Slant/Fin Prodigy 21 KC-50 Installation And Operating Instructions Manual page 17

STEP A: CALIBRATE BLOWER AIR FLOW
Note: This step will set the air flow required at the
proper air/gas ratio for the specified input rate.
• Connect tubing to differential pressure gage as fol-
lows:
1.From Blower Outlet Pressure Fitting to GAGE
HI side.
2.From Burner Enclosure Pressure Fitting to GAGE
LO side.
FOR HIGH FIRE OPERATION:
• Set the Operation Selector Switches as follows:
Switch 1 (left)
Switch 2 (center)
Switch 3 (right)
• Turn power ON. (Red power light and amber full rate
light will come on. Blower will start.)
• Allow about 30 seconds for pressure to stabilize.
• Read gage. Reading should be 25 mm (1.00") w.c.
• Adjust as necessary. Using HI Blower Speed Adjust-
ment Pot, turn in small increments (clockwise to
increase reading or counterclockwise to decrease
the reading). Allow to stabilize between adjustments.
FOR LOW FIRE OPERATION:
• Set the Operation Selector Switch 3 to DOWN, LO
position. (Amber light goes off, green reduced rate
light comes on.)
• Allow about 30 seconds for pressure to stabilize.
• Read gage. Pressure reading should be 6.35 mm
(0.25") w.c.
• Adjust as necessary. Using LO Blower Speed
Adjustment Pot, turn in small increments (clockwise
to increase reading or counterclockwise to decrease
the reading). Allow to stabilize between adjustments.
Notes on Input Rate:
1. Refer to the Input Rate Specifications Charts on
page 2 for the appropriate input rate setting on
each model boiler.
2. If a gas meter is available, follow the Step C proce-
dure to verify the specified input rate. If a gas
meter is not available, the Step A procedure is ade-
quate for obtaining the specified input rate.
3. For altitudes between 610 and 1372 m (2,000 and
4,500 ft.), derating is not necessary.
UP MAN
DOWN CAL
UP HI
STEP B: CALIBRATE GAS VALVE
Note: This step will set the air/gas ratio for optimum
combustion. The purpose of this step is NOT to set
input rate. Follow Step A and/or Step C to adjust input.
PURPOSE OF GAS VALVE CALIBRATION IS TO
ADJUST AIR-GAS RATIO ONLY - NOT INPUT.
• Connect tubing to differential pressure gage as fol-
lows:
1. From Blower Outlet Pressure Fitting to GAGE HI
side.
2. From Gas Valve Outlet Pressure Fitting to GAGE
LO side.
• Disconnect any wires from T1, T2 and A1-A2 termi-
nals and set up a jumper wire across T1-T2 termi-
nals to control operation at boiler. Open zone valves.
FOR LOW FIRE OPERATION:
• Set the Operation Selector Switches as follows:
Switch 1 (left)
Switch 2 (center)
Switch 3 (right)
• Open manual main gas shutoff valve and turn boiler
gas valve ON.
• Place the jumper across the T1 and T2 terminals.
• After about 20 seconds, boiler will start. (Green
reduced rate light on.)
• Allow about 30 seconds for pressure to stabilize.
• Read gage. Reading should be 0 mm (0") w.c.
±0.25 mm (±0.01").
• Adjust as necessary. Remove round screw cap cov-
ering gas valve adjustment. Position screwdriver into
adjustment screw slot carefully. Observe gage while
adjusting and turn screw slowly. Turn adjustment
screw clockwise to decrease reading if over 0 set-
point. Turn adjustment screw counterclockwise to
increase reading if under 0 setpoint.
Note: Remember that the gas pressure is on the low
side of the gage. Consequently, decreasing the differ-
ential reading actually is INCREASING the gas pres-
sure reading, since the blower outlet pressure is on
the high side of the gage and not changing.
FOR HIGH FIRE OPERATION:
• Set Operation Selector Switch 3 (right) to the UP, HI
position. (Green light goes off. Amber full rate light
comes on.)
• Allow about 30 seconds for pressure to stabilize.
• Read gage. Pressure reading should be about
0 mm (0") w.c. ±1.25 mm (±0.05"). If reading slight-
ly off "zero", DO NOT re-adjust gas valve. This would
alter the more critical low setting. This step is done
only to check boiler rate switching ability.
• REPLACE SCREW COVER ON GAS VALVE
ADJUSTMENT. Double check gage reading with
cover on.
• Disconnect gage adapters and replace service fitting
caps hand tight.
• If gas meter is available, proceed to Step C to check
input rate.
• Always be sure to follow the Step E procedure to put
boiler back in Automatic Operation after any setup of
troubleshooting procedure is complete.
UP MAN
UP OP
DOWN LO
17