lay-z-spa, fix EO2 - flow sensor paddle

thingiverse

Update: added V7 file, please use this instead of the V5. Improved paddle design better matches original (previous design caused some fluttering after being fitted for a few months). Re-positioned and resized magnet mount slightly. Decreased mounting hole size slightly so it could be accurately drilled using 2.5mm drill bit. PLEASE READ BEFORE PRINTING This is a replacement flow sensor paddle for Lay-z-spa pump units. This part fixes repeated EO2 fault codes caused by loss of magnetism by the sensor paddle without the need or cost of replacing the entire sensor unit. I hold no responsibility for any damage caused to yourself or your hot tub if you decide to fit this part. water and electric is highly dangerous so please don't attempt this fix unless you know exactly what you are doing!! There are 2 sensor units in the pump, one in front of the other. switch off and unplug the pump unit. remove both sensor units. diagnosis is simply carried out by measuring the resistance of the switch and manually moving the paddle back and forth. If you get a reading without having to press the paddle hard against the sensor unit the assembly is fine, it's either the other sensor or you're problem lies elsewhere. If you find an inoperable sensor, test again using a known good magnet. if the sensor fails to operate still, the sensor is dead and requires replacement. if the sensor activates this signifies the magnetic paddle is no longer activating the sensor and my part will fix the issue. PLA is UNSUITABLE for this part given the environment it's going to have to live in. Print in current orientation at 100% infill (air gaps will cause the paddle to permanently float and it will not operate correctly) no supports necessary. once printed test fit to sensor unit. it should swing freely under its own weight. drop a 5-6mm diameter 3-4mm depth neodymium magnet in the cup and seal with a suitable adhesive/silicone (I used hi-temp hot glue). refit everything into the pump ensuring the sensor goes back in the correct orientation, check for leaks and hopefully your EO2 woes will be over!