Ignite Plumbing & Heating
Boiler Not Working — No Heating or Hot Water
Most boiler failures are caused by low pressure, a tripped condensate pipe, or a lockout fault code. Check these before calling an engineer.
Low boiler pressure
Most common cause of boiler lockout. The pressure gauge should read 1–1.5 bar when cold. Below 0.5 bar the boiler won't fire. You can repressurise it yourself using the filling loop.
Frozen condensate pipe
In cold weather (common in Norwich winters), the external condensate pipe freezes, blocking drainage and causing lockout. Thaw with warm water — never boiling.
Fault code lockout
Boilers lock out automatically when they detect a problem — ignition failure, overheating, fan fault, etc. The display shows an error code. Some are user-resettable; others need an engineer.
Gas supply issue
Check other gas appliances (hob, gas fire) are working. If not, contact Cadent Gas on 0800 111 999.
Pilot light out (older boilers)
Older boilers with a standing pilot light can have the pilot go out. The manual will show how to relight it.
Practical checks and next steps
Two of the most common boiler failures are fully DIY-fixable: repressurising a low-pressure boiler (under 1 bar) and thawing a frozen condensate pipe in winter. Everything else — fault codes, ignition failures, heat exchanger issues — needs a qualified engineer.
- Check the pressure gauge — if below 1 bar, repressurise using the filling loop (instructions in your boiler manual).
- In cold weather, check if the condensate pipe outside is frozen — it's the white plastic pipe exiting through the wall.
- Note any fault code on the display and look it up for your boiler model.
- Try resetting the boiler (usually a reset button or holding a button for 3 seconds).
- Check your gas supply — does the hob work?
- If none of these apply or the boiler relocks, call an engineer.
How do I repressurise my boiler?
Locate the filling loop (usually a silver flexi-pipe under the boiler with two valves). Slowly open both valves until the pressure gauge reaches 1–1.5 bar, then close both. Reset the boiler.
What is a condensate pipe?
Modern condensing boilers produce water vapour as a byproduct of combustion. The condensate pipe drains this water away. In cold weather it can freeze, triggering a lockout. It's the small white plastic pipe that exits through an outside wall.
How old is too old for a boiler?
Most boilers have a useful life of 10–15 years. Beyond that, parts become scarce and efficiency drops. If your boiler is over 12 years old and breaking down regularly, replacement is usually more cost-effective than repair.