There’s nothing quite like turning on the tap or switching up the thermostat and getting absolutely nothing back. No hot water, cold radiators and that sinking feeling in your stomach. I’ve lost count of how many calls I’ve taken over the years for urgent boiler repair Surrey, especially on cold mornings when people are trying to get the kids ready for school.
The good news is that not every loss of heating or hot water means a major fault. Quite often it’s something simple you can safely check yourself. Below is a practical step by step guide to help you work out what’s going on and what to do next.

Common Reasons You May Lose Hot Water or Heating
Boilers usually stop working for one of a handful of reasons. In homes around Camberley, Guildford and Woking, I tend to see the same issues crop up again and again.
The most common causes are:
- Low boiler pressure
- A tripped fuse or power supply issue
- Thermostat problems
- Frozen condensate pipe in winter
- Ignition or pilot light faults
- A system fault requiring a reset
Before you assume the worst, work through the checks below. You might save yourself time and a call-out.
Initial Checks You Can Do Safely at Home
These are all safe, visual checks. If you ever smell gas or suspect a leak, stop immediately and call the emergency gas number.
1. Check the Power Supply
It sounds obvious, but you’d be surprised how often a boiler has simply lost power. Make sure:
- The boiler switch is on
- The fused spur hasn’t tripped
- Your consumer unit hasn’t thrown a breaker
If everything else in the house is working except the boiler, it could still be an internal fuse, but start with the basics.
2. Look at the Boiler Display
Modern boilers usually show an error code. Make a note of it before you do anything else. A quick look in the manual often tells you whether it’s low pressure, ignition failure or something else simple.
3. Check the Thermostat
Make sure your thermostat is turned up above room temperature. I’ve attended plenty of “no heating” calls where the thermostat batteries had died or it had been knocked down to 15 degrees.
If you’ve got a programmer, check the time and schedule. Power cuts can reset them.
4. Check the Boiler Pressure
On most combi boilers, the pressure gauge should sit between 1 and 1.5 bar when the system is cold. If it’s dropped below 1, the boiler may lock out.
If you’re confident topping it up using the filling loop, follow the manufacturer’s instructions carefully. Bring it up slowly to the correct level and close the valves properly. If you’re unsure, it’s better to leave it alone.
When to Reset Your Boiler and What to Look For
Most modern boilers have a reset button on the front. If you’ve checked pressure, power and thermostat settings, a reset can sometimes clear a temporary fault.
Press and hold the reset button as instructed in your manual. The boiler should attempt to restart. You’ll usually hear the fan kick in followed by ignition.
If it fires up and runs normally, keep an eye on it over the next day or two. If it keeps locking out, there’s an underlying issue that needs attention.
Never keep repeatedly resetting a boiler that won’t stay on. That’s a sign something isn’t right.
Common Boiler Faults Explained
Low Pressure
If pressure keeps dropping, there may be a leak somewhere in the system or an issue with the expansion vessel. You might notice damp patches near radiators or the pressure falling shortly after topping up.
Thermostat Issues
Wireless stats can lose signal, wired ones can fail with age. If the boiler works for hot water but not heating, the thermostat is often the culprit.
Pilot Light or Ignition Faults
Older boilers with a pilot light can go out due to drafts or component wear. Modern boilers use electronic ignition, and faults here usually throw up an error code.
Ignition issues are not DIY jobs. They need proper testing by a Gas Safe engineer.
Frozen Condensate Pipe
In colder parts of Surrey during winter, I see this every year. If your boiler is gurgling and showing a fault during freezing weather, the external condensate pipe may have frozen.
You can carefully pour warm, not boiling, water over the pipe to thaw it. Once cleared, reset the boiler.
When to Call a Professional Engineer
If you’ve worked through the basic checks and still have no heating or hot water, it’s time to get proper help.
You should call an engineer if:
- The boiler keeps locking out after a reset
- Pressure drops repeatedly
- You smell gas
- There are unusual banging or whistling noises
- Error codes indicate internal faults
Gas appliances should only be opened and repaired by a qualified Gas Safe registered engineer. Safety always comes first.
If you’re based locally and your boiler is beyond repair, it may be worth looking at options for Camberley, Guildford or Woking installations depending on where you are.
Preventing Future Heating and Hot Water Issues
The best way to avoid waking up to a cold house is regular maintenance. An annual boiler service keeps things running safely and spots small issues before they turn into breakdowns.
Other practical tips:
- Keep an eye on boiler pressure every few months
- Bleed radiators if they feel cold at the top
- Lag external condensate pipes before winter
- Replace thermostat batteries once a year
I often tell customers that boilers rarely fail without warning. Odd noises, fluctuating pressure or inconsistent hot water are usually signs that something needs attention.
Staying Warm and Safe
Losing heating or hot water is stressful, especially in the middle of winter. Start with the simple checks. Look at the pressure, power and thermostat. Try a single reset if it’s safe to do so.
If the problem persists, don’t ignore it or keep fiddling. A qualified engineer can diagnose it properly and get you back up and running safely.
If you need expert help fast, contact our team today. DS Gas Services supports homeowners and tenants across Surrey with straightforward advice and proper repairs, so you can get the heat and hot water back on without the guesswork.