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  Frequently Asked Questions - Softeners



  • What are the five cycles of a water softener? Service, Backwash, Brine, Slow Rinse, Fast Rinse

  • How is the softening process controlled? Click on question for answer.

  • Why add salt to a water softener? Click on question for answer.

  • Why buy a water softener? Click on question for answer.

  • Why buy a Water King water softener? Click on question for answer.

  • How do you size a water softener? Click on question for answer.

  • Do you have an example set of calculations for softener sizing? Click on question for answer.

  • What is the difference between "ppm" and "mg/L"?  1 mg/L is a unit of concentration. The more fundamental measure is ionic concentration in moles or equivalents per liter. All other units of mg/L or ppm are the product of ionic concentration and molecular weight or equivalent weight.  If we assume that mg/L represents a mg of a substance dissolved in a liter of water the mass of the water will be 1000 grams or 1,000,000 mg. Thus 1 mg/L is the same as 1 mg per 1,000,000 mg of water or 1 part per million. Thus, mg/L and ppm are synonymous.  

  • What is a Super Flow Kit? A super flow or service flow by pass kit consists of and inlet and outlet diaphragm valve, some tubing and fittings, and a solenoid. The solenoid opens the valves when the Task Master III is in service and closes when it is in regeneration. See Catalog Section 370

  • How can I tell which softener is in service / stand-by?

  • How much water does it take to regenerate? It takes about 3 to 4 % of the produced water to regenerate a softener. For a specific softener, the volume of water for regeneration can be accurately calculated knowing the cycle times and flow rates.

  • What is a Shut Off Kit? A shut off kit prevents the bypass of hard water during regeneration. The Task Master III is ported to automatically allow water to bypass hard water during regeneration. For simplex units this is useful to avoid cutting off the water during regeneration. A shut off kit consists of outlet diaphragm valve, some tubing and fittings, and a solenoid. The solenoid closes  the valves when the Taskmaster III is in regeneration. It is open during service. See catalog section 370

  • What is N+1 Sparing?
    Answer: Sizing a system so that N units supply the required flow and capacity and a third of the same size is added for redundancy.
    Discussion: Redundancy is a basic principle of sizing of any process equipment. The idea is to always be able to take at least one process unit out of service and still be able to maintain production. Hence, if you have two process units, one should be able to handle full production. If you have three process units, two should be able to handle full production. The expectation is to have one spare unit or N+1.
    The use of N+1 sparing in water softeners.
    Let us consider a required flow of 600 gpm.
    Case 1, N=1: The flow could be provided by one unit at 600 gpm and then for redundancy, an additional 600 gpm softener can be installed. In this first case, N = 1 and N+1 = 2. The required capacity per unit is 600/1 = 600 gpm.
    Case 2, N=2: In this case, the flow is provided by two units at 300 gpm with an additional 300 gpm softener. In this case, N = 2 and N+1=3. The capacity per unit is 600/2 = 300 gpm.
    Case 3, N=3: We could use three units at 200 gpm each with one 200 gpm spare. In this case, N = 3 and N+1=4. The capacity per unit is 600/3 = 200.
    Once the peak flow requirement is determined, flow requirements for the individual units are easily determined based on N+1 sparing.

  • What are the different system configurations available for water softeners?  Water King offers a wide variety of system and tank configurations that help to perform many different tasks.  These configurations are named according to the number of tanks: (Answer from SOP 8703)

Part No. Extention

Description

Model No. Extenstion

No of Tanks

ERCd

ERCt

Flow Meters

Secondary

Stagers for VN

STND - no extension

Simplex Timer

SX

1

X

1

X

X

1-MPV1

STND - no extension

Twin Timed System (has SOK / SFK)

T

2

X

2

X

X

1-MPV1

-T

Twin Timed System (has SOK / SFK)

T

2

X

2

X

X

1-MPV1

-5

Simplex Metered

SM

1

1

X

1

X

1-MPV1

 

 

 

 

 

 

 

 

 

STND - no extension

Twin

Timer

T

2

X

2

X

X

2-MPV1

-10

Twin Sequential (2 BTA)

TS

2

1

1

1

X

2-MPV1

-11

Twin alternating

TA

2

1

X

1

1

1-MPV3

-12

Twin Parallel

TP

2

2

X

2

X

2-MPV1

-14

Triplex

TX

3

3

X

3

X

3-MPV1

-15

Triplex Sequential

TXS

3

1

2

1

X

3-MPV1

-16

Quad Sequential

QS

4

1

3

1

X

4-MPV1

-17

Quad Parallel

QP

4

4

X

4

X

4-MPV1

-18

Triplex Parallel

TXP

3

3

X

3

X

3-MPV1

Notes:

 

Sequential system meters must handle flow from all units while meters for parallel or twin alternating systems are dedicated to the flow from a single softener. Sequential systems must have two brine tanks. One brine tank does not work because the brine does not have time to saturate between sequential regenerations.

 

The traditional T extension will mean a twin unit with two mineral tanks, and one brine tank with timer rather than metered controllers. Historically these systems did not have shut off kits and they were added at the time of quotation. Henceforth, the twin (twin timed) units will have shut off kits or super flow kits as necessary. They will be included in the pricing. Also note that in the MF and RF part numbers, the last digit is the number of tanks so for RF and MF part numbers in which the last digit is a 2, with no extension, it is implied the system will be a T, twin timed unit. For example, 920152 means a time clock regenerated twin MF 150 with two ERCt controllers and two shut off kits.

  • How do I size a twin alternating system?  Size the unit using Water King standard sizing: Size the piping so that each of the units will handle the full peak flow. Size the capacity so that each of the units can handle half of the grains per day of hardness to be removed.

