Central Heating - Balancing Radiators

In order to ensure an even distribution of hot water toOpen the lock shield valve and the control valve using
the radiators in a system you'll need to 'balance thean adjustable spanner closed small. This is the valve
system'. Often the radiators near to the boiler/pumpyou use to turn the radiator on and off.
would tend to be warmer than the radiators furtherFit the radiator thermometers to the Inlet and Outlet
away, balancing the system will even out the flow ofpipes of the radiator which is nearest to the boiler and
the hot water.switch the heating back on.
To do this we use the lockshield valve which isClose the lockshield valve on the first radiator to
normally hidden under a push on cover at one end ofalmost closed, as the temperature of the systems
the radiator. Adjusting these valves will regulate thecomes up, gradually open up the valve until the
flow of water to the radiator. By partially closing thetemperature difference between the two radiator
valves, flow to the radiators nearest the boiler can bethermometers is about 12°C (20°F)
more limited than to those further away. To reduceMove the thermometers to the next radiator away
the water temperature at the outlet pipe, the lockfrom the boiler. Close down the lockshield valve and
shield is closed; to increase the temperature the valveadjust it until the temperature difference increases to
is opened up.about 12°C (the temperature difference will
The idea is to get temperature drop across eachprobably start at less than 12 degrees as both valves
radiator to be about 12 °C (20 °F). Theare fully open).
easiest way to measure the temperature drop acrossIf you repeat this for all of them in order, you should
the radiators is to use a set of radiator thermometers.have a balanced system so that all radiators heat up
These clamp-on thermometers have springs whichefficiently.
hook around the inlet and outlet pipes of a radiator.Once the radiators in a system have been balanced,
They can be found at any DIY story.the valves should not need to be adjusted again unless
Before you begin make sure the system is turned offthe radiators or the pipes are changed.
and let the water cool down.