❄️ Boiler Not Heating? Quick Fixes

No hot water or central heating is miserable, especially in winter. Before you assume your boiler is broken, try these quick checks. Many heating problems have simple solutions that take minutes to fix.

1. Check the Boiler Display

What to look for:

1. Is the boiler switched on? Check the on/off button and power indicator
2. Is there an error code displayed? (e.g., F1, F28, A00, E1)
3. Take a photo of any error code - your engineer will need it
4. If display is blank, check the power switch and circuit breaker

Error codes tell you what's wrong. Google your boiler make + error code for quick diagnostics.

2. Check the Pressure Gauge

Low pressure is the #1 reason boilers stop heating.

What you need to do:

1. Locate the pressure gauge on your boiler (dial with numbers, usually 0–3 bar)
2. It should read between 1 and 2 bar when cold
3. If it's below 1: Pressure is too low and heating won't work

How to restore pressure:

1. Find the filling loop - a small lever or valve under or near the boiler
2. Slowly open it (turn anticlockwise) - you'll hear water rushing in
3. Watch the pressure gauge rise to about 1.5 bar
4. Close the filling loop when pressure reaches 1.5
5. Wait 10 minutes, then test your heating

3. Check the Thermostat

• Is it switched on?
• Is the temperature set higher than room temperature?
• Try setting it 5°C higher and wait 5 minutes
• If it's a smart thermostat, check the battery level
• Is the thermostat away from cold walls or drafts that might make it think the room is colder?

4. Bleed the System

Air in the heating pipes stops heat circulating. This is called "bleeding the radiators."

Quick bleed check:

1. Feel the radiators - are they hot at the bottom but cold at the top?
2. If yes, they need bleeding
3. Use a radiator bleed key (turn the small square valve on the radiator) to release air
4. Open slightly until water starts to drip, then close immediately

See our "How to Bleed a Radiator" guide for detailed steps.

5. Reset the Boiler

1. Turn off the boiler at the control panel
2. Wait 30 seconds
3. Turn it back on
4. Listen for a clicking/whooshing sound - this is the ignition
5. Wait 2 minutes for the system to stabilize

If the boiler doesn't make an ignition sound, the burner isn't firing - you'll need an engineer.

6. Check for Frozen Pipes

In winter, pipes outside or in unheated spaces can freeze, blocking water flow.

Signs of freezing:

• No water coming from taps (besides hot water from the boiler)
• Visible frost or ice on external pipes
• Strange gurgling sounds in pipes

How to thaw:

• Use a heat gun or hot water bottle on the frozen section
• Never use a blowtorch or open flame - risk of fire
• Prevent future freezing by insulating pipes with foam lagging

When to Call an Engineer

• Pressure won't stay above 1 bar (indicates a leak)
• Boiler displays an error code that doesn't clear
• Boiler won't ignite (no clicking or whooshing sound)
• Radiators are hot but no hot water, or vice versa
• You smell gas or burning
• None of the above checks fix the problem

Information to Have Ready

• Boiler make and model
• Any error codes
• Pressure gauge reading
• Age of the boiler (when installed?)
• When was it last serviced?
• What's not working - heating, hot water, or both?

Key Takeaways

• Low pressure is the most common heating issue - check and refill via the filling loop
• Thermostats must be set higher than room temperature and switched on
• Air in radiators stops heating - bleed them if they're cold at the top
• Frozen pipes can block water flow in winter - thaw gently with heat
• If your boiler won't ignite or shows persistent error codes, call a professional