Watts Benchmark Aerco OMM-0122 - 5.3 HIGH GAS PRESSURE TEST; 5.3.1 HIGH GAS PRESSURE TEST: BMK 750 - 2500

Benchmark 750-3000 Boiler Installation & Startup Manual
SECTION 5 – SAFETY DEVICE TESTING
OMM-0121_D • GF-205 • 5/9/2019 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page 82 of 122
5.3 HIGH GAS PRESSURE TEST
Complete the instructions in Section 5.3.1 for BMK 750 – 2500 units, or in Section 5.3.2 for BMK
3000 units, which have different High Gas Pressure switches.
5.3.1 HIGH GAS PRESSURE TEST: BMK 750 – 2500
To simulate a high gas pressure fault, refer to Figure 5-3a through 5-3c and perform the
following steps:
HIGH Gas Pressure Test Instructions: BMK 750 – 2500
1. Close the leak detection ball valve located at the High Gas Pressure switch.
2. Remove the 1/4" NPT plug from the High Gas pressure leak detection ball valve shown in
Figures 5-3a through 5-3c.
3. Install a 0 - 16” W.C. (0 – 4.0 kPa) manometer or gauge where the 1/4" plug was removed.
4. Slowly open the leak detection ball valve.
5. Press the MENU key on the C-More Controller and access the Setup
menu, enter the
password 6817 and then press the ENTER key.
6. Start the unit in MANUAL mode at a valve position (firing rate) between 25% and 30%.
7. With the unit running, monitor the gas pressure on the manometer installed in step 2 and
record the gas pressure reading.
8. Slowly increase the gas pressure using the adjustment screw on the SSOV while
counting the number of turns you make.
9. The FAULT
indicator should start flashing and the unit should shut down and display a
GAS PRESSURE fault message at approximately the value shown in Table 5-2 (the
pressure setting of the HIGH Gas Pressure switch):
TABLE 5-2: HIGH Gas Pressure ± 0.2” W.C. (± 50 Pa)
Benchmark Model
Natural Gas
Propane
BMK 750/1000 FM & DBB Single-Fuel
4.7” W.C. (1.17 KPa)
4.7” W.C. (1.17 KPa)
BMK 1500/2000 Single-Fuel
4.7” W.C. (1.17 KPa)
–
BMK 1500/2000 DBB Single-Fuel
4.7” W.C. (1.17 KPa)
–
BMK 1500/2000 Dual-Fuel
4.7” W.C. (1.17 KPa)
4.7” W.C. (1.17 KPa)
BMK 1500/2000 DBB Dual-Fuel
3.5” W.C. (0.87 kPa)
3.5” W.C. (0.87 kPa)
BMK 2500 FM & DBB Single-Fuel
3.0” W.C. (0.75 kPa)
–
BMK 2500 Dual-Fuel
7.0” W.C. (1,74 kPa)
2.6” W.C. (0.65 kPa)
BMK 2500 DBB Dual-Fuel
7.0” W.C. (1,74 kPa)
2.6” W.C. (0.65 kPa)
BMK 3000 FM & DBB Single-Fuel
3.0” W.C. (0.75 kPa)
–
BMK 3000 Dual-Fuel
6.6” W.C. (1,64 kPa)
2.6” W.C. (0.65 kPa)
BMK 3000 DBB Dual-Fuel
6.6” W.C. (1,64 kPa)
2.6” W.C. (0.65 kPa)
10. Reduce the gas pressure
by returning the SSOV adjustment screw back to its position
before starting step 7 (the value recorded in step 6). This pressure should be within the
range used during combustion calibration, shown in Table 4-1 (Natural Gas) and Table 4-4
(Propane gas).