Weil-McLain Evergreen EVG 220, Manual

Page: 107 / 136

Part number 550-100-131/0120
– 107 –
®
gas
-
fired water boiler
— 220/299/300/399 Boiler Manual
Figure 103
Troubleshooting suggestions for
Evergreen ®
boilers
— Fault displays, diagnostics and corrective actions
Troubleshooting
(continued)
Display
Condition Diagnostics Corrective Action(s)
LOW WTR
CUTOFF OPEN
Occurs if internal low water
cutoff contacts open.
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.
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.
SUPPLY 58° F >
RETURN
Boiler Out temperature
has exceeded the Boiler In
temperature by more than
58º F.
Automatically resets after 30
second delay when conditions
no longer exist or using manual
reset on display.
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.
RETURN >
SUPPLY
Occurs if a return water
temperature is greater than
the corresponding supply
temperature by 10º F or more.
Automatically resets when
condition no longer exists.
Verify proper flow 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.
SUPPLY WATER
TEMPERATURE
TOO HIGH
Occurs when the System
Supply temperature goes
above 200º F when the
burner is running.
Automatically resets when
Supply temperature goes below
200º F.
Verify proper flow direction of the boiler circulator. This circulator must be
installed to push water through the system.
TEMPERATURE
SENSOR FAULT
Occurs if a temperature
sensor has electrically shorted
(SHORT) or has become
disconnected (OPEN).
Will automatically reset if the
condition clears.
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 99, page 103. 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.
Occurs if dual temperature
sensors values have spread by
more that 10º F if the burner
is on.
Automatically resets when
sensors are within 10º F.
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.
FLUE TEMP
TOO HIGH
Occurs if flue temperature
sensor exceeds 210º F
(Warning) or 220º F (Lockout).
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.
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.