balancing radiators

[tvmo]

Hello

Can anyone explain to a complete biff how to balance radiators please?

I had a double-storey extension and can't seem to get the rads in my new living room to warm the room properly.

Cheers

[Roger Mills]

Start by reading

and come back if you have any questions.

[john]

Balancing a radiator! Never read so much rubbish, some will be cooler if a room is often much colder. Maybe fitting the correct sized radiator would help. Use a thermostatic radiator valve on each radiator and it will control it all for you.

[David Hansen]

On Sun, 13 Jan 2008 02:04:23 -0800 (PST) someone who may be tvmo wrote this:-

1) know the pipe runs to each radiator. 2) balance two radiators on each leg to each other. 3) balance any more radiators on the same leg, one by one, to the ones already balanced. 4) do the same for each other leg. 5) then balance each leg against the other(s).

If there are no valves to make 5) easy then it will need to be done by adjusting each radiator on a leg by the same amount.

[Roger Mills]

Now who's talking rubbish?!

Even with TRVs, you *still* need to balance with the TRVs fully open (or preferably with the heads removed). This ensures that the house heats up evenly when the system is first turned on. If you rely on TRVs, you have to wait for some rooms to get fully hot before you get any flow to the other rooms.

I agree that the principle of balancing assumes that each room has more or less the right size of rad to balance the heat losses - but you *still* have to balance the rads to get the right *distribution* of heat between rooms.

[diy-newby]

Make sure the temp drop (from inlet to outlet) is roughly the same on all rads. I think the accepted drop should be 20 deg F. Adjust the LSV to achieve this. Rads furthest away from the boiler will need the LSV to be opened more than those nearer the boiler to achieve ther

20 deg drop.

[Dave Liquorice]

I'm not convinced that the difference of a few degrees in room temps will have a great affect on the temp drop across a radiator with the supply water at 80C or there abouts. It will have some affect but probably masked by measuring inaccuracies. And more to the point ones is setting a consistent temp drop across all rads so the affect is cancelled out anyway.

[Roger Mills]

Or 11 degC if you prefer.

Agreed.

Maybe! Which ones need throttling depends on a number of factors - including radiator size and pipe size/layout - not just distance from the boiler. The best approach is to start turning down the lockshields on the rads which have the smallest temperature drops, regardless of position.

[Roger Mills]

I don't think I said that, did I? When I referred to getting the right distribution, I meant getting a flow to each rad which is proportional to its heat output - which you physically achieve by getting even temperature drops across all rads.

[diy-newby]

Sorry, I meant to say "Rads furthest away from the boiler *MAY* need to be opened....."