Hayward ProSeries 16 In Top-Mount Sand Pool Filter
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Hayward ProSeries W3S166T 16-Inch Top-Mount Sand Pool Filter
The Hayward ProSeries W3S166T is a 16-inch top-mount sand filter for above-ground and smaller residential in-ground pools. The 7-position Vari-Flo multiport valve sits directly above the tank for easy access to all operating modes from a single lever handle. The flange clamp design allows 360-degree valve rotation to simplify plumbing alignment at installation.
The filter ships with the valve, pressure gauge, laterals, and tank base. 100 lbs of #20 silica sand is required for operation and sold separately.
Hayward W3S166T ProSeries Sand Filter Key Features
- 7-position Vari-Flo top-mount valve - Filter, Backwash, Rinse, Recirculate, Waste, Closed, and Winter positions on a single lever handle mounted directly above the tank.
- 360-degree valve rotation - Flange clamp design lets the valve rotate to any orientation to simplify plumbing without modifying the tank.
- Integral top diffuser - Distributes incoming water evenly across the full sand bed surface on entry, preventing channeling that reduces effective filtration area.
- Umbrella-fold self-cleaning laterals - Precision-engineered laterals provide balanced flow across the sand bed and thorough, even backwashing.
- Integral sight glass - Visual confirmation of backwash cycle completion, so the pump stops when the outflow is clear rather than on a fixed timer.
- Large pressure sand and water drain - Full-size drain port at the base for quick winterizing or sand changes without tilting the tank.
- Corrosion-proof thermoplastic tank - UV-stable construction rated for continuous outdoor exposure and all-weather operation.
Hayward W3S166T ProSeries 16-Inch Sand Filter Specifications
Sand not included. Always use #20 grade silica pool filter sand. Do not use play sand, beach sand, or construction sand.
ProSeries Top-Mount Sand Filter Lineup: W3S166T in Context
The W3S166T is the smallest tank in the ProSeries top-mount sand filter line. The table below shows published flow rates across the lineup to help confirm sizing against your pump output. For the 21-inch model, see the ProSeries 21-inch top-mount sand filter.
| Model | Tank Diameter | Sand Capacity | Design Flow Rate |
|---|---|---|---|
| W3S166T (this model) | 16 in. | 100 lbs | 30 GPM |
| W3S180T | 18 in. | 150 lbs | 35 GPM |
| W3S210T | 21 in. | 200 lbs | 37 GPM |
| W3S244T | 24 in. | 300 lbs | 50 GPM |
| W3S270T | 27 in. | 325 lbs | 75 GPM |
| W3S300T | 30 in. | 500 lbs | 100 GPM |
Flow rates per Hayward published specifications. Pool coverage depends on pump sizing, turnover rate targets, and site conditions.
Maintaining the Hayward W3S166T ProSeries 16-Inch Sand Filter
Backwash when operating pressure rises 8 to 10 PSI above the recorded clean baseline. Switch the valve to Backwash and run the pump until the sight glass runs clear, then switch to Rinse for 15 to 30 seconds before returning to Filter. Always use the sight glass rather than a fixed timer to confirm the backwash is complete.
Plan to replace the sand every 3 to 5 years under standard residential use. Signs that replacement is overdue include persistent cloudiness after correct backwashing, fine sand appearing at the pool's return fittings, or unusually short intervals between required backwash cycles.
Installing the W3S166T and Matching the Pump
The W3S166T is rated for 30 GPM at the system's operating head. Exceeding that ceiling results in elevated operating pressure, faster sand loading, and more frequent backwash cycles. Confirm your pump's flow rate at actual system head before installation. If the pump output exceeds 30 GPM, the W3S180T (18-inch, 35 GPM) or W3S210T (21-inch, 37 GPM) is the appropriate step up.
Before loading sand, fill the tank halfway with water to cushion the lateral assembly, then add 100 lbs of #20 silica sand gradually. After loading sand, run a full Rinse cycle before placing the filter in Filter mode to flush fine dust from the new media before it can enter the pool.
Winterizing the W3S166T
Drain the tank fully through the base drain, leave the drain plug removed through winter, and set the multiport valve to the Winter position to drain the valve body and prevent freezing in the valve passages. For above-ground pool installations, the filter is typically stored indoors or in an insulated location for the off-season.
Hayward W3S166T ProSeries Sand Filter Frequently Asked Questions
Does the W3S166T come with sand?
No. The W3S166T ships with the tank, 7-position Vari-Flo valve, pressure gauge, laterals, and base. 100 lbs of #20 silica pool filter sand must be purchased separately before putting the filter into service.
Is the W3S166T suitable for in-ground pools?
Yes, for smaller in-ground pools. The W3S166T is rated for both above-ground and in-ground pool applications and ships with standard 1.5" NPT connections compatible with in-ground pool plumbing. For larger in-ground pools with higher pump outputs, a larger ProSeries model is more appropriate.
What is the valve position count on the W3S166T?
The W3S166T includes a 7-position Vari-Flo top-mount valve. The seven positions are Filter, Backwash, Rinse, Recirculate, Waste, Closed, and Winter.
How often should the sand be replaced in the W3S166T?
Every 3 to 5 years under typical residential use. Replace sooner if you notice persistent cloudy water that does not resolve after correct backwashing, fine sand at the return fittings, or very short pressure intervals between backwash cycles.
Can the multiport valve be repositioned to simplify plumbing?
Yes. The flange clamp design allows the valve to rotate 360 degrees on the tank body so the inlet and outlet ports can be oriented toward the pump and return plumbing without modifying the tank or cutting additional pipe runs.