Midco Unipower G-Series - Manual (Page 15)

XIV Special Equipment
(OEM Versions)
■ ■ Special equipment, either factory or field installed, can cause variations in the procedures and
descriptions given in this manual. Generally, any burner ordered with special factory installed equipment
will be supplied with the appropriate wiring diagram and related instruction manuals from the special
equipment manufacturer. Consult these manuals to identify any differences in construction, operation
and testing. Field installed special equipment is the responsibility of the installing contractor.
■ ■ For example, when a high/low gas pressure switch is used, the high gas pressure setting must be
higher than the maximum manifold pressure during initial start-up and the low pressure setting must be
set below the normal minimum inlet pressure to prevent nuisance shutdowns during the start-up
p r o c e d u r e .
■ ■ After the burner is started, the low pressure setting should be raised until the burner shuts off.
Reduce the setting and set the low pressure switch to restart the burner. Reduce the high pressure
setting until the burner shuts off. Then raise the setting slightly and reset the high pressure switch to
restart the burner. Do not make the adjustments too close to trip points or nuisance shut downs may
occur. Anytime the burner gas supply is shut off with the main manual valve, the low pressure switch
will require resetting.
■ ■ If any doubt exists concerning burner operation when special equipment is involved, contact the
installing contractor or MIDCO INTERNATIONAL INC. (front cover).
Make sure the thermostat and operating controls are calling for heat. Defective wiring or loose
connecting can simulate the component defects outlined below. Check associated wiring before
replacing a component. ELECTRICAL AND FLAME CHECKS MUST BE MADE IN THE ORDER
L I S T E D .
A . No power to flame safeguard
B . Flame safeguard locked out
C . Defective flame safeguard
D . Defective motor relay
E . Motor overload "out"
A . Motor overload "out"
B . Defective motor
C . Defective flame safeguard
A . Defective air switch
B . No air pressure at air switch
C . Defective purge timer
D . Defective flame safeguard
A . No pilot gas
B . Low pilot gas pressure
C . Defective pilot gas regulator
D . Misadjusted pilot regulator
E . Blocked pilot regulator vent
F . Defective pilot solenoid valve
G . Defective spark electrode
H . Misadjusted spark electrode
I . Defective spark cable
J . Defective spark generator
K . Clogged or incorrect pilot orifice
L . Defective pilot tip
M . Excess pilot air
N .
Air orifice missing
O . Clogged pilot air tube
P . Defective flame safeguard
A . Poor flame signal
B . Poor pilot flame
C . Misadjusted pilot regulator
D . Low gas pressure
E . No pilot air (see above)
F . Excess pilot air (see above)
G . Defective pilot tip
Trouble Char
I. Motor Fails
II. Motor Fails to Start, Flame
Safeguard Energized
III. Motor Runs Continuously,
No Lighting Attempt
IV. Pilot Does Not Light, Flame
Safeguard Locks Out
15
V. Pilot Lights, Flame
Safeguard Locks Out