lp-445-r4 Rev. 006 Rel. 027 Date 7.21.20
50
D. User Interface Display
Cascade Control Fault Codes
Screen
Description
Possible Remedy
SYS SUPPLY SENSOR
PUMP OFF E03
E03 indicates a problem with the system
sensor circuit. The circuit could be open or
shorted. Possible reasons for this error are:
There is no system sensor connected to the
Master Boiler.
The system sensor is faulty.
There is a short circuit in the system sensor
wiring; possibly from a staple placed through
the wire, or damage to the wire causing both
conductors to touch.
The system sensor wiring is open due to
defect or damage.
Disconnect the system sensor from the wiring and
measure it’s resistance. Compare the measured resistance
to the table in this manual to see if it corresponds to the
temperature of the sensor. If the resistance does not
agree with the sensor, replace the sensor. If the sensor
is OK, disconnect the sensor wiring from both the boiler
and the sensor and check continuity using an ohmmeter.
Repair or replace as necessary.
If this error is present, the boilers in the cascaded group
will run and ignite simultaneously when there is a heat
demand. Each boiler will modulate to maintain set
point temperature on its own supply sensor. This code
automatically resets when repair is complete. This code
will not display if system setting function ERROR SYSTEM
SENS is set to OFF.
TEMPER BLOCKING
PUMP ON TT
TT indicates there is a demand for heat on
the boiler, the pump is powered on, and the
supply sensor temperature is too high for
the boiler to ignite. This occurs because the
water temperature measured by the supply
sensor is higher than the tank temperature –
ignition diff setting.
This message will stay present until the water
temperature measured by the supply sensor is less than
the tank temperature – ignition diff setting.
TEMPER BLOCKING
PUMP ON DHW
DHW indicates there is a demand for
heat on the boiler from the DHW circuit,
the pump is powered on, and the supply
sensor temperature is too high for the
boiler to ignite. This occurs because the
water temperature measured by the supply
sensor is higher than the tank temperature –
ignition diff setting.
This message will stay present until the water
temperature measured by the supply sensor is less than
the BOILER SUPPLY – boiler supply differential (5
o
F) or
DHW SETPOINT is satisfied and no longer calls for heat.
LOW WATER LEVEL
PUMP OFF LEO
Water level in the boiler is low.
1. Check boiler feed water system to be sure it is supplying
make-up water to the boiler system.
2. Be sure all air is bled from the system.
3. Check for leaks in the boiler and system piping and
repair as necessary.
4. Inspect low level switch and wiring for damage and
repair as necessary.
HIGH FLUE PRESS FLU
PUMP ON
FLU indicates excessive flue pressure. This
code resets automatically after the high
pressure condition is resolved. The second
line indicates pump status.
1. Assure the flue is not blocked.
2. Check the switch wiring by applying a jumper in place
of the switch. If the code clears with the jumper in place,
REPLACE the flue switch and connect the wires to the
new switch BEFORE running boiler.
WARNING:
Do not use jumper to remedy an FLU error. Faulty switch MUST be replaced. Failure to follow this instruction could result in
serious personal injury or death.
