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).
