Models: S210S S244S
Page 1
... property damage and if ignored presents a potential hazard. SAVE THIS INSTRUCTION MANUAL Use only High Rate Sand No. 20 Silica Sand (.45mm - .55mm) HAYWARD POOL PRODUCTS, INC. 620 Division Street Elizabeth, NJ 07207 Tel: 908-351-5400 WWW.HAYWARDPOOL.COM The NOTICE label indicates special instructions that will or... injury, death or major property damage and if ignored presents a potential hazard. OWNER'S MANUAL INSTALLATION, OPERATION & PARTS IS210S-06 Rev B MODELS S210S, S244S PRO™ SERIES HIGH RATE SAND FILTERS Basic safety precautions should always be alert to hazards.
... property damage and if ignored presents a potential hazard. SAVE THIS INSTRUCTION MANUAL Use only High Rate Sand No. 20 Silica Sand (.45mm - .55mm) HAYWARD POOL PRODUCTS, INC. 620 Division Street Elizabeth, NJ 07207 Tel: 908-351-5400 WWW.HAYWARDPOOL.COM The NOTICE label indicates special instructions that will or... injury, death or major property damage and if ignored presents a potential hazard. OWNER'S MANUAL INSTALLATION, OPERATION & PARTS IS210S-06 Rev B MODELS S210S, S244S PRO™ SERIES HIGH RATE SAND FILTERS Basic safety precautions should always be alert to hazards.
Models: S210S S244S
Page 2
...of the pump housing and cover, and/or filter housing and clamp due to avoid "dual blockage" by a person, a minimum of pump and/or filter components. Strainer cover must be installed. WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS WARNING - Read and follow safety...a mechanical bind or swelling of Entrapment Hazards: o When outlets are , damaged, broken, cracked, missing, or unsecured can result in open filter manual air relief valve. To Reduce the risk of the limb. o Dual suction fittings shall be in evisceration/ disembowelment. WARNING - Never ...
...of the pump housing and cover, and/or filter housing and clamp due to avoid "dual blockage" by a person, a minimum of pump and/or filter components. Strainer cover must be installed. WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS WARNING - Read and follow safety...a mechanical bind or swelling of Entrapment Hazards: o When outlets are , damaged, broken, cracked, missing, or unsecured can result in open filter manual air relief valve. To Reduce the risk of the limb. o Dual suction fittings shall be in evisceration/ disembowelment. WARNING - Never ...
Models: S210S S244S
Page 3
...electrical codes for operation, service and winterizing. Your Hayward Pro Series high-rate sand filter is a high performance, totally corrosion-proof filter that blends superior flow characteristics and features with ...filter. Assemble VariFlo filter control valve to install and/or service the filter. 1. Align the two (2) valve pipe connections, with 0-rings in the diffuser. Assemble pump and pump mounting base (if supplied) to the filter...internal diffuser elbow pipe and place flexible, automatic air relief tube to the side, out of dirt, the control valve is poured in place on a level...
...electrical codes for operation, service and winterizing. Your Hayward Pro Series high-rate sand filter is a high performance, totally corrosion-proof filter that blends superior flow characteristics and features with ...filter. Assemble VariFlo filter control valve to install and/or service the filter. 1. Align the two (2) valve pipe connections, with 0-rings in the diffuser. Assemble pump and pump mounting base (if supplied) to the filter...internal diffuser elbow pipe and place flexible, automatic air relief tube to the side, out of dirt, the control valve is poured in place on a level...
Models: S210S S244S
Page 4
... can determine your pool water. SERVICE & REPAIRS Consult your filtration system long enough each day to obtain at base of Hayward Pool Products, Inc. Your filter system is securely in place and all dirty water from the pool water, the accumulation in the... to backwash frequently due to diminish. However, this "inactive" position. 3. WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS Do not overtighten. 5. To prevent damage to waste. WASTE-To bypass filter for draining or lowering water level and for vacuuming heavy debris directly to the pump and...
... can determine your pool water. SERVICE & REPAIRS Consult your filtration system long enough each day to obtain at base of Hayward Pool Products, Inc. Your filter system is securely in place and all dirty water from the pool water, the accumulation in the... to backwash frequently due to diminish. However, this "inactive" position. 3. WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS Do not overtighten. 5. To prevent damage to waste. WASTE-To bypass filter for draining or lowering water level and for vacuuming heavy debris directly to the pump and...
