Draining a hot water system All aspects of plumbing questions and answers, help, tips and information

[Barry Bunsen]

Hi
If I drain a hot water system - for example to repair a hot downstairs tap on an indirect system - is there any danger of the boiler or immersion heater causing damage to an empty hot water storage cylinder?
Thanks

[htg engineer]

If you were to drain the cylinder completely, and then turn the immersion or boiler on - then yes you could damage the immersion heater or the cylinder.

If you only turn off the cold supply to the cylinder and open the hot tap, to drain the hot water pipes, then you're not draining the cylinder. The cylinder will still be full and therefore no damage will occur.

[simpleton]

You dont need to drain the hot water to fix a tap. But if you did drain the cylinder and the immersion and central heating was on then yes I imagine you would damage the cylinder

[Oliver_murphy]

Just ensure everything is turned off before you start, then only turn it back on when your system is full again

[Barry Bunsen]

Thanks for these responses. They are most helpful.