How to Fix a Leaking Radiator Valve

Overview

A leaking radiator valve can cause water damage. This guide covers fixing a leaking radiator valve.

Step-by-Step Fix

1. Before attempting any repairs, switch off your central heating system completely at the boiler or thermostat. Allow plenty of time for the radiator and its pipes to cool down fully, as hot water can cause severe burns. Ensure the radiator is cold to the touch before proceeding.
2. Carefully examine the gland nut, which is located just below the valve handle on the body of the valve. Use an adjustable spanner or appropriate wrench to gently tighten this nut by a quarter turn clockwise. Avoid overtightening, as this could damage the valve and worsen the leak.
3. If the leak persists after tightening, you'll need to repressurise the valve stem by repacking the gland. First, loosen the gland nut slightly, then carefully wrap 3-5 layers of PTFE tape clockwise around the valve spindle, ensuring it sits neatly within the gland. Finally, re-tighten the gland nut firmly but carefully to compress the new packing.
4. Should the leak continue or if you observe visible cracks, corrosion, or significant damage to the valve body itself, the valve will need replacing entirely. This is a more involved task that may require draining the system or isolating the radiator, and you might consider calling a professional. Ensure you have the correct replacement valve before starting this job.
5. Once you are confident the leak is resolved and all connections are secure, switch your central heating system back on. Carefully monitor the radiator valve area for any signs of continued leakage for at least 30 minutes. Check the system pressure and top it up if necessary according to your boiler's instructions.

Common Symptoms & Diagnostic Resolutions

Review the common error codes and operating symptoms below to quickly identify the root cause of the fault before ordering replacement parts.

Frequently Asked Questions