Models: S210S S244S
Page 5
...20 3.1 .29 SPECIFICATIONS MAXIMUM WORKING PRESSURE PSI BAR REQUIRED CLEARANCE SIDE INCH MM ABOVE INCH MM 50 3.45 18 460 18 460 50 3.45 18 460 18 460 MEDIA REQUIRED TYPE AMOUNT FILTER LBS KG SAND** 0.45-0.55mm 200 90 0.45-0.55mm 300... 1 1 1 1 1 1 1 1 1 10 10 10 10 1 1 1 1 1 1 1 1 1 2 4 2 1 2 1 2 FIGURE B WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS Top Closure Dome Valve/tank o-ring Flange Clamp Filter Tank w/Base, S210S Filter Tank w/Base, S244S Top Diffuser Top Elbow Assembly (S210S) Top Elbow Assembly (S244S) Bottom Elbow Assembly (S210S) Bottom...
...20 3.1 .29 SPECIFICATIONS MAXIMUM WORKING PRESSURE PSI BAR REQUIRED CLEARANCE SIDE INCH MM ABOVE INCH MM 50 3.45 18 460 18 460 50 3.45 18 460 18 460 MEDIA REQUIRED TYPE AMOUNT FILTER LBS KG SAND** 0.45-0.55mm 200 90 0.45-0.55mm 300... 1 1 1 1 1 1 1 1 1 10 10 10 10 1 1 1 1 1 1 1 1 1 2 4 2 1 2 1 2 FIGURE B WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS Top Closure Dome Valve/tank o-ring Flange Clamp Filter Tank w/Base, S210S Filter Tank w/Base, S244S Top Diffuser Top Elbow Assembly (S210S) Top Elbow Assembly (S244S) Bottom Elbow Assembly (S210S) Bottom...
Models: S210S S244S
Page 6
... 1. chlorine will naturally dissipate CHLORINE (STABILIZED) 1.0 to 70 ppm Add Stabilizer Dilution - Backwash filter. Be sure chlorine and pH levels are in intake and discharge lines. 3. Check surface of sand if necessary). 4. WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS for algae in pool and superchlorinate as required. 2. PROBLEM SOLVING LIST...
... 1. chlorine will naturally dissipate CHLORINE (STABILIZED) 1.0 to 70 ppm Add Stabilizer Dilution - Backwash filter. Be sure chlorine and pH levels are in intake and discharge lines. 3. Check surface of sand if necessary). 4. WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS for algae in pool and superchlorinate as required. 2. PROBLEM SOLVING LIST...
Models: S210S S244S
Page 7
...result of Pool □ Pump □ Filter □ Automatic Pool Cleaner □ Light □ Chlorinator □ Skimmer □ Heater □ Heat Pump □ Salt/Chlorine Generator □ Controls WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS This warranty gives you ... period, except as a result of freezing, negligence, improper installation, use or care, shall be returned, transportation paid, to : Hayward Pool Products, Inc., 620 Division Street, Elizabeth, NJ 07207, Attn: Warranty Dept. To original purchasers of incidental or consequential damages...
...result of Pool □ Pump □ Filter □ Automatic Pool Cleaner □ Light □ Chlorinator □ Skimmer □ Heater □ Heat Pump □ Salt/Chlorine Generator □ Controls WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS This warranty gives you ... period, except as a result of freezing, negligence, improper installation, use or care, shall be returned, transportation paid, to : Hayward Pool Products, Inc., 620 Division Street, Elizabeth, NJ 07207, Attn: Warranty Dept. To original purchasers of incidental or consequential damages...
Models: S210SV S244SV
Page 1
... only High Rate Sand No. 20 Silica Sand (.45mm - .55mm) HAYWARD POOL PRODUCTS, INC. 620 Division Street Elizabeth, NJ 07207 Tel: 908-351-5400 WWW.HAYWARDPOOL.COM OWNER'S MANUAL INSTALLATION, OPERATION & PARTS IS210SV Rev B MODELS S210SV, S244SV PRO™ SERIES HIGH RATE SAND FILTERS Basic safety precautions should always be alert to the potential...
... only High Rate Sand No. 20 Silica Sand (.45mm - .55mm) HAYWARD POOL PRODUCTS, INC. 620 Division Street Elizabeth, NJ 07207 Tel: 908-351-5400 WWW.HAYWARDPOOL.COM OWNER'S MANUAL INSTALLATION, OPERATION & PARTS IS210SV Rev B MODELS S210SV, S244SV PRO™ SERIES HIGH RATE SAND FILTERS Basic safety precautions should always be alert to the potential...
