No Hot Water but Central Heating OK — External control fault

What does No HW, CH OK mean?

The boiler heats the central heating radiators normally, but no hot water is available for taps or showers. This typically indicates a problem with external components.

• A fault with external controls such as the hot water programmer
• Faulty hot water cylinder thermostat
• The diverter valve failing to direct heat to the hot water cylinder

Click steps to track your progress.

1. 1

   Check your hot water programmer settings and ensure it's set to call for hot water.

2. 2

   If you have a hot water cylinder, check its thermostat setting and ensure it's not turned down too low.

3. 3

   If your boiler has a diverter valve, listen for any sounds of it operating or inspect its position if visible.

4. 4

   If these checks don't resolve the issue, contact a qualified electrician or heating engineer to inspect external controls.