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C. Pretreatment

The RO feed water must be pretreated in order to prevent mem-

brane damage and/or fouling. Proper pretreatment is essential for 

reliable operation of any RO system.
Pretreatment requirements vary depending on the nature of the feed 

water. Pretreatment equipment is sold separately. The most common 

forms of pretreatment are described below.

Media Filter -

 Used to remove large suspended solids (sediment) 

from the feed water. Backwashing the media removes the trapped 

particles. Backwash can be initiated by time or differential pressure.

Water Softener -

 Used to remove calcium and magnesium from 

the feed water in order to prevent hardness scaling. The potential 

for hardness scaling is predicted by the Langelier Saturation Index 

(LSI). The LSI should be zero or negative throughout the unit unless 

approved antiscalants are used. Softening is the preferred method of 

controlling hardness scale.

Carbon Filter -

 Used to remove chlorine and organics from the  

feed water. Free chlorine will cause rapid irreversible damage to  

the membranes.

The residual free chlorine present in most municipal water supplies 

will damage the thin film composite structure of the membranes 

used in this unit. Carbon filtration or sodium bisulfite injection should 

be used to completely remove the free chlorine residual.

Chemical Injection -

 Typically used to feed antiscalants, coagulant, 

or bisulfite into the feed water or to adjust the feed water pH.

Prefilter Cartridge -

 Used to remove smaller suspended solids and 

trap any particles that may be generated by the other pretreatment. 

The cartridge(s) should be replaced when the pressure drop across 

the housing increases 5 - 10 psig over the clean cartridge pressure 

drop. The effect of suspended solids is measured by the silt density 

index (SDI) test. An SDI of five (5) or less is specified by most mem-

brane manufacturers and three (3) or less is recommended.

Iron & Manganese -

 Iron should be removed to less than 0.1 ppm. 

Manganese should be removed to less than 0.05 ppm. Special me-

dia filters and/or chemical treatment is commonly used.

pH -

 The pH is often lowered to reduce the scaling potential.

Silica:

 Reported on the analysis as SiO2. Silica forms a coating on 

membrane surfaces when the concentration exceeds its solubility. 

Additionally, the solubility is highly pH and temperature dependent. 

Silica fouling can be prevented with chemical injection and/or reduc-

ing the recovery.

Summary of Contents for Pure Water PWR4021 Series

Page 1: ...ial Reverse Osmosis Systems Series PWR4021 IOM WQ PWR4021 WARNING Please read carefully before proceeding with installation Your failure to follow any attached instructions or operating parameters may...

Page 2: ...evention of fouling or scaling of the membranes is not only a mat ter of system design but also a matter of proper operation Record keeping and data normalization are required in order to know the act...

Page 3: ...day gallons per minute Maximum production based on standard membranes and feed water of 25 C SDI 3 1000 ppm TDS and pH 8 Individual membrane productivity may vary 15 3600 2 5 5400 3 75 7200 5 0 9000...

Page 4: ...pplies will damage the thin film composite structure of the membranes used in this unit Carbon filtration or sodium bisulfite injection should be used to completely remove the free chlorine residual C...

Page 5: ...sure Gauge Indicates the pump dis charge pressure G Reject Pressure Gauge Indicates the reject pressure H Reject Flow Meter Indicates the reject flow rate in gallons per minute gpm I Product Flow Mete...

Page 6: ...6 Figure 2 B Controller Drawing...

Page 7: ...7 B Controller Drawing continued Figure 3...

Page 8: ...e in the prefilter housing Figure 1 item K 4 Open the reject control valve completely Figure 1 item B by turning it counterclockwise Close the reject recycle control valve completely Figure 1 item C b...

Page 9: ...r Retighten to 25 in lbs when vent port runs a steady stream of water Vented Priming Plug Drain Plug It is very important to vent the mechanical seal during startup Failure to vent the seal may result...

Page 10: ...AC 1 amp Motor Contactor Coil 24 VAC 1 amp Circuit Protection Main Power Fuse F1 5 x 20 mm 2 Amp Relay XFMR Fuse F2 5 x 20 mm 0 125 Amp Other Dimensions 11 5 tall 9 3 wide 6 7 deep Nema 4X non metalli...

