I am playing aorund with making a controller that will turn on my fans and turn them off in regards to water temps. I have a heap of oddball sensors, relays etc, and just started to cobble things together to see if its feasible. What I have so far is this. I used an old hob type heater (non submersible) penn plax or it may have been an old HArtz brand heater. I pulled it apart and removed the heating element, and use only the temp sensor portion and switch. I wired it up to a latching type coil/relay, so that when the contacts on the switch in the heater is closed, it holds the contacts in the relay open, so there for no power is going to the fan. When the water itself heats up and the switch contacts open, the latching coil is de-energized, the relay allows power to the fans.......Since the entire sensing unit is still in the tube submersed in the water its sensing water temp and not air temp under the hood. I hope to do this with a thermister once my freind that knows electronics finds some time...but in the mean time it does seem to be working pretty good. I still have a spread of about 2 to 3 degrees from fan on and off, but thats not too bad considering what I am using for a sensing unit. Its been running pretty well trouble free for over 5 days now.....My plan is to eventualy use a thermistor submerged, or possibly an submersible 25 watt heater to convert to a sensing unit.
DIY fan controller
- Thread starter chipmaker
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