No Heating or Hot Water? Emergency Troubleshooting Guide
Woken up to no heating or hot water? Before you panic, there are several quick checks that might get your boiler working again. This guide walks you through what to check—and when you need to call a professional.
Quick Checks (5 Minutes)
Before calling an engineer, run through these simple checks. Many "breakdowns" are actually simple fixes:
1 Check the Boiler Display
Is there a display showing? Look for:
- Error code? Note it down - see our error code guide
- Blank screen? Could be a power issue (see step 2)
- Flame symbol flashing? Boiler trying to ignite
- Pressure reading? Should be 1-1.5 bar
2 Check Power Supply
Surprisingly common! Check:
- Is the boiler switched on? Check the switch near/on the boiler
- Has the fuse tripped? Check your fuse box for tripped switches
- Power cut in area? Check other appliances
- Timer/programmer set correctly? Check it hasn't been knocked
3 Check Boiler Pressure
Low pressure is the #1 cause of boiler shutdowns:
- Pressure gauge should read 1-1.5 bar
- Below 1 bar? Your boiler won't fire up
- How to top up: Use the filling loop underneath the boiler
4 Check Gas Supply
Is gas getting to the boiler?
- Do other gas appliances work? Try your gas hob
- Is the gas meter showing credit? (if prepay)
- Has the emergency control valve been turned off?
5 Check Thermostat Settings
Simple but often overlooked:
- Room thermostat turned up? Above current room temperature
- Batteries OK? Wireless thermostats need batteries
- Correct mode selected? Not set to "off" or "summer"
- Timer correct? Check AM/PM settings
6 Check for Frozen Condensate
Very common in cold weather:
- Is it freezing outside? Below 0°C
- Find the condensate pipe - white plastic pipe going outside
- Thaw with warm water - NOT boiling
- Reset boiler after thawing
Try a Boiler Reset
If you've checked all the above and found no obvious issue, try resetting the boiler:
- Find the reset button (usually has a flame symbol)
- Press and hold for 3-5 seconds
- Wait 1-2 minutes for the boiler to attempt ignition
- Listen for the boiler firing up
No Hot Water But Heating Works?
If your radiators are hot but you have no hot water from taps:
Combi Boiler
- Diverter valve fault - Common issue, needs engineer
- Flow sensor issue - Not detecting water demand
- Hot water turned off? - Check boiler controls
System Boiler (with cylinder)
- Cylinder thermostat - Check it's turned up
- Motorised valve stuck - Needs engineer
- Immersion heater? - Try as backup
Heating Works But No Hot Water From Some Taps?
If some taps have hot water but others don't, the issue is likely plumbing rather than the boiler:
- Airlock in pipes - Common after plumbing work
- Faulty thermostatic mixer valve - In shower or tap
- Blocked hot water supply - Debris or scale buildup
Still No Heating or Hot Water?
If you've tried the above and still have no heating, it's time to call a professional. We're available 7 days a week.
When You MUST Call an Engineer
Call Immediately If:
- You smell gas anywhere
- Boiler is leaking water
- Boiler making loud banging or kettling noises
- Black marks or soot around boiler
- Yellow or orange flame (should be blue)
- Error code won't clear after reset
- Burning smell from boiler
Staying Warm While You Wait
If you're waiting for an engineer, here are some ways to stay warm:
Electric Heaters
Portable electric heaters can heat a room quickly. Focus on one room to stay warm efficiently.
Layer Up
Multiple thin layers are more effective than one thick layer. Don't forget warm socks and slippers.
Hot Drinks
Hot water bottles and warm drinks help maintain body temperature from the inside.
Close Doors
Keep internal doors closed to retain heat in occupied rooms. Use draft excluders.
Prevent Future Breakdowns
Annual Boiler Service
The single best way to prevent breakdowns is an annual boiler service. A qualified engineer will:
- Check all components are working correctly
- Clean burners and heat exchangers
- Test safety devices
- Identify worn parts before they fail
- Ensure efficient operation (saving you money)
Cost: From £105 on average for an average 3 bed home - far less than an emergency callout!
Book Annual ServiceEmergency Heating Repairs
Gas Safe registered engineers serving Crawley, Horsham, Redhill, Reigate, Horley, East Grinstead and all West Sussex & Surrey