SECTION 3: START-UP & OPERATION

SEQUENCE OF OPERATION

For sequence of operation of the particular boiler being installed, refer to Figures 2.13 through 2.18 in Section 2 of this manual.

Spill and rollout switches are mounted on Model GB250-5L, GB250-5H, and GB250-6 boilers.

For boilers with a spill switch, the switch detects the escape of combustion products through the draft diverter relief opening and interrupts the power to the gas valve preventing unsafe boiler operation. Escape of flue products could be caused by a blocked or collapsed chimney or inadequate chimney draft. This is a manual reset-type device and can be reactivated by depressing the spill switch reset button mounted on the left of the boiler’s draft hood (see Figure 2.1 for switch location).

For boilers with a flame rollout switch, the switch prevents flame rollout from the boiler combustion chamber, caused by blocked boiler flue passageways, by interrupting power to the gas valve to prevent unsafe boiler operation. This is a manual reset-type device and can be reactivated by depressing the rollout switch reset button mounted on the lower front jacket panel. Flue passages must be inspected by a qualified installer if this problem occurs, prior to resetting the button.

WARNING: If boiler cannot be restored to normal operation after re-setting of spill switch, or if flame rollout switch has tripped, do not attempt to put the boiler in operation. Immediately contact a qualified service professional.

PRESSURE

PRESSURE

CONTROL

RELIEF VALVE

PRESSURE

 

GAUGE

 

 

WATER

 

LEVEL

 

INDICATOR

GAS VALVE

FIGURE 3.1

PRIOR TO START-UP

Fill system with water until the water level indicator (sight glass) is approximately 2/3 full. This water level is 23" from the surface on which the boiler sits.

SYSTEM START-UP & ADJUSTMENTS

Safe lighting and other performance criteria were met with the gas manifold and control assembly provided on the boiler when the boiler underwent tests specified in ANSI Z21.13.

WARNING: Keep boiler area clear and free from combustible materials, gasoline and other flammable vapors and liquids. Otherwise fire or explosion may result.

1.Check combination gas valve on boiler and make sure it is in the OFF position.

2. For vent damper-equipped models, with the thermostat set to call for heat, observe that vent damper position indicator rotates to the open position. Damper must be in the open position when appliance main burner is operating.

a. After damper opens, spark should appear at the pilot ignition electrodes.

b.Set thermostat to no longer call for heat. Spark should stop. Observe that damper position indicator rotates to the closed position.

c. Set thermostat to call for heat.

3.Light the boiler. For Model GB250 boilers with standing pilot see lighting instructions for Continuous Pilot on page 18. For Model GB250 boilers with intermittent pilot, see lighting instructions for Intermittent Pilot on page 18.

4.Observe pilot and main burner flame (see Figure 3.2). All burner ports should be ignited and burn with a steady blue flame.

 

FIGURE 3.2

Q3451B

Q314A/Q309A

INTERMITTENT

CONSTANT PILOT

IGNITION PILOT

MODELS

MODELS

 

NORMAL PILOT FLAME

NORMAL

LIFTING

YELLOW

YELLOW

(HARD FLAME) (TOO MUCH AIR)

TIPPING

FLAME

 

 

(MARGINAL)

(TOO LITTLE AIR)

MAIN BURNER FLAMES

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