Herbie drain is a pain

[Potatohead]

Originally Posted by input80

Check your pump, might be varying flow? I had the same issue with the level changing every couple of hours. Changed out the (seemingly failing) pump & haven't had a problem since.

Been thinking about this the last hour or so and I think what may be happening, is if the pump is getting periods of slightly higher voltage, (which likely happens depending on other loads on the circuit) it will increase flow very slightly. This of course is a problem because the drain isn't set up for the extra flow so water accumulates in the overflow. It has even gotten to the point where the DT level is rising. It then also gets exacerbated because the ATO keeps topping off before it actually should be.

So, if I get a ball valve on the return side and set it at or slightly lower than the current return rate, it should be more stable... In theory . At the very least it eliminates another variable.