NFT Pump minimum water level cut off device

[rememberingnever]

Any suggestions on this? I have only come up with some sort of normally closed float switch drilled into the side of the reservoir wired to the pump.

 

Added a top up tank via pump which seems to be working well after monitoring but i'd like if I go away for some time, that if that reservoir level does drop, the pump doesn't end up dying/burning out from running dry (seems to have lasted only 10 days early flower, so probably only 7 if i'm lucky later on!) and will have the power cut to it. Pressure switches aren't really applicable in this setup I feel.

[GreenVision]

I'ts likely you can, it feels like I've seen something like this somewhere. That said though if your not there and the res / tank runs dry in NFT I'd think you have bigger issues than a dead £10 pump.

 

If it were me and I was set on leaving it for a long period I'd be thinking more along the lines of a huge 200l water butt or something similar to feed the res when it gets low. Not really much point in leaving a crop / plant going if its dead when you get back so rather than a cut off a large top up would be my advice.

 

 

 

 

 

[stu914]

Agreed GV...float valve in the res linked to a top up tank would work...

[rememberingnever]

I have one but it will maybe last 10 days topping up the NFT tank (space problems). Sometimes its inevitable that I have to leave them to go wild, they don't mind the neglect that much in my experience although the past month they've had my undivided attention multiple times daily as i've found myself with more time to dedicate to the hobby :'). The current top up is around 32ltrs as is in the form of a 40ltr eurobox. I've avoided a totaly crispy crop ruin situation so far thankfully :').

[Nuttyprof]

@rememberingnever would a bilge pump float switch do what you require? In my stoned mind it would ... A  relay probably needed on second thought.

Edited November 21, 2023 by Nuttyprof

[rememberingnever]

On 21/11/2023 at 11:43 AM, Nuttyprof said:

@rememberingnever would a bilge pump float switch do what you require? In my stoned mind it would ... A  relay probably needed on second thought.

I think some kind of bilge float to allow the pump to operate when its submurged would work and then cut the contacts to the pump when the level drops. Just seem to be 12v so will need a relay of some sort to allow the trigger from the bilge float I suppose! I certainly need to do something, I can technically leave it around 9-10 days currently the way it is setup but then risk the pump burning out in the top up tank... if I could save that pump the nft res could then run down for another week pretty safely I feel, at a minimum it'd allow for 4 days extra during peak flower.

Edited November 29, 2023 by rememberingnever

[rememberingnever]

Ok, I've settled on a horizontal float switch to be installed externally as all the bilge float switches I could find aren't designed to be submerged fully for extended periods of time. I guess I can run it 180 degrees to whatever I need it to do depending whether its open or closed and then the relay can in turn do whatever it needs to do with the pump. I'll run a 12v dc PSU to the switch/coil on the relay. Not sure if I want the float switch to be normally closed/open and the coil charged or uncharged... I'm thinking uncharged under normal operation and then charged when I want the relay to stop the pump being powered.

Edited November 29, 2023 by rememberingnever