Weil-McLain Series 2 Manual page 100

® S
ERIES
Troubleshooting Troubleshooting
Figure 107 Troubleshooting suggestions for ECO boilers — Fault displays, diagnostics and corrective actions
Condition
Display
Occurs if a temperature
TEMPERATURE
sensor has electrically
SENSOR
shorted (SHORT) or has
become disconnected
(OPEN).
Occurs if dual temperature
sensors values have spread
by more that 10°F if the
burner is on.
Occurs if flue temperature
FLUE TEMP
sensor exceeds 216°F.
TOO HIGH
Occurs if low water cutoff
LOW WTR
contacts open.
CUTOFF OPEN
Occurs if display
DISPLAY COMM
communications out for 30
seconds.
Occurs if manual or
LIMIT OPEN
automatic reset limit opens.
100
2
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G
AS FIRED WATER BOILER
(continued) (continued)
Diagnostics
Will automatically reset if the
condition clears.
Automatically resets when
sensors are within 10°F.
Automatic reset occurs if
temperature drops below 210°F
for 2.5 minutes.
Manual reset is required if the
temperature rises above 220°F.
Reset using manual reset screen
on display.
Automatic reset occurs if contacts
are open at least one second, but
less than 5 seconds.
Manual reset of control module
if contacts are open longer than
5 seconds.
Automatically resets when
communication is re-established.
Automatic external limit will reset
2½ minutes after external limit
device closes.
Manual limit fault must be reset
using manual Reset screen on the
display.
— Boiler Manual
Corrective Action(s)
Check all the temperature readings of the boiler on the DIAGNOSTICS -
TEMPERATURES menu to determine if any sensors are currently displayed
as SHORT or OPEN. Compare this to the boiler temperatures recorded
in the DIAGNOSTICS - ERRORS - LOCKOUT HISTORY # - TEMPERATURES
during the last several lockout conditions.
Determine which sensors are suspect and measure their resistance
value and compare it to the values shown in Figure 102, page 96. If the
resistance values are incorrect replace the temperature sensor. Refer to
repair parts section for proper part number.
OUTDOOR TEMP is the optional outdoor air temperature sensor. If this
is not being used it will always be shown as NONE. This is normal unless
the sensors were installed.
Check wire harness for loose connections and pin engagement at sensor
connection and the control module. Unplug connection at sensor and at
control module and check continuity between ends.
If problem persists after checking items above replace control module.
Refer to repair parts section for kit number.
Follow procedure above for SHORT and OPEN sensor conditions to
properly diagnose sensor. If measured resistance values of sensors
convert to temperatures separated by more than 10º F replace the
sensor.
Follow procedure for above for SHORT and OPEN sensor conditions
to properly diagnose sensor. In addition inspect heat exchanger
combustion chamber and flue ways for abnormal wear or buildup.
Inspect vent system for abnormal wear or damage.
Contact Weil-McLain Technical Support.
Check for low water condition in system. Repair system as necessary refer
to piping section of this manual.
If low water condition does not exist, check Diagnostics — Inputs screen
to view status of Low Water Cutoff. If shown as OPEN check wiring
between LWCO and control module. If wiring is correct and functioning,
then replace the LWCO.
If LWCO option is not installed, check the wiring of the jumper in control
module's plug P12.
Check for a loose connection at the molex plug on the control and
connection on the back of the display.
Is there an external safety device connected? If yes, trouble shoot the
external limit to determine and correct the cause that opened the limit.
Also check for loose wiring connections.
Inspect the connector on control module's plug P13.
Ensure a jumper is installed across the left two (Pins 1&2) terminals if not
using a manual reset external limit.
Ensure a jumper is installed across the right two (Pins 3&4) terminals if
not using an automatic reset external limit.
Part number 550-142-190/1218