Sheet 1597-5 Page 3
OPERATION
MAINTENANCE
Operating Sequence on Burner Start-up The Valve Proving Device becomes energized when all limits and the burner operating switch are closed. At that point, the internal motor pumps gas from the upstream side of the main safety shutoff valve into the manifold between the two safety shutoff valves. During the test period the integrated differential pressure senor moni- tors the manifold pressure. It will trip when the gas pressure between the shutoff valves is increased by approximately 8"w.c. compared to the pressure upstream of the main valve. When the test pressure is attained the motor pump switches off. The amber light on the Valve Proving Device flashes all the time to indicate that a test is in progress. If the manifold between the two safety shutoff valves has no detect- able leak, the "RUN" T5 contact is energized within less than 26 seconds. The release time is dependent on the test volume (max. 0.14 cu ft). The amber light glows continuously after the test period. If the Valve Proving Device is wired as shown in diagram 1, the contact 1CR1 (5) closes and the flame safeguard is activated. If the test pressure of 8"w.c. cannot be attained during the test period of 26 seconds the manifold between the two safety shutoff valves has a detectable leak. The amber light turns off, the red light turns on, and the "ALARM" T3 contact (3) is energized. A manual reset can be performed by pressing the red button. The Valve Proving Device will start a new test run.
Functional Test • The Valve Proving Device is a protective device. Check it at least once a month for proper operation. A recommended test procedure is: • Shut off all gas supply to the system. • Start the Valve Proving Device. • Open the screw plug in the test port 4 during the pumping time to simulate a gas leak in the manifold between the two safety shutoff valves. • If the Valve Proving Device dœs not detect the leak, immediately shut down the system, remove the Valve Proving Device, and return it to the factory for replacement. • CAUTION : All gas piping and test ports must be properly tightened before any gas is reapplied to the system. • CAUTION : Return the Valve Proving Device to the factory for repair or replacement. Do not try to repair the unit by yourself. You may interfere with its normal operation and cause a fire or explosion. If you disassemble the Valve Proving Device, you will void the approvals, the factory warranty, and exchange policies.
DMV …
pa
pe
pa
pe
V1
V2
Gas Inlet
Test Port 3 Test Port 4
Gas Outlet
VPS 504
Test Port 3
Test Port 4
Operating Sequence on Burner Start-up and Shutdown To operate the Valve Proving Device on burner start-up and shutdown, additional interface equipment has to be provided. A typical wiring is shown in diagram 2. Two additional time delayed relays are necessary to toggle the supply power to the Valve Proving Device either through the limit switches (9) on start-up or through the contacts 1TD1 and 2TD2 (2) on shutdown. The time delay should be between 2 and 5 seconds. The contact 2CR1 (13) provides a means to operate a blower in case the Valve Proving Device energizes the "ALARM" contact (3). The relay 1CR (9) initializes a Valve Proving Device test run in case the flame safeguard energizes the alarm terminal. The Valve Proving Device will start a test cycle when the main power switch (1) is closed. The contact 1TD3 (4) prevents a burner start-up without testing after the initial test.
Made with FlippingBook flipbook maker