Pentair Coil/Tubesheet Sealing O-Ring Kit | Max-E-Therm 400 & MasterTemp 400 Heaters | 77707-0119 PS3868 locate the date code on

locate the date code on your heater's rating label — typically found on the inside of the heater cabinet door or on the rear panel

The Pentair Seal Diffuser (355030Z) is the OEM replacement seal diffuser for the Challenger High Flow

confirm the part number stamped or molded on your existing hose cone matches K121110

Replacing worn or cracked unions at service time restores a leak-free seal at the pump's plumbing connections

no compromises

Pentair Coil/Tubesheet Sealing O-Ring Kit | Max-E-Therm 400 & MasterTemp 400 Heaters | 77707-0119 PS3868 locate the date code onThe Pentair Coil Tubesheet Sealing O Ring Kit (77707 0119) is the OEM replacement O ring set for the water system coil and tubesheet sealing points in the Max E Therm 400 and MasterTemp 400 series heaters. This kit contains 12 O rings the complete set required to service all coil tubesheet sealing positions in the 400 model heat exchanger assembly. IMPORTANT: KIT OF 12 O RINGS NOT A SINGLE PIECE This listing is a kit of 12 O rings. All 12 are required