Install Instructions

Troubleshooting (continued)
Figure 97 Troubleshooting suggestions for EVG boilers — Fault displays, diagnostics and corrective actions
Part number 550-100-191/0917
111
®
gas-fired water boiler — 70/110/155 Boiler Manual
Display
Condition Diagnostics Corrective Action(s)
Nothing shown
on display
screen and boiler
will not respond
to call for heat
Control is not receiving 24V
power.
Check wiring for short circuit or
incorrect wiring.
Correct wiring per wiring diagram including connection of transformer
to the control.
Check 3-amp low voltage fuse
on control shown on page 108 .
Replace fuse with proper part found in replacement part section of this
manual. If fuse blows again recheck wiring per diagram.
Check transformer connection
to the control per wiring
diagram. Check for 24V output
of transformer.
Replace transformer if it is receiving 120VAC, but not outputting 24VAC.
Nothing is
shown in display
screen and no
other boiler
components are
operating
Control is not receiving 120V
power.
Check service switch and/or
circuit breaker to boiler is turned
on.
Turn on service switch to power boiler.
Is there 120 VAC at the service
switch?
Troubleshoot and correct the power supply to the service switch.
Check for 120 VAC at the line
voltage terminal block located at
P1 on the control module.
Correct wiring to control module using the wiring diagram in this
manual.
Inspect 12-amp fuse as shown
on page 108 . Replace if
necessary.
Replace the fuse with proper part found in the replacement part section
of this manual. If fuse blows again recheck wiring per diagram.
Nothing is
shown on
display screen,
but boiler is
operating
Occurs if the communication
is lost from the control to the
display.
or
Display contrast needs to be
adjusted.
Check for loose connections
and proper pin alignment/
engagement on the control's
plug P9, Comm. board JP6 +
J1, and the back of the display
circuit board.
Check for continuity on the wire harness from the display to the
communications board and Comm. board to control module. See repair
parts section for proper replacement part.
Cycle power off and on using
boiler power switch and check
for operation.
Replace with new display module. See repair parts section for proper
replacement part.
Look at the screen from other
angles.
Power cycle the boiler, wait about 45 seconds then Press and hold
the Enter button. While holding the Enter button, tap the up or down
buttons to adjust the contrast level. If this does not work replace display.
TEMP RISE TOO
QUICKLY
Occurs if supply water
temperature in heat exchanger
rises faster than 2º F per
second during the fi rst two
minutes the burner is on.
Automatically resets after 1
minute delay or using manual
reset on display.
Manual reset is necessary after 5
automatic resets have occurred
during the same Priority heat
demand. Reset using manual
reset screen 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.
DISPLAY COMM
Fault
Occurs if display
communications out for 30
seconds.
Automatically resets when
communication is re-established.
Improper connections may display the incorrect model numbers.
Check for a loose connection at the molex plug on the control and
Comm. board, and connection on the back of the display.
Hardware Fault Occurs when micro-controllers
on main board have a RAM or
ROM error, or communication
is cut off .
Check for hardware damages. RAM or ROM errors can be reset with the manual reset option.
If problems persist, replace main board.