Why Gas Safe registration is a legal requirement
Anyone installing, servicing or repairing a gas appliance or gas pipework in the UK must by law be on the Gas Safe Register, which replaced CORGI in 2009. This covers boilers, gas fires and gas cookers. Using an unregistered engineer for gas work isn't just risky, it's illegal, and any resulting certificate isn't valid.
Common heating engineer jobs
Heating engineers install, service and repair boilers and central heating systems: annual boiler services, fault diagnosis, radiator installation and balancing, powerflushing, and full system replacements. Many also work on unvented hot water cylinders and, increasingly, heat pumps and other low-carbon heating.
Combi vs system vs conventional boilers
A combi heats water on demand with no tank or cylinder, suits smaller properties with one bathroom. A system boiler uses a hot water cylinder but no cold water tank, better where several taps might run at once. A conventional (regular) boiler uses both a tank and cylinder, common in older or larger properties, or where mains pressure is poor.
Common heating myths, busted
"Leaving heating on low all day is cheaper than on/off" — not reliably true; it depends on the property's insulation and the specific system. "A hissing boiler just needs bleeding" — hissing more often points to a pump or valve issue than trapped air. "Bigger boiler means faster hot water for everyone" — it's more about cylinder size and flow rate than boiler output alone.
Gas safety duties for landlords
Landlords must have a valid Gas Safety Certificate (CP12) renewed every 12 months for any gas appliance in a rented property, and provide a copy to tenants. It's a legal requirement, and letting agents/insurers routinely check for it — failing to have one can invalidate insurance and result in prosecution.
Frozen condensate pipes in winter
A frozen condensate pipe (the small plastic pipe draining from a condensing boiler, often outside) is one of the most common winter boiler breakdowns — it causes the boiler to shut down as a safety measure. Pouring warm (not boiling) water over the pipe to thaw it, if safely accessible, sometimes fixes this without a call-out.
Oil-fired boilers, what's different
Oil boilers are common in properties off the mains gas network, need an oil storage tank with its own maintenance and safety considerations, and are serviced by OFTEC-registered engineers rather than Gas Safe (which only covers gas). If you're off-grid, confirm your engineer's OFTEC registration specifically.
Heating regulations, FAQ
Do I need Building Regulations sign-off for a new boiler? A Gas Safe registered engineer self-certifies this as part of the installation. Can I service my own boiler? No — servicing a gas appliance legally requires a Gas Safe engineer. What if my installer isn't Gas Safe registered? The work is illegal and any certificate issued isn't valid.