Check the Colour of Your Boiler Flame
A healthy gas flame burns crisp blue. If your pilot light or burner is yellow, orange or lazy, this can indicate incomplete combustion — a serious sign of carbon monoxide risk. Switch the appliance off and call a Gas Safe engineer immediately.
Test Your Carbon Monoxide Alarm
Every home with a gas appliance should have an audible CO alarm in each room containing one. Press the test button monthly and replace the batteries annually. No alarm at all? Get one fitted today — they cost less than £20.
Look for Sooty Marks Around Appliances
Black or yellow staining on or above a boiler, fire or hob is a tell-tale sign that exhaust gases are not venting properly. Do not ignore it — book a gas safety inspection straight away.
Check Your Boiler's Pressure Gauge
Most combi boilers should sit between 1.0 and 1.5 bar when cold. Constantly dropping pressure usually means a leak somewhere in the system. Persistently high pressure can damage components — both warrant a check.
Listen for Banging, Kettling or Whistling
Strange noises from your boiler often mean limescale build-up on the heat exchanger, trapped air or a failing pump. Catching it early avoids a much bigger repair bill or premature boiler replacement.
Spot Damp Patches and Drips Quickly
Walk around radiators, under sinks and around your boiler at least monthly. Damp walls, water stains on ceilings below bathrooms, or limescale crusts on pipework all point to leaks that need a plumber.
Review Your Last CP12 or Service Date
Landlords must hold a current CP12 renewed every 12 months. Homeowners should have an annual boiler service to keep the warranty valid. If yours is overdue, book one before it costs you.
Watch For Symptoms of CO Poisoning
Headaches, dizziness, nausea or breathlessness that ease when you leave the house can be signs of carbon monoxide. If you suspect a leak, open the windows, switch off the gas at the meter and call the National Gas Emergency line on 0800 111 999.
Still Not Sure?
Book a professional gas safety inspection and get certainty. Our Gas Safe registered engineers will tell you exactly where your boiler and pipework stand.
Book Your Inspection