Reznor UDX User Manual

45
I-UBX-UBZ-UDX-UDZ (03-21) 1034344-0
Figure 21. DSI Control Module Troubleshooting Flowchart
Trial for Ignition
Call for Heat
Is there a
spark across gap at
ignitor?
Does gas
ignite?
Is there minimum
flame current at the
flame sensor?
Is there
minimum flame current
at the control
module?
Replace control
module.
Check connections to flame
sensor and/or moisture in the
burner assembly.
Is the flame
sensor corroded?
Clean flame
sensor.
Is the sensor
located in flame
correctly?
Replace flame
sesnsor.
Reposition
flame sensor.
Is gas
flowing?
Is the ignitor
position correct in the
gas flow?
Check gas pressure
and supply voltage.
If either are low,
correct and repeat
startup.
Reposition
spark ignitor.
Is there
24VAC at the gas
valve?
Is there 24VAC
from gas valve output on
control module to
chassis?
Check wiring and
connections to
gas valve.
Replace
ignition
control
module.
Replace gas
valve.
Is there
spark voltage at
control?
Check high
voltage wire
continuity.
Is there 24V P1-2
to power control?
Replace
control
module.
Check wiring
and/or 24VAC
transformer output.
YES NO
YES NO
YES NO
YES
NO
YES
NO
YES
NO
YES NO
YES
NO
NO
YES
YESNO
YES
NO
YES
NO

Reznor UDX Specifications

General

Model	UDX
Category	Heater
Fuel Type	Natural Gas or Propane
Ignition System	Direct Spark Ignition
Installation	Horizontal or Vertical
Heat Exchanger Material	Aluminized Steel
Dimensions	Varies by model
Weight	Varies by model
Heating Capacity	30, 000 to 400, 000 BTU/hr
Efficiency	83%
Vent Type	Separated Combustion
Voltage	115V
Control Type	Thermostat
Type	Gas-fired unit heater