Instruction manual

Servicing should only be performed by a Qualied Service Agent

LOW FIRING RATE SETTING

Set the boiler/water heater to the low ring 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 re gas setting to achieve the CO

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 re 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 ring 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 ow,

counterclockwise rotation decreases gas ow. 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 ame voltage will be between 10-15 volts for low re and 25-32 volts for high re 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)

*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 eld 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 ring 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.