Why are my radiators not getting warm?

After a (hopefully) long summer it can be very frustrating to find one or more of your radiators stubbornly refusing to warm up when the central heating is on. Most likely this problem is caused by the pin in your radiator valve being stuck in the closed position and therefore not letting any, or at most very little, hot water into the radiator.

To fix this is a very quick job and one that can be done with WD40 and a pair of pliers or, ideally, mole grips (locking pliers).

Step 1:

First you need to remove the Thermostatic Radiator Valve (TRV) control to reveal the offending pin underneath. Twist the screw top and then pull it off.

Radfan on radiator behind a sofa

Radfan - A warmer home, guaranteed

Feel warmer here >

Step 2:

With the pin revealed you first need to check if there is any movement in it. Using a flat part of your pliers carefully give the pin a firm push, if it doesn't make a noticeable movement then it is indeed stuck. If this is the case then spray it with a little WD40, securely clamp the tip of the pin between your pliers and very gentle pull and push the pin up and down - make sure to move in a straight line as you don't want to bend it. After a few moments of this you should find the pin naturally moving between to set points, open and closed.

This pin is actually quiet long and it is difficult to pull it out - if you do accidentally pull it out there is a strong change you will spray yourself and your wall with water. If this happens then quickly, and as calmly as possible, push the pin back in the hole (using a pair of locked mole grips makes this much easier than using a pair of pliers, not that I am speaking from first hand experience of course!)

Step 3:

Replace the TRV control cap and set it to what ever you like - generally for downstairs rooms this is 4 and upstairs this is 2 or 3.

If this doesn't solve the problem then it would be worth bleeding the radiator and potentially getting a plumber in to take a look for you.

  Simon Barker

  broken radiator valve, central heating, cold radiators, plumbing, radiators

The Radfan Classic Family

Radfans that live on top of your radiator redirecting heat into your room - perfect for most radiators.

Classic Small


Classic Medium


Classic Large


The Radfan Slim Family

Radfan Slim fits to the bottom of your radiators to accelerate the warm air flow up and around your room. Use with radiators where the Radfan Classic won't fit.

Slim Small


  • Perfect for: Smaller obstructed radiators, home office
  • 47cm / 18.5in long
  • 2 integrated fans
  • £2/year running cost
  • 1 W power
  • ★★★★★
    Customer reviews

Slim Medium


Slim Large


  • Perfect for: Large obstructed radiators, kitchen diners
  • 139.5cm / 54.5in long
  • 6 integrated fans
  • £6/year running cost
  • 3 W power
  • ★★★★★
    Customer reviews