O-ring 2" Flat Gasket

The 2" Flat Gasket is a flat-profile rubber gasket used at the heater body union on Arctic Spas — specifically the connection between the heater housing and the heater wetend. It sits between two flat mating faces and seals by compression rather than seating into a groove.

Why this seal matters: The heater wetend connection is the most thermally cycled joint in the entire spa plumbing run. Every heating cycle expands the gasket; every cool-down contracts it. Over years of cycling the rubber loses its springiness and begins to weep at the seal. Catching the leak early matters — the spot directly under the heater is also where the heater controller and high-limit sensor live, and water onto live electrical components is a real risk.

When to replace: Any time you see water around the heater body, when you're servicing the heater for any reason, or any time the existing gasket has visible compression damage, hardening, or splits at the inner edge.

How to install: Drain the spa below the heater first. Disconnect the union, remove the old gasket, clean both mating faces with a paper towel (any debris on the face will leak), and seat the new gasket flat. Hand-tighten the union; never use a wrench on a plastic spa union.

Quick tips:

• This gasket and the 2" Flat O-ring Gasket (heater unions) are similar but not identical — bring the old one to one of our three Ontario showrooms for matching if you're unsure which you need
• Replace any heater-area gaskets in pairs — they age at the same rate and you don't want to be back here in three months
• Inspect the heater itself while you're in there — scale buildup or visible corrosion is the cue to replace the heater, not just the gasket