Midco EC200 & EC300 - Manual (Page 14)

Midco ® International Inc. - 4140 West Victoria Street - Chicago, Illinois 60646 - toll free: 866 705 0514
tel: 773.604.8700 - fax: 773.604.4070 - web: www.midcointernational.com - e-mail: [email protected] 14
Printed in USA
8471 38
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Trouble Chart
NOTE: ELECTRICAL AND FLAME CHECKS MUST BE MADE IN ORDER LISTED.
1. Check status of electronic burner control diagnostic indictor LED.
A. LED On = electronic burner control fault.
B. 1 fl ash = air fl ow fault.
C. 2 fl ashes = fl ame with no call for heat.
D. 3 fl ashes = ignition lockout.
2. Confi rm that both main manual shut off valve and manual gas cock knob on combination gas
valve are in the ON position. Make sure that the thermostat, operating controls and safety
controls are calling for heat. Defective wiring or loose connections can simulate malfunctioning
components: or any of the conditions below. Check associated wiring and connectors before
replacing a component. Whenever the burner fails to light during the seven second trial for
ignition, or if the fl ame is lost during the burner run cycle and not re-established within 37
seconds (30 second pre-purge), the electronic burner control will shut OFF the combination gas
valve and lockout the burner. To reset, set the operating control to OFF or thermostat below set
point for at least 30 seconds.
3. Confi rm that:
A. Burner is properly grounded (Green wire to ground).
B. Line voltage is present between L1 (Black wire) and L2 (White wire). If not present, check
line power source.
C. Line voltage is present between L1 (Black wire) and Ground (Green wire).
D. There is no voltage present between L2 (White wire) and Ground (Green wire)
4. Confi rm that 24V is present at:
A. Transformer, 24V secondary side (Yellow wires). If not present, replace transformer
B. R terminal on electronic burner control and Ground.
C. First Blue wire in electrical box labeled “T” (thermostat) and Ground, second Blue wire in
electrical box labeled “T” (thermostat) and Ground. If power is only present at one Blue
wire, check thermostat and thermostat wiring.
D. TH terminal on electronic burner control and Ground. If no power is present at TH terminal,
check thermostat and thermostat wiring.
5. Blower motor should now be ON. If ON, proceed to step 7. If not ON:
A.
Confi rm that line power is present at IND wires at the electronic burner control
NOTE: IND wires exit the back side of the electronic burner control and one IND wire goes to the
line power hot side of the blower motor (White and Blue wires for 115V, White and Black wires
for 230V).
B. Confi rm that line power neutral (L2, White wire) is connected to motor neutral wires
(Orange and Black wires for 115V, Orange and Blue wires for 230V). Line power is being
delivered to the blower motor and it is not running, replace the blower motor.
6. With blower motor running, confi rm that 24V power is present at PSW terminal on the
electronic burner control and Ground. If power is not present, check wires and wire connections
of the internal motor interlock switch (2 red wires exiting the motor). If the blower motor is
running and the internal blower motor interlock switch is open, replace the blower motor.
7. After 30 second blower motor pre-purge, confi rm 24V power at V1 terminal on electronic burner
control and Ground. If power is not present, replace electronic burner control.
NOTE: After the pre-purge period, the controller will simultaneously energize the gas valve and send
power to the spark rod, causing an ignition spark at the end of the rod.
CAUTION: Spark generating circuit is HIGH VOLTAGE !
If an ignition spark is not present at the tip of the spark rod, turn the power supply OFF. Inspect
ignition wire/connectors, spark rod, spark rod positioning, spark rod gap and spark rod ceramic
insulator. Adjust, repair or replace as necessary. If an ignition spark is still not present, perform
a spark test on the electronic burner control per the electronic burner control manufacturers
recommendations. If spark test fails, replace electronic burner control.
8. Once ignition spark is present, main fl ame should be present. If not present:
A.
Confi rm that there is no air in gas line. If so, purge air from gas line.
B. Confi rm that 24V power is being delivered to the gas valve (V1 and V2 on electronic burner
control).
C. Check for adequate fl ame current signal strength with an electrical meter (Refer to the
electronic burner control manufacturers specifi cation sheet that is supplied with the burner
as noted in Section VIII, sub-section 6).
9. Once main fl ame is established and fl ame current signal strength is good, proceed to “Part 2
Service, Section VIII Burner set-up/ adjustment” to fi nalize the burner set-up.
Trouble Chart
Continued