21
Figure 23: Main Burner Flame
3. Main burners and pilot burner will extinguish and
blower stop when water pressure drops below 10
psi. Verify limit, thermostat or other controls have
not shut off boiler.
4. Close drain valve.
5. Adjust thermostat to lowest setting. Refi ll boiler.
L. Check Boiler High Limit.
1. Adjust thermostat to highest setting.
2. Observe temperature gauge. When temperature is
indicated, adjust limit to setting below observed
temperature. Main burners and pilot burner should
extinguish, and blower stop.
3. Adjust limit to setting above observed temperature.
Ignition sequence should begin.
4. Adjust thermostat to lowest setting. Adjust limit to
desired setting, at least 20°F above the tank aquastat
setting.
M. Adjust gas input rate to boiler.
1. Adjust thermostat to highest setting.
2. Check manifold gas pressure. Pressure should be
stamped on the rating label located in the boiler's
vestibule compartment. Adjust gas valve pressure
regulator as necessary (turn adjustment screw
counterclockwise to decrease manifold pressure, or
clockwise to increase manifold pressure). If pressure
cannot be attained, check gas valve inlet pressure. If
less than minimum indicated on the boiler's rating
label, contact gas supplier for assistance.
3. Clock gas meter for at least 30 seconds. Use Table 9
to determine gas fl ow rate in Cubic Feet per Hour.
Figure 24: Pilot Burner Flame
20°F below boiler high limit setting to allow tank water
to reach desired temperature before boiler water reaches
the high limit setting.
J. Ignition system safety device test. Disconnect ignitor/
sensor cable from Terminal 9 (SPARK). Gas valve
should close and pilot and main burners should
extinguish.
K. Check water pressure switch.
1. Adjust thermostat to highest setting.
2. Connect hose to drain valve and run to bucket or
fl oor drain. With boiler operating, partially open
drain valve and slowly drain boiler.