AERCO Modulex EXT 321 - 1123 - Manual (Page 119)

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
Installation, Operation & Maintenance Manual
Table 6-4: BMM Fault Codes (Continued)
CODE DESCRIPTION EFFECT CORRECTION RESET
E 14
Return sensor
fault. All burners
turned OFF. Check return sensor or
wiring. AUTOMATIC
E 15
Maximum Δ-
temperature
protection.
Flow
temperature -
Return
Temperature >
Water Δ-Temp
Protection +
50°F.
All burners
turned OFF
and Pump ON
at maximum
speed. Check the system
installation. AUTOMATIC -
when Δ-
temperature <
Water Δ-Temp
Protection.
E 16
Boiler pipe is
frozen. Flow
sensor
temperature 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.
E 20
Flame signal
detected after
burner is OFF. Ignition is
inhibited. Disconnect gas valve wire
from BMM. If failure goes
away, check wiring or
change BMM. If failure
remains, check or change
gas valve. MANUAL - push
reset switch or
cycle power.
E 22
No air flow at
burner after fan
started for 30
seconds. Ignition retry
after 60 second
delay and
failure remains
until a
successful
burner
operation. If fan is stopped, check
supply voltage and fan
wiring. If OK, try another
fan. If still not working,
change the BMM.
If fan is not stopped, check
the exhaust gas outlet for
blockage. If OK, check the
air pressure switch wiring. If
still not working, try another
air pressure switch. If still
not working, change the
BMM. AUTOMATIC/MAN
UAL
E 23
The air
pressure switch
doesn't switch
off. Ignition is
inhibited. Disconnect the air proving
switch. If problem goes
away, install a new switch.
If not, check the wiring. If
wiring is OK, change BMM. AUTOMATIC
OMM-0087_0E AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 Page 119 of 148
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