Midco 400B-02 - Manual (Page 11)

1. TURN (DEPRESS) MANUAL GAS COCK KNOB ON COMBINATION VALVE TO OFF.
2. TURN BURNER POWER ON. SET THERMOSTAT OR OPERATING CONTROL TO
CALL FOR HEAT. LET MOTOR RUN 5 MINUTES TO PURGE COMBUSTION
CHAMBER AND CHIMNEY.
3. SET OPERATING CONTROL TO OFF OR THERMOSTAT BELOW ROOM
TEMPERATURE.
4. TURN MANUAL GAS COCK KNOB ON COMBINATION VALVE TO PILOT.
DEPRESS KNOB, OR RED BUTTON IF SO EQUIPPED, AND HOLD.
5. PUSH PIEZO IGNITOR BUTTON SEVERAL TIMES TO LIGHT THE PILOT.
6. AFTER ONE MINUTE, RELEASE MANUAL GAS COCK KNOB ON COMBINATION
VALVE, OR RED BUTTON IF SO EQUIPPED, AND TURN TO ON.
7. ADJUST THERMOSTAT OR OPERATING CONTROL TO DESIRED SETTING.
TO SHUT OFF
1. TURN (DEPRESS) MANUAL GAS COCK KNOB ON COMBINATION VALVE TO OFF.
2. TURN BURNER POWER OFF.
SHOULD OVERHEATING OF THE GAS UTILIZATION EQUIPMENT OCCUR:
1. SHUT OFF THE MAIN MANUAL SHUT-OFF VALVE TO THE EQUIPMENT.
2. DO NOT SHUT OFF THE POWER SWITCH TO THE ECONOMITE BURNER, OR THE
EQUIPMENT PUMP OR BLOWER.
Make sure the thermostat and operating controls are calling for heat. Defective wiring or loose
connections can simulate the component defects outlined below. Check associated wiring before
replacing a component. ELECTRICAL AND FLAME CHECKS MUST BE MADE IN ORDER LIST-
ED.
A. Manual Gas Cock Knob on Combination Valve, or red button if so equipped, is not
depressed in the PILOT position.
B. Main Manual Shut-Off Valve is not in open position.
C. Air in pilot gas line (See Section VIII Initial Start-up/Adjustment).
D. High or low pilot flame gas pressure (See Section IX Venturi Casting and Pilot).
E. Clogged pilot orifice(s) (See Section IX Venturi Casting and Pilot).
F. Defective ignitor, ignitor wires, spark rod or improper spark gap (See Figure 8).
G.Excessively high or negative draft condition (See Section I Ventilation and Section IV
Chimney, Vent Connector and Draft Control).
A. Excessively high or negative draft condition (See Section I Ventilation and Section IV
Chimney, Vent Connector and Draft Control).
B. High or low pilot flame gas pressure ( See Section IX Venturi Casting and Pilot).
C. Burner tube extends into combustion chamber (See Section III Combustion Chamber).
D. Lint or dust in pilot (See Section IX Venturi Casting and Pilot).
E. Clogged pilot orifice(s) (See Section IX Venturi Casting and Pilot).
F. Defective thermocouple (See Section IX Venturi Casting and Pilot).
G.Defective pilotstat safety control (See Section IX Venturi Casting and Pilot).
H.
Clogged pilot filter in Combination Valve; entire valve must be replaced.
A. Confirm 120V between strip terminals 1 and 2 and verify the circuit polarity and electrical
ground between strip terminal 1 and burner chassis metal.
B. Check 24V* operating control circuit;
1. Between left strip terminal T and GND.
a. No voltage, transformer defective.
b. Very low voltage*, circuit overloaded or transformer defective.
2. Between right strip terminal T and GND.
No voltage, circuit between T and T is open.
C. Confirm 120V between strip terminal 2 and motor relay terminal 4:
1. No voltage, motor relay is defective.
2. Voltage present, motor is defective.
11
Lighting Instructions
Trouble Chart
I. Pilot Will Not Light
II. Pilot Goes Out
Frequently
III. Motor Will Not Run