21/05/2026
Ever wondered what’s actually inside your boiler and how it keeps your home warm and your hot water flowing? Here’s a quick breakdown of the key boiler parts and the important jobs they do 👇
🔧 Heat Exchanger🔧
This is where the magic happens! It transfers heat from the burner into the water that heats your radiators and taps.
🔥 Burner🔥
The burner creates the flame that heats the water inside the boiler. No burner = no heating!
💨 Fan💨
The fan helps move fresh air into the boiler and safely pushes harmful gases out through the flue.
🚿 Pump 🚿
The pump circulates hot water around your home, sending warmth to your radiators and hot water to your taps.
⚙️ Expansion Vessel ⚙️
As water heats up, pressure builds. The expansion vessel absorbs that extra pressure to protect the system.
🔄 Diverter Valve 🔄
In combi boilers, this clever part switches between heating your radiators and supplying hot water to your taps.
🌡️ Thermostat 🌡️
The thermostat monitors temperature and tells the boiler when to heat up or switch off.
🛡️ Pressure Relief Valve 🛡️
A built-in safety feature that releases pressure if it gets too high.
💻 PCB (Printed Circuit Board) 💻
Think of this as the boiler’s brain — it controls and coordinates the whole system.
🚨 Regular servicing helps keep all these parts working safely and efficiently, reducing the risk of breakdowns and helping your boiler last longer.
Need help with boiler repairs, servicing, or replacements? And the best part is at EXPRESS BOILER REPAIRS we have 2 great gas engineers on the team who are truly hands on, take pride in their work, and always turn up with a positive attitude. Quality workmanship and great customer service go a long way — and these two deliver both every day (so call 01253 449742 to book Andrew & Finley in 🔥🌪️
