
Ufly Controller and BCM for Modulex EXT
CHAPTER 8: TROUBLESHOOTING
OMM-0159_A
• 6/28/2022 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page
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8.1.1 BCM (Boiler Communications Module) Fault Codes
The table below lists the fault codes and troubleshooting tips associated with the BCM.
FAULT CODE
DESCRIPTION
EFFECT
CORRECTION
RESET
HCM: 2
Low gas pressure
Gas Pressure Switch -
NOT APPLICABLE.
HCM: 8
Low water pression
Water Deficiency -
NOT APPLICABLE.
HCM: 9
Outer temperature
sensor
Outdoor sensor
Enabled but not
connected
Outdoor Reset not
available.
AUTOMATIC -
Outdoor Reset will be
available once
outdoor sensor is
connected.
HCM: 13
DHW Temperature
sensor
DOMESTIC HOT
WATER sensor fault
DHW service not
active
Check DHW sensor
and its resistance
using the
resistance/Temp
table); check the
sensor connections.
AUTOMATIC
HCM: 14
CH return sensor
Global return sensor
failure
All burners turned
OFF.
Check return sensor
or wiring.
AUTOMATIC
HCM: 17
Global frozen
Boiler pipe is frozen.
Flow sensor temp. is
36°F or less.
Ignition is inhibited.
Pump runs for 5 min
at max speed.
Carefully defrost
boiler.
AUTOMATIC - when
Flow sensor is
greater than 41°F.
HCM: 18
Global differential
temperature
Maximum Δ
-
temperature
protection.
Fault is detected if
[Global FlowSensor
–
Return Sensor] >
[Param 483 + 50°F].
Note: Referred
parameter is BCM
Param. 483
All burners turned
OFF and Pump ON at
maximum speed.
Check circulation,
check installation
AUTOMATIC - Fault is
cleared when [Global
FlowSensor
–
Return
Sensor] < Param 483.
Note: Referred
parameter is BCM
Param. 483
HCM: 19
Global overheating
High outlet
temperature. Flow
sensor temperature >
203°F.
All burners turned
OFF and pump ON at
maximum speed.
Check Flow Sensor or
system pump.
AUTOMATIC - when
Flow sensor < 176°F.
HCM: 28
Chimney closed
Flue/Chimney
Obstruction
Ignition is inhibited.
Check flue/chimney
MANUAL
HCM: 29
Condense level
Water inside the
combustion
chamber.
Ignition is inhibited.
Check for water in
the exhaust manifold
AUTOMATIC
HCM: 30
Service parameters
Settings corrupted.
Ignition is inhibited.
Contact factory.
MANUAL - push reset
switch
HCM: 37
Parameters memory
BCM: Internal fault
Contact factory.
MANUAL
HCM: 38
Factory parameters
Settings corrupted by
electromagnetic
interference.
Ignition is inhibited.
Contact factory.
MANUAL - push reset
switch
HCM: 39
User parameters
Settings corrupted by
electromagnetic
interference.
None
Contact factory.
AUTO
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