Biasi M90E24s no hot water?????????

[Ginger plumbing]

Please help!!! Ive been trying to diagnose a fault with this boiler as i cant get any hot water from it. when going into service mode the lights indicates thats its theres a fault in the primary flow circuit , does this mean the DHW flow sensor???? when reading MI it says that DHW sensor is working when a red LED comes on when hot tap is run and have checked this and it does. Also diverter valve seems to be working as can see pin moving back and forward on the micro switch and clicking . Also customer says can only get hot water when calling for heat. Massive thanks if any one can help as Ive just become GSR and am new to breakdowns.

 

[Billy Bob Bob]

has it got a black motor on top of the DV?

 

[diamondgas]

Sounds like usual suspect Plate hex IMO, first thoughts. Does the boiler actually fire up on hot water only?

 

[gasmarc]

run the tap when the heating is cold and see if the heating pipes get hot , if so diverter valve could be the problem

 

[Ginger plumbing]

yes it has a black moter actuater on top and no the boiler doesnt even fire when on hot water mode even when i open hot taps. Diagnostic lamps indicate a fault in the primary circuit no water or absence of flow.

 

[gasmarc]

we are getting there lol , try resetting it

 

[Mbear]

Not being funny but why would a primary flow circuit fault indicator make u think that the hw ntc is faulty?

 

[Ginger plumbing]

i didnt find the diagnostic lamp section till after a qwick couple of checks

Not being funny but why would a primary flow circuit fault indicator make u think that the hw ntc is faulty?

 

[Billy Bob Bob]

right,its not your plate hex as you have stated they are getting hot water with the heating on thats that one eliminated,its not your thermister,you dont mention it running hot and cold,either the black motor has failed or the divertors shot this boiler will have a reid switch on the dhw is this illuminating red?

 

[Ginger plumbing]

Yes when I turn hot tap on the red light comes on which indicates the flow sensor is ok as per MI thanks for your help gas man really want to fix this any other ideas mate really appreciate it.

 

[Billy Bob Bob]

try removing the black motor,can u push the spindle down by hand? if so DV may be ok motors shot,if not look at dv

 

[diamondgas]

I agree with the gas man, ruled out plate hex ..... Should be getting 230v Black to blue on diverter actuator on H/W and a 8-10kohm resistance through the motor, if the boiler the same I have mi's for M90F?

 

[gasmarc]

It could be the flow switch perhaps ?

 

[Ginger plumbing]

Took the primary flow switch off and run the hot tap and clicked the switch a screw driver and boiler fired up. Pushed the pin in and out and reassembled it and now it's seems to work fine so pin must of been sticking, massive thanks for your help though.

 

[gasmarc]

Happy days hopefully we all learned something new i did :juggle2: