Amtrol 110-P/1-1/4 FILL-TROL Expansion Tank, 4.4 Gallon (110-10) The Amtrol FILL-TROL 110-P/1-1/4 Expansion Tank system consists of a specially adapted EXTROL pre-pressurized, diaphragm-type expansion tank, the FILL-TROL, a specially designed, automatic, pressure-reducing fill valve, Purger, and Vent. • Provides accurate system make up • Fully Adjustable up to a maximum working pressure of 100 psig • Factory pre-charged to 12 psig Amtrol FILL-TROL 110-P/1 Expansion Tank Specifications: • Model Number - 110-P/1 • Tank Volume (Gallons) - 4.4 • Max. Accept. Volume (Gallons) - 2.5 • A Height (Inches) - 17-3/8 • B Diameter (Inches) - 11 • System Conn. (NPTF) - 1-1/4 • Air Purge: 444 • Air Vent: 700-C • Maximum Working Pressure = 100 PSIG • Maximum Operating Temperature = 240°F • Factory Precharge = 12 PSIG How the Amtrol FILL-TROL 110-P/1-1/4 Expansion Tank System Works: Water enters the FILL-TROL valve, pushing open the check valve, and flows into the heating system. The automatic shut-off valve is kept open by the diaphragm pressing against the pressure plate, raising the stem of the fill gate, which compresses the automatic shut-off valve spring. When the heating system reaches fill pressure (12 psig), the tank's diaphragm depresses, and the automatic shut-off valve is closed. Whenever system pressure falls below 12 psig, the automatic shut-off valve is pressed open by the diaphragm. Make-up water flows into the system to restore pressure."