LAARS EDN Series - Installation, Operation and Maintenance Instructions - Manual (Page 33)

Endurance Page 33
7. 10 seconds after establishing combustion and
proof of flame (via the flame rod signal to
ground), the ignitor will be de-energized.
8. For EDP/EDN units only, the display should
indicate a rapid rise in temperature to 150º
F (1-2 min. duration). During this period the
thermostatic union at the flow outlet is closed and
the boiler is operating in the internal recirculation
mode. [Service note: If the temperature rise is not
rapid the thermostat may be defective.] At 150°
F the thermostat will allow increased flow to the
system.
9. A gradual rise in temperature will be indicated
until the temperature approaches the Burner
Control Point. The firing rate will modulate based
on the rate of change in temperature as it seeks
the control point.
10. If, during a call for heat, the temperature reaches
the Burner Off Point, the Endurance combustion
will be de-energized, and will allow the
temperature to fall to the Burner On Point before
turning on again.
11. When the call for heat ends on an EDP or EDN
model, the gas valve shuts off, and the pump
post-purge begins, if activated. When the call for
heat ends on an EBP model, the anti-condensing
valve closes, and the Endurance goes into
tank charge mode, until the burner off point
temperature is achieved on the supply sensor.
9.2.1 Fault Code Identification
The boiler control can display the following fault
codes:
• F1 = Boiler control internal error
• F3 = Gas valve status is on, with no call for
heat
• F4 = Supply sensor error
• F5 = Tank sensor error (EBP only)
• F6 = Return sensor error
• F8 = OAT sensor unreliable
• LO = Lockout
• OFF = Controller is off
• ICE = Low temperature protection
The boiler shows an alarm condition by flashing
the code and then showing the supply temperature.
All of the fault conditions shown on the boiler control
will prevent the Endurance from operating, with the
exception of F8. If the outside air temperature sensor is
found by the controller to be unreliable, the controller
will override the outdoor reset function, and will run
the Endurance in setpoint mode, instead of outdoor
reset mode.
The ignition control uses LED indication to
display the following fault codes:
• Steady On = Internal control failure
• 2 Flashes = Erroneous flame signal
• 3 Flashes = Ignition Control Lockout
9.2.2 Fault Correction
F-1 Switch off boiler and restart. If F-1 repeats,
replace boiler control.
F-3 In normal operation, the ignition control
sends a “gas valve energized” signal to
the boiler control, so the controller will be
able to time its PI algorithms correctly. An
F-3 fault code indicates that the ignition
control is sending a signal that the gas valve
has been energized, but there is no call for
heat. The boiler control will not allow the
Endurance to fire in this condition. This
fault indicates that there is either something
mis-wired on the boiler, or that the relay
in this circuit has seized. Check the relay
for seized contacts first, and if the relay is
operational, check the wiring circuit on the
boiler.
F-4 Check for damaged wiring or poor
connection at sensor plug. If they are OK
disconnect the sensor plug and check the
resistance across the sensor terminals. The
resistance of a good sensor is 10,000 ohms
@ 77°F (25°C). Replace sensor if resistance
is less than 500 or more than 20,000 ohms.
F-5 Correct in the same manner as F-4.
F-6 Correct in the same manner as F-4.
F-8 Check that the outdoor air sensor is
installed properly, and that the wire
and/or connection are not damaged. If
okay, disconnect the sensor and check the
resistance across the sensor terminals. The
resistance of a good sensor is 10,035 ohms
at 77°F (25°C). Replace sensor is resistance
is less than 500 or more than 20,000 ohms.
LO See Section 9.2.3
OFF Control power is off. Press and hold the
power button (upper left button) on the
boiler control for 3 seconds to restore
control power. The control will flash “ON”
and then will return to normal operation.
9.2.3 Resolving Lockouts (LO)
There are many causes for lockouts. The six most
common causes are: (a) poor combustion,
(b) poor flame sensor signal, (c) inadequate gas supply,
(d) ignitor failure, (e) blocked or contaminated air
source, (f) safety limit trip. If you get LO on boiler
control, you need to check the ignition control to see if