Weil-McLain Evergreen EVG 70 Manual page 112

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Troubleshooting Troubleshooting
Figure 98 Troubleshooting suggestions for EVG boilers — Fault displays, diagnostics and corrective actions
Condition
Display
LOW WTR Occurs if internal low water
CUTOFF OPEN cutoff contacts open.
Boiler Out temperature
SUPPLY 58° F >
has exceeded the Boiler In
RETURN
temperature by more than
58º F.
Occurs if a return water
RETURN >
temperature is greater than
SUPPLY
the corresponding supply
temperature by 10º F or more.
Occurs when the System
SUPPLY WATER
Supply temperature goes
TEMPERATURE
above 200º F when the
TOO HIGH
burner is running.
Occurs if a temperature
TEMPERATURE
sensor has electrically shorted
SENSOR FAULT
(SHORT) or has become
disconnected (OPEN).
Occurs if dual temperature
sensors values have spread by
more that 10º F if the burner
is on.
Occurs if fl ue temperature
FLUE TEMP
sensor exceeds 210º F
TOO HIGH
(Warning) or 220º F (Lockout).
112
as-fired water boiler —
(continued) (continued)
Diagnostics
Automatic reset occurs if
contacts are open at least one
second, but less than 5 seconds.
Manual reset of control if
contacts are open longer than
5 seconds.
Automatically resets after 30
second delay when conditions
no longer exist or using manual
reset on display.
Automatically resets when
condition no longer exists.
Automatically resets when
Supply temperature goes below
200º F.
Will automatically reset if the
condition clears.
Automatically resets when
sensors are within 10º F.
Automatic reset occurs if
temperature drops below 210º F
for 2½ minutes.
Manual reset is required if the
temperature rises above 220° F.
Reset using manual reset screen
on display.
Boiler Manual
70/110/155
Corrective Action(s)
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. If wiring is alright, remove LWCO and Clean
probe. If problem still exist, then replace the LWCO.
Verify water pipe is installed correctly per instructions in this manual.
Verify proper circulator and speed for boiler size and system
requirements.
See message displayed TEMPERATURE SENSOR and follow procedure for
loose connections.
Verify proper fl ow direction of the boiler circulator.
Verify proper placement of system sensors for single or multiple boiler
system. System sensors should be on system piping not on the boiler
loop.
Verify sensors are wired to correct terminal locations.
System sensors may need to be located further away from the boiler
loop connection to the system, if proximity to the boiler loop is causing
sensors to be heated inaccurately.
Verify proper fl ow direction of the system circulator. This circulator must
be installed to push water through the system.
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 92, page 108 . If the
resistance values are incorrect replace the temperature sensor. Refer to
repair parts section for proper part number.
Check wire harness for loose connections and pin engagement at sensor
connection, chassis mount connection through control housing, and
the control. Unplug connection at sensor and at control and check
continuity between ends.
If problem persists after checking items above, replace control. Refer to
repair parts section for kit number.
Follow procedure for 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 fl ueways for abnormal wear or buildup.
Inspect vent system for abnormal wear or damage.
Contact Weil-McLain Technical Support.
Part number 550-100-191/0917