Weil-McLain Ultra 3 series User Manual page 104

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gas fired water boiler
Troubleshooting Troubleshooting
Figure 112 Troubleshooting suggestions for Ultra boilers
Condition
Display
Occurs when a return water
RETURN >
temperature is greater than
SUPPLY
the corresponding supply
temperature by 10ºF or more.
Applies to system sensors or
boiler sensors.
Condition must occur for 10
minutes for system sensors.
Occurs when a temperature
TEMPERATURE
sensor has electrically shorted
SENSOR
(SHORT) or has become
disconnected (OPEN).
Occurs when flue
temperature sensor exceeds
216ºF
Occurs when dual
temperature sensors values
have spread by more that
10ºF
Occurs when Low Water
LOW WTR
Cutoff Device contacts open
CUTOFF OPEN
for more than 1 second
104
— Boiler Manual
(continued) (continued)
(continued)
Diagnostics
Automatically resets when
condition no longer exists.
Reset using manual reset screen
on display
Automatic reset occurs if
temperature drops below 216ºF
for 1.5 minutes.
Manual reset is required if the
temperature rises above 225°F.
Reset using manual reset screen
on display
Automatically resets when
sensors are within 10ºF.
Requires manual reset of
U-Control and may require
manual reset of LWCO device
depending on model.
Corrective Action(s)
Verify proper flow direction of the boiler circulator. This circulator should
be installed to push water through the boiler's return pipe as shown in
Figure 4 on page 11.
Verify proper placement of system sensors for single or multiple boiler
systems. System sensors should be on system piping not on the boiler
loop.
System sensors may need located further away from boiler loop
connection to the system if proximity to the boiler loop is causing
sensors to be heated inaccurately.
Check all the temperature readings of the boiler on the DIAGNOSTICS -
TEMPERATURES menu to determine if any sensors are currenty 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 109. If the resistance
values are incorrect replace the temperature sensor. Refer to repair parts
section for proper part number.
OUTDOOR TEMP, SYSTEM SUPPLY, and SYSTEM RETURN are the optional
outdoor air temperature and system water temperature sensors. If these
are not being used they will always be shown as OPEN. This is normal
unless the sensors were installed.
Check wire harness for loose connections and pin engagement at sensor
connection, chassis mount connection through sheetmetal cabinet, and
U-Control module. Unplug connection at sensor and at U-Control and
check continuity between ends.
If problem persists after checking items above replace U-Control. Refer
to repair parts section for kit number.
Follow procedure for above for SHORT and OPEN sensor conditions
to properly diagnose sensor. In addition inspect heat exchanger
combustion chamber and flueways for abnormal wear or buildup.
Inspect vent system for abnormal wear or damage.
Contact Weil-McLain Technical Support.
Follow procedure for above for SHORT and OPEN sensor conditions
to properly diagnose sensor. If measured resistance values of sensors
convert to temperatures seperated by more than 10ºF replace the sensor.
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 U-Control.
Part number 550-100-090/0809