In message , Cod Roe
writes
My Eco 80 is once again giving me trouble (curse the previous owner who
had it fitted), it lights, waits 6 or 7 seconds then goes out again,
waits another 30 seconds or so and tries again, same thing, and so on
to infinity I assume. Following the fault finding guide in the manual
I checked the flame sensing electrodes, they seem fine, but I cleaned
the tarnish off just in case, checked the sensor current with a
multimeter and got 4-5uA and the manual says approximately 1uA should
be present so I assume this is ok. The manual then says change PCB, so
at enormous expense I have done that, no difference. I'm at a bit of
loss as to what to do next, my only thoughts are the modulating gas
valve, does it light on a low pressure, and then once its happy it has
a flame close that valve and open another to switch up to a high
pressure? Any other possibilities? I have checked the resistance of
the temperature sensor and it is approximately the 11k the manual dictates.

Assuming that you are getting a spark and GV operating, i.e. that there
is a flame to sense ...


Reasons for flame sensing failure are

1) pcb - unlikely from what you have said above

2) break in the wire from the electrode to the pcb (are you really
getting 5uA ?) the only way I know of reliably testing the lead is to
give it a tug at both ends to see if the wire is attached to the
connector

3) Electrode not in the flame

4) bad earthing

5) Live and neutral transposed (unlikely unless you have recently done
some electrics)




--
geoff