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USSC 21
Error Codes
Below is a chart describing the Error Codes that might be displayed if an error occurs with your furnace.
Error
Code
Err1
Err2
Err3
Err4
Err5
Err6
Err7
Err8
Error
Descrption
The high limit temperature sensor
has tripped.
Furnace ran out of fuel during normal
operation.
The furnace was unable to reach the
Room Fan On temperature within the
startup time.
The power failed while the furnace was
hot, and when power was restored, the
fire was out.
The Auger output fuse has blown.
The Agitator output fuse has blown.
The Draft Fan (Exhaust Fan) output
fuse has blown.
The Room Fan blower output fuse has
blown.
Possible
Causes
• Inadequate ventilation.
• Room fan failure.
• Exhaust Blockage.
• Electrical Open in the over temperature switch or wiring.
• Hopper Empty.
• Auger output failure or jam.
• Flame of fuel quality caused fire to burn too slowly or go out.
• Electircal Open in low temperature switch or wiring.
• Flame or Fuel quality caused the fire to burn too slowly or go
out.
• Auger output failure or jam Hopper empty on startup.
• Electrical Open in low temperature switch or wiring.
• Power loss
• Electrical Open in low temperature switch or wiring.
• Auger motor jammed or bad.
• Agitator motor jammed or bad.
• Draft Fan motor jammed or bad.
• Room fan motor jammed or bad.
Several situations or events are indicated in normal operation by blinking display indicators or segments in the display:
Flashing On Indicator : This means that the furnace is in the “Lighting” state waiting for either a 3 minute timeout to
begin burning or for the furnace to reach the warm temperature whichever comes first.
Flashing Off Indicator : This indicates that the furnace is in the “Shutdown” state waiting for the OFF button, or for a
15 minute period after the furnace was turned off, or for the furnace to cool down, or for the door to be closed.
Flashing dash “-“ in Heat Range Display : This indicates that the furnace is in the normal run mode and is ramping
from the current heat range setting to the target heat range setting. Once the ramp is complete, the “-“ will stop
flashing. For ramping from heat range 1 to 5, the default time is 90 seconds between internal settings.
Flashing Automatic Mode Indicator : This indicates that the furnace is in normal operation and is running in the
automatic mode. However, either the Draft Fan or Auxiliary setting is manually configured.
Flashing Draft Fan Setting Indicator : This indicates that the furnace is in normal operation and that the vacuum
sensor detects a loss of pressure either because the door is open or because there is a negative pressure in the room
with respect to the exhaust.
Flashing Heat Range Setting Indicator : This indicates that the furnace is in normal operation and that an
overtemperature condition exists causing the fuel to stop.
Flashing Auger Delay Indicator : This indicates that the furnace is in normal operation and that the hopper lid is
open.
Flashing Indicators