Patrick77
10/17/2007, 11:03 AM
Hi Everyone,
Patrick here from aquahub.com. As many of you have been our customers, I wanted to post some helpful information about float switches and automatic top off. Some of our customers occasionally experience problems with float switches because they don't understand how to use these little guys properly and then they end up with a bunch of water where they don't want it. We hate to see this happen to anyone in an automatic top-off app.
Here are a couple essential tips about float switches and auto top-off.
First, float switches use tiny magnetically activated reeds inside the stem. A magnet in the float moves by this reed and draws the contacts together, completing or breaking a circuit between the float switch's wires. This technology has been around since WWII and is the same technology used in your dishwasher to fill it up with water and empty it out. Used properly, these reeds (ours are made by the huge conglomerate OKI of Japan) last for millions of cycles.
The thing about these reeds is that their tiny connectors cannot directly handle pump or solenoid current. A pump or solenoid may only be rated for 10 watts vs. the float switch's rating of 50 watts, but that pump or solenoid may draw 100 or even 150 watts when it starts up or shuts off. Controlling a pump or solenoid directly with a float switch without utilizing a relay may work for months or even a year, but eventually the float switch reed will overheat, weld closed and stop turning these devices off when you want them off. The right way to control a pump with a reed float switch is by having the float switch turn a relay on and off and having that relay control the pump or solenoid.
Lesson two is that the epoxy potting that holds the wires inside the float switch stem is only water resistant, not waterproof. So if your specific application has that wire potting under water at any point in a normal operating cycle, you need to find a way to keep those wires dry. Otherwise, water eventually will seep down into the switch and corrupt the internal reed. We sell a 1/2" tubing adapter that, combined with silicon and 1/2" tubing, normally does the trick (although depending on temperature variations you have to keep an eye out for condensation).
Most top off set-ups keep the float switch up out of the water, so that only the float is barrel is submerged, but I know that every aquarium is unique, so if yours needs that float to ever be under water, please protect the wire potting.
In our suggested set-up, we suggest using a backup float switch just in case the primary ever fails. If the primary float switch ever does fail in this situation, it will obviously become submerged, but there is no need to protect the wire potting from it just because this may some day happen, since at that point it's toast anyway. Again, float switch failures are extremely rare when these puppies are used correctly.
I hope all of this is helpful. I know it's a no-no for vendors to post trying to sell stuff and that's not the goal here. Buy your float switches wherever you like (although I think we at aquahub.com serve the community really well), but please follow these tips to avoid disappointment or disasters! All of this information is illustrated in detail on various pages on aquahub.com. Thanks for your support!
Patrick here from aquahub.com. As many of you have been our customers, I wanted to post some helpful information about float switches and automatic top off. Some of our customers occasionally experience problems with float switches because they don't understand how to use these little guys properly and then they end up with a bunch of water where they don't want it. We hate to see this happen to anyone in an automatic top-off app.
Here are a couple essential tips about float switches and auto top-off.
First, float switches use tiny magnetically activated reeds inside the stem. A magnet in the float moves by this reed and draws the contacts together, completing or breaking a circuit between the float switch's wires. This technology has been around since WWII and is the same technology used in your dishwasher to fill it up with water and empty it out. Used properly, these reeds (ours are made by the huge conglomerate OKI of Japan) last for millions of cycles.
The thing about these reeds is that their tiny connectors cannot directly handle pump or solenoid current. A pump or solenoid may only be rated for 10 watts vs. the float switch's rating of 50 watts, but that pump or solenoid may draw 100 or even 150 watts when it starts up or shuts off. Controlling a pump or solenoid directly with a float switch without utilizing a relay may work for months or even a year, but eventually the float switch reed will overheat, weld closed and stop turning these devices off when you want them off. The right way to control a pump with a reed float switch is by having the float switch turn a relay on and off and having that relay control the pump or solenoid.
Lesson two is that the epoxy potting that holds the wires inside the float switch stem is only water resistant, not waterproof. So if your specific application has that wire potting under water at any point in a normal operating cycle, you need to find a way to keep those wires dry. Otherwise, water eventually will seep down into the switch and corrupt the internal reed. We sell a 1/2" tubing adapter that, combined with silicon and 1/2" tubing, normally does the trick (although depending on temperature variations you have to keep an eye out for condensation).
Most top off set-ups keep the float switch up out of the water, so that only the float is barrel is submerged, but I know that every aquarium is unique, so if yours needs that float to ever be under water, please protect the wire potting.
In our suggested set-up, we suggest using a backup float switch just in case the primary ever fails. If the primary float switch ever does fail in this situation, it will obviously become submerged, but there is no need to protect the wire potting from it just because this may some day happen, since at that point it's toast anyway. Again, float switch failures are extremely rare when these puppies are used correctly.
I hope all of this is helpful. I know it's a no-no for vendors to post trying to sell stuff and that's not the goal here. Buy your float switches wherever you like (although I think we at aquahub.com serve the community really well), but please follow these tips to avoid disappointment or disasters! All of this information is illustrated in detail on various pages on aquahub.com. Thanks for your support!