Swimming Pool Blog
by Rob Cox October 4, 2013
Pool Filter Parts Pictorial
In our final pool parts pictorial, we look closely at the most common parts sold for today's pool filters.
Sand, D.E. or Cartridge - all have unique Filter Parts specific to their type of pool filter. The only part shared between all pool filters would be pressure gauge, available in either back mount, or bottom mount.
Cartridge filters don't have a valve to backwash with, because you can't backwash a cartridge pool filter. Sand can have either a top mounted or side mounted valve, and DE filters will have a side mounted valve. A multiport valve can be used, which usually has 6 functions, or the 2 function slide valve, aka push-pull valve, for backwashing.
Backwash valves, multiport or push-pull, are considered parts of the Valve Parts family, and are not included here. When looking for a pool filter part, are you really in need of parts for the backwash valve?
Sand Pool Filter Parts
Laterals and Hubs: Laterals are slotted pipes on the bottom of the tank that allow water to push through tiny slits, but not the filter sand. They attach into a hub, or manifold, with either threaded, push and twist or ball and socket type of connection. The hub is connected to a standpipe, which runs straight up and connects into a top mounted multiport, or for side mounted valves, turns 90 degress and connects to the bulkhead assembly.
Drain Assembly: Sand filters have more complicated drain assemblies than DE or cartridge filters. This is because you need the option to drain water only, and keep the sand in the tank. In some cases though, you may want to remove the entire assembly, to flush out remaining sand during a sand change, for instance, or to repair a leaking or damaged drain assembly.
D.E. Pool Filter Parts
DE Filter Grids: Here we have several gilter grid 'assemblies', with the grids assembled with other conjoining parts. DIfferent designs have been used over the years, with Hayward's Perflex design of hanging 'fingers', the more standard curved grid arrangement, and my personal favorite, the vertical grid arrangement used by Sta-Rite. Grids can develop holes, or become clogged with minerals or oils. Give them an annual cleaning and inspection, and replace any broken or torn grids. Note: one or more grids in the assembly may be of a different size. Same height, different width.
DE Manifold: A manifold is used to force water to travel in certain directions. Manifold design helps ensure proper flow and pressure through the filter, and forces the water to go through the DE grids, before it exits the filter. Most manifolds have an air bleeder assembly, which allows air in the tank to be pushed out to the pool. DE powder in the pool? If it's not a torn grid, it could be a cracked manifold, or missing air bleeder screen. It could also be loose through bolts - if the assembly is not tight, pulling the grids fully into the manifold, gaps can occur where DE can leak through to the pool.
Cartridge Pool Filter Parts
Cartridges: Pleated polyester, wrapped around a PVC core and capped with heat welded plastic caps. When the cartridge inside hole(s) are connected to the pipe out of the filter, the water has no choice but to enter through the pleats to make it's way out of the filter. Cartridge filters can fail by developing holes, or cracked or separated end caps. Blue cartridges, now available in some sizes, are made with Microban.
Cartridge Manifold: These are used when there is more than one cartridge in the filter, these manifolds are used to direct the water out of the filter tank, after it has been pushed through the filter cartridge. Cracks in the manifold, or not having the cartridge pushed down firmly enough into place, will cause water to bypass the filter cartridge.
Parts Common to all Pool Filter Types
Pressure Gauges: Pressure gauges tell you how the filter is operating. Every filter will have it's own unique pressure reading. Some filters normally run low, under 5 lbs, and some filters run high pressure, over 25 lbs. Whatever your start-up pressure is, the filter needs cleaning when the pressure reading is 5-10 lbs higher. Gauges are cheap instruments and break often, so always be suspect. The gauge should return to zero when the pump shuts off. Bent faces or dials can distort the reading, as can small bits of rust inside the gauge. I like to give them a fingernail flick, to be sure I see the needle bounce.
Bulkheads: A bulkhead is a flanged assembly around a hole in a pool filter tank. Under high pressure, the pipes entering and exiting the filter tank must connect to a sturdy flange design. Bulkheads are not usually troublesome, but if you see cracks or leaks, it would be best to replace the parts needed.
Clamp Bands: Most DE and Cartridge pool filters have a split tank design with a heavy duty clamp band used to hold together the tank halves, against high pressure. Clamp and nut design have changed over the years, becoming much larger and much safer. Replace a clamp band if it becomes cracked or weld joints loosen, or if the clamp bolt becomes stripped. Top mount sand filters use a smaller clamp and flange arrangement to hold the valve to the top of the tank.