Boiler guides
Clear answers for your next boiler decision.
From choosing a boiler to planning the installation, start with the questions that matter to your home. Find practical guides to sizing, replacement, installation time, moving a boiler and handover paperwork in one place.
Still deciding whether to repair or replace? There is guidance for existing boiler problems too. For the service itself, see JustFix boiler installation.
Choosing and installing a new boiler
Compare your options, understand what the work involves and prepare the right questions before you book.
Combi boiler installation and replacement
Understand combi boiler installation, replacement and suitability, from hot water demand and system changes to controls, handover and your quote.
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How long does boiler installation take?
Find out what affects boiler installation time, how a simple replacement differs from a conversion, and how to prepare for heating and hot water disruption.
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What size boiler do I need?
Learn how heat loss, radiators, bathrooms and mains water supply affect boiler sizing, and why bedroom count alone cannot tell you the right output.
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Moving a boiler: locations, planning and what to check
Planning to move a boiler? Understand how location, flue routing, access and pipework affect the work, and what to confirm before choosing a new position.
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Boiler installation certificates and paperwork explained
Understand boiler installation certificates, commissioning records, warranty registration and handover documents, and what to do if paperwork is missing.
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Combi, system or regular: which boiler is right for your home?
Compare combi, system and regular boilers by hot water demand, storage space and existing setup, then understand what to check before replacing yours.
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How much does a new boiler cost, really?
What goes into a boiler installation quote, and the questions worth asking before you commit to a price.
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Signs your boiler needs replacing
Compare boiler condition, repeated breakdowns and repair costs to decide whether a new installation is right for your home.
Read guide →Understanding an existing boiler problem
A fault does not always mean you need a replacement. These guides explain common symptoms and when to arrange a professional diagnosis.
Heating but no hot water? Here's what to do
Experiencing heating but no hot water? Discover common causes and solutions for your boiler issues, and find out when it's time to call a professional.
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Baxi boiler error codes explained
Discover common Baxi boiler error codes, their meanings, and tips to help you diagnose issues quickly. Learn when to call a professional for help.
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Vaillant boiler error codes explained
Discover common Vaillant boiler error codes and their meanings. Get quick fixes for issues with heating and hot water systems for efficient troubleshooting.
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Why is my boiler making a banging noise?
Is your boiler making a banging noise? Discover common causes and solutions for noisy boilers, from loud banging to kettling, and when to call a professional.
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Hot water but no heating? Here's what to do
Have hot water but no heating? Learn common causes and simple fixes to get your heating back on track. When in doubt, contact a professional for help.
Read guide →Ready to explore a replacement?
Start with your fuel type and a few questions about your home. JustFix currently installs mains gas boilers, with Gas Safe registered installation and a 12-month workmanship guarantee.
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