Rewiring RO Machine

[Overachiever]

Hey guys,

Anyone have any idea on how I can rewire my RO machine to bypass the circuit boards and just have it turn on/off when the float switch says to? The circuit boards got hit by a hose leak and burnt up. I don't care about the TDS meter / toggle switch features it had on it but I'm trying to save myself from having to buy a new machine.

 

[MEP001]

Yes, literally just run the solenoid and contactor power through a float switch. There are still some manufacturers that do it. If the solenoid and starter coils aren't the same voltage, you'll need a transformer to make them so. I would recommend putting a low pressure cutoff switch on the water supply - they make ones with a small orifice so the switch won't kick on and off several times while the system starts. You can even get a TDS monitor light that just goes inline on a tee from the membrane outlet.

 

[MEP001]

Here's the switch I've used, the system I replaced it on uses a float switch to open the solenoid, then the water pressure closes this switch to send 240V to the motor.

Square D Pressure Switch, (1) Port, 1/4 in FNPS, DPST, 4 to 45 psi, Reverse Action 9013FRG22J36P | Zoro

Order Square D Pressure Switch, (1) Port, 1/4 in FNPS, DPST, 4 to 45 psi, Reverse Action, 9013FRG22J36P at Zoro.com. Great prices & free shipping on orders over $50 when you sign in or sign up for an account.

www.zoro.com

 

[Overachiever]

Thanks @MEP001. I guess I'm a little slow when it comes to this stuff but i'm sure it'll make sense next time I get over there and take a look at the machine. I didn't realize RO machine's had a solenoid! lol.

 

[MEP001]

There may be more than one, some have a flush solenoid, but you won't use that one. It needs an inlet solenoid or it will run water all the time.

 

[Greg Pack]

Miles does that switch you listed have the anti chatter feature you speak of?

Overachiever it is indeed pretty simple. its often best just to disregard what you see with your eyes and write a diagram both wiring and plumbing on a piece of paper. I don't know why the carwash industry tends to make complex control boards and their systems so expensive in comparison to the water treatment industry.

 

[Overachiever]

It looks like I might have gotten lucky, it already seems to have a pressure switch on it on the water supply in. Hopefully I'll have some time tomorrow to get this thing up and running again.

 

[MEP001]

Miles does that switch you listed have the anti chatter feature you speak of?

Yes, the one on the unit I ordered it for didn't have the feature, which I'm sure is why it went out. It would still kick off once and back on again each time it started, but it was better than the 5 or 6 times before.