Sunday, June 24, 2012

How to fix a leaking pool filter

How to fix a leaking filter

This does not cover a leak at the inlet or outlet ports, at the pressure or air relief valve, or a crack in one of the main tanks. Written by
This is a guide on fixing a leaking filter around the band or lid area and only this area.

The way the tank o-ring works is that the top and bottom half of the filter are pressed together with a rubber gasket in between them. When the filter band is tightened, a waterproof seal is created which should hold back water from leaking, even under the high pressure of a running filter.

A list of things to try will be given; try them in order, as I will go from easiest to most extreme to stop the leak.

Note: Some leaks will stop on their own. This happens when there is a small area allowing not only water to pass though but also dirt to be pushed though the filter as the pump. The dirt fills this gap, eventually stopping the leak.

Note: if the area around where the o-ring sits has cracked or a part has broken off, it may not be possible to stop the leak. One of the two halves or the entire filter will need to be replaced in this case.

1) Tighten the band around the filter
While the pump is off, tighten the band around the filter (or clamp assemblies). While rare, the lid may have loosened and slid further down on to the bottom half during normal pump operation.

Note: Over tightening can strip the blots/screws or bend the bolt. (See pic below)

Turn back on the pump and check for leaks.

2) Clean the Filter o-ring section and the band bolt
With the pump turned off, remove the band and then the tank lid.
Clean the area around where the o-ring sits, including the o-ring itself.
Clean the area of the lid and the area on the lower tank that will cover the o-ring while in place.

Also, clean the bolt and screw that holds the band together. When dirt gets into these, it can stop the bolt from tightening all the way down.

3) Use a filter lubricant

Using a filter lubricant on the o-ring itself can help the top and bottom halves of the filter tank to pull closer together.
Using the lubricant on the areas inside of the band all around filter

 and band screw will allow the band to sometimes pull tighter together than without.

Note: Always use a lubricant made for use on swimming pool filters as these were tested and will not degrade the rubber o-ring.

4) Change the filter tank o-ring
Filter o-rings can expand and shrink with normal use. New tank o-rings usually cost between $9 to $40. These can be purchased at most local swimming pool stores.

Note: If you are using a new o-ring and the filter still leaks, double check that the correct tank o-ring is being used. It is common for filter tank o-rings to look similar but have significantly different diameters.

Note: Some will say if you can rub your finger along the o-ring and get a black smudge on your finger to replace the o-ring. Instead, keep it simple- if steps 1-3 fail to stop the leak, then replace the o-ring regardless if it smudges or not.

5) Gasket maker

If all of the above failed, it is possible that either the top or bottom half to have been physically damaged or deformed. This final method should be the last resort and only used if every other method was tried and failed. Using gasket maker does not always work but it is far cheaper than replacing either the top or bottom filter tank. As the name implies, gasket maker only creates a rubber gasket; it will not glue the top half to the bottom half of the filter.

Gasket maker can be purchased from most automotive supply stores.

Apply a layer of gasket maker on a clean lower tank and new o-ring.

Place the lid (upper half) back onto the lower half and over the gasket maker.
Reattach the band and tighten.

Check the instructions for appropriate drying time. Afterwards, restart the pump and check for leaks.

At this point if the system still leaks you can try a local pool professional for a second opinion, but most likely the top, bottom or both half's will need to be replaced to stop the leak.


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  3. That's pretty nice that some of the leaks will stop on their own. Although that is nice, it might be good to still have it checked out. It's just a precaution that I think will help to check if there are is anything wrong with the pump that's causing the leak.

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