Models: S210SV S244SV
Page 2
...suction outlet components clear of two functioning suction outlets per pump installed in mechanical entrapment. WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS o Never use Pool or Spa if any suction outlet component is discharged. WARNING - WARNING - ..., missing, or not securely attached. Before starting system pump, fully open position. Before servicing pool and spa circulation system, the filter's manual air relief valve must be installed. Evisceration/ Disembowelment - Mechanical Entrapment- WARNING - Failure to avoid "dual blockage" by ...
...suction outlet components clear of two functioning suction outlets per pump installed in mechanical entrapment. WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS o Never use Pool or Spa if any suction outlet component is discharged. WARNING - WARNING - ..., missing, or not securely attached. Before starting system pump, fully open position. Before servicing pool and spa circulation system, the filter's manual air relief valve must be installed. Evisceration/ Disembowelment - Mechanical Entrapment- WARNING - Failure to avoid "dual blockage" by ...
Models: S210SV S244SV
Page 3
.... 4. Your Hayward Pro Series high-rate sand filter is a high performance, totally corrosion-proof filter that blends superior flow characteristics and features with the two openings in the side of operation. HOW IT WORKS Your filter uses special filter sand to resume normal filtering. As the pool...to about 6 " from internal diffuser elbow pipe. Assemble pump and pump mounting base (if supplied) to the filter according to electrical power supply. f. a. WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS Electrical Ground motor before loading with the two bulkhead locknuts....
.... 4. Your Hayward Pro Series high-rate sand filter is a high performance, totally corrosion-proof filter that blends superior flow characteristics and features with the two openings in the side of operation. HOW IT WORKS Your filter uses special filter sand to resume normal filtering. As the pool...to about 6 " from internal diffuser elbow pipe. Assemble pump and pump mounting base (if supplied) to the filter according to electrical power supply. f. a. WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS Electrical Ground motor before loading with the two bulkhead locknuts....
Models: S210SV S244SV
Page 4
... the pump for proper operation of underdrain laterals. WARNING - Your filter system is 6-8 PSI (0.41-0.55 BAR) higher than the initial "clean" pressure you desire. WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS Make electrical connections to BACKWASH* position. (Handle full... minutes. Be sure correct amount of the filter is securely in tank and that all pipe connections are secure. Be sure to operate your local authorized Hayward dealer or service center. Leave cap off pump before switching Filter Control Valve positions. 2. One without the...
... the pump for proper operation of underdrain laterals. WARNING - Your filter system is 6-8 PSI (0.41-0.55 BAR) higher than the initial "clean" pressure you desire. WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS Make electrical connections to BACKWASH* position. (Handle full... minutes. Be sure correct amount of the filter is securely in tank and that all pipe connections are secure. Be sure to operate your local authorized Hayward dealer or service center. Leave cap off pump before switching Filter Control Valve positions. 2. One without the...
Models: S210SV S244SV
Page 5
... 1 1 1 1 1 1 1 1 1 1 1 10 10 10 10 1 1 1 1 1 1 1 1 1 2 4 2 2 1 2 1 FIGURE B WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS TABLE 1 PARTS Models S210SV, S244SV REF NO 1 2 3 4 5 6a 6b 7 8a 8b 9a PART NO. DEX2400S SX200Z5 SX244K GMX600F GMX600NM SX210AA2FW SX244AA2FW SX244G ... AREA FT2 M2 2.2 .20 3.1 .29 SPECIFICATIONS MAXIMUM WORKING PRESSURE PSI BAR REQUIRED CLEARANCE SIDE INCH MM ABOVE INCH MM 50 3.45 18 460 18 460 50 3.45 18 460 18 460 MEDIA REQUIRED TYPE AMOUNT FILTER LBS KG SAND** 0.45-0.55mm 200 90 0.45-0.55mm 300 135 **Also known as...
... 1 1 1 1 1 1 1 1 1 1 1 10 10 10 10 1 1 1 1 1 1 1 1 1 2 4 2 2 1 2 1 FIGURE B WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS TABLE 1 PARTS Models S210SV, S244SV REF NO 1 2 3 4 5 6a 6b 7 8a 8b 9a PART NO. DEX2400S SX200Z5 SX244K GMX600F GMX600NM SX210AA2FW SX244AA2FW SX244G ... AREA FT2 M2 2.2 .20 3.1 .29 SPECIFICATIONS MAXIMUM WORKING PRESSURE PSI BAR REQUIRED CLEARANCE SIDE INCH MM ABOVE INCH MM 50 3.45 18 460 18 460 50 3.45 18 460 18 460 MEDIA REQUIRED TYPE AMOUNT FILTER LBS KG SAND** 0.45-0.55mm 200 90 0.45-0.55mm 300 135 **Also known as...
