Help: Installing a float switch inside a holding tank

[shaniac]

Greetings everyone. I need to install a float switch in my 1000 gal holding tank. The directions I see online seem to imply you already have a rod mounted inside your tank. then you zip tie the switch to the rod so it can float and do its thing.

My holding tank is your typical PVC tank with a screw on lid and 2 inch port at the base. I suppose I could remove the lid, drill a hole in the top, drop a PVC pipe through the hole then thread some couplings on either side of the lid which would hold things in place. Is there a better way from people who have theses float switches already? Seems silly to reinvent the wheel.

Thanks in advance!!!!

[Volvo farmer]

My cistern is concrete and has a 4" vent cap. I wedged a piece of 3/4" pvc between the bottom of the tank and the square part of the cap.  Don't know if you could wedge something under your cap or not but maybe you could glue something to the bottom of your screw cap that would capture a piece of pipe and not have to drill through it.

[shaniac]

Thank you Volvo, I always appreciate the help.

The cap to my cistern (large plastic holding tank) looks like what you see here.


From what I can tell there are two ways to install the float switch.

The first way is from the side of the tank dangling down. To do this I guess some kind of tank wall sealing pass through is used or the tank would leak there when full. Which for me will be most of the year. (Note these are NOT images of MY tank.)

SIDE MOUNT


The other way seems to be from the top... down on a PVC pipe. As seen here. This was what I was going to originally do unless someone has a better idea???

TOP MOUNT looking down into a tank.


The blue float switch is mounted on the pipe, toward the bottom, as seen here.


To mount the PVC pipe inside my tank without opening it up to outside critters I was going to drill a 1 inch hole in the cap, thread a PVC coupling on each side then glue the PVC pipe, to the coupling and allow for a way to thread my wires through the cap.

This solutions would allow me to remove the whole kit and kaboodle for when it needs servicing.

Does anyone else have a better suggestion? I have been known to over engineer ideas in the past.

Thank you everyone!

[Volvo farmer]

That sounds like a good plan. I don't know why you want the float switch toward the bottom though? If you want your pump to turn on when the cistern is 80% full and fill it to the top, you want the switch at the top of the tank, right?

On mine, the pipe runs clear from the bottom to the top and it's only function is to anchor the float switch, which is attached near the top.

[shaniac]

Thank you. My tank is a holding tank that is level with my pump that pushes the water 200 feet up to the top of the ridge. I need the float switch to turn OFF the pump in case the holding tank gets empty. That way the pump will not be destroyed from running while dry.

The installation went well. I wound up installing the PVC pipe through the lid, wired up the switch, tested it then sealed everything up. If the tank gets to low, my pump just turns off until the tank is full again and the water supply is now safe to pump again.

Thanks for your help!