I recently had a new condensing boiler fitted. The pump is now in the boiler rather than being up stairs in the airing cupboard. The problem that I now have is that the radiators up stairs are getting hot but the downstairs radiators are very slow to heat up and never seem to get to the required temperature. The problem I think is to do with balancing the system. I would be grateful for any advice on how this is done.
Balancing a central heating system
- Thread starter surfrider
- Start date
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As far as I know, it goes something like this!
Firstly you will need radiator thermometers (two thermometers one at each end of the radiator).
Turn the boiler off, make sure the system is cold!
Then open up the wheel and any TRV all the way and turn the boiler back on!
You might want someones help for this bit, try to see in which order (a definite sequence) the radiators get hot. You can always let it cool and do it again if your unsure.
When you are pretty sure you have got it e.g. 1-10. Go to the first radiator and hang a thermometer on each end.
You are looking to get a temperature difference of 10-12C between the two ends. If its more, which is likely to be at the first radiator, slowly turn the outgoing valve clockwise (shutting) until you have a 10-12C drop.
Make sure you note how many turns/half turns to achieve this!
Do the same sequentially at each radiator i.e 1,2,3 etc, so that all have a 10-12c drop across them.
The valve should need less and less turning as you go on (as the resistance in the system is already higher due to the longer pipe run).
If the radiator are not balanced then the flow tends to take the easiest route i.e the shortest pipe runs!
Is your boiler upstairs?
Are the downstairs radiators fed by microbore (8 or 10mm)?
Downstairs radiators tend to have pipe runs ~ 4-5 metres longer than an upstairs radiator in the same position. Upstairs radiators are closer to the main (22mm) pipe run.
Good Luck it takes some time.
Andy
Firstly you will need radiator thermometers (two thermometers one at each end of the radiator).
Turn the boiler off, make sure the system is cold!
Then open up the wheel and any TRV all the way and turn the boiler back on!
You might want someones help for this bit, try to see in which order (a definite sequence) the radiators get hot. You can always let it cool and do it again if your unsure.
When you are pretty sure you have got it e.g. 1-10. Go to the first radiator and hang a thermometer on each end.
You are looking to get a temperature difference of 10-12C between the two ends. If its more, which is likely to be at the first radiator, slowly turn the outgoing valve clockwise (shutting) until you have a 10-12C drop.
Make sure you note how many turns/half turns to achieve this!
Do the same sequentially at each radiator i.e 1,2,3 etc, so that all have a 10-12c drop across them.
The valve should need less and less turning as you go on (as the resistance in the system is already higher due to the longer pipe run).
If the radiator are not balanced then the flow tends to take the easiest route i.e the shortest pipe runs!
Is your boiler upstairs?
Are the downstairs radiators fed by microbore (8 or 10mm)?
Downstairs radiators tend to have pipe runs ~ 4-5 metres longer than an upstairs radiator in the same position. Upstairs radiators are closer to the main (22mm) pipe run.
Good Luck it takes some time.
Andy
Andy,
Many thanks for your advice.
My boiler is downstairs and I do have some pipe lengths again downstairs that are small bore.
I have 19 rads most of which are double convectors and my boiler is 160,000 btu's
Although there are a lot of rads the boiler should hopefully cope adequately.
The problem would therfore I think be related to balancing
Dave.
Many thanks for your advice.
My boiler is downstairs and I do have some pipe lengths again downstairs that are small bore.
I have 19 rads most of which are double convectors and my boiler is 160,000 btu's
Although there are a lot of rads the boiler should hopefully cope adequately.
The problem would therfore I think be related to balancing
Dave.
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