A.O. Smith 100 Series, Руководство по обслуживанию

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Servicing should only be performed by a Qualified Service Agent
LOW FIRING RATE SETTING
Set the boiler/water heater to the low firing rate by setting the Low Firing Rate RPM as described below. Check combustion readings
using a combustion analyzer. If combustion readings are not in accordance with the chart shown below adjust as follows: remove
the cap on the gas regulator using a slotted screwdriver. For more information, refer to the Instruction Manual. This will expose the
offset adjustment screw. Using a TORX
®
T40 or a 5 mm hex wrench, carefully adjust the low fire gas setting to achieve the CO
2
level
prescribed in Table 8.
Adjustments to the offset pressure regulators should not exceed 1/4 turn at a time before allowing the readings to respond and
stabilize.
After proper low fire offset adjustment is made, reinstall the slotted cap on the regulator.
Following all gas valve adjustments, check for proper light-off and verify correct fuel/air mix and combustion quality throughout the
entire firing range (from lowest to highest fan speed).
Note: The rotation of the Low Fire adjustment is opposite of the High Fire as follows: Clockwise rotation increases gas flow,
counterclockwise rotation decreases gas flow. Make sure the Manual Mode is set back to Automatic Mode to each of the burners,
once the required settings are done. Turn off the individual burner before proceeding to the next burner settings. Depending on the
boiler/water heater size and capacity, the flame voltage will be between 10-15 volts for low fire and 25-32 volts for high fire settings.
Check for gas valve settings and combustion for varied voltage levels.
TABLE 8. LOW FIRE RATE SETTING
MODELS (XB/XW)
RPM
(APPROXIMATE FACTORY SET)
CO
2
*MANIFOLD PRESSURE
INCHES W.C (KPA)
NATURAL
GAS
PROPANE NATURAL
GAS
PROPANE NATURAL GAS PROPANE
1000 1650 1540 7.3 - 8.2% 8.4 - 8.8% -0.3 (-0.07) -0.25 (-0.06)
1300 1650 1600 7.3 - 8.2% 8.4 - 8.8% -0.2 (-0.05) -0.14 (-0.03)
1700 1700 1700 7.3 - 8.2% 8.4 - 8.8% -0.2 (-0.05) -0.23 (-0.05)
2000 1550 1540 7.3 - 8.2% 8.4 - 8.8% -0.3 (-0.07) -0.31 (-0.07)
2600 1700 1600 7.3 - 8.2% 8.4 - 8.8% -0.2 (-0.05) -0.14 (-0.03)
3400 1700 1700 7.3 - 8.2% 8.4 - 8.8% -0.2 (-0.05) -0.23 (-0.05)
* NOTE: Values listed in Table 7 and Table 8 are tested under laboratory conditions with minimum vent length. Values may slightly vary
depending on ambient conditions and field equipment accuracy.
TURNING THE BOILER/WATER HEATER OFF
NEVER TURN OFF POWER TO THE BOILER/WATER HEATER WHILE IT IS FIRING unless an emergency shut down is required.
Repeated sudden stops while firing can damage the boiler/water heater. To shut down the boiler/water heater safely do one of the
following so the boiler/water heater can go through a normal shut down sequence with post purge cycles that cool down the Heat
Exchanger and purge the combustion chamber:
• Lower the Operating Set Point to it’s lowest setting.
• Lower the set point of the external Primary System Control in use to it’s lowest setting.
• Then turn the boiler/water heater off using the Lead Lag Master switch on the display.