Pool parts
Pool filter parts
A sand filter has fewer parts than it looks. Most repairs come down to a handful of components. Know what each one does and you can match a symptom to a part without pulling the whole filter apart first.
Filter parts at a glance
The table below covers the parts found on most residential sand filters. Cartridge and DE filters share some of these (valve, gauge, tank seals) but differ in the internal filtration components.
| Part | What it does | Common failure symptom |
|---|---|---|
| Multiport valve | Rotates to select filter, backwash, rinse, waste, recirculate or closed | Wrong flow direction or water leaking between positions |
| Spider gasket | Seals the flow channels inside the multiport valve body | Water exits to waste while in Filter; handle moves between positions loosely |
| Laterals | Collect filtered water at the bottom of the tank while holding sand back | Sand or fine debris returning to the pool through the returns |
| Standpipe | Connects the lateral assembly to the valve and carries filtered water up | Sand returns or circulation is poor after media was disturbed |
| Pressure gauge | Reads internal filter pressure and signals when cleaning is needed | Gauge stuck at zero, pegged high, or not moving when flow changes |
| Air relief valve | Bleeds trapped air from the filter tank before and during startup | Air gurgling from returns; pressure spikes at startup |
| Tank O-ring / seal | Seals the joint where the valve or lid meets the tank body | Water dripping or spraying at the point where valve meets tank |
| Drain plug | Seals the drain port at the bottom of the tank | Slow drip or puddle below the filter tank |
Where the parts are located
Understanding the physical layout makes diagnosis faster. The diagram below shows a top-mounted multiport valve sand filter, which is the most common residential configuration.
What each part does
Multiport valve
The multiport valve is the control center for the entire filtration system. Rotating its handle changes the internal flow path between six positions: Filter, Backwash, Rinse, Waste, Recirculate, and Closed. The valve body contains a rotating disc that aligns different internal channels depending on where the handle points.
Always turn the pump off before moving the handle. Manufacturer instructions from both Pentair and Hayward specify this. Moving the valve under pressure can damage the internal gasket and the valve body itself. For a full explanation of every position, see the pool filter valve positions page.
Spider gasket
The spider gasket is a flat multi-port seal inside the valve body. Its web-shaped arms separate the valve's internal channels so each position stays isolated. When the gasket wears, water finds its way between positions without going through the intended path.
The most common symptom is water flowing to the waste line while the valve is set to Filter. A secondary symptom is the handle not snapping cleanly into position. Replacement gaskets are sold by valve model number, which is stamped on the valve body. For more on gasket types and replacement, see the pool gaskets page.
Laterals
Laterals are the plastic arms at the bottom of the filter tank, arranged around the base of the standpipe like the spokes of a wheel. Their job is to collect filtered water after it passes through the sand while keeping the sand media inside the tank. The slots or perforations in each lateral are sized to pass water but not sand particles.
A cracked lateral, even a hairline crack, lets sand through and into the pool returns. If you find sand in the pool, inspect the laterals before replacing the media. Replace any lateral that shows any crack, not just the ones that are visibly broken.
Standpipe
The standpipe is the central pipe that runs vertically through the filter tank, connecting the lateral assembly at the bottom to the multiport valve at the top. It carries filtered water from the laterals up to the valve and back to the pool.
A cracked standpipe usually causes similar symptoms to a cracked lateral: sand in the pool or poor filtration. Damage typically occurs when the filter is disassembled for media replacement and the standpipe is stressed or dropped. Inspect it any time the filter is opened.
Pressure gauge
The pressure gauge is the primary maintenance signal for a sand filter. It tells you the resistance the water is experiencing as it passes through the media. A reading near your clean baseline means the filter is flowing freely. A reading that has risen 8 to 10 psi above that baseline is the standard backwash trigger, as specified in Hayward's documentation for high-rate sand filters.
A gauge that is stuck at zero, pegged at maximum, or does not respond when the pump cycles on and off is not doing its job. A dead gauge removes your only reliable signal for when to backwash. Replace it. Gauges are inexpensive and sold in standard thread sizes. For more on what pressure readings mean, see the high filter pressure page.
Air relief valve
The manual air relief valve allows you to bleed trapped air from the filter tank before and during startup. Air accumulates in the tank when the system is shut down or when air enters through the suction side. Starting the pump with a full air pocket in the tank can cause pressure spikes and erratic flow.
Open the air relief before starting the pump after any shutdown. Close it once water flows steadily from the valve. If air continues to enter the tank repeatedly, trace the source on the suction side rather than just bleeding it each time.
Tank O-ring and tank seal
The seal where the multiport valve or lid meets the filter tank body is critical. On most residential filters this is a large O-ring or a flat tank gasket that compresses when the valve is secured. If it hardens, flattens, or develops a crack, water sprays or drips at the valve-to-tank joint under operating pressure.
