The matched upper and lower seals for MyWaterClub Big Blue housings — sold as a pair, because a housing needs both and mixing sizes is the usual cause of a leak.

What it does

Your housing seals against the cap on two O-rings sitting in separate grooves — a smaller one on the inner lip, a larger one below it. Both are under line pressure whenever the water is on, and both compress a little more every time you tighten the housing back up.

Over a year or two the rubber takes a permanent set: it stops springing back, hardens slightly, and stops filling the groove the way it did when new. That is when a housing that has never leaked starts weeping at the seam, usually within a day or two of a filter change.

Replacing both together restores the original seal. Replacing only one, or fitting a ring of the wrong cord thickness, leaves the joint unevenly loaded — which is why we sell them as a matched pair rather than separately.

Key benefits

• ✓Matched pair — upper and lower supplied together, no risk of ordering the wrong one
• ✓Correct cord thickness for MyWaterClub housings — the dimension most often gotten wrong
• ✓Fits both 10″ and 20″ housings — same cap, same seals
• ✓Food-grade rubber rated for potable cold water
• ✓Cheap insurance — a seal costs a fraction of the water damage a slow leak causes

How to replace them

1. Shut off the water and press the pressure-relief button on the cap.
2. Unscrew the housing with a wrench and tip out the water.
3. Lift both old O-rings out of their grooves. Note which groove each came from — the smaller ring goes on top.
4. Wipe both grooves clean. Grit left behind will hold the new ring off its seat.
5. Lightly coat the new rings with food-grade silicone grease and seat them fully, without twists.
6. Hand-tighten the housing, then a small turn with the wrench. Do not overtighten — crushing the ring shortens its life.

Turn the water on slowly and watch the seam for a minute before walking away.

Specifications

While you’re in there