FMM Optical Switches vs BOB Float Switch

[Tha Bizness]

So I have switched out my BOB/Float switch combo for a FMM/Optical switch combo. In the days of the BOB/Float one of the best practices was to set the "action" on a BOB/Float to when the float was showing "CLOSED" instead of "OPEN". The thinking on this is that if a BOB failed or accidentally disconnected it would default to the "OPEN" status. If you have a ATO set to run on "OPEN" you would end up with a RODI flood if the BOB ever became disconnected.

With the FMM/Optical Switch combo CLOSED=COVERED WITH WATER. Because of this my ATO has to be programmed with "If SUMPLO OPEN Then ON". If for some reason the FMM or Optical switch would be disconnected it would default to OPEN and start the ATO. As a safety I used "When On > 005:00 Then OFF" so it would turn off after 5 min but it still bothers me.

Is there any way to change the status via future update in module or other ways to protect against a flood outside of what I am doing?

[bhofosho]

Maybe incorporate a long defer time to make sure you need to fill it?


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[Tha Bizness]

Hey B!

I do use a DEFER 005:00 on that outlet too but its more for my one button water change when my system goes between ATO mode and AWC mode (long story/code)

When I was using a BOB/Float I had more of a sense of safety because if the BOB became disconnected it would not trigger the ATO. I have a minor fear using FMM (even tho I like the thought of using optical switches more)

[Xero]

Pretty sure this was covered somewhere already, but if you yank out the cord to the optical sensor - it will default correctly to closed, not open, so this won't be a problem. It doesn't seem intuitive - but the optical sensor isn't really a contact switch at all - it basically outputs a voltage based on the intensity of the reflection of an LED - needless to say the apex has to have some logic to handle it regardless, and when it senses nothing, I think they have it covered to default to CLOSED. I believe if the module goes into an error state for whatever reason, it also goes to CLOSED, as when i've had errors my ATO just wouldn't run at all....

[RussM]

@Bizness, @Xero- both of you are correct and both of you are wrong

It depends on how the optical sensor port is configured.

If a FMM port used for an optical sensor has auto-detect enabled, and the optical sensor is unplugged, that port reverts to WoF (water on floor) sensor type, which is the default mode for a FMM port, and will then read as OPEN.

If that same FMM port is configured with auto-detect disabled and hard set to optical sensor mode, it will stay in optical sensor mode and indicate CLOSED if the sensor is disconnected.

So, in effect, you can choose which you want it to be (OPEN or CLOSED) when a optical sensor is disconnected.

[Tha Bizness]

That's the info I was looking for. Thanks Russ.