I'm stuck, can't work out why supposedly fresh backflush water
is testing > 1000 ppm, tastes quite salty.
I have pickled, disconnected membrane and Clark pump. So I can easily sample the flush water
right where it exits the pre-filter housings.
Solenoid is acting when flush cycle is started at the panel. Only pump #1 is active.
First I removed and inspected the check valve that is supposed to prevent sea water from invading when the fresh water line is pressurized via energizing the backflush solenoid. I see no issues with check valve, just a faint film of green biofilm (see photo).
Reinstall check valve, test flush water. 1st bucket tests ERror tastes salty. So I set Spectra intake valve = blocked, so only possible source of water is shore water via solenoid. My third bucket of 'backflush water' collected after prefilters tested 850ppm, 2nd bucket about 700. Vs. shorewater 140, so I decide there must be a solenoid malfunction
which might be restricting the volume of freshwater enough that check valve opens.
I demount, inspect 24V solenoid valve (see photo). Coil functions, valve operate correctly as best I can tell by blowing on input.
It is a pain to reinstall, deinstall the backflush assembly, so before doing that I'm hoping someone can point to where I have gone wrong?