ravenheat little star no hot water

[1450HOG]

Hi all I'm having a problem with my raven heat boiler t no hot water CH works fine just no hot water had a engineer look at it he said it was the DHW sensor so got him to replace the sensor that didn't work he said it was the PCB I replaced that no change , the three way valve had a little leak so i'v changed that as well
If i the bolers lit IE heating on and i turn the hot water on the boiler goes off
If the CH is off and i turn on the hot water tap the pump starts to run but the boiler dosen't start
little question on DHW sensor should there be a resistance across the pins or is it a open and closed switch
thanks Chas

 

[Agile]

The only fault would have been the £20 switch or the £120 diverter valve.

Its not clear to me who has done what but obviously the combination has cost a lot of money and not even repaired the boiler!

The switch is a NC switch which when fitted in position is then in the NO position.

Tony

 

[1450HOG]

Hi tony the engineer replaced the DHW sensor and diagnosed the PCB
I replaced the PCB and the three way valve
the switch on top of the three way valve seems to be working I take it thats the flow switch if i operate it manually the pump starts up
Its the DHW sensor i was wondering about iv checkd it with a multimeeter and it dosn't seem right its a small sensor that screws into the hot water pipe