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COMMERCIAL AND INDUSTRIAL APPLICATIONS

Rev C

Figure 22 - 100 to 720 Gallons (378 to 2725 Liters) Per Day Permeate Water Use

Merlin RO Assembly

Carbon Backwash Filter -
size according to water
use needs - reduce to 
0ppm chlorine

Water Softener - 
size according to
water use needs - 
reduce hardness,
manganese, and 
iron to 0 grains

System
Inlet 
Water

Replace prefilter 
with 10-micron 
sediment filter

High capacity 
post filter

Shutoff Valve-
use when 
permeate
systems  
are in 
regeneration

To point 
of use

NOTE:  

Additional pretreatment may be necessary for high turbidity, 

high iron, or pH imbalanced water. 

Summary of Contents for Merlin

Page 1: ...GE Infrastructure Water and Process Technologies Merlin Point of Use Drinking Water System Application Guide for Water Treatment Professionals ...

Page 2: ...RLIN DESCRIPTION 4 SYSTEM PERFORMANCE 5 THE MERLIN FLOW SYSTEM 16 MERLIN BOOSTER PUMP 17 PREFILTER 18 MEMBRANE LIFE 20 MERLIN PERMEATE STORAGE SYSTEMS 22 SALT DIFFUSION 23 COMMERCIAL AND INDUSTRIAL APPLICATIONS 29 TROUBLESHOOTING 31 FLOW ESTIMATION WORKSHEETS 33 ...

Page 3: ...st applications for the Merlin RO system Information is included on reverse osmosis systems in general The Merlin differences are highlighted where appropriate This Application Guide is not intended to be used as an installation or maintenance manual An Installation and Mainenance Manual PN 1262366 is available from your Merlin supplier The information provided here is not intended to be the answe...

Page 4: ...ogies The Merlin RO system is designed for residential use and light commercial applications including Restaurants Coffee Shops Aquariums Grocery Misters The Merlin system is the most revolutionary innovation in point of use RO technology since the first such units were introduced Water treatment professionals can now offer their residential and light commercial customers an exclusive improvement ...

Page 5: ...Merlin include Net driving pressure NDP Inlet water temperature Inlet water conductivity TDS Installation factors An understanding of these factors and how they affect flow is critical for maximizing the Merlin s performance To estimate Merlin s performance follow these steps 1 Determine inlet TDS 2 Determine inlet water temperature 3 Determine net driving pressure 4 Consult Table 1 for estimated ...

Page 6: ...let pressure to the Merlin This is the flowing pressure within 12 inches of the Merlin inlet Often this pressure is less than indicated by a home s well pump pressure gage NOTE Use the flow rate worksheet located at the end of this document to estimate flow from the Merlin NOTE Net Driving Pressure Inlet Pressure System Pressure Drop RO Assembly Faucet Carbon Postfilter Elevation above unit Length...

Page 7: ...gnored The farther the permeate travels through the tubing the greater the pressure drop To estimate pressure drop through tubing follow the steps below 1 Estimate flow rate into the tubing using Table 1 Use inlet pressure into the Merlin as the Net Driving Pressure for the purposes of this estimation By using inlet pressure as the Net Driving Pressure in Table 1 flow directly from the Merlin with...

Page 8: ...op and increase system performance EXAMPLE Q A Merlin will be installed with inlet conditions that will produce 0 5 gpm based on Table 1 The installation requires 20 ft of permeate tubing Find the tubing pressure drop A Tubing pressure drop for this installation will be 0 11 psi ft of 3 8 inch tubing or 0 02 psi ft of 1 2 inch tubing according to Figure 4 Because 20 ft of tubing will be used the t...

Page 9: ... according to the following equation Pressure drop 0 43 psi ft X elevation in feet Pressure drop 0 1 bar m X elevation in meters Figure 6 EXAMPLE Q A Merlin will be installed with 1 tee 2 valves and 1 elbow Find the obstruction pressure drop A The obstruction pressure drop is found as follows 4 fittings X 1 2 psi 0 034 bar each 2 psi 0 137 bar obstruction pressure drop weuro iefos qwe ru qweri uir...

Page 10: ...structions as the Net Driving Pressure for the purposes of this estimation 2 Using the estimated flow rate found in step 1 above find the pressure drop through the tubing with Figure 8 EXAMPLE Q A Merlin will be installed with 8 feet 2 4 m elevation difference between the Merlin and the faucet Find the elevation pressure drop A The elevation pressure drop is found as follows 8 feet X 0 43 psi foot...

Page 11: ...er 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 0 16 14 12 10 8 6 4 2 0 Inlet Flow Rate gpm Faucet Pressure Drop psi 1 10 97 83 69 55 41 27 14 0 75 1 13 1 51 1 89 2 29 2 65 3 03 3 41 3 78 Inlet Flow Rate Lpm Faucet Pressure Drop bar Estimated Faucet Pressure Drop For Water Between 40 100 F 4 5 38 C EXAMPLE Q A Merlin will be installed with the estimated flow into a faucet at 0 4 gpm 0 27 Lpm Find the faucet ...

