Watts AERCO Benchmark 2.0, User Manual

Page: 33 / 97

INITIAL START-UP
4-3
4. Engage the tool’s screwdriver blade into the
regulator’s adjustment screw slot.
REGULATOR
ADJUSTMENT
TOOL (P/N 123643)
REGULATOR
ADJUSTMENT
TOOL (P/N 122643)
DIVERTER VALVE
HANDLE LOCATION
FOR PROPANE
DIVERTER VALVE
HANDLE LOCATION
FOR NATURAL GAS
CAP
GASKET
REGULATOR CAP
REGULATOR CAP
CAP GASKET
Figure 4.4
Installation of Differential Regulator
Adjustment Tools for Dual-Fuel Unit
NOTE:
For Dual Fuel Units, first perform the natural
gas combustion calibration procedures in
para. 4.3, then perform the propane
combustion calibration procedures in para.
4.4.
4.3 NATURAL GAS COMBUSTION
CALIBRATION
The Benchmark ships combustion calibrated
from the factory. Recalibration as part of a start-
up is necessary due to altitude, gas BTU
content, gas supply piping and supply
regulators. Factory test data sheets are shipped
with each unit as a reference.
It is important to perform the following procedure
as outlined. This will keep readjustments to a
minimum and provide for optimum performance .
NOTE:
If calibrating a dual fuel unit, ensure that the
diverter valve handle is set to the horizontal
position for Natural Gas before proceeding.
1. Open the water supply and return valves to
the unit and ensure that the system pumps
are running
2. Open the natural gas supply valve(s) to the
unit.
3. Using the 16” manometer, ensure that there
is adequate supply gas pressure. If using a
non-lock up regulator, static pressure should
be between 9" to 14" WC, but no higher than
14" WC. If using a lock-up style regulator,
adjust the static supply gas pressure for
approximately 9" WC.
4. Set the
ON/OFF
switch in the
OFF
position.
Turn on AC power to the unit. The display
will show LOSS OF POWER and the time
and date.
5. Set the unit to the Manual Mode by pressing
the AUTO/MAN key. A flashing Manual Fire
Rate message will be displayed with the
present rate in % . Also, the MANUAL LED
will light.
6. Adjust the rate to 0% by pressing the ▼
arrow key.
7. Set the ON/OFF switch to the ON position.
Change the fire rate to 40% using the ▲
arrow key. The unit should begin its start
sequence and fire.
8. Next, gradually increase the firing rate to
100% in 20% increments and adjust the
supply gas pressure to 7.0” for FM gas
trains and 7.4” W.C. for IRI gas trains at
100% firing rate.
9. Lower the firing rate to 40% using the
▼
arrow key. Insert the combustion analyzer
probe into the stack and allow enough time
for the combustion analyzer to settle.
Compare the measured oxygen level to the
oxygen range for inlet air temperature in
Table 1.
10. If needed, adjust the differential regulator
until the oxygen reading is within the
specified range in Table 1.