Pentair Sta-Rite MasterTemp 400/Max-E-Therm 400 Natural Gas Orifice (77707-0411) filburmfg 0kW trombone style heater is

0kW trombone style heater is built for that type of setup

end cap style

filtration performance can suffer and sand may appear in the pool return lines

The SPX3210X15XEPE is a practical replacement for compatible Hayward TriStar XE systems that need renewed motor performance and cleaner long-term operation

and this Filbur FC-0419 cartridge is designed for 7CH-322 and PCS32-2W/OAD applications

Pentair Sta-Rite MasterTemp 400/Max-E-Therm 400 Natural Gas Orifice (77707-0411) filburmfg 0kW trombone style heater isThis natural gas orifice is intended for compatible 400K MasterTemp and Max E Therm heater gas systems. The part helps meter natural gas flow to support the correct burner operation for the heaters design. It may be needed during gas train service, repair after incorrect parts were installed, or fuel configuration work. Because combustion safety depends on accurate part selection and testing, service should be performed by a qualified technician.