Watts R4X40-3 - Manual (Page 11)

F. Operation and Maintenance Log
DATE PRODUCT
GPM
REJECT
GPM
PUMP
DISCHARGE
PRESSURE
FEED
TDS
PPM
PRODUCT
TDS
PPM
FEED
WATER
TEMP
FEED
WATER
HARDNESS
FEED WATER
CHLORINE
LEVEL
PRE FILTER
INLET
PRESSURE
PRE FILTER
OUTLET
PRESSURE
REMARKS
Note: Change the prefilter when the differential pressure increases by 5 - 10 psi over the clean differential pressure.
Clean the RO membrane(s) when the product flow drops by 15% or more. (See appendix)