Inspect this seal any time you open the filter for media replacement or lateral inspection. A seal that is visibly deformed should be replaced before the filter is closed up again. They are sold by filter model.
Drain plug
The drain plug at the base of the tank allows the filter to be fully emptied for winterization, media replacement, or lateral inspection. Most drain plugs have a small O-ring or washer as their seal. A slow drip below the filter tank is often nothing more than a loose or degraded drain plug seal.
Check and reseat the drain plug before assuming a larger leak. Replace the O-ring if the plug drips after retightening.
Which part is causing the problem?
Start with the symptom you can see or measure, not with a list of parts. This table maps observations to the most likely component to inspect first.
| What you see or measure | Parts to inspect first | Where to start |
|---|---|---|
| Sand or grit in the pool returns | Laterals, standpipe | Inspect laterals first |
| Water flows to waste while in Filter position | Spider gasket | Replace spider gasket |
| Handle won't click into position cleanly | Spring, handle, spider gasket | Inspect valve internals |
| Pressure gauge never changes reading | Pressure gauge, gauge fitting | Replace gauge; check fitting |
| Water leaking where valve meets tank | Tank O-ring, valve gasket | Replace tank seal |
| Drip below the filter tank | Drain plug, drain seal | Reseat or replace drain plug |
| Air gurgling from returns at startup | Air relief valve, tank seal | Open air relief; inspect tank seal |
| Pressure stays high after backwash | Laterals, media, valve internals | Check media age; inspect laterals |
| Poor filtration despite clean pressure | Laterals, media, spider gasket | Inspect media and laterals |
Parts by filter type
Not all of the above applies to every filter. The internal parts differ significantly between filter technologies.
Sand filter parts
Multiport valve, spider gasket, laterals, standpipe, pressure gauge, air relief valve, tank seal, drain plug, and the sand media itself. Sand filters have the most internal parts of the three common types. Media replacement is a major maintenance job every three to five years, though the schedule depends on water chemistry and bather load.
Cartridge filter parts
Cartridge filters have no laterals, no standpipe, and no backwash valve. The main serviceable parts are the cartridge element itself, the lid seal or O-ring, and the pressure gauge. Some cartridge filters use a simple push-pull or diverter valve rather than a multiport. The cartridge is the primary wear item and is rinsed, deep-soaked periodically, and eventually replaced.
DE filter parts
Diatomite filters use grids or fingers coated in DE powder instead of sand. They share the multiport valve and tank seal with sand filters but differ in the filtration media and internal grid assembly. DE is added through the skimmer after each backwash. DE filters are less common in residential above-ground settings.
How to find the correct replacement part
Pool filter parts are not interchangeable between brands or even between models from the same brand. A spider gasket that fits a Hayward SP0714T valve does not fit a Hayward SP0410X48, even though both are Hayward multiport valves. Follow this sequence before ordering.
- Find the valve or filter model number. The model number is stamped or printed on the valve body, the tank label, or the data plate near the base of the tank. On above-ground combo units it is usually on a sticker near the motor.
- Look up the part number in the manufacturer's documentation. Hayward, Pentair, and Jandy all publish parts diagrams and part numbers for their equipment, usually available on the manufacturer's website under the model's support section. Use the parts diagram rather than ordering by appearance.
- Note the part number before searching. Search by that number rather than by description. A search for "Hayward spider gasket" returns dozens of options. A search for the specific part number returns the right one.
- Confirm dimensions only when a part number is unavailable. If the original part is missing its number, measure the relevant dimensions: spider gasket diameter and arm count, O-ring cross-section and inner diameter, lateral length and thread type. Match by measurement only when a part number is not obtainable.
- Check compatibility notes before ordering aftermarket parts. Aftermarket spider gaskets and O-rings are widely available and often work well. Confirm they list compatibility with your specific valve model, not just the brand name.
When to replace versus when to inspect
Not every problem requires a new part. Some parts need inspection and cleaning first; replacement follows if inspection confirms damage.
| Part | Inspect first | Replace when |
|---|---|---|
| Spider gasket | Seating, visible tears, wear pattern | Cracked, torn, or no longer sealing between positions |
| Laterals | Each arm for cracks, especially near base | Any crack, even hairline - sand will pass through |
| Pressure gauge | Needle movement with pump on and off | Stuck, erratic, or reads zero when pump is running |
| Tank O-ring | Compression, surface cracks, deformation | Flattened, cracked, or brittle - do not reuse a damaged seal |
| Standpipe | Cracks along the pipe body and at the base | Any crack |
| Drain plug | Thread condition and O-ring if fitted | Dripping after retightening; O-ring cracked or missing |
| Multiport valve | All internals including gaskets and channels | When repair cost approaches replacement cost |