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Stephen Day

Gas Safe Engineer at iHeat

Stephen Day is a Gas Safe registered and FGAS certified engineer with over 20 years of hands-on experience in the heating, cooling, and renewable energy industry, specialising in boiler installations, air conditioning, and heat pump systems.

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About Stephen Day

Stephen Day is a Gas Safe registered and FGAS certified engineer with over 20 years of hands-on experience in the heating, cooling and renewable energy industry.

Throughout his career, Stephen has designed, installed and maintained thousands of systems across homes and businesses in the UK. His background on the tools, combined with his directorship role at iHeat, gives him a rare understanding of both the technical and operational sides of the industry.

He has helped to secure Which? Trusted Trader accreditation all with a focus on delivering great service and long-term value for customers. He also writes for the iHeat blog, sharing practical advice and explaining heating topics in plain, helpful language.

Stephen continues to stay up to date with the latest heating technologies, building regulations and low-carbon innovations.

Gas Safe ID: 5910722

Expertise

  • Boiler systems and installation
  • Heat pumps and hybrid heating systems
  • Gas safety and compliance
  • System design
  • Renewable and low-carbon technologies
  • Technical training


Articles by Stephen Day are reviewed by iHeat’s technical team for accuracy and reliability.

Stephen Day's latest articles

Worcester Bosch Boiler E9 Fault

05th February, 2026 Guides

Worcester Bosch Boiler E9 Faul...

Boiler error codes are sequences of numbers or letters displayed on the control panel of y...

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Why Is My Boiler Whistling?

05th February, 2026 Guides

Why Is My Boiler Whistling?

The persistent whistling from your boiler is more than just a nuisance; it signals underly...

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Why is My Boiler Making a Loud Vibrating Noise?

05th February, 2026 Guides

Why is My Boiler Making a Loud...

Several factors can lead to a boiler making loud vibrating noises. It's crucial to pinpoin...

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Why is My Boiler Making a Humming Noise?

05th February, 2026 Guides

Why is My Boiler Making a Humm...

Boiler noises are frequent issues that signal varied problems within the system. From slig...

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Why Does My Boiler Fire Up in the Night?

05th February, 2026 Guides

Why Does My Boiler Fire Up in...

Occasionally, boilers turn on during the night due to specific triggers. These include the...

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What Type of Boiler Is Right for Me?

05th February, 2026 Guides

What Type of Boiler Is Right f...

Our guide explores the different types of boilers available, including combi, system, and...

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What is Boiler Pump Overrun? - Functions, Issues, and Fixes

05th February, 2026 Guides

What is Boiler Pump Overrun? -...

Pump overrun in boilers is a feature that helps cool down the system and manage residual h...

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What is Boiler Modulation?

05th February, 2026 Guides

What is Boiler Modulation?

A modulating boiler not only adjusts its output to meet the varying heat demands of your h...

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What Is An Expansion Vessel?

05th February, 2026 Guides

What Is An Expansion Vessel?

An expansion vessel is an essential component of a modern boiler system, serving a pivotal...

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What Is A System Boiler?

05th February, 2026 Advice

What Is A System Boiler?

The best boiler for your home will be one that can meet the demands for hot water and cent...

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What is a Boiler PCB?

05th February, 2026 Guides

What is a Boiler PCB?

Our helpful PCB blog provides a comprehensive explanation of the Printed Circuit Board (PC...

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What is a Boiler Filling Loop? In-Depth UK Guide

05th February, 2026 Advice

What is a Boiler Filling Loop?...

When it comes to Boilers, there can be some confusing jargon. Just what exactly is a Boile...

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