Heating Works but No Hot Water? What to Check First
If your radiators are heating normally but the taps are running cold, the fault is often more specific than a complete boiler breakdown. The heating side of the system is working, but something is preventing the boiler or hot-water system from delivering hot water correctly.
Heatline is based near Sutton Coldfield Town Centre and helps households across Sutton Coldfield with hot-water faults, from properties around The Parade and Sutton Park to homes near Good Hope Hospital, Four Oaks, Mere Green, Boldmere and Wylde Green. The likely causes depend on whether you have a combi boiler or a system/regular boiler with a hot-water cylinder.
First: identify what type of system you have
A combi boiler normally heats water for your taps on demand and does not use a separate hot-water cylinder. A system or regular boiler commonly works with a cylinder, which may be in an airing cupboard.
This matters because a hot-water problem on a combi boiler can have different causes from a cylinder system.
Checks you can make safely
Check the boiler display
Look for a fault code, warning light or message. Note the code before resetting anything, because it can help an engineer diagnose the issue.
Check the boiler pressure
If your boiler uses a sealed system and the pressure is too low, the appliance may not operate correctly. Follow the manufacturer’s instructions if you need to check or restore pressure.
Try more than one hot tap
If one tap has a problem but other hot taps work normally, the issue may be at that tap or mixer rather than the boiler.
Check timers and hot-water controls
On systems with a cylinder, confirm the hot-water programme is actually calling for heat. A timer, thermostat or motorised valve fault can affect hot water while leaving space heating available.
Common causes on a combi boiler
Possible causes include a sensor problem, flow-detection fault, diverter valve issue, scale or debris affecting a heat exchanger, low system pressure or an electronic fault. A diverter valve is a common suspect when heating works but the boiler does not switch correctly to hot-water demand.
Common causes on a cylinder system
If you have a hot-water cylinder, the problem could involve the programmer, cylinder thermostat, motorised valve, circulation, boiler controls or the cylinder itself. If you have an immersion heater, it may provide temporary hot water on some systems, but only use it if you know it is fitted and safe to operate.
Should I reset the boiler?
One reset in line with the manufacturer’s instructions can be reasonable for a simple lockout. If the fault returns, repeated resetting is not a repair. Record the error code and arrange an engineer.
When to call Heatline
If you have heating but no hot water, intermittent hot water, fluctuating water temperature or recurring boiler fault codes, Heatline can diagnose the problem across Sutton Coldfield and Birmingham.
See our boiler repair service, or if the problem relates to a stored hot-water system, see hot water cylinders.
For help, call 0121 517 0585 or contact Heatline.