Radiators Cold at the Top
The bottom of the radiator is hot and the top stays cool, so the room never quite warms up..
The bottom of the radiator is hot and the top stays cool, so the room never quite warms up.
What is actually going on
The bottom of the radiator is hot and the top stays cool, so the room never quite warms up.
The realistic causes, in order
Air trapped in the top of the radiator, the ordinary cause Hydrogen gas produced by internal corrosion, which keeps coming back after bleeding An over-pressurised or under-pressurised system drawing air in at a fitting
What we test on site
Whether the gas that bleeds off is air or hydrogen, which changes the diagnosis completely System inhibitor level and water quality Automatic air vents and the pump for signs of air being drawn in
Get radiators cold at the top diagnosed properly
Correcting water treatment and fitting a magnetic filter deals with the cause, not just the cold patch.
Questions we get asked
Why does radiators cold at the top affect some radiators and not others?
Air trapped in the top of the radiator, the ordinary cause
What normally puts radiators cold at the top right?
Correcting water treatment and fitting a magnetic filter deals with the cause, not just the cold patch.
Is it safe to keep using the system with radiators cold at the top?
Repeated bleeding on the same radiator means corrosion is ongoing, and the system needs treating rather than the symptom being managed.