Flow Sensors on Drain Pipes?

[nickkohrn]

I’m currently in the plumbing stage of my build, and I’m going to be purchasing a FMK for my Apex so that I can ensure proper flow rates through accessory equipment. I was thinking about purchasing a couple of extra sensors to monitor the pipes that drain into my sump. It would be nice to be alerted if the flow rate in the main drain pipe is reduced and the flow rate in the emergency drain pipe is increased (or any measurement higher than zero GPH is detected).

Have you added flow sensors to your drain pipes? If so, then do you have any thoughts, recommendations, or experiences to share?

Do you have a reason not to add flow sensors to drain pipes?

Thanks!

 

[garbled]

So much air goes down a drain pipe normally, that the readings will be complete nonsense. However, if you just want it for a binary "there is flow, there is not flow" it should be OK.

 

[Handegard]

When I get around to redoing my plumbing I can Ill be placing one in my emergency drain. Only as an on/off sensor though, to let me know if something blocks the main I've had my FMK since launch, and while I find it useful, I don't find the numbers useful persay, just for tracking trends.

 

[garbled]

Yeah, the numbers are, maybe not 100% accurate, however, I can tell when something isn't right by looking at the trend, so I like it for that. I also have it set to alarm me if it drops really low, just in case the return pump does something silly.

 

[LobsterOfJustice]

I do not recommend them on drains. They will not read accurately and will easily clog. I spent $400 on putting flow meters on all my drains and returns and they’re all completely useless, the smallest thing will cause them to drop to zero so they are not reliable enough to use for alarms. They also make the trip from tank to sump hazardous for any fish that take the trip (it happens). I’m trying to figure out how to get them out if my setup.

 

[ca1ore]

I’ve been running flow sensors on siphon drains for a couple of years. As long as they are siphons, and you have screens or strainers on them, the sensors work just fine and I see no issues. If it’s a mixed water/air drain then the readings will be nonsense. Interestingly, I’ve had more trouble with clogged sensors on my returns. Also, always upsize the sensor.

 

[nickkohrn]

I’ve been running flow sensors on siphon drains for a couple of years. As long as they are siphons, the sensors work just fine and I see no issues. If it’s a mixed water/air drain then the readings will be nonsense.

I have a Waterbox 100.3, which is the first system that I have had that is not an AIO. It has two drains; one is the main drain with a gate valve, and the other is an emergency drain. I assume that the main drain is a full-siphon drain. Is that correct?

 

[ca1ore]

When I get around to redoing my plumbing I can Ill be placing one in my emergency drain. Only as an on/off sensor though, to let me know if something blocks the main I've had my FMK since launch, and while I find it useful, I don't find the numbers useful persay, just for tracking trends.

Depends. I actually run a five drain oveflow with three siphons. One feeds my ATS and being able to know flow (within the error of the sensor) is useful.

 

[ca1ore]

There are other ways to monitor on/off for drains. I used a float enabled small catch basin for example - probably more than most folks would bother with, but it was an interesting approach. As long as you configure the herbie properly such that the primary is a siphon, it works.