 smart TRVS that just arrived today in the post.
Recently my only smart room was the living room and i set the wallsensor as primary and the smart TRV just called for what ever it needed to do - this for some reason confused my boiler and the heating is far better if i just remove the smart TRV from the room - instead of doing that am i better making my TRV independent? and if so how? I thought the point of the TRV was to communicate with the TADO wireless?
Cheers in advance
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so I have all the rads wide open and will start tweaking there:
First rad near the boiler: 39 in 35 out, boiler is 37.8 - this is surprising as i thought this was the rad that needed throttling at the lockshield - Or do they heat up quicker if the outflow is slower?
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@hipponax1973 There can sometimes be a situation where an SRT is connected to the zone controller and calls for heat, but does not open the valve far enough to permit water to pass. Maybe this is a fault with the Tado control of the pin, but it could be that the valve itself has a poor or unusual response to movement of the pin.
This could cause the boiler to fire, but the very room that wants heat does not receive any. Eventually Tado will observe that the room is not heating and will open the valve further. Maybe this is the problem you are experiencing, maybe not.
I've experienced this very problem with at least two of my radiators. Maybe there are others, but I've not noticed. My solution is that only one room can control the boiler. This is the master bedroom, set to 19C day and night.
All the other rooms are independent, so they cannot cause the boiler to fire. They can only receive heat when the bedroom needs heat. All of these independent rooms are set to 21C. They may not reach 21C - it is a limit, not a target - but this means that whenever the bedroom turns on the boiler all the other rooms are already wide open and able to use the heat available.
This has several benefits....
- Whenever the boiler is lit there will always be several radiators able to emit heat. Therefore the boiler is never lit in a wasteful fashion and stuck fighting against a valve that hadn't opened far enough.
- With several radiators (usually all of them) able to take the heat there is very effective dispersal of heat from the radiators and my 9 kW boiler output can be shared amongst them and is not forced into a single radiator from where it is impossible for the heat to escape fully.
- The consequence of all radiators active is that my return temp is kept as low as possible, despite my oversized boiler.
- The philosophy I'm following is to heat the house as a whole, not just individual rooms. They all work together to heat each other. No cold spots, no drafts.
- This is a solution is arrived at for myself, but supported and reinforced by YouTube videos from Heat Geek.
- It is actually the groundwork to see whether a heat pump will be a viable alternative to a boiler for heating my home, especially while avoiding upsizing radiators. I run the same temps 24x7 and try to keep flow and return as low as I can, with the lowest boiler output possible. Therefore the system never has to sprint to raise temps rapidly in the morning. It's kept simmering gently day and night - low and slow as the heat pumpers would say.
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random q for you- are your TADOs TRVs on the returns on your rads? they almost look like it? i’ve just flooded one room discovering that german return valves clockwise here0
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Some are on flow, some on return. They were fitted in 1988 and I guess the plumber did whatever he fancied. No obvious rhyme or reason.
It shouldn't matter, so long as the valves beneath are designed for the direction of water flow. All that the Tado SRTs do is to close the pin. And closing the pin is no different to closing the lockshield and vice versa.1 -
These are my valves - very strange - they dont really seem to affect the outflow temp really even when grossly adjusted ps going too many times anticlockwise and the bolts pop out- they have a little o-ring under each thats quite tempremental - eg leaky.
If these dont really do anything how do you balance the rads?
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Lockshield valves usually pass water quite quickly with only a very small turn anti clockwise from fully closed. Typically the valve nearest the boiler might only be opened 1/4 turn or something like that.
When I balance I try to do it with the house in silence. Then I close the valve in question completely and back it off just slightly, guided by my ears to judge when the water starts flowing and then guess how much further to go. Once I've got a controlled flow I can then fine tune the temp.1 -
i use the trvs the same way listening for flow- wonder if there’s any difference because the in and outlet pipe are on the same side0
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so tonights been a total failure cant get two thermometers to take remotely a repeatable or accurate reading - even when they are both taped to the same bit of the pipe there can be a large difference (see pic)
In addition whilst I am sure these are a german version of the lockshield valve, im not sure Im using them right - second valve leaked as soon as i touched it (they arent really a valve they are a hexagonal nut with an o ring just under the thread.)
I wonder whether the rads nearest the boiler are simply just hotter as its an old flat and with the 4 extra TRVs in the sale the other day and im tempted to just fit them anyway and see how it all goes? I essentially want the the kitchen and the bathroom to be warmer than the rest especially during wake up time, and then the living room warmer inthe evening. The kitchen and the bathroom are the fastest and easiet to heat and the living room is one of the harder to heat radiators so i suppose i could use timing of three TRVs to concentrate hot water around the house when reqwuired?
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Following this thread with interest!
I found these online:
https://www.amazon.co.uk/Inkbird-Wireless-Bluetooth-Hygrometer-Thermometer/dp/B07DRC4M88?th=1
Anyone got a link to a reliable but cheaper option?
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