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Central Heating

Shower goes hot then cold

shower powered by combi boiler keeps warming up, then going cold after 30 seconds, then warming up again, then go cold again, and so on. Not sure if it's an air leak or something else causing it? Also the sink in the bathroom has started making gurgling noises, not sure why?

2 Answers from MyBuilder Heating Engineers

First check the hot water outlets.
If you have hot water at the taps
and its just the Shower Misbehaving.
1 Common Cause faulty Thermostatic cartridge.
2 Hot & Cold Supply crossed.
A J Gas & Water Limited.


Answered 25th Jan 2016

The above answer is correct, assuming it is in fact a thermostatic shower???

Failing that i would suggest having the domestic hot water heat exchanger checked on your combination boiler. This would cause the exact same effect on your shower. These heat exchangers get scaled up easily and depending where you live the hardness of water can vary.
If this is the case and you have to replace the DHW heat exchanger ask the engineer to fit an in-line scale reducer (around £25.00) for you to help the problem happening again.



Answered 18th May 2015

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