Legend LB 1000 Installation Operation & Maintenance - Troubleshooting
34
If the ADJUST push-button is held down long enough, the
set-point will reach 110°F (43°C), the minimum value (or 190°F
[88°C], the maximum value) and stop. At this point, if the desired
set-point is not obtained, release the ADJUST push-button and
depress it again. The set-point value will now restart at 110°F
(43°C) to 190°F [88°C] and once again increase (decrease) in
value for as long as the ADJUST push-button is pressed.
Display Board LED Indicators
The Display Board contains eleven (11) solid state LED indicators
for viewing various states of appliance operation and for
troubleshooting if problems occur. Under normal operating
conditions, the appropriate LED’s will sequence with steady
illumination according to the particular appliance operating state.
In cases where problems or a lockout occurs, the appropriate LED’s
will illuminate indicating the general area where the problem exists.
A description of the LED’s and their corresponding functions are
as follows. See figure 20.
LED (GREEN)
Controller Function
Call for Heat
*** Monitors the outlet probe & switching
differential. LED is ON when the temperature
at the outlet is less than the set-point minus
the switching differential.
Flow Switch
Monitors the condition of the flow switch.
LED is ON when the flow switch closes,
indicating water flow through the system.
Pressure Switch
Monitors the condition of the pressure
switch(s). LED is ON when the pressure
switch(s) are in their correct state.
Ignitor Current
Monitors current flow through the ignitor
element. LED is ON when current flow
through the ignitor is sensed.
***Note: The call for heat function will also monitor the tank
probe or a 24 volt control, depending upon the application, when
one is connected to the control board. It will cycle on the control
with the lowest temperature setting, however, the 1502 control
board will not allow the appliance outlet temperature Set-Point
to be set below that of the tank probe supplied with LW models.
Gas Valve
Monitors Gas Valve output. LED is ON when
the output relay supplying power to the gas
valve(s) is closed.
Flame Sense
Monitors the Flame Sense Rod. LED is ON
when a signal from the flame rod is sufficient
to indicate flame.
LED (RED)
Controller Function
Blocked Flue
Indicates a blockage or interference at the
appliance flue.
Gas Pressure Fail
Indicates low gas pressure at the inlet of the
appliance or a malfunctioning switch.
NOTE: On CSD-1 models can also indicate
a high manifold pressure problem
Blower Fail
Indicates an error/malfunction in the blower
motor circuit.
Circulate Fail
Indicates an error/malfunction in the
circulating pump circuit.
Ignition Fail
Indicates a malfunction in the ignition system
circuit.
TROUBLESHOOTING
SHORTCYCLING
Shortcycling is a condition where the boiler starts up and shuts
down frequently in a short time period. This usually indicates
that an abnormal operating condition is present.
Monitor the DIA-SCAN II display board to pinpoint the shortcycling
source, then determine the probable cause(s) and take the
necessary corrective actions to eliminate them.
If the DIA-SCAN II display board shows normal sequence of
operation, the problem is field related; check the field wiring or
the system controller.
Note: In hot water applications, this condition is often caused
by the system control and the unit’s operating control being
set too close. A thirty (30) degree [17°C] separation between
the two control settings is recommended.
HARD STARTS
A “hard start” occurs during start up and is indicated by small
rumbling noises and/or minor quivering. This condition is a result
of improper air/gas mixture. Before making any adjustments to
the boiler, ensure that adequate combustion and ventilation air
are provided, see the “AIR REQUIREMENTS” section. If “hard
starts” are experienced, often an air or gas manifold pressure
adjustment will remedy the problem. An air shutter is provided to
help fine-tune the air/gas ratio.
TROUBLESHOOTING ERROR CODES
The WHC1502 Series Control System has many inherent
diagnostic and fault detection routines built into its operating
hardware and software. These routines, in conjunction with the
four (4) digit LED display and eleven (11) LED status indicators
on the Display Board, can greatly assist any service person in
quickly pinpointing the source of a problem which may occur
within the appliance. In certain circumstances, multiple LED’s
will illuminate to better pinpoint the target area(s).
The following list defines the error code messages that scroll
across the LED display:
ERROR MESSAGE
REPORTED ERROR
OPEn InLEt ProbE
No probe detected at connector CN1
on Control Board.
OPEn OutLEt ProbE
No probe detected at connector CN2
on Control Board.
Circulation FAIL
No flow detected at flow switch.
Inducor FAIL
No pressure detected at pressure
switch.
FLAmE SenSE FAIL
Flame sense detected before gas valve
is turned on.
SenSor FAIL
One of the sensors, Flow, Pressure, Hi
Gas, or Lo Gas was not in the correct
state.
Ignitor FAIL
No Ignitor current sensed (no Ignition).
no Ignition
Flame not detected after 1 or 3 tries.
ECO FAIL
ECO/High Limit switch opened.
Control FAIL
Relay did not open or close properly.