Finding yourself with no hot water when you turn on the taps can be frustrating, especially if it happens suddenly. Many homeowners in Liphook and surrounding areas such as Bordon, Whitehill, Alton and Farnham experience this from time to time, and in many cases the issue is something you can diagnose yourself. This guide explains the most common causes and what you can safely check before calling out a Gas Safe engineer.
Quick checks you can do now
Before diving into more detailed troubleshooting, here are fast and safe checks that often solve the problem.
- Make sure the boiler has electrical power.
- Ensure your hot water taps are fully open.
- Check that the boiler display is not showing an error code.
- Confirm water supply is running normally in other taps.
If you’re still experiencing no hot water from combi boiler after these checks, continue with the steps below.
Common reasons you have no hot water from your combi boiler
Combi boilers supply hot water on demand, so any interruption to fuel, water flow, or internal components can stop the system from heating properly. The following are the most frequent causes reported by homeowners across GU35, GU34 and GU9.
- Low system pressure – Often caused by small leaks or radiator bleeding.
- Faulty diverter valve – Prevents hot water reaching your taps.
- Frozen condensate pipe – More common during winter cold snaps in Bordon and Liphook.
- Sensor or thermostat faults – The boiler may not recognise that you’re calling for hot water.
- Blocked or restricted plate heat exchanger – Can limit the boiler’s ability to heat water.
Check your combi boiler pressure
Your boiler relies on the right water pressure to operate. If the pressure is too low, the boiler will shut down to protect itself.
Most boilers have a pressure gauge on the front. When the system is cold, the needle should sit around 1.0–1.5 bar.
- If it’s below 1.0 bar, the boiler may struggle to produce hot water.
- If it’s at zero, the system may have lost water entirely.
If you feel comfortable, you can re-pressurise the boiler using the filling loop. Instructions are normally found in the user manual. If pressure continues to drop after refilling, you may have a slow leak somewhere in the system and should arrange a repair.
Check for fault codes and indicator lights
Modern combi boilers will display an error code if something is wrong. Codes vary by manufacturer, but common fault signs include flashing lights or warning symbols. Even if you don’t understand the meaning, noting the code can help a Gas Safe engineer diagnose the issue more quickly.
In many Liphook homes, simply resetting the boiler after identifying the code (if the manual allows it) can clear a temporary issue. Only attempt this if the manual confirms it is safe to do so.
Is your diverter valve stuck?
The diverter valve controls where the heated water goes—towards your taps or towards your radiators. If radiators are heating but your taps remain cold, a stuck diverter valve is a strong possibility.
This is not something a homeowner should attempt to repair. However, recognising the symptom can save time during a visit from a heating engineer.
Check for a frozen condensate pipe
During very cold weather, the condensate pipe—usually a plastic pipe running outside—can freeze. This can cause the boiler to shut down, leaving you with no hot water from combi boiler at the taps.
- Look for gurgling sounds or an error code relating to the condensate line.
- Feel the external pipe to see if it’s icy or extremely cold.
- If safe, pour warm (not boiling) water over the pipe to thaw it.
Frozen pipes are especially common in exposed areas of homes in Bordon, Whitehill and similar nearby villages.
Could the hot water sensor or thermostat be faulty?
Your boiler relies on sensors to detect temperature and flow. If they fail, the boiler may not fire up when you open the tap. Typical signs include:
- The boiler lights up for heating but not for hot water.
- Hot water that runs warm for a few seconds and then goes cold.
- Error messages related to flow or temperature.
A professional will need to test and replace the faulty sensor, but recognising the symptoms helps speed up the repair.
Check the plate heat exchanger
This component transfers heat from the boiler to the domestic hot water. Over time it can become blocked by scale or debris, particularly in hard water areas. Liphook and nearby towns such as Alton and Farnham have patches of moderate hardness, so this issue isn’t uncommon.
A blocked heat exchanger often leads to inconsistent water temperatures or very slow heating. Cleaning or replacement must be done by a professional.
When it’s time to call a professional
If you’ve completed the checklist above and still have no hot water, the fault is likely internal and requires the skills of a qualified Gas Safe engineer. Issues such as damaged valves, faulty sensors, internal blockages or wiring problems should never be handled by a homeowner.
Homes in Liphook and the GU35 area sometimes develop recurring hot water issues caused by older boilers or hard water debris, so arranging a professional inspection can help prevent repeated failures.
Next steps if you still have no hot water
If the problem persists and you need a reliable Gas Safe engineer in Liphook or nearby towns, you can book a visit at https://www.embassygas.com/book