Main Combi 30 Eco Elitie Temperature Issues

[Sandeep89]

Hi Guys,

Just changed a sink tap for customer and when turned the hot water on the boiler temp rose to 90 within few seconds and burner cut out, temp came down to 78 and the boiler then fired up again and keeps cycling like this.

Customer said this has been happening for a few months now, I noticed the return pipe was hot as well and the flow pipe was cold and heating was off.

Could the temperature rising so quick be due to a faulty diverter valve or would it be the plate heat exhange, or a sensor.

Any help would be appreciated.

Thanks

 

[Deleted member 120897]

Strange the return pipe heating up, are you sure it’s that one? Did you isolate the flow/return to see if it made a difference?

 

[WelshAndy]

Hi Sandeep89
Does the CH work ok, or does it cut-out through overheat too? If so, providing the pump is ok, it's a blockage in the main heat-exchanger.
If the CH is fine, it's a blockage on the plate heat-exchanger.

 

[Sandeep89]

Hi Sandeep89
Does the CH work ok, or does it cut-out through overheat too? If so, providing the pump is ok, it's a blockage in the main heat-exchanger.
If the CH is fine, it's a blockage on the plate heat-exchanger.

Hi WelshAndy,

CH is working fine customer has said no issues on that just the DHW.

Checked the pump, removed the bleed screw and pump looks all good.

 

[EvilDrPorkChop]

Blocked Plate Heat exchanger more than likely.

 

[hometech]

DHW thermistor readings. Did you take them and compare against operational norm?