Solenoid for Ro/Di

[sphelps]

For noise check for loose screws on the top of the unit, I have a similar one and it made a loud buzzing sound when one of the screws holding the solenoid on came loose.

Verify that the voltage is in fact 24VDC, not very typical. 24VAC is standard for sprinkler solenoid, which you can also use, rainbirds have been very reliable IME.

If you're using this for top off directly from an RO unit be sure you have enough safety built in to it so it won't be accidently left on too long or stay on from a faulty float switch or even the solenoid.