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Sookook Corporation
2B. Check Pressure Switch
[Figure 2B-A. Air/Gas Pressure Switch]
Air Pressure Switch (PAS) Settings
This device stops the burner when the fan is malfunctioning and the combustion air is not sufficiently in-flowed.
Gas Pressure Lower Limit Switch (PGSL) Settings
When the gas supply pressure is low, the required fuel is not supplied. This device prevents the combustion of too much air caused by it. While
slowly closing the manual shutoff valve in the combustion state, check the minimum gas supply pressure for safe combustion and use the
pressure at that time as setting value. The order of detailed calibration is as follows.
- When the burner is running, measure the port pressure from the intake side of the gas filter. Slowly close the manual shutoff valve until
the measured pressure reaches 70% lower.
- Check the burner's CO emissions and if the observed value is less than 100ppm, turn the adjustment ring nut VR in Figure 2B-A until
the burner stops.
- If the CO emissions are higher than 80ppm, open the shutoff valve until the СО value reaches 100ppm and turn the adjustment ring nut
until the burner stops.
- Open the manual shutoff valve completely.
If this is not feasible on the site, set it at 70% of normal supply pressure.
Internal Leakage (PGLK) Settings
If the maximum capacity of the burner exceeds 350kW (300,000kcal/h), two gas valves shall be installed in series, this device automatically
checks the gas leakage in the valve when the burner is running.
At low pressure supply, set the pressure to 50% of the gas supply pressure. At medium pressure supply, set to 50% of the outlet pressure of
the gas governor.
Gas Pressure High Limit Switch (PGSH) Settings
The gas governor is installed when the gas supply pressure is higher than 3.3kPa (330mmH2O), If the gas pressure supplied to the burner
becomes higher than the normal range due to failure of the gas governor, incomplete combustion occurs due to excessive gas. If incomplete
combustion occurs, there is possibility of accidents such as gas duct explosion due to soot and increase of CO concentration in the exhaust
gas. The gas pressure upper limit switch is installed to prevent this.
When the gas pressure is increased over the normal operating range using the gas governor, PGSH set value shall be the pressure when the
CO concentration in the exhaust gas is 100 ppm or more, If this is not feasible on the site, set the pressure 20% higher than checked pressure
at PGSH installation in the entire burner operation range. The order of detailed calibration is as follows
- Keep the burner at maximum output.
- Turn the adjustment ring nut VR in Figure 2B-A counter clockwise until the burner stops.
- Slightly turn the adjustment ring nut counter clockwise to adjust the value displayed on the scale to be 30% higher value.
Note: After completing the adjustment, be sure to replace the clear plastic cover that was removed for adjustment at all pressure
switches..
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