I am going to balance my radiators this weekend, I just want to check some facts that hopefully some of you can help me with.
I need to open up all the control and LSVs and find out what the flow is and find the index radiator. As I understand it the control valve should be where the flow is in and the LSV on the outflow. Two of my radiators appear to the the other way round - is it a simple matter of just swapping over the knob from the control valve and putting it on the LSV?
Do I leave the index radiator fully open and work back to the boiler or do I start from the radiator closest to the boiler?
From what I understand I might have to adjust the speed of the pump. I have no idea how to do that! I have a Potterton Puma 100 boiler and I can't even see a pump let alone adjust the speed! I understand that some boilers have automatic pumps - is that right? Does my boiler have one?
Yes but it doesn't answer all of the questions though, it doesn't say which order you do the rads in, nor does it say anything about if you can just swap the control or LSV. I have a 3 story house, so where you start could make a difference!
Yes, provided the two valve bodies are the same, and one of them isn't a thermostatic valve!
Neither. Firstly, go round and measure and record the temperature drop across *every* radiator. You will need a non-contact IR thermometer to be able to do this is a reasonable time. Then turn down the LSVs on the rads with the *lowest* drops - regardless of their position relative to the boiler. This will restrict the flow - and increase the drop - of these, so starting to even things up. Aim to get all the drops more or less the same - without worrying too much about the *actual* value at this stage. It is an iterative process - because decreasing the flow on one rad will increase it on the others - so you'll have to go round the lot several times - allowing a bit of time for any adjustments to take effect. The LSV on the rad with the largest drop should remain fully open at all times.
Once all the drops are the same, you can adjust the pump speed - if necessary - to achieve the desired value. For a conventional (non-condensing) boiler, the norm is 11 degC (20 degF). If the drop is significantly less than this, slow the pump down a bit - and vice versa. A bit of fine tuning on the rads may be needed after this. [Don't be *too* much of a perfectionist - it isn't an exact science!]
[I've no idea about your specific boiler/pump. Some boilers have a pump inside the casing. Some systems use external pumps - often in the airing cupboard. Once you find the pump, you should find a speed control lever or knob on the side somewhere].
One other point worth noting: When you're rushing round measuring one rad after another, you need the flow temperature to stay as constant as possible - otherwise you won't be comparing apples with apples. This means running the system flat out - with the room stat turned up to max. This time of year, you'll probably need to open a few doors and windows while you do it in order to dump the heat.
I didn't say it did - I was just referring you to a very good article on the subject which, despite not answering all your questions, I though would be a worthwhile read if you were undertaking the task.
That's because there isn't one - that was an unnecesary compication you added yourself. As the article explains, you are simply trying to make the resistance across each radiator the same - you will discover which ones have the most/least resistance when you take your first readings.
I would say that it probably wouldn't matter which one you use to restrict the flow as long as you end up with the desired temperature drop but I'm sure others will disagree!
I think Set Sqaure has covered most of the points.
It makes no difference which valve you choose as the locksheild (for balancing) and which you choose as the user valve. However generaly one valve or other will be the more convinient for a user valve. Obviously if one of the valves is a TRV then the other is a lockshield.
Not most valves have just about no effect until the last 1/2 a turn to closed. Beaware that older valves can have a certain amount of backlash in them so adjust them down to the settings if you need to open one up then open it up a lot then down to what you what.
Finally setting the closest 1/3 of all the radiators to the boiler (as the pipes run not as the tape measures) to about 1/2 turn open rather than fully open [1] might save you one whole cycle of measurements. [2]
[1] All non-quarter turn valves are fully opened if they are open full on less about 1/4 turn. This is too prevent them jamming in the open position.
[2] This would be the finish of the subject for the mediocre professionals.
It's not somthing I made up myself. I have looked at various sites and there is conflicting advice this site for examples says you should balance the radiators working back to the boiler
Most of your points have been covered by others, but just to clarify one or two things...
The term 'index' is a very old one deriving from a crude rule of thumb design method. What they mean by 'index' is simply the radiator that has the most resistance to flow. It is the one that has the longest/thinnest pipe run and is often (but not always) the furthest from the boiler. This one should have both its valves wide open during balancing.
Start by opening all of the valves on both sides. Then generally the Rads closest to the boiler will take more than their fair share of the flow so you will start by turning them down to get a larger temperature drop.
There is usually a switch or dial on the pump itself, marked 1, 2, 3 (3 being fast) or similar. The pump may even be under the floor, in which case don't worry unless you really suspect a problem with it.
No. What matters is that all rads have roughly the same drop and have really hot water reaching them. In other words they are all getting HOT!
That's true so far as literal balancing goes. The whole point of a LSV is that the lock (as in Lock Shield Valve) prevents anyone from messing with the setting after you have balanced it.
However, it is quite in order to swap the caps around, or - if you are up to it - even completely remove the valves from the rad and reverse them. As others said, it does not matter which end they are on. As an aside, that is not always the case with TRVs (Thermostatic radiator Valves) - some models have an arrow determining whether they must go on the flow or return.
Angela, If you haven't got one you can get tolerable results simply by following the procedure, but simply turning each LSV until the flow is
*very* hot to the touch and the return feels almost as hot. In fact that is probably the best way to get an initial balance, before fine tuning with a thermometer.
Cheers Phil, that's very helpful advice. The pump is inside the boiler casing according to the installation booklet, and I can't see anyway of adjusting it so it will just have to stay as it is!!
I have managed to borrow an infrared thermometer..........I can't stop playing with it - Although I can't think of a single use for one apart from balancing radiators!!!
you have a 'system boiler' (ie with all/most of the peripherals like the pump contained in the case). The pump illustration looks as though there is no speed control, and the pump is a Myson C61 'special'. I imagine the 'special' means it has the speed switch omitted. It is possible that the pump is controlled by the boiler electronics instead.
As you say, leave it as is. You only need to look into it if it is too fast; = noisy and very low temp rise across boiler, or too slow; = not enough heat in radiators, boiler short cycles, large temp rise (well over 11C).
You can get a rough measure of your body temp by pointing it into your ear, but clinical IR thermometers have a narrower probe to facilitate that, and have a 3 digit display to measure to 0.1degree.
Other than that - hot food, though you really want to know the temperature inside it. Freezer, fridge, oven (not through the glass though).
I meant to add that I find that it helps to get consistent readings with the IR thermometer if I stick a small square of black PVC tape on all the flow and return pipes, just below the valves, as a target for the IR reading. Without that, the reading depends somewhat on the state of the pipe surface and whether it is painted or not, and varies according to which bit of pipe you point the meter at. I'm not sure that black is any better than any other colour in practice, although in theory black is the ideal colour. The main thing is to get a consistent emissivity surface to take readings from.
I wrote an article on balancing rads which was part of the FAQ for a number of years, it has now been dropped off it ... however if you want a copy of the article send me a mail .. happily send it to you.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.