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Benchmark 750-3000 Boiler Installation & Startup Manual
SECTION 5 – SAFETY DEVICE TESTING
HIGH Gas Pressure Test Instructions: BMK 750 – 2500
1/4" NPT
PLUG
(install
manometer
here for HIGH
GAS
PRESSURE
FAULT TEST)
HIGH GAS
BALL VALVE
MANUAL
SHUT-OFF
VALVE
Figure 5-3c:
5.3.2 HIGH GAS PRESSURE TEST: BMK 3000 Only
To simulate a high gas pressure fault, refer to Figure 5-4 and perform the following steps:
HIGH Gas Pressure Test Instructions: BMK 3000 ONLY
1. Locate the port on the side of the High Gas Pressure switch (see Figure 5-4, below) and
loosen the screw in the port a few turns to open it. Do not completely remove the screw.
Alternatively, you can remove the 1/4 inch plug shown in Figure 5-4 and install a hose barb
fitting in that location.
2. Attach one end of the plastic tubing to the port or barb fitting and the other end to a 0 – 16"
W.C. (0 – 4.0 kPa) manometer.
3. Apply the reading of the manifold pressure taken in Step 15 of section 4.4.1 (natural gas
units) or Step 15 of section 4.4.2 (propane units) and plug it into the following formula,
which calculates the maximum allowable gas pressure:
•
Gas Pressure ______ x 1.5 = ______ max gas pressure
4. Remove the cover from the High Gas Pressure switch and set the dial indicator to 20
(the maximum).
5. Open the external gas supply ball valve upstream of the unit.
6. Press the MENU key on the C-More Controller and access the Setup menu, enter the
password 6817 and then press the ENTER key.
7. Start the unit in MANUAL mode and adjust the Air/Fuel Valve position to bring the unit up
to 100%.
OMM-0121_D • GF-205 • 5/9/2019
HIGH GAS
PRESSURE
SWITCH
TO
AIR/FUEL
VALVE
HIGH Gas Pressure Fault Test
BMK 2500:
Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
NATURAL
GAS INLET
SSOV
LOW GAS
PRESSURE
SWITCH
Page 84 of 122
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