Low Gas Pressure Test; Low Gas Pressure Test: Bmk750 - 2500 - Watts AERCO Benchmark BMK5000 Operation And Service Manual

Benchmark Platinum-Edge [ii]: Operation-Service Manual
SECTION 5 – SAFETY DEVICE TESTING

5.2 LOW GAS PRESSURE TEST

Complete the instructions in Section 5.2.1 for BMK750 – 2500 units, or in Section 5.2.2 for
BMK3000 – 6000 units, which have different Low and High Gas Pressure switches.
5.2.1 Low Gas Pressure Test: BMK750 – 2500
To simulate a low gas pressure fault, refer to Figure 5-1a to 5-1c and perform the following
steps:
LOW Gas Pressure Test Instructions: BMK750 – 2500
1. Remove the front panel from the boiler to access the gas train components.
2. Close the leak detection ball valve located at the Low Gas Pressure switch.
3. Remove the 1/4" NPT plug from the ball valve at the Low Gas Pressure switch.
4. Install a 0 - 16" W.C. (0 – 4.0 kPa) manometer or gauge where the 1/4" plug was removed.
5. Slowly open the 1/4" ball valve near the Low Gas Pressure switch.
6. On the Controller, go to
7. Enable the Manual Mode parameter. The Comm LED will go off and the MANUAL LED
will light.
8. Adjust the Air/Fuel Valve position between 25% and 30% using the + (Plus) and – (Minus)
controls.
9. While the unit is firing, slowly close the external manual gas shut-off valve upstream of the
unit (not shown).
10. The unit should shut down and display a Fault Lockout - Gas Pressure Fault message at
approximately the pressure shown in Table 5-1 (the pressure setting of the Low Gas
Pressure switch):
TABLE 5-1: LOW Gas Pressure, ± 0.2" W.C. (± 50 Pa)
Benchmark Model
BMK750/1000 FM SINGLE-Fuel
BMK750/1000 DUAL-Fuel
BMK1500/2000 FM & DBB Single-Fuel
BMK1500/2000 Dual-Fuel
BMK1500/2000 DBB Dual-Fuel
BMK2500 FM & DBB Single-Fuel
BMK2500 Dual-Fuel
BMK2500 DBB Dual-Fuel
11. Close the ball valve near the Low Gas Pressure switch (opened in Step 5).
12. Fully open the external manual gas shut-off valve (not shown) and press the Controller's
CLEAR button.
13. The fault message should clear, the FAULT indicator should go off, and the unit should
restart.
14. Upon test completion, close the ball valve, remove the manometer and replace the 1/4"
NPT plug removed in step 3.
OMM-0137_J •
12/20/2022
Main Menu → Diagnostics → Manual
2.6" W.C. (648 Pa)
5.2" W.C. (1294 Pa)
3.6" W.C. (896 Pa)
4.4" W.C. (1,096 Pa) 2.6" W.C. (648 Pa)
2.6" W.C. (648 Pa)
3.6" W.C. (896 Pa)
7.5" W.C. (1,868 Pa) 3.6" W.C. (897 Pa)
7.5" W.C. (1,868 Pa) 3.6" W.C. (897 Pa)
Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
Run.
Natural Gas
7.5" W.C. (1,868 Pa)
5.2" W.C. (1294 Pa)
–
2.6" W.C. (648 Pa)
–
Propane
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