Float Switch

[bannerd]

Howdy, been looking for a float switch that will cut power to a 120V pump running around 7amps. I have a small oil sump that is filled with oil for my waste oil furnace. What I would like see happen is when the tank is full the pump is off. When oil is used and the level decreases the float will fall causing the oil pump to kick on to deliver the oil.

Easy enough concept, anyone have a part number or url where I can find a switch like this? The oil is heated but it's only heated to about 80F so it's not hot enough to destroy a standard switch.

 

[bannerd]

So I may have answered my own question,

http://www.reed-sensor.com/pdfs/Other_Sensor_Horizontal_Float_FS-H.pdf

I could pickup one of these.. Which I could flip

 

[larry_g]

So I may have answered my own question,

http://www.reed-sensor.com/pdfs/Other_Sensor_Horizontal_Float_FS-H.pdf

I could pickup one of these.. Which I could flip

Other than it is only rated at 2.5 amp and you spec'ed 7 amp in the first post.

Look around Grainger http://www.grainger.com/Grainger/ww...tch&op=search&Ntt=float+switch&N=0&sst=subset

Make sure that you get one with enough hysteresis to prevent the transfer pump from constant cycling. What is the rise distance from empty to full?

lg
no neat sig line

 

[bannerd]

Rise distance will be about 5-6 inches. It's a small oil heating box that I mig welded together. I just need something to cut the current.

http://www.********.me/image/2530

I do worry about if the switch fails and causes the pump to run. That would be a massive oil leak.

 

[dave67fd]

Also the switch you show is NO (normally open) When oil is low pump will be off. When full (switched closed) the pump will run. You need a NC switch.

Most liquid level switches switches are not designed for the high current you need and if rated are very very expensive.
You are also submerging or in close proximity to a semi-flamable liquid. Switch should be of the sealed type and rated for the liquid your using.

The proper hook-up for this would be to use a low current/voltage control circuit. In other words using the float switch to turn on a high current relay or contactor that has a 12-24vdc coil. This will of course require more components. The power supply which doesn't need to be expensive and the relay or contactor that switches the motor on and off.

You could also add another switch slightly above but still below your max fill for a fail safe situation with audible or visual alarming indication.

http://www.mcmaster.com/#liquid-level-switches/=ge4e96