The L404F should always be mounted above the water line in steam boiler applications. NOTE: For accurate operation, supplemental heat should be added to installations where temperatures fall below -29°C (-20°F). A steam trap must be connected between the L404F and the boiler (see Fig. 2) to prevent boiler scale and corrosive vapors from attacking the elbows or diaphragm. PRESSURE GAUGE 4-1/2 TO 5-1/2 (114.3 TO 139.7) BOILER STEAM TRAP (SIPHON LOOP) TEE PRESSURE CONTROLLER 1 1 1/4 IN. PIPE WITH 1

L404T,V PressureTrol® Controllers are for use on oil burner systems for pressures up to 1035 kPa or 150 psi. PRODUCT DATA FEATURES • Models available in a series of control ranges, and pressure scales in kPa and psi. • All models automatically reset and have an adjustabledifferential. • Models have snap switch to open or close a circuit ona pressure rise. • Case has a clear plastic cover so setpoints can beobserved. • 1/4 inch—18 NPT connection for pipe on diaphragm assembly. • Ground screw term

The high oil pressure controller should be located as near to the burner as possible. Mounting Mount the oil pressure controller directly on the main pipe. Insert a tee in the pipe line, and connect a pipe nipple of appropriate size to the tee (see Fig. 4). Screw the hexagonal fitting (1/4-18 NPT internal thread) of the pressure controller to the pipe nipple. To avoid leaks and damage to the case, use a parallel jaw wrench on the hexagonal fitting close to the pipe nipple. Do not tighten the pre