That is handled by the 3 way solenoids and the control circuit. When you
hit the backwash button the pressure relief solenoid opens the product side
to waste bypassing the regulator and the backwash solenoid to the intake and
fresh water supply line. House system pressure circulates fresh water
through the membranes for 1 minute with the HP pump running then the HP pump
shuts down and, after 5 seconds to avoid any water hammer effect, the
relief solenoid closes. This forces fresh water back through the
pre-filters for 15 or 20 seconds.
I am estimating about 5 gallons of fresh water for one cycle. Once I see how
it is working I may eliminate the pre-filter backwash from the cycle. I am
afraid it will just push gunk back and forth between filters and strainer
unless I use a lot more fresh water. Probably better to just leave them
alone until the vacuum switch turns on indicating that the filters need
changing/washing.
BTW, disregard that control circuit. It will work but since that one was
built I figured out how to program microprocessors and eliminated 90% of the
chips and all but 2 relays. I can also adjust all the parameters in
software without changing resistor and capacitor values. It works great on
the bench but will probably require some tweaking once in use.
--
Glenn Ashmore
I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at:
http://www.rutuonline.com
Shameless Commercial Division:
http://www.spade-anchor-us.com
"Geoff Schultz" wrote in message
.. .
Glenn,
I was just looking at your site and was looking at the RO control panel
schematic. One thing that I didn't understand was that it appears that
the
fresh water flush tees into the brine water supply line to the pump. How
do you adjust the water pressure so that you're not feeding 800 PSI RO
water to the membranes? I've been told not to run the pressure above 200
PSI when flushing with non-brine water as it will over drive the membrane.
Also, when the solenoid is open, won't you potentially end up with fresh
water back flowing through the pre-filters and out through the seacock? I
suppose that just flushes the pre-filters.
-- Geoff
www.GeoffSchultz.org