Re: Central Heating System Balancing

[Phil Addison]

Shabs wrote:

> > I have read about a central heating system being balanced. I recently > > removed all radiators to flush the gunge out of them. Whilst doing > > this I had to close both sides of the radiator valves. Upon rehanging > > the radiators I have opened fully the valve on the opposite side to > > the thermostatic valve, ie the water inflow to the radiator. How > > should these inflow valves be set as i have radiators over 3 floors > > with 2 on the bottom, 4 on the 1st, and 2 on the 2nd. Any advice > > greatly appreciated in getting the balance back. > > Look at > Describes the process.

For an alternative view see

Addison The uk.d-i-y FAQ is at NOSPAM from address to email me

[Set Square]

lockshield valve (by counting the number of turns required to close it) when turning it off. Then you can restore it to more or less the same position.

I suspect that, even then, a further bit of fine tuning would be required.

When performing the balancing operation, it helps *enormously* to have a non-contact IR thermometer (costing about 30 quid) - which enables you to zoom round all the rads and to record the flow and return temperature of each very quickly. This makes the iterative process (of progressively restricting the flow to the rads with the lowest temperature drop) much faster than it would otherwise be.

[Phil Addison]

Already there. "3. Record initial LSV positions in case you want to return the system to what it was."

Quite so. In fact I added the following to that part of the Balancing FAQ a few weeks ago :-)

• Since writing the above I have obtained a non-contact (infra-red) thermometer and this makes the task VERY much easier and quicker. As the reading from this type of instrument depends on the emissivity of the surface being measured, the reading will vary slightly depending on whether it is pointed at a dark copper pipe, chrome fittings or white radiator paint. I found the easiest way to overcome this was to fix a piece of black PVC tape on each of the points I wanted to measure. That gave me consistent results which agreed well with my old thermo-couple thermometer. The instrument I have is a model IR-88 Pocket InfraRed Thermometer obtained from CPC for £35, part number IN02293.

-- Phil Addison The uk.d-i-y FAQ is at

NOSPAM from address to email me

[Set Square]

Sorry for re-inventing the wheel! I must admit that I didn't read the updated FAQ before posting.

I tend to assume anyway that people (if they're like me!) will often read in-line text before (and maybe in preference to) following up external links.