Page 12: ...ons multiply measured TDS by 0 0002 and add 0 15 Add answer to Table data to achieve actual flow rate Estimated flow change from 750 ppm NaCl 0002 X measured TDS 0 15 b Net Driving Pressure Flowing Inlet Pressure System Pressure Drop NOTE Pressure drop throughout the system is caused by such things as frictional tubing losses vertical tubing runs post filter faucet and obstructions See section on ...

Page 13: ...gpm 300 ppm NaCl Use Figure 4 to determine the pressure drop for 1 ft tubing 0 138 psi Tubing Pressure Drop for 15 ft 15 x 0 138 psi 2 07 psi 3C Calculate the Obstruction Pressure Drop 1 obstruction the elbow X 0 5 psi 0 5 psi 3D Calculate Elevation Pressure Drop 6 ft elevation X 0 43 psi ft 2 58 psi 3E Calculate Postfilter Pressure Drop 1 postfilter X 3 psi 3 psi 3F Calculate Faucet Pressure Drop...

Page 14: ...se Figure 4 to determine the pressure drop for 304 meter tubing 0 0095 bar Tubing Pressure Drop for 4 6 m 4 6 0 304 x 0 0095 bar 0 143 bar 3C Calculate the Obstruction Pressure Drop 1 obstruction the elbow X 0 03 bar 0 03 bar 3D Calculate Elevation Pressure Drop 1 83 m elevation X 0 095 bar 0 18 bar 3E Calculate Postfilter Pressure Drop 1 postfilter X 0 21 bar 0 21 bar 3F Calculate Faucet Pressure...

Page 15: ...d on 750 ppm NaCl Inlet Watera Typical Single Faucet Installation Flowing Inlet Pressure psi bar Temperature F C 80 5 5 75 5 2 70 4 8 65 4 5 60 4 1 55 3 8 50 3 4 45 3 1 40 2 8 80 27 0 77 0 73 0 68 0 64 0 59 0 55 0 50 0 45 0 40 70 21 0 72 0 68 0 63 0 59 0 55 0 50 0 46 0 41 0 36 60 16 0 65 0 61 0 57 0 53 0 49 0 45 0 40 0 36 0 31 50 10 0 57 0 53 0 49 0 45 0 42 0 38 0 34 0 30 0 26 a To adjust data to ...

Page 16: ...OFF PRESSURE The Merlin stops the flow of inlet water when the system is not in use An internal shut off valve will close when pressure in the permeate line reaches approximately 1 3 of the system inlet pressure This function saves water by turning the unit off when permeate water is not being used The inlet valve will open and the Merlin will start making permeate water when pressure in the perme...

Page 17: ...ater flow rate is at least 2 gpm 7 6 Lpm Pump Specifications Inlet water pre pump pressure range 20 to 60 psi 1 38 to 4 14 bar Pump outlet pressure 60 to 68 psi 4 14 to 4 69 bar Necessary water flow for proper pump operation 2 to 4 gpm 7 6 to 15 1 Lpm Pump electrical ratings 110 to 120 VAC 60 Hz 500 watt Pump duty cycle intermittent operation 1 hour Figure 10 We recommend using only the Merlin pro...

Page 18: ...or 5000 gallons 18 900 liters of inlet water Use the following formula to estimate prefilter life Example Commercial Applications Commercial applications will use far more water than most residential applications In commercial applications the prefilter may only last a few days We recommend not using the standard carbon prefilter on applications that will use more than 20 gallons 75 liters of perm...

Page 19: ...out chlorine Figure 11 EXAMPLE Q A light commercial application uses 200 gals 757 liters permeate water per day Estimate the prefilter life A weuro iefos qwe ru qweri uiro weurio wier weuro iefos qwe ru qweri uiro weurio wier weuro iefos qwe ru qweri uiro weurio wier Prefilter life days 5000 4 X 200 gals 6 25 days Standard Merlin Prefilter 5 micron nominal 3 NTU max turbidity 5000 gal capacity 1 p...

Page 20: ...ne system the less waste water is sent to drain Recovery is the measured permeate product water volume produced as a percentage of inlet water consumed This is measured directly from the membrane element Efficiency is the measured permeate product water volume produced as a percentage of inlet water consumed But Efficiency is measured taking into account the complete system This measurement includ...

Page 21: ...e environment Consider that the average consumer is using only 8 12 oz of water at a time An RO system with a storage tank generally is operating under 10 efficiency Table 3 Standard Home RO Merlin RO Gallon 1 1 gallon of permeate water 20 efficiency 4 gallons of water to drain 1 gallon permeate 25 efficiency 3 gallons to drain Gallon 2 1 gallon of permeate water at 10 efficiency 9 gallons of wate...

