Why Are My Radiators Hot When The Heating Is Off?

When you think of heating problems, most of us imagine a broken-down boiler in a freezing cold winter. But what if your heating won’t turn off? We get calls from people whose radiators are hot even though their heating is off! This is often combined with lukewarm water from the hot taps.

Why Are My Radiators Hot When The Boiler Is Off?

Radiators have two ways of getting hot water into them to make them hot. Depending on your heating system, the radiator might stay hot for a different reason.

1. Stuck diverter/ zone valve

A faulty diverter valve is a common issue with heating systems.

A diverter valve can either be inside the boiler or separate, usually close by. When the boiler is on, the diverter valve diverts water to the radiators or hot water taps. It opens and closes to dictate where the water goes.  

When it gets stuck in the mid position, hot water being sent to the taps will also be going to your radiators – even if your heating is turned off.

2. A broken check valve

With older boilers, it could be a broken check valve. This is a small component inside the boiler that activates when you switch off the boiler – if the boiler is still hot, but your thermostat is turned down, the check valve stops the heat from coming out. If it breaks, then heat still reaches your radiators.

If you have a faulty diverter valve or a check valve, you’ll need to call a Gas Safe Registered plumber to clean or possibly replace it. Call your local plumber and get a quote for repairing or replacing the valve and before you know it you’ll have heat where you want it – and not where you don’t.

L&W Heating and Plumbing

If you need a heating engineer call L&W Heating and Plumbing Gas Safe registered plumbing and heating experts on one of the numbers below for a free quote:-

Plumbers Wigan 01942 417220
Plumbers St Helens 01744 776140
Plumbers Newton Le Willows 01925 394260
Plumbers Warrington 01925 394260
Plumbers Runcorn 01925 394260
Plumbers Widnes 01925 394260