Humidity/PIR extract fan controller

[Harry Bloomfield]

I've just got around to investigating our bathroom fan, and determined that the humidity + PIR + plus timer module has failed. It's one of these modules 72573901 Icon. Mk 1 eyeball, followed by meter, suggests that a 100 Ohm resistor has failed - slight burn mark on it, plus open circuit. The resistor is in the live supply to the entire module, the fan, and the shutter wax module - which appear to be controlled by a triac, and appears to be just a 1/4 watt. The 100 Ohms, seems to be too low a value, I see brown, black, black, black, space, brown - which I interpret as 100 Ohms, 1%. Is my interpretation of the value correct, please? It's R23 a discrete, on the front of the pcb..

Everything, on a quick look, appears to be supplied via this single resistor. What I plan to do, is replace the single resistor, with a pair of 200 Ohms, in parallel.

 

[Harry Bloomfield]

I found another roundtuit today, and managed to dig out a slightly more substantial 100 Ohm resistor, than the one which had failed, and replaced it. It fired up the fan, straight away, as soon as power was applied - whereas in the failed condition, it didn't. That suggests it might indeed, be fixed. To confirm, I just need to wait for the 20 minute run time timer, to time out, then it should hopefully switch off.

If it's fixed, that's between £80 and £120 saved, just on the cost of this control module. No fan included for that, just the fancy PIR/humidy/timer module

And the good news is, it is fully working again. That's the second time I have had to repair that fan. The first time, the heated wax capsule, which opens the shutter failed. I managed to source a replacement capsule.