Hot water/Heating mixing ?

[Canton]

I’ve noticed that when the wife runs the bath that the central heating gets much hotter than normal when running lately. When she has finished running the bath the heating cools back down to it’s called for setting. Further investigating this with the heating in the off position the heating flow pipe is getting hot well below the wall mounted Baxi Platinum 28 HE Combi boiler when running the hot water. Do I suspect that the diverter valve has seen better days now the boiler is 8 years old and that the hot water heating side is finding it’s way past the seals in the valve into the heating side ?

 

[Aire]

Sounds like a sticking diverter valve, get an engineer to come have a look at it.