  • How do I size a triplex system? Size the system using N+1 sparing: For a triplex with N+1, size the piping so that each of the units will handle half of the peak flow. Size the capacity so that each of the units can handle half of the grains per day of hardness to be removed. This sizing follows N+1 sparing.

  • Are there different ways to choose the capacity of a multiple tank water system? Yes, the sizing depends on the time between regenerations or the minimum run time choosen by the designer.

  • What is the minimum time between regenerations?
    Answer: Operationally softeners should be regenerated at 6 hour intervals. (6 to 12 hours is used for design purposes)
    Discussion: The minimum time between regenerations is first set by the regeneration cycle, which is usually two hours. The other issue is the recovery time of the brine tank. After brining, the brine tank must refill and then the salt must dissolve to create a saturated brine. The minimum time is generally set at six hours which is two hours for the regeneration cycle and four hours for the brine tank to recover.

  • How do I size the inlet and outlet headers for a softener or filter?
    Answer:
    For simplex systems you should match the softener inlet / oulet piping size.
    For twin alternating systems you should match the softener inlet / oulet piping size.
    For triplex at N+1 size the header to match two of the units. So if you have a triplex with 3" piping, size the header so that the cross sectional area is the same as two 3" pipes at 7.07 in2 each or 14.14 in2 total. Calculating the minimum diameter gives D = Sqrt((4/PI)*14.14) = 4.24 inches. The veloicity of flow in a 4" pipe at 350 gpm is 8.9 fps so this would not be an unreasonable choice. A 6 inch diameter pipe would assure full flow and can supply all three units making higher flows available. Answer: 4" is adequate, 6" provides for expansion.

  • How do I convert Conductivity to Total Dissolved Solids (TDS)?
    Answer (from Stevens Water):
    "Electrical Conductivity sensors are used to measure the ability of water to carry an electrical current. Absolutely pure water is a poor conductor of electricity. Water shows significant conductivity when dissolved salts are present. Over most ranges, the amount of conductivity is directly proportional to the amount of salts dissolved in the water.

    The amount of mineral and salt impurities in the water is called total dissolved solids (TDS). TDS is measured in parts per million. TDS tell how many units of impurities there are for one million units of water. For example, drinking water should be less than 500 ppm, water for agriculture should be less than 1200 ppm, and high tech manufactures often require impurity-free water. One way to measure impurities in water is to measure the electric conductivity of water.

    A conductivity sensor measures how much electricity is being conducted through a centimeter of water. Specific conductivity is expressed as mhos per centimeter (M/cm), sometimes called siemens per centimeter (S/cm). Because a mho (or siemen) is a very large unit, the micromho (microsiemen) or millimho (millisiemen) typically is used (mS/cm).

    To convert the electric conductivity of a water sample (mS/cm) into the approximate concentration of total dissolved solids (ppm), the mS/cm is multiplied by a conversion factor. The conversion factor depends on the chemical composition of the TDS and can very between 0.54 0.96. A value of 0.67 is commonly used as an approximation if the actual factor is not known [(TDS)ppm = Conductivity S/cm x 0.67].

    Since conductivity varies with temperature, it is necessary to correct the readings for changes in temperature. Most instruments contain circuits that automatically compensate for temperature and correct the readings to a standard 25C.

    Water purity varies widely. Therefore, Greenspan offers conductivity ranges from 0 70,000 S/cm."
     

  • Is the Task Master III valve suitable for Ozone?
    Answer (from Pentair Water):

    The stainless steel used for the valve is compatible with Ozone, as is the EPDM configuration on the piston seals.  The injector, however is made of Noryl which is not recommended for ozone as it will degrade over time.  The application of using this valve for Ozone is only recommended if the injector is treated as a "spare" part that can be replaced every six months.

    What is the difference between an ASME Code and a non-code fiberglass vessel?
    Answer (from Pentair Water - Water King uses only Structural Fibers / Pentair Fiberglass composite mineral tanks):

    For every ASME tank we must bring in a 3rd party certified inspector, who monitors the production build of the tanks.  There is also a slightly higher amount of fiberglass used in order to achieve the higher burst ratings associated with the ASME certification.  Then every three years Pentair must re-qualify each tank sku.  This is done by building the particular ASME tank and then testing the tank to destruction (basically blow the tank up).  ASME certification costs per production run and for requalification are the drivers in the price gap you are seeing. 

     Here are the testing requirements as well:

     Pentair

    • Safety factor: 4:1
    • Minimum burst at 600psi
    • Tested to 250,000 cycles without leakage

    NSF

    • Safety factor: 4:1
    • Minimum burst at 600 psi
    • Tested to 100,000 cycles without leakage

    ASME

    • Top/bottom flange
      • Safety factor: 5:1
      • Minimum burst at 750 psi
      • Tested to 33,000 cycles without leakage
    • Side flange
      • Safety factor: 6:1
      • Minimum burst at 900 psi
      • Tested to 100,000 cycles without leakage

    Erik Koglin - Midwest Territory Account Manager - Pentair Filtration & Process

    How much salt is required to fill the brine tank?

    The "original load" of salt is the amount of salt required to fill an empty brine tank from the top of the grid plate or salt platform to withing 4 inches of the top. The installing contractor should plan on supplying this amount in the brine tank when they leave the project. Follow this link to see salt requirements for Water King's standard brine tanks.

    What is the salt storage capacity of a brine tank?

    The salt storage capacity of a brine tank is calculated as the salt required to fill a brine tank level to the top with dry salt, plus the salt contained in the saturated brine. Follow this link to see salt requirements for Water King's standard brine tanks.

     

 

 
Water King, Inc. S 102 Charbonnet Road  S Duson,  LA  70529  S (337) 988-2360