LDU11说明书.pdf

7696 Automatic Valve Proving Control LDU11 ISO 9001 UL recognized FM approved Features • Performs leak test of the gas shut-off valves before start-up and/or immediately after burner shut-down • No inlet gas pressure limitations • Easy-to-read dial indicates progress of test program • Ability to eliminate or leak test the vent valve • Cost effective control improves system safety • Globally Approved – cULus, FM, CE Application The LDU11... control detects leakage of the shut-off valves on gas trains with two safety shutoff valves. During each burner cycle, the LDU control unit automatically sequences, and if a leak is detected, initiates a lockout and prevents the burner from starting up. Function The LDU11 (or control unit) is used in a gas-fired combustion system with or without a vent valve in the gas train. Installed with one or two pressure switches mounted between the gas valves, the LDU automatically initiates gas valve proving either • prior to burner start-up • immediately after the controlled shutdown, or • both prior to burner start-up and immediately after shutdown The valve leak test is completed in two stages: • First test phase «Test1»,