Tip: RO Membrane & Shutoff Solenoids

[newkie]

Just a heads up if you happen to be using a pressure activated solenoid to cut off your waste water (such as Kent's Float Kit or one of the many generic solenoids on the market):

Visually your waste water stops in 20 seconds or less. If its not, then the pressure exerted on the membrane will stretch it out and ruin it.

I just learned this the hard way and had to purchase a new membrane. After only 3 months the water tested before the DI (which can mask actual TDS) was well over 100! It took over 3 minutes for my Kent soloind to shut off.

 

[O P Ing]

...if you happen to be using a pressure activated solenoid to cut off your waste water ...

hi.
I am not too sure about stretching on the membrane, but do you mean you use a solenoid to shut off the RO by blocking the waste water outlet? Please comfirm, since it is not the usual way to do it. In most setup, there is an automatic shut off (ASO) valve on the unit. If the output of the RO (good water, not brine (waste)) is increase due to the solenoid closing, the ASO will shut off the input to the RO. For a properly installed ASO valve setup, the brine will shut off almost immediately.

I guess I am confused by your tip... :?