Page 22: ...surized storage tanks create a backpressure on the system that will reduce performance For this reason we recommend the use of an atmospheric storage tank with a float shutoff for storing permeate water as shown in Figure 13 Figure 13 Option 1 with Mechanical Float Figure 14 Option 2 with Solenoid Merlin RO Assembly Inlet Pressure Pump To Point of Use Vented to atmosphere Mechanical float must tra...

Page 23: ... tank Over time the salt concentration within the storage tank slightly increases The end users are eventually forced to use salt diffused water This is one reason why most RO manufacturers recommend flushing holding tanks on a weekly basis it minimizes but does not eliminate salt diffusion effects Salt Diffusion in the Merlin After extended periods of inactivity in the Merlin system any salt diff...

Page 24: ...the 1 4 inch light blue elbow on the Merlin The kit forces permeate water to flush the high salt concentrate water from the membrane elements By doing this the system rests with low salt concentrations on both sides of the elements Because low salt concentrations remain on each side of the membrane salt diffusion is greatly reduced The kit uses approximately 0 7 gallons 2 5 liters of permeate wate...

Page 25: ...Salt Diffusion Flush Step 2 Accumulator begins to fill Figure 17 Flush Tank Filling with Water Faucet Off Inlet Drain Merlin System is Producing Permeate Water for Flush Prefilter Element 1 Element 2 Post Filter Air compresses ...

Page 26: ...N Rev C Salt Diffusion Flush Step 3 Accumulator is filled Figure 18 Flush Tank Full Pressure Equalizes Faucet Off Inlet Drain Merlin System Stops Producing Permeate Water Prefilter Element 1 Element 2 Post Filter Water ...

Page 27: ... Step 4 Membrane flush begins Figure 19 Faucet Off Inlet Drain Merlin System Begins Flush Prefilter Element 1 Element 2 Water Permeate water is directed back to unit Permeate water begins flushing high TDS water out of system to drain Post Filter ...

Page 28: ...ystem stops Figure 20 Flush Tank All water is purged from Tank Faucet Off Inlet Drain Merlin System Is Off Air Prefilter Element 1 Element 2 Low TDS water has flushed out the inlet side of the elements Complete process may take 3 to 8 minutes Post Filter ...

Page 29: ...ns Pretreatment The Merlin works best when the inlet water has been pretreated The membrane element and system life will be maximized when the inlet water quality is maximized An inlet water quality of 0 grains hardness 0 ppm iron 0 ppm manganese 0 ppm chlorine will result in a maximized membrane element and system life We recommend pretreating your water in one of the following methods Figure 21 ...

Page 30: ... needs reduce to 0ppm chlorine Water Softener size according to water use needs reduce hardness manganese and iron to 0 grains System Inlet Water Replace prefilter with 10 micron sediment filter High capacity post filter Shutoff Valve use when permeate systems are in regeneration To point of use NOTE Additional pretreatment may be necessary for high turbidity high iron or pH imbalanced water ...

Page 31: ...s 5 Install booster pump for applications where an increase in inlet pressure will provide acceptable flow according to Figure 2 6 Replace plugged prefilter Consider sediment prefilter for non chlorinated applications 7 Replace membrane elements 8 Adjust faucet t bar setting as tight as possible without causing leaks from the faucet 9 If flow into the postfilter is acceptable replace postfilter 10...

Page 32: ... reducing net driving pressure 3 Refrigerator ice maker water inlet screen is plugged 1 Use larger tubing diameter Never use 1 4 inch tubing Reduce elevation difference between Merlin and dispensing location 2 Remove built in filter according to refrigerator ice maker manufacturer instructions 3 Clean inlet screen according to refrigerator ice maker manufacturer instructions Cloudy ice 1 Dissolved...

Page 33: ...low Rate Adjustment Factor gpm Tubing Flow Rate gpm gpm gpm ppm NaCl Use Figure 4 to determine the pressure drop for 1 ft tubing psi Tubing Pressure Drop for ft ft x psi psi 3C Calculate the Obstruction Pressure Drop obstructions X 0 5 psi psi 3D Calculate Elevation Pressure Drop feet elevation X 0 43 psi ft psi 3E Calculate Postfilter Pressure Drop postfilter X 3 psi psi 3F Calculate Faucet Press...

Page 34: ...Rate Adjustment Factor Lpm Tubing Flow Rate Lpm Lpm Lpm ppm NaCl Use Figure 4 to determine the pressure drop for 0 304 m tubing bar Tubing Pressure Drop for m 1 m 0304 m x bar bar 3C Calculate the Obstruction Pressure Drop obstructions X 0 5 bar bar 3D Calculate Elevation Pressure Drop meters elevation X 0 095 bar bar 3E Calculate Postfilter Pressure Drop postfilter X 0 21 bar bar 3F Calculate Fau...

Page 35: ...COMMERCIAL AND INDUSTRIAL APPLICATIONS 35 Rev C ...

Page 36: ... Copyright 2007 General Electric Company P N 1266624 Rev C ...

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