Losing hot water is one of the most common heating complaints, and the cause depends on what type of system you have. A combi boiler heats water on demand, while a system with a hot water cylinder relies on the cylinder, its immersion heater, and related valves working correctly.
We diagnose no hot water faults across Cheam and Sutton on both combi boiler systems and cylinder-based systems. If your heating works but hot water does not, this again often points to a diverter valve on a combi system, or a cylinder-related fault on other systems.
It is worth checking a few simple things yourself first, covered below, since occasionally the cause is a setting rather than a fault.
Common causes on a combi boiler
- Diverter valve stuck in the heating position
- Low pressure triggering a lockout
- Faulty plate heat exchanger
- Blocked or scaled internal components
Common causes on a cylinder system
- Failed immersion heater element or thermostat
- Faulty motorised valve controlling flow to the cylinder
- Boiler fault preventing water reaching the cylinder coil
- Cylinder thermostat or programmer settings incorrect
Checks to try first
Check your programmer is set to provide hot water at the current time, check the boiler pressure gauge, and, for cylinder systems, check whether the immersion heater switch is on as a backup.
How charging works
No hot water call-outs are charged by time at our standard hourly rate, plus parts. See /our-rates for current rates depending on the day and time of your visit.
