Vaillant turbomax 828 no hot water

[Reidy828]

i have seen plenty of previous no hot water ch working fine as mine.
No demand or running lights come on when tap turned on. Also water diverted works as pre heat water works.
But on mine the aqua sensor lead black and red gives 4.8 v but black and green also gives 4.8v regardless of wether tap is open or closed not the 0v off and about 2.5v open as stated in book.
Wondered if any one new if this could be circuit board or some sensor elsewhere

 

[cross thread]

It’s normally the impeller in the sensor ,isolate the cold and open taps put a towel in case of spill’s around the pcb area , remove circling and it may come out in one piece,or have one ready to fit.

 

[Deleted member 267285]

Does the boiler do anything when a hot tap is opened?

 

[Reidy828]

It’s normally the impeller in the sensor ,isolate the cold and open taps put a towel in case of spill’s around the pcb area , remove circling and it may come out in one piece,or have one ready to fit.

Hi its just the voltage is wrong regardless of whether the sensor is connected to the aqua sensor or not.

 

[Reidy828]

Does the boiler do anything when a hot tap is opened.

No demand or flow lights

 

[Deleted member 267285]

I’d say aqua sensor then. Careful though, opening up some boiler covers need to be checked by a competent person afterwards, as part of regulation 26.9

 

[Reidy828]

Ok thanks ill order one

 

[ianmcd]

BEWARE before you even think about closing the cold water inlet valve and removing the aqua sensor circlip, test and double test that the hot and cold have not been crossed over, lost count of the number of times , "no nobody has done any plumbing recently " well except for the new kitchen or bathroom or shower, if you do it without testing, you wont do it again , simply run the CH and open a hot tap and be 100% sure that it is the hot outlet pipe that is heating up and not the cold inlet

 

[Reidy828]

Impeller removed in 20 pieces new one fitted and hot water up and running again