lp-666 Rev. 003 Rel. 001 Date 2.25.20
70
Code
Message
Description
Possible Remedy
F24
Burner Door
This code indicates that the burner door
switch has tripped. The burner door switch
trips if there is excessive heat on the heat
exchanger.
1. Use an ohmmeter to check the burner door switch for continuity.
First disconnect the switch and determine if it has tripped. If the
switch has no continuity it has tripped:
a. Check bolts on hx door. If door is not tight, a minor combustion
leak will cause elevated door temperatures.
b. Check for warm spots on the heat exchanger with an infrared
thermal sensor.
c. Check for a cracked / damaged refractory.
d. Investigate the flue for blockages.
e. Repair / replace components as necessary.
2. If switch has not tripped, push RESET on the boiler. If the boiler
tries to ignite or ignites and only runs for a short time and an
error code returns, measure temperature surface with an infrared
thermal sensor. If the temperatures are low (below 300 F) and the
sensor has not tripped then it is most likely a loose wire connection.
Check all wires and terminations for loose or broken connections.
3. If the door is cool and the switch continues to trip the switch is
faulty and needs to be replaced.
F26
Gas Pressure
The following switches are optional equipment
that may be installed on boiler. These devices
have indicator lights that illuminate if tripped.
High gas pressure switch – Trips if there is
excessive gas pressure on the outlet side of
the gas valve and must be manually reset.
Low gas pressure switch – Trips if there is low
gas pressure on the inlet side of the gas valve
and must be manually reset.
1. If an indicator light is illuminated, investigate the source of the
code for that particular switch.
2. With boiler in service mode, measure the gas pressure in the
supply line with a gas pressure meter. Monitor the gas pressure
during both low and high fire conditions for correct pressure
range.
3. If there are no optional switches or none of the indicator lights
is illuminated on the optional switches, use an ohmmeter to test
each of the switches one at a time. Turn the power off to the
boiler and disconnect the switch to be tested from the boiler to
determine which has tripped.
When you find the tripped switch investigate the cause of the fault
based on the purpose of the switch.
F31
Program
Error
There was a code while programming the
control and the memory is corrupt. The
boiler control will not function in this state
and the pump will be off as indicated on
the bottom line. This code only occurs if a
technician is programming the control and
the programming function fails. The only way
to recover from this code is to reprogram the
control. If this code occurs at any time other
than when a technician is servicing the boiler,
the control has failed and must be replaced by
a qualified technician.
The control must be reprogrammed. If programming does not
solve the problem, the control must be replaced.
F41
Hard Fault
Cond
This code indicates there is an internal fault in
the circuit within the control connected to the
condensate switch.
1. Inspect the ground wires for damage or loose connections.
2. Inspect the condensate wiring for damage and repair as
necessary.
3. Ensure no high voltage wires are routed in parallel with the
condensate low voltage wiring.
4. Replace control.
F42
Hard Fault
LWCO
This code indicates there is an internal fault in
the LWCO circuit.
1. Inspect the ground wires for damage or loose connections.
2. Inspect the LWCO wiring for damage and repair as necessary.
3. Ensure no high voltage wires are routed in parallel with the
LWCO low voltage wiring.
4. Replace control.
F43
AD Saft Fault
The temperature of either the flue or supply
sensors has risen nine degrees in 100
milliseconds and not returned to normal
within 1 second.
Ensure the connections to the flue and supply sensors are intact. If
wires are intact, check sensor resistance. If the problem persists or
the sensors are out of normal resistance range, replace the sensors.