Baxi 105e - Hot water only warm

[Peanuts890]

Have a Baxi 105e and had venturi and hot water valve replaced recently by engineer. He suggested turning flow down to minimum (admittingly he had other jobs on).
Get about 2/3 litres of very hot water, then the water is only warm. Reducing flow helps slightly but still not hot. CH okay, in fact it can be too hot to touch pipes. Any help would be appreciated.
Thank you
IanS

 

[powell30]

Thermistor or scaled plate heat ex

 

[Peanuts890]

Thank you powell30 for a fantastic quick response. Will try the thermistor first as it should be easier. Assume you mean the HW sensor.
Many thanks again.

 

[powell30]

HW temp sensor yes.......should be bottom right on the hydraulic section (left hand side).....if memory serves it's connected with 2 green wires and a molex type connector