Safety Device Testing; Testing Of Safety Devices; Low Gas Pressure Test - Watts Aerco Benchmark OMM-0124 Installation And Start-Up Manual

Natural gas, propane gas and dual fuel fired modulating & condensing boilers
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Benchmark 5000-6000 Boiler Installation & Startup Manual
SECTION 5: SAFETY DEVICE TESTING
SECTION 5: SAFETY DEVICE TESTING

5.1 TESTING OF SAFETY DEVICES

Periodic safety device testing is required to ensure that the control system and safety devices
are operating properly. The boiler control system comprehensively monitors all combustion-
related safety devices before, during and after the start sequence. The tests check to ensure
that the system is operating as designed.
Operating controls and safety devices should be tested on a regular basis or following service or
replacement. All testing must conform to local codes such as ASME CSD-1.
NOTES:
MANUAL and AUTO modes of operation are required to perform the following tests. For
a complete explanation of these modes, see Section 3: Modes of Operation in the
Benchmark 5000 – 6000 Operation and Maintenance Guide, OMM-0124 (GF-208).
It is necessary to remove the front door and side panels from the unit to perform the tests
described below.
WARNING!
Electrical voltages in this system include 120, 208, 460, 575 and 24 volts AC. Power must
be removed prior to performing wire removal or other test procedures that can result in
electrical shock.

5.2 LOW GAS PRESSURE TEST

The steps and pressure setting required to check the Low Gas Pressure switch are described
below. This switch is in the normally open (N.O.) position. Refer to Figure 5-1 for the location of
the switch and where to connect the water column manometer/gauge when performing the test.
The Low Gas Pressure switch is adjustable; the instructions below set it to the correct position.
LOW Gas Pressure Test Instructions
1. Shut off the external gas supply upstream to the unit by closing the external gas supply
ball valve (not shown).
2. Remove the front panel from the boiler to access the gas train components.
3. Locate the port on the top of the Low Gas Pressure switch (see Figure 5-1) and loosen
the screw inside a few turns to open it. Do not remove this screw completely. Alternatively,
you can remove the 1/4 inch plug shown in Figure 5-1 and install a hose barb fitting in that
location.
4. Attach one end of the plastic tubing to the port or barb fitting and the other end to a 0"
W.C. to 2 psi (0 – 14 kPa) manometer.
5. Apply the reading of the manifold pressure taken in Step 15 of Section 4.5.1 (Natural Gas
train) and/or Section 4.5.2 (Propane gas train) and plug them into the following formulas,
which calculate the minimum allowable gas pressure:
Natural Gas Pressure →____ x 0.5 + 6.0 = ______ min gas pressure
Propane Gas Pressure →____ x 0.5 + 3.7 = ______ min gas pressure
6. Remove the cover from the Low Gas Pressure switch and set the dial indicator to 2 (the
minimum).
OMM-0123_E • GF-207 • 12/17/2019
Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
Page 63 of 95

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