Watts Aerco Modulex MLX EXT 1530 - Page 117

Modulex EXT Commercial Series Boilers User Manual
CHAPTER 7: Troubleshooting
OMM-0095_0H AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 Page 117 of 144
GF-139 Phone: 800-526-0288 09/15/2017
TABLE 7-4: BMM Fault Codes
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/MANUAL
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