Radiator Not Heating? Fixes for Cold Radiators

Diagnose Your Radiator Problem

Where your radiator is cold tells you what's wrong:

Fix 1: Bleed Your Radiators

For: Radiators cold at the top

Time: 5 minutes per radiator

You need: Radiator key (£1-2 from hardware store), cloth/towel

1. Turn off your heating and wait for radiators to cool
2. Place a cloth under the bleed valve (small square fitting at top corner)
3. Insert radiator key and turn anticlockwise (quarter turn)
4. You'll hear hissing as air escapes
5. When water starts to dribble out, close the valve
6. Repeat for all radiators
7. Check boiler pressure - top up if below 1 bar

Fix 2: Check the Valves

For: One radiator completely cold when others work

Check the TRV (Thermostatic Radiator Valve)

The TRV is the valve with numbers on it. Check:

• Is it turned up? (Try setting to 5/max)
• Is the pin stuck? (Remove the head and check the pin moves freely)

Unsticking a TRV pin:

1. Remove the TRV head (usually unscrews or pulls off)
2. You'll see a small pin
3. It should move in and out when pressed
4. If stuck, tap gently with a hammer or grip with pliers and wiggle
5. Spray WD-40 if very stuck
6. Replace head and test

Check the Lockshield Valve

On the opposite end from the TRV, there's a plain valve (lockshield). Check:

• Remove the cap
• Use pliers to check the valve can turn
• It should be open (turned anticlockwise)

Fix 3: Balance Your Radiators

For: Some radiators hotter than others

If radiators near the boiler are hot but those further away are cool, your system may need balancing.

This involves adjusting lockshield valves to ensure hot water reaches all radiators evenly. It's a bit fiddly - many people prefer to get an engineer to do it.

Fix 4: Powerflush

For: Radiators cold at the bottom, or poor heating throughout

A powerflush uses a machine to pump cleaning chemicals and high-flow water through your system, removing sludge, rust, and limescale.

Signs you need a powerflush:

• Radiators cold at the bottom
• Radiators take ages to heat up
• Noisy boiler or pump
• Heating system is over 10 years old
• Discoloured water when you bleed radiators
• Frequent boiler breakdowns

Cost: £300-£600 for a full system

Time: 4-8 hours depending on system size

When to Call an Engineer

Call a professional if:

• Bleeding doesn't help
• You can't free a stuck valve
• Multiple radiators are affected
• You need a powerflush
• The boiler is making noise
• You're not confident doing the checks

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