"Glenn Ashmore" wrote in
:

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.

Thanks for the explaination. I personally don't want any electronic
controls on a watermaker. From 7 years of experience with on my own 2+
watermakers and others, they're only a source of problems. I happy
manually turning valves and sticking with the KISS principle. I also
believe that you need to observe the unit while its starting up and
shutting down. 800 PSI has a way of causing problems.

-- Geoff
www.GeoffSchultz.org