Balancing radiators

fjon

I think my radiators need balancing, but want to make sure before I attempt it.

When the heating comes on some radiators are hot, while others are lukewarm, or are warm on top and cold at the bottom.
When I turn off all radiators except the ones that are cold or half-cold then they heat up perfectly. However, when I then turn all the other rads on again, typically the last one or two I turn on will end up being the cold ones.

Does this sound like something balancing would fix?

Someone posted this a while ago so I was going to try to follow it:

http://www.diyfaq.org.uk/plumbing/rad-balance.html

Ronan H

I had this problem for ages in my house. I had our usual plumber look at it a couple of times and balance it, but it never really made any significant difference. Eventually we ended up upgrading the pump in the (gas) boiler and that sorted the problem out once and for all. Hot radiators everywhere, all the time. Win.

While he was looking at one particular culprit (radiator that is), he took the radiator off the wall and emptied out the contents of it, which was a manky black dust and (small bits of) rubble filled water. He suggested that this might have been contributing to the issue also if it was blocking the flow etc.

Anyway, the upgraded pump sorted it totally. No harm keeping that in mind if the problem is a persistant one.

Ro

fjon

Thanks for that! May sound like a stupid question, but where is the pump? Is it part of the boiler or is it separate? Reason I ask is that the (gas back) boiler just got serviced, and would this not have been something that would have shown up during that?
The rads are maybe 5 years old, but have only been used in the last year - the place was lying empty before that. I'm not sure how much rust and dirt would have accumulated in that time.

Ronan H

Well the pump on my boiler is just in behind the control panel on the boiler, pretty easily accessible once the front is off. I imagine it is the same in most boilers but I'm open to correction on that if there is a plumber watching!

I should have said in my last post that there was nothing actually wrong with my old pump, it was working fine. The plumber just mentioned upgrading as an option we could consider in trying to address the hot and cold radiator problem we were having, because the balancing didn't work.

So, as far as an issue showing up in a service goes, unless the pump is malfunctioning or broken, then I don't think the service would show anything pump-related that might cause concern.

I guess there are so many variables that will affect how the heating system works, so there is no catch-all solution. Sometimes (like in my case) a stronger pump sorted it, for some people the balancing works, some people need the system flushed out, the TRVs might be goosed, radiators full of ****e etc.

For me it was totally worth the couple of hundred quid to guarantee that the kids rooms would be hot when we wanted them to be. It was a no brainer and as far as I am concerned is now a totally justified purchase.

Anyway, as I said, it is something for you to consider if the balancing doesn't work. At least you can give the balancing a shot with no cost, and it seems pretty easy to do (from watching the plumber do it that is!)...

Let us know how you get on? T'would be good to have a start and end to the thread as it might be useful for others too.

Ro

oikster

Pipe sizing can cause problems like this and if done incorrectly can make a system harder to balance. So by putting a stronger pump on you are really covering up a popular short cut. i.e. smaller pipes cost less. Just a suggestion.

Ronan H

I guess it is easier to install a stronger pump than to change the pipes? Now that you mention it, the plumber may have mentioned that as another of the factors that can contribute to balance issues...

fjon

Just to follow up on this thread in case it helps anyone else.

Balancing did not have any noticeable difference. While previously cold rads are now warm, it's still not possible to have every rad on at the same time. There are 9 of them in a medium sized apartment.

Interesting thread about the smaller pipes. I've no way of knowing this, but it wouldn't surprise me. The build quality of the apartment isn't amazing.

So I really don't have a solution yet. For now the workaround is to turn on the most important rads first (kids room and other cold rooms), and then gradually turn the other ones on as needed. The last one to be turned on will most likely not warm up at all.

fjon

Just out of a matter of interest, I don't suppose there's any easy way for me to know what size pipes are used? I assume most of it is hidden away underfloors and walls?

gdavis

do u know the size of ur boiler?how many kilowatts?/btu's?and how many rads is it heating,double/single panelled? boiler may be undersized

Ronan H

Good point about the possibility of being an undersized boiler. I had our boiler serviced last week and I was telling the guy about the upgraded pump. He mentioned that the boiler might hav ebeen undersized to start with, so that is another possibility worth looking into. I think you can work it out based on a few different figures like those mantioned above...

fjon

I've had difficulty finding the size of the boiler. It's a Glowworm back boiler, but unless I remove the fire grate and unscrew a plate I just can't get to see the label that has that info on it.
There are 9 radiators, all double. there are 3 large ones, 3 medium and 3 small.
So possible causes so far include: pump, undersized boiler, too small pipes.
Looks like it's really not going to be very easy to fix.

Ronan H

Y'know what, I have just noticed that you referred to your boiler as a "back boiler". I was wondering what you were referring to when you were talking about fire grates and plates etc., and then I saw "back boiler"...

Ergo , it appears that much of what I have written is in fact not relevant to your problem, because the boiler I have been referring to in my house is a typical gas boiler that is installed on the wall in a utility room, not the back boiler type that you are referring to. I believe they are different things. I do not even know for sure if your back boiler has a pump, in fact, I know more or less nothing about them...

I must admit that in your second post on this thread, you did mention a "gas back" boiler, but I obviously didn't (read) see that properly and hence went of on a tangent about a different sort of boiler altogether! I do apologise about that, I should have been paying more attention!

I believe this is a thread fail on my part!

RebelButtMunch

fjon wrote: »

I've had difficulty finding the size of the boiler. It's a Glowworm back boiler, but unless I remove the fire grate and unscrew a plate I just can't get to see the label that has that info on it.
There are 9 radiators, all double. there are 3 large ones, 3 medium and 3 small.
So possible causes so far include: pump, undersized boiler, too small pipes.
Looks like it's really not going to be very easy to fix.

I had a similar problem. I emptied the system, flushed a suspect rad, and in the end only replacing the pump fixed the problem

heinbloed

The OP wrote:

Balancing did not have any noticeable difference.

There was no balancing done then. How was the balancing done in this case, with the aid of a thermometer? What where the meassured temperatures at the outlets of the radiators?

Increasing the pump's capacity might be a solution, but with old gravity systems this can cause further problems.

gdavis

as far as i know the gloworm bbu are 13-16 kw so may well be too small