Hot water issue

[richardd]

Hi,

combi boiler sealed system . Apartment

A customer of mine has phoned and stated they are getting hot water at there taps ( BATH,WHB ) for only 10-15 seconds it then dies and goes cold. Althought the gas ignition light is still on when the hot is still running and turned cold.

The hot at the kitchen sink right beside the boiler stays warm constantly.

Anyone came across this before. I want to resolve the issue quick.

 

[gasleak]

what boiler is it? burner pressure and flow rate all ok?

Are there mixer taps in the bathroom? have you checked the cold mains isn't passing through to the hot?

 

[richardd]

Thers a thermostatic bar shower . The shower is getting no hot whatsoever i think it may be passing thru it . I am going to disconnect it and but two valves on the outlets then check the hots at each tap.

 

[gasleak]

If the isolation valves to the combi look like they are not going to leak, turn of the cold mains in. Then run the hot tap in the bathroom, it should stop pretty quick. If you are still getting a cold water flow then you know the cold mains is backfeeding into the dhw side. Most probably from the shower or a mixer tap