DIY Auto-Top off with Solenoid - Page 12

festus · #**276** 05/06/2006, 11:52 AM

Quote:

If the solenoid ever fails open (unlikely, as it is a normally closed valve) the float switch will prevent the sump from getting too much fresh water.

I've seen such solonoids fail. Usually from hard water deposits that prevent it from sealing properly even though they are closing.

But your second float would stop a flood. And then when the water bill came I'd be sure to notice the solonoid was leaking ;-)

Looks great I may just try to implement this rather than some other rube goldberg like device I was ginning up on my own.

Thanks.

douggiestyle · #**277** 05/06/2006, 12:39 PM

Quote:

Originally posted by festus
I've seen such solonoids fail. Usually from hard water deposits that prevent it from sealing properly even though they are closing.

agreed but... hardwater deposits will be HARD to come by with ro/di water.

pun intended

H20ENG · #**278** 05/09/2006, 09:23 PM

Dont buy those switches from Herbach!!! They are not the correct range and do not have any adjusting screw.

"Operates on 0.5 PSI (Â±5%) coupled to a SPDT Microswitch with contact rating of 20 Amps "

A good giveaway is the 20A switch rather than the 3A switch. I bought and returned 10 of them from Herbach and it took 2 months for my refund.

This has been the biggest problem with building the air switch setups- finding a good supply of switches.

That said, Rich made a kick butt setup there

thereefgeek · #**279** 05/09/2006, 09:56 PM

Thanks, H2OENG!

I just pulled the Herbach link outa' my butt, surfing for air pressure switches.

The Micro Pneumatic Logic switch part # that I used is a 601 series http://www.pressureswitch.com/fs_int/multi1.htm

Aquatic Eco Systems http://www.aquaticeco.com/index.cfm/.../1101/cid/2249 sells them, but they're something like $25!!!!

I picked mine up from a local electronics surplus house in Sacramento for $5 each and bought all that they had

Keep your eyes opoen for the deals, or pony up the $25 for an ultra reliable top-off switch.

You could always buy the Spectrapure unit, but then it wouldn't be a DIY

BeanAnimal · #**280** 05/09/2006, 11:56 PM

I gave chris a link a while back to some decent switches.... I will look and see if I can find it.

stugray · #**281** 05/10/2006, 12:12 AM

Sorry if I didnt read the whole thread...

Any mention of the optical liquid level sensors coupled with a Square-D Programmable Logic Controller?

I have two of the sensors & the PLC working together. I just havent tried it with SW yet.

I can easily program the PLC to turn on/off pumps based on the state of the LL-sensors.

The sensors look just like these:

http://www.fluidswitch.com/pages/Opt...nsorOS-900.htm

I just need to encapsulate the sensors into a tube or shield because they are sensitive to stray light & salt creep.

Stu

BeanAnimal · #**282** 05/10/2006, 02:03 AM

I have pondered the use of those several times, but in the end did not want to deal with the salt creep or slime coat (or the price). Good old mechanical reed floats are my choice.

douggiestyle · #**283** 05/10/2006, 09:26 AM

i read a thread here where someone used optical sensors and had the problems bean described salt creep. also was some other problem, i cant remember.

eleben · #**284** 05/10/2006, 10:03 AM

I have been using the Tunze Osmolator without any problems (over a year and a half now). As you may already know, Tunze relies on the optical sensor and uses a regular vertical float sensor in case the top off pump doesn't shut off. I've checked for salt creep and haven't had any problems with it. I check for slime every once in a while and find some collecting on there but the accuracy of the sensor hasn't changed because this.

H20ENG · #**285** 05/10/2006, 09:34 PM

Bean,
I believe it was World Magnetics. The real sensitive switches are about 4" dia but you could use them to topoff a tank without a sump. They are hair trigger sensitive.
Several companies make spa air switches, but its hard to get any specs on them. They just give you a part # for a such and such controller.
I guess I COULD bite the bullet and pay retail for some....

BeanAnimal · #**286** 05/10/2006, 10:39 PM

Almost all the spa parts and equipment companies are now owned by 2 major corporations. Nobody in any part of the chain knows or understand any part of their product lines. Take a look at "Spa Builders" or "Spa Builders Support Group". They have snatched up every major spa-pack and parts OEM on the planet.

I never did order the world magnetics smaller switches (I thought I had a small one speced out that would work for our needs).

thereefgeek · #**287** 05/11/2006, 09:35 AM

What exactly was the problem with the MPL switches from Herbach? They look exactly like the MPL 600 series (don't know the exact Pt#) switches I picked up from HSC Electronics in Sac.
Supposedly they're all user-adjustable:
http://www.pressureswitch.com/products600.html
http://www.pressureswitch.com/dimens...nsions600.html

H20ENG · #**288** 05/11/2006, 10:43 PM

They were 0.5psi, not Inches of Water, and there was no adjustment screw to remove. A nice little switch, but the wrong model # for us

thereefgeek · #**289** 05/12/2006, 08:32 AM

Oooooooooh.
0.5 psi is nearly 14" of water!! (0.433psi/foot of head pressure)

Here's a conversion table I found on MPL's website:
http://www.pressureswitch.com/refere...nversions.html

guzz64 · #**290** 05/20/2006, 05:01 PM

I use the parts from Mcmaster and it works well. I use two floats and two solenoids. I have the floats about 1/4" different elevations mounted on a hangon plexiglass holder I made. Both floats are set to remove power from the relay on a water rise to close the solenoid valves. I put back to back solenoid valves as I had the misfortune of the single sticking on two seperate occaisions. The floats are tied in to a time delay relay that waits 1 hour after the float signals for water. This eliminated the on/off due to waves. In my system it adds water every hour and everything seems good. I run it through my kalk reactor and life has been good since the addition of the second solenoid valve. I am going to add one more float and solenoid about 1" higher than the level I maintain in the sump as a fail safe (hopefully) to stop the whole system in case of tragedy.