Install Instructions

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I-UBX-UBZ-UDX-UDZ (04-21) 1034344-0
Table 20. Fault Modes
Fault Mode Condition Action
Undesired
flame
Flame is sensed longer than
20 seconds while gas valve is
deenergized
Control runs venter motor and runs fan/blower motor on heat speed
When flame is no longer sensed, venter motor runs through post-purge and fan/
blower motor runs through selected delay OFF time
Control proceeds to soft lockout but still responds to open limit and flame
SSD displays “6” when lockout is due to undesired flame
Gas valve
relay fault
Control senses that gas valve is
energized for more than 1 second
when control is not attempting to
energize gas valve or control senses
that gas valve is not energized when it
is supposed to be energized
Control proceeds to lockout (SSD is blank)
Control assumes either that contacts of relay driving gas valve have welded shut or
that sensing circuit has failed
Venter motor is forced OFF to open pressure switch to stop gas flow unless flame is
present
Control senses that gas valve is
closed when it should be open (has
not deenergized after venter motor has
been shut off for 15 seconds
Venter motor is re-energized to vent unburned gas
Soft lockout
Control does not initiate call for heat or
call for continuous fan operation while
in lockout
Control still responds to open limit and undesired flame
Lockout is automatically reset after 1 hour
Lockout may be manually reset by removing power from control for more than 1
second or by removing thermostat call for heat for more than 1 but less than 20
seconds
Hard lockout Control detects fault on control board
SSD is blank or displays “L” (fault dependent)
Control remains in lockout as long as fault remains
Hard lockout automatically resets when hardware fault clears
Power
interruption
Momentary interruption or voltage level
is below minimum operating voltage
(line voltage or low voltage)
System self-recovers without lockout when voltage returns to operating range
Interruption <80 milliseconds Control does not change operating state
Interruption >80 milliseconds Control may interrupt current operating cycle to restart
Vent System Testing
For each heater or utility heater connected to the venting system and placed in operation while any other appliance(s)
connected to the venting system(s) is not in operation, test the vent system as follows:
1. Seal unused openings(s) in vent system.
2. Inspect vent system for proper size and horizontal pitch as required in National Flue Gas Code (ANSI Z223.1/
NFPA 54) or Natural Gas and Propane Installation Code (CSA B149.1) and in venting instructions in Table 1.
3. Verify that there is no blockage or restriction, leakage, corrosion, and/or other deficiencies that could cause any
unsafe condition.
4. In so far as is practical, close all doors, windows, and other open spaces within building and all doors between
space in which appliance(s) is connected and space where vent system is located.
5. Close any fireplace dampers.
6. Turn on clothes dryers and any exhaust fans (such as range hoods and bathroom exhausts) so that they operate
at maximum speed. Do not operate a summer exhaust fan.
7. Following lighting instructions provided with heater, place utility heater being inspected in operation. Adjust
thermostat so that utility heater will operate continuously.
8. After it has been determined that each utility heater connected to vent system properly vents when tested as
outlined above, return doors, windows, exhaust fans, fireplace dampers, and any other gas-burning appliance
to their previous condition of use.
9. If improper venting is observed during above tests, vent system must be corrected.