Velocity K2WTC-135, Installation, Operating And Service Instructions

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99
107774-02- 4/18
XII. Start-Up and Checkout
(continued)
To return the boiler to automatic modulation, press AUTO FIRE. Note: If the Auto Fire button is not pressed,
boiler will remain in manual fire for around 10 minutes. After 10 minutes boiler automatically returns to auto-
matic modulation.
At both high and low fire, CO readings should be less than 200 PPM air free. Typical CO
2
and O
2
readings are
shown in Table 12.5A. Final readings should be taken with all doors and covers in place. If adjustments are
needed, make them as follows:
a. With burner at high fire, adjust gas valve throttle (Fig 12.4) as needed to obtain CO
2
(or O
2
) setting shown
in Table 12.5A.
• To reduce the CO
2
(increase the O
2
), turn throttle clockwise.
• To increase the CO
2
(reduce the O
2
), turn throttle counter-clockwise.
Make adjustments in increments of 1/8 to 1/4 turns and allow the boiler at least a minute to respond before
making another adjustment.
b. With the burner at low fire, adjust gas valve offset regulator (Fig 12.4) as needed to obtain CO
2
(or O
2
)
setting shown in Table 12.5A.
• To reduce the CO
2
(increase the O
2
), turn offset regulator counter-clockwise.
• T o increase the CO
2
(reduce the O
2
), turn offset regulator clockwise.
Make adjustments in increments of no more than 1/8 turns and allow the boiler at least a minute to
respond before making another adjustment.
17. Perform a check of the ignition safety shut-off device. With the burner firing, carefully unplug the orange
flame rod wire at the flame rod using a pair of insulated pliers (Figure 12.1). The burner should shut
off immediately.
18. Test any external limits or other controls in accordance with the manufacturer’s instructions.
19. Refer to the Operation Manual to set-up the control for the system in which the boiler is installed. Some
common set-up tasks include:
• Setting the CH temperature set-point.
• Defining the system pump operation.
20. Adjust the heating thermostat to its final set point.
WARNING Improper gas valve adjustments can result in unreliable operation, substantial property
damage, personal injury or loss of life due to carbon monoxide (CO) poisoning. Observe the following
precautions:
• Do not attempt to adjust gas valve without a combustion analyzer.
• Each boiler is tested at the factory and adjustments to the gas valve are normally not necessary when
operating on natural gas at sea level. Before making any adjustments, make sure that the analyzer is
calibrated and that combustion readings have stabilized.
• Regulator (“offset”) screw used for low fire adjustment is very sensitive. Adjust no more than 1/8
turn before checking combustion with analyzer. Maximum total regulator adjustment is ± 1 turn from
factory setting.