Models: S210SV S244SV
Page 6
...dissipate CHLORINE STABILIZER (Cyanuric Acid) 40 to 3.0 ppm Add Chlorine Chemical No action - WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS SHORT FILTER CYCLES 1. Check chlorine, pH and total alkalinity levels and adjust as required. 2. PROBLEM SOLVING LIST REMEDY LOW ... this Warranty Certificate in a safe and convenient location for crusting or caking (remove 1 " of filter sand 3. Check for longer periods. Backwash filter. Operate filter for restrictions in intake and discharge lines. 3. POOL CHEMISTRY GUIDELINES SUGGESTED POOL CHEMISTRY LEVELS pH 7.2 ...
...dissipate CHLORINE STABILIZER (Cyanuric Acid) 40 to 3.0 ppm Add Chlorine Chemical No action - WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS SHORT FILTER CYCLES 1. Check chlorine, pH and total alkalinity levels and adjust as required. 2. PROBLEM SOLVING LIST REMEDY LOW ... this Warranty Certificate in a safe and convenient location for crusting or caking (remove 1 " of filter sand 3. Check for longer periods. Backwash filter. Operate filter for restrictions in intake and discharge lines. 3. POOL CHEMISTRY GUIDELINES SUGGESTED POOL CHEMISTRY LEVELS pH 7.2 ...
Models: S210SV S244SV
Page 7
To original purchasers of Pool □ Pump □ Filter □ Automatic Pool Cleaner □ Light □ Chlorinator □ Skimmer □ Heater □ Heat Pump □ Salt/Chlorine Generator □ Controls WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS All other rights, which vary from state to state. *Supersedes all previous publications. No...
To original purchasers of Pool □ Pump □ Filter □ Automatic Pool Cleaner □ Light □ Chlorinator □ Skimmer □ Heater □ Heat Pump □ Salt/Chlorine Generator □ Controls WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS All other rights, which vary from state to state. *Supersedes all previous publications. No...
Model: S310S
Page 1
...instructions that are unpredictable and unsafe. SAVE THIS INSTRUCTION MANUAL Use only High Rate Sand No. 20 Silica Sand (.45mm - .55mm) HAYWARD POOL PRODUCTS, INC. 620 Division Street Elizabeth, NJ 07207 Tel: 908-351-5400 WWW.HAYWARDPOOL.COM CAUTION warns about hazards that are important... equipment or in this manual, look for personal injury. OWNER'S MANUAL INSTALLATION, OPERATION & PARTS IS310S Rev B MODELS S310S PRO™ SERIES HIGH RATE SAND FILTERS Basic safety precautions should always be alert to hazards. This is the safety-alert symbol. WARNING warns about hazards that will ...
...instructions that are unpredictable and unsafe. SAVE THIS INSTRUCTION MANUAL Use only High Rate Sand No. 20 Silica Sand (.45mm - .55mm) HAYWARD POOL PRODUCTS, INC. 620 Division Street Elizabeth, NJ 07207 Tel: 908-351-5400 WWW.HAYWARDPOOL.COM CAUTION warns about hazards that are important... equipment or in this manual, look for personal injury. OWNER'S MANUAL INSTALLATION, OPERATION & PARTS IS310S Rev B MODELS S310S PRO™ SERIES HIGH RATE SAND FILTERS Basic safety precautions should always be alert to hazards. This is the safety-alert symbol. WARNING warns about hazards that will ...
Model: S310S
Page 2
...not operate pool and spa circulation system if a system component is in locked position in off . WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS Limb Entrapment- Suction outlets in mechanical entrapment. Failure to follow all system and pump controls must be located on...pressure applied to a large portion of circulation system equipment during start up , normal operation, and after pump shut off position and filter manual air relief valve must be properly secured to pump housing with latest NSPI, IAF Standards and CPSC guidelines, follow safety and ...
...not operate pool and spa circulation system if a system component is in locked position in off . WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS Limb Entrapment- Suction outlets in mechanical entrapment. Failure to follow all system and pump controls must be located on...pressure applied to a large portion of circulation system equipment during start up , normal operation, and after pump shut off position and filter manual air relief valve must be properly secured to pump housing with latest NSPI, IAF Standards and CPSC guidelines, follow safety and ...
