Duo-Tec hot water issues

[Dave T]

Called to repair Baxi Duo-Tec Combi no hot water? Replaced plate heat exchanger blocked solid replaced change over cartridge and DHW sensor still the same issue Boiler comes on reaches 43-45* then shuts down then reignites and then same again? I took the inner door panel off while the hot tap was running the boiler fired up and stayed on the hot water reached temperature? When refitting the inner door the water temperature dropped back down to the 43-45* and kept recycling? Cleaned the Venturi the sensing tube checked the vertical flue for blockages it’s clear put everything back together still the same problem? Central heating working ok just issues with hot water. Just so stumped!!!!!!
Any advise welcome.

 

[Deleted member 120897]

If it works with the inner door panel off, I’d be looking in that area, such as the air intake.

 

[Andersons]

Did you get a fix on this issue?

 

[king of pipes]

Check the continuity of the flue with your anylser and it's co /co2 ratio ?? . Kop