These basic parameters should be met by inlet water for RO systems ‐ check with "Required water parameters for RO methods" section. And finally, 4‐way valve could be clogged by massive quantities of ions of calcium, magnesium and iron. One Other cause might be damaged seal of considered one of membranes forming the 4‐way valve. "System sweating" happens with a large distinction in tem... https://pad.geolab.space/__DeJa3RRc-T-16X3zy4LA/