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Fix SoonCommon in SepRecommended trade: Heating Engineer

Heating On but No Hot Water

Central heating radiators work normally but the hot water taps run cold.

What Is Causing This?

  • 1Faulty diverter valve stuck in heating-only position
  • 2Broken mid-position valve
  • 3Hot water cylinder thermostat set too low or failed

How Urgent Is This?

Fix Soon

This should be fixed in the coming weeks. Leaving it may allow the problem to worsen and cost more to repair.

What Needs to Be Done

A heating engineer will test the diverter or mid-position valve, check the cylinder thermostat, and replace the faulty component to restore hot water.

How Much Will It Cost?

£928 – £2,726

National average estimate

Labour: £565 – £1,488 | Materials: £363 – £1,238

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Prices are estimates based on typical UK rates. Actual costs depend on the specific issue, accessibility, and your location. All quotes from tradespeople on Tradesfolk are completely free.

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How to Prevent This

Have the diverter valve checked during annual boiler servicing. Set the cylinder thermostat to 60 degrees. Avoid switching the system on and off frequently.

Related Problems

No Hot Water

Hot water taps run cold or lukewarm despite the boiler or immersion heater being switched on.

No Heating or Hot Water

Both the central heating and hot water have stopped working completely, often during cold weather.

Thermostat Not Working

The room thermostat does not respond, displays incorrectly, or the heating does not follow the set temperature.

Other Heating Engineer Problems

Radiators Cold at Bottom

Radiators that are hot at the top but cold at the bottom, reducing heat output.

Noisy Central Heating

Banging, gurgling, ticking, or clicking sounds from radiators, pipes, or the boiler when the heating is running.

Thermostat Not Working

The room thermostat does not respond, displays incorrectly, or the heating does not follow the set temperature.

Underfloor Heating Not Working

Underfloor heating that has stopped producing heat or heats unevenly across the floor.

Frequently Asked Questions

What causes heating on but no hot water?
Faulty diverter valve stuck in heating-only position. Broken mid-position valve. Hot water cylinder thermostat set too low or failed.
Is heating on but no hot water serious?
This should be fixed in the coming weeks. Leaving it may allow the problem to worsen and cost more to repair.
How much does it cost to fix heating on but no hot water?
Typical costs range from £928 to £2,726 depending on severity and location. Get a free quote from a local heating engineer on Tradesfolk.
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