How to Break Down and Service a Purex-Triton Nautilus FNS DE Filter - Dengarden - Home and Garden
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How to Break Down and Service a Purex-Triton Nautilus FNS DE Filter

Rob is a pool-service industry professional with over 20 years of experience.

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Servicing DE Filters

It is recommended that DE filters be dismantled and inspected at least once per year— ideally, every 6 months to prevent DE powder "blow-back." Blow-back occurs when a filter is back washed, DE is then added, and most, or all of the DE, ends up in the pool rather than coating the grids and staying in the filter. This can be caused by a number of reasons:

  • Build up: Too much DE can build up over time and back-washing no longer pushes the old DE off of the filter grids when the flow is reversed during the back-wash cycle.
  • Torn Grids: When a filter grid is torn, DE powder will escape through the tear. Very minor tears will still allow the filter to hold DE. Normally when a minor tear in a grid happens, It's usually not long after that other grids begin to tear as well. Although individual grids can be purchased, It's recommended to replace to replace the entire set.
  • Manifold: The manifold on the top of the grid assembly directs flow through the grids. These can crack and allow most, if not all of the DE powder to blow back into the pool. In this case, the manifold will need to be replaced.

Dismantling the Filter

Be sure the pool pump won't come on. Shut timer off, or "service mode" in automated systems. Service mode isn't usually accessible from the remote. Will need to execute service mode from the outside control panel.

Remove the Drain Plug

Drain Plug is located on the bottom of of the filter, in back.

Drain Plug is located on the bottom of of the filter, in back.

Remove the 2 Side Bolts

There are two 7/8" band clamp bolts. One on each side. Loosen one of them, and remove the other

There are two 7/8" band clamp bolts. One on each side. Loosen one of them, and remove the other

Remove the Lid

These grids have severe DE build-up. This was causing the "blow-back" to the pool/spa returns.

These grids have severe DE build-up. This was causing the "blow-back" to the pool/spa returns.

Rinse the Tank Out

Remove the grid assembly set it aside

Remove the grid assembly set it aside

Cleaning the Grid Assembly

There's no need for using any harsh chemicals to clean the filter grids. Just rinse the grids with a good jet nozzle on the hose. Do NOT take the grid assembly apart unless you like puzzles. Can be a bit of a hassle to re-assemble. When the grid assembly is clean it will need inspected. Look for cracks on the Manifold (top large plastic piece that holds the grid assembly together) Also be sure to inspect the grids themselves and look for rips or tears in the material.

Clean the Grids

Rinse the entire grid assembly clean. This can take awhile since there is build up in the center as well.

Rinse the entire grid assembly clean. This can take awhile since there is build up in the center as well.

Re-Assembling the Filter

There is an inner metal ring on the inside perimeter of the lower half of the filter, the split point. The rubber o-ring is wrapped around this metal ring. Remove both from the filter and rinse clean both the metal ring and o-ring. Rinse the split point on the filter housing of any loose debris.

O-Ring and Inner Metal Ring

Rinse clean the o-ring, metal ring, and split point on the housing

Rinse clean the o-ring, metal ring, and split point on the housing

Replace the Grid Assembly

Line the grid assembly up correctly and replace. Make sure the manifold sits deep enough on the return pipe.

Line the grid assembly up correctly and replace. Make sure the manifold sits deep enough on the return pipe.

Before Replacing the Lid

Make sure that the o-ring is lubricated with a sealant/lubricant specifically designed and manufactured for swimming pool equipment. Set the lid on and turn lid slightly right and left to set the lid well into the lubricated o-ring. Replace the band clamp and tighten both bolts on each side of the filter housing. Replace the drain plug on the back of the filter. Close air relief valve.

Clean Filter Pressure

Take note of what the pressure (PSI) is after pump is running and fresh DE powder has been added. This is the "clean" filter pressure. Backwash when PSI exceeds more than 5 PSI over clean filter pressure.

Take note of what the pressure (PSI) is after pump is running and fresh DE powder has been added. This is the "clean" filter pressure. Backwash when PSI exceeds more than 5 PSI over clean filter pressure.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

© 2018 Rob Hampton

Comments

Rob Hampton (author) from Port Richey, Florida on January 14, 2019:

csr@BorderTransportationSystem.com....

The o-ring can be found here..

https://www.amazon.com/Pentair-195008-Ring-Replace...

Also, if you can't lift the grid assembly out, you should still be able to clean the grids but won't be able to inspect them for damage. Move grid assembly back and forth while pulling upwards and should be able to remove it.

csr@BorderTransportationSystem.com on January 13, 2019:

The grid will not lift out. Afraid to put too much vertical pull on it so as to not break the pipe. Second, after cleaning everything and putting the O-ring and top back on, it leaks water at 20+ PSI. Used Silicon Plumbers lube on all sides of the O-ring, and tightened the band to specs. Now seeking NEW O-ring and find that Purex Triton Nautilus FNS 36 parts do not exist under this name. suggestions?