Ideal logic combi 24 no hot water

[Rdeepo]

Gas engineer here. Been to an ideal logic combo 24, (the older model with brass manifolds either side) customer complained about temperamental hot water. Did the usual checks solid red light on hall sensor diverter head ok diaphragm springs back return thermistor above pump ok thought it must be the plate heat exchanger. Changed and still having issues! Spoken to ideal at least 5 times and they suggest an ideal engineer attends but at the cost of £299 all in. Anybody got any ideas ?

 

[ShaunCorbs]

Heating ok ?

 

[Rdeepo]

Heating ok ?

Hearings fine

 

[Rdeepo]

Hearings fine

Heating*

 

[ShaunCorbs]

Would check the difference between pump return and hot water out more then 5 dc difference you have a blockage

also if it’s a 24 might be the cold water mains eg 35 dc rise on a 5dc water temp will give you 40dc hot water which might not be enough for them

also check your flow rate should be around 10lpm