Page 11: ...24V3 Schematic Rev NC Dec 2015 POWER INPUT PUMP Contactor FLUSH VALVE INLET VALVE DIVERT ALARM Divert Valve Alarm contacts can be powered or dry contact selectable with switch S1 Close on Fault Alter...

Page 12: ...verview Keypad System On Off Up Arrow Down Arrow Manual Run Manual Flush Display 4 line 20 character Provides feedback on the system status CPU Board Conductivity Probe Connections Programing Port Ter...

Page 13: ...13 Figure 6 Wiring Diagram Pictorial Schematic of a Typical ROC 4 System...

Page 14: ...d updates of CPU 4 firmware Main interface port Connects via ribbon cable to Terminal Board Detailed View Optional Feed Conductivity Probe Permeate Conductivity Probe Programming Port Standard USB pri...

Page 15: ...15 Figure 8 Controller Detail Terminal Board TB 3 See Fig 3 for schematic TB24V3...

Page 16: ...Tee or equivalent location Orient the probe so that air cannot become trapped in the area near the probe Conductivity Probe Flow Flow Input wiring for new jumper less transformer Line 2 input for 460...

Page 17: ...ls on the CPU Board See Figure 6 Repeat Steps 6 7 for the Feed Conductivity cell if your system will utilize both feed and permeate conductivity measurement 6 Provide power to the RO system 7 Press th...

Page 18: ...ramming Accessing the hidden menus 1 With the System ON Press and Hold the UP and DOWN Arrows 2 With the UP and Down Arrows depressed press the System On Off Switch The menu will switch to the RO Pres...

Page 19: ...delay Seconds 5 5 1 1 Pump start retry interval restart delay after LP fault Seconds 60 60 60 60 Low pressure fault shutdown of faults Faults 5 5 5 5 Low pressure fault shutdown time period to count f...

Page 20: ...20 Figure 11 Controller Programming Menu Navigation...

Page 21: ...ts 5 Low pressure fault shutdown time period to count faults Minutes 10 Low pressure fault shutdown reset after shutdown 0 value no restart Minutes 60 These three values work together to determine how...

Page 22: ...Fault Permeate conductivity is higher than the alarm set point Line 1 Service Fault Line 2 Permeate TDS xxx ppm or Permeate Cond xxx uS Line 3 Alarm SP xxx ppm or Alarm SP xxx uS Line 4 To Reset Push...

Page 23: ...ing Programming Interface Overview The Programming interface is a Windows based tool for making changes to the ROC software This screen shows the RO settings available There are 4 field selectable set...

Page 24: ...x B Controller Programming Programming Interface Overview The WQ screen allows the configuration of the conductivity probes The status screen shows the input and output status and other operational in...

Page 25: ...UCT 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 increase...

Page 26: ...pes and vessels Shock dosage of sodium bisulfite Continuous feed of low conc Of bisulfite at reduced pH Formaldehyde sterilization Clean with alkaline anionic surfactant Chlorine dosage up stream with...

Page 27: ...e drop Use higher voltage on transformer terminals or reduce load Check connections Check conductors for proper size Broken rotor bars or loose rotor Look for cracks near the rings A new rotor may be...

Page 28: ...earing Check alignment side and end thrust Broken ball or rough races Replace bearing first clean housing thoroughly These instructions do not cover all details or variations in equipment nor provide...

Page 29: ...Membrane Replacement 1 Turn off the system and close the feed water shutoff valve 2 Disconnect the membrane feed hoses by loosing the brass fittings between the end of the hoses and the pressure vess...

Page 30: ...llowing tables are intended as a guide to determining the flow rates for the PWR4021 series RO systems All flows are in gallons per minute GPM Nominal flows for systems with reject recycle and a feed...

Page 31: ...31 Notes...

Page 32: ...y remedies stated in such warranties are exclusive and are the only remedies for breach of warranty EXCEPT FOR THE APPLICABLE PRODUCT WARRANTY IF ANY WATTS MAKES NO OTHER WARRANTIES EXPRESS OR IMPLIED...

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