Trouble chart contintued – Midco 400B-02 User Manual
Page 12
A.
Manual Gas Cock Knob on Combination Valve not in ON position.
B.
Check for 24V* between blower interlock switch terminal NC and GND;
1. If no voltage, motor interlock switch or centrifugal actuator is defective. (See Section X
Blower Assembly).
2. If voltage is present, valve operator is defective; entire valve must be replaced.
A.
Low manifold gas pressure.
B.
Main gas spud orifice too small.
C.
Primary air adjustment open too far.
A.
High manifold gas pressure.
B.
Main gas spud orifice too large.
C.
Primary air adjustment closed too far.
D.
Dirty Blower Wheel
A.
Electric Valve Operator(s) of Combination Valve is defective and entire valve must be
replaced.
* Normal low voltage:
Motor running-24V minimum
Combination Valve energized-21V minimum.
** IMPORTANT: If changes are made in the main spud orifice size manifold gas pressure or pri-
mary air adjustment, change the installation data tag accordingly.
12
IV. Motor Runs
Continuously, Pilot is On,
But No Main Flame
V. Short Flame**
VI. Long, Hazy Flame**
VII. Gas Fails to Shut Off
Trouble Chart Contintued
Midco International Inc. 4140 West Victoria Street - Chicago, Illinois 60646
tel 773.604.8700 fax 773.604.4070 web www.midco-intl.com email [email protected]
201
8470 75
Printed in USA