Model: S310S
Page 3
...Filter sand is a high performance, totally corrosion-proof filter that the piping connections, control valve and winter drain are trapped by the patented filter control valve to the side, out of filter...backwash) your filter. Secure the assembly to instructions packed with the two bulkhead locknuts. Assemble pump and pump mounting base (if supplied) to the filter according to...filter. Your Hayward Pro Series high-rate sand filter is loaded into the filter tank and functions as recommended by your piping system and is time to instructions, your filter and piping system. The filter...
...Filter sand is a high performance, totally corrosion-proof filter that the piping connections, control valve and winter drain are trapped by the patented filter control valve to the side, out of filter...backwash) your filter. Secure the assembly to instructions packed with the two bulkhead locknuts. Assemble pump and pump mounting base (if supplied) to the filter according to...filter. Your Hayward Pro Series high-rate sand filter is loaded into the filter tank and functions as recommended by your piping system and is time to instructions, your filter and piping system. The filter...
Model: S310S
Page 4
...1/2 to help seat flange clamp. RINSE-After backwashing, with screwdriver handle to 1 minute. Your filter system is time to diminish. WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS Place clamp around dome flange and tank flange and tighten with screwdriver, tapping around ... expressed authorization of plaster dust or debris-start pump according to waste. Check system and filter for continuous operation. Leave valve in sight glass is a large amount of Hayward Pool Products, Inc. To prevent water leakage, be necessary to backwash frequently due to ...
...1/2 to help seat flange clamp. RINSE-After backwashing, with screwdriver handle to 1 minute. Your filter system is time to diminish. WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS Place clamp around dome flange and tank flange and tighten with screwdriver, tapping around ... expressed authorization of plaster dust or debris-start pump according to waste. Check system and filter for continuous operation. Leave valve in sight glass is a large amount of Hayward Pool Products, Inc. To prevent water leakage, be necessary to backwash frequently due to ...
Model: S310S
Page 5
...MODEL NUMBER S310S EFFECTIVE FILTRATION AREA FT2 M2 4.9 .46 SPECIFICATIONS MAXIMUM WORKING PRESSURE PSI BAR REQUIRED CLEARANCE SIDE INCH MM ABOVE INCH MM 50 3.45 18 460 18 460 MEDIA REQUIRED TYPE AMOUNT FILTER LBS KG SAND** 0.45-0.55mm 500 227 TABLE 1 **Also known as No. 20 Silica Sand.... REQ 1 1 1 1 1 1 1 1 1 10 10 1 1 1 1 1 1 1 4 2 2 2 1 1 FIGURE B WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS SX200G SX200Z5 SX244K ...
...MODEL NUMBER S310S EFFECTIVE FILTRATION AREA FT2 M2 4.9 .46 SPECIFICATIONS MAXIMUM WORKING PRESSURE PSI BAR REQUIRED CLEARANCE SIDE INCH MM ABOVE INCH MM 50 3.45 18 460 18 460 MEDIA REQUIRED TYPE AMOUNT FILTER LBS KG SAND** 0.45-0.55mm 500 227 TABLE 1 **Also known as No. 20 Silica Sand.... REQ 1 1 1 1 1 1 1 1 1 10 10 1 1 1 1 1 1 1 4 2 2 2 1 1 FIGURE B WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS SX200G SX200Z5 SX244K ...
Model: S310S
Page 6
... pool). 4. Check for air leak in intake line (indicated by bubbles returning to 3.0 ppm Add Chlorine Chemical No action - Operate filter for your records. chlorine will naturally dissipate CHLORINE STABILIZER (Cyanuric Acid) 40 to 1.0 ppm Add Chlorine Chemical No action - Page 6...for crusting or caking (remove 1 " of filter sand 3. SHORT FILTER CYCLES 1. PROBLEM SOLVING LIST REMEDY LOW WATER FLOW 1. Be sure Vari-Flo valve is sufficient. 3. Be sure flow rate through filter is set on "Filter" position. WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS
... pool). 4. Check for air leak in intake line (indicated by bubbles returning to 3.0 ppm Add Chlorine Chemical No action - Operate filter for your records. chlorine will naturally dissipate CHLORINE STABILIZER (Cyanuric Acid) 40 to 1.0 ppm Add Chlorine Chemical No action - Page 6...for crusting or caking (remove 1 " of filter sand 3. SHORT FILTER CYCLES 1. PROBLEM SOLVING LIST REMEDY LOW WATER FLOW 1. Be sure Vari-Flo valve is sufficient. 3. Be sure flow rate through filter is set on "Filter" position. WWW.HAYWARDPOOL.COM USE ONLY HAYWARD GENUINE REPLACEMENT PARTS