DIY flow sensor pump protection?

[Pool_Newbie]

Hello, I am new to pools, but am helping my Dad with his. He has gone through two pumps because the water has gone too low and the pump runs without water. We thought about either trying to install some sort of float sensor for the water level or adding a flow sensor on a t-fitting inline to turn off the pump.

Mounting and running wire for the float sensor didn't seem very elegant. The flow sensor could work, but we need it to only check flow once the pump has kicked on. The pump is on a timer and can also be temperature activated, which makes it a little trickier. This is under control of an Intermatic pf1202t controller.

Seems like a common problem so I wanted to see if anyone had any thoughts for a cheap off the shelf or DIY solution.

So, pool enthusiasts, any suggestions? Any and all input is appreciated. Thanks!

 

[JamesW]

You could use an A.O Smith motor with eMod, which will protect the motor from running dry, running under excessive load, from excessive voltage, excessive current and it qualifies as a safety vacuum release system to help prevent suction entrapment.

http://www.aosmithmotors.com/uploadedFi ... Letter.pdf

 

[scooperhsd]

You can get some auto-fill devices that connect to a garden hose as well
I've had one for several years and it certainly makes it easier to take care of the pool.

Mine originally had PVC pipe in it - when that broke due to freeze damage - I put in PEX pipe and it's been good ever since.

 

[Pool_Newbie]

Thanks for the replies.

JamesW, The A O Smith motor is a good option but we already replaced the motor so we aren't in need of one right now. I'm impressed it is competitively priced and still has the extra emod technology.

Vtwin, you're right that we should solve the real problem, which is the water level. The problem is, ironically, that there is no water access by the pool. It is outside about 100 ft from the house down an incline. Then there is about a 8 ft retaining wall. At the base of which is the pool deck. The deck surrounds the pool by about 6-7'. So, it would be quite a job to trench for the pipe, go under the deck, through the sidewalk and add a float detector. Also, my dad does not live in the house and is only there about 1 weekend a month. So he is concerned that a malfunction that would cause the water to run would not get caught for quite some time and be very expensive. That already happened once. Not ruling this out yet, since it's obviously the right solution. Do you have links to an auto flow setup you like that might not be too bad to install?

Scooper, I'm hesitant to use a hose driven auto fill system since it's prone to a leak. Given that my dad is only there one weekend a month even a relatively reliable setup could eventually prove expensive. Can you shoot me a link to your setup or recommendations?

Anyway, I am going to kick these ideas around for a few days. Really appreciate the help...

 

[Bama Rambler]

Flow switches are available but they're not cheap. Grainger has some that will work for you.

 

[johndoe]

How about an inline water level float switch? Look for safety switch ss1
http://www.rectorseal.com/index.php?sit ... ct_id=2057
Tee from your suction side to 3/4", install height at the lowest water height you want. They have a tiny magnetic reed switch which comes setup to open the circuit on water rise, however you can remove a c clip and flip the float over and it will open at fall. You'll need to glue it closed and if it has a breather hole silicone it water tight. Its a low amperage switch, I'd hook it up as follows: all hvac or electric motor supply house parts, 24vac transformer, double pole contactor with 24vac coil, float switch interrupts the coil, power from clock output goes to l1 and l2 of the contactor and t1 t2 terminals power the pump. parts should cost about $40. you could also install a 24vac delay on break timer to insure the float doesn't bob and short cycle the motor on and off. In TX most a/c supply houses won't sell to you without a master license, but most electric motor supply houses can sell to anyone, or you can buy online.

 

[spishex]

In order to set up what you originally explained you'd need a countdown timer wired in parallel so the pump would get power through the timer at first, then through the flow switch after 5-10 minutes. There are cheap ones that you could wire into a relay, or you could get a beefier one and wire it directly.

 

[spishex]

BTW, a stingl switch would also stop the pump in the event of low vacuum pressure plus you'd get the benefit of benefits of a SVRS, but it's an expensive solution.

 

[johndoe]

Would the amps go up if pumping dry? Size the breaker close to running wet, say 15 amp instead of 20?

 

[spishex]

Amperage is proportional to water flow, so the more water you're moving the more current the pump will pull. Good thought though.