Is your radiator not getting hot enough? There are several possible reasons for this issue, and most of them are easy to fix.
If all your other radiators are working, but one stays cold, it might initially seem confusing.
But with a little troubleshooting, you can get your radiator back to full heat.
In this guide, we’ll walk you through the most common causes of a cold radiator and provide simple solutions that you can do yourself.
Whether it’s air in the radiator, a stuck valve, or a simple pressure issue, we’ve got you covered.
So let’s dive in!
Here Are 7 Easy Steps To Fix A Cold Radiator
1. Check the LockShield Valve
First, check if the lock shield valve is fully open.
This valve controls the flow of water into the radiator. If it’s closed, water can’t flow properly.
You’ll find the lock shield valve under the cap at one end of the radiator.
Use a wrench to turn it anti-clockwise and open it up.
Once done, check for heat by feeling the two pipes connected to the radiator.
One should be warm. If there’s still no heat, you might have air trapped inside.
2. Bleed the Radiator
Air in the radiator can cause cold spots, especially at the top.
To fix this, you’ll need to bleed the radiator.
First, turn off the boiler and the pump. Make sure both radiator valves are open.
Grab a radiator key and insert it into the valve at the top of the radiator. Slowly open it.
If air is trapped, you’ll hear a hiss.
Once the water starts to flow out, close the valve.
Wipe up any excess water, and the radiator should heat up.
3. Check the Thermostatic Radiator Valve (TRV)
Another culprit could be the thermostatic radiator valve (TRV).
Sometimes, the pin inside the TRV can get stuck.
If this happens, the radiator won’t get enough flow.
To fix it, remove the TRV head.
Depending on the model, this might involve unscrewing a collar or popping out a plastic lug.
Press the pin down gently to see if it springs back up.
If it’s stuck, you can use long-nosed pliers to pull it up.
Be careful not to force it, as this could cause damage. If the pin doesn’t move, it may be time to replace the TRV.
4. Ensure Proper Flow and Check for Cold Spots
After these fixes, check if the radiator is heating evenly.
If one side is warm and the other isn’t, the issue could still be air, or the lock shield valve might need further adjustment.
5. Look for Balancing Issues
It could be a balancing issue if multiple radiators aren’t heating up.
Balancing ensures the hot water is evenly distributed across all radiators.
This requires adjusting the valves on each radiator to ensure consistent flow.
If you’re unsure how to balance the system, it’s best to call a professional plumber.
6. Check Boiler Pressure
Lastly, make sure the boiler pressure is adequate.
Low pressure can prevent the system from heating up properly.
If the pressure is too low, follow the manufacturer’s instructions to top it up.
You also need to track the signs that your gas boiler needs replacement.
7. Call a Professional for Complex Issues
If these fixes don’t solve the problem, the issue may lie deeper within the system.
A broken diverter valve, rust buildup, or even a malfunctioning boiler could be the cause.
In these cases, it’s best to call a heating engineer to diagnose and repair the system.