Introduction

Adding inhibitor to your heating system doesn’t mean draining everything. In fact, most UK homeowners now use a simple method that takes under 20 minutes.

This guide shows you exactly how to do it safely.

---

What You’ll Need

• Radiator dosing tool funnel
• Central heating inhibitor
• Radiator key
• Cloth or towel

---

Step-by-Step Method

Step 1: Turn Off Heating

Let the system cool fully.

Step 2: Pick the Right Radiator

Choose an upstairs radiator if possible.

Step 3: Release Pressure Slightly

Bleed a small amount of air.

Step 4: Remove the Bleed Valve

Carefully unscrew.

Step 5: Add Inhibitor

Use a dosing tool to pour it in slowly.

Step 6: Reassemble & Bleed

Refit valve and remove air.

Step 7: Restart System

Check boiler pressure.

---

Why This Method Works

• Uses gravity to distribute inhibitor
• Avoids introducing air into the system
• No full drain required

What is radiator dosing tool funnel?

How to use a dosing tool

---