Part number 550-100-168/0516
104
SlimFit
®
Series 3
COMMERCIAL
CONDENSING
GAS
-
FIRED
WATER
BOILER
—
Boiler Manual
Display
Condition
Diagnostics
Corrective Action(s)
GAS PRESSURE
SW FAULT
Gas pressure switch is open
(high or low).
Either the low gas pressure
switch or high gas pressure
switch has opened due to
incorrect gas pressure being
supplied to the boiler. Remove
front door of boiler and look at
pressure switches. The upper
switch is the high gas pressure
switch and the lower one is a low
gas pressure switch. Whichever
switch has locked-out will
have an indicator light on.
Switches can be reset by
pushing on plastic cover
in the middle of the dial as
indicated on the switch.
Control will also need reset
using display after gas pressure
switch has been reset.
Check gas pressure at tee mounted behind gas pressure switches during
high and low fire and boiler off. Pressure should always be with limits on
rating label. Undersized gas supply pipes or regulators may cause low
gas pressure issues while the boiler is operating and possibly high gas
pressure when the boiler shuts down.
Insure the pressure regulator in the gas supply line is a lockup-type.
Ensure gas pressure switch settings are correct.
Low Pressure Switch Setting = 2 inches H2O
High Pressure Switch Setting = 14 inches H2O
HW FAULT
EXPANSION
BRD
Expansion Control Board
hardware has failed.
Expansion Control Board has
detected an issue with it’s
hardware and has locked out.
Requires a manual reset.
Check boiler size selected in Control against boiler rating label. Correct if
necessary to select the proper boiler size.
GV FAULT
EXPANSION
BRD
Gas valve output of the
Expansion module.
Expansion Control Board has
detected an issue with the gas
valve circuit. Requires a manual
reset.
Check the wire harnesses between the Control, Expansion module, and
gas valve.
EXP BOARD
COM FAULT
Expansion Control Board
communication fault.
Communication has been lost
between the Control and the
Expansion Control Board.
Check the communication wire harness between the two controls.
PS Fault Exp.
Board
Pressure switch issue
detected on expansion board.
Unit receives manual reset.
Check connections to expansion board.
Check air and gas pressure switches
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.
(ARDWARE
&AULT8
The control has detected a
problem with its gas valve
output circuit.
Auto reset if condition is clear
after lockout, then 1 hour
automatic reset if condition clear,
then manual reset required.
Check for physical damages.
Check connections to gas valve and gas pressure.
If problem persists, replace main board.
#LOSURE
3WITCH&AULT
Proof of Closure connections
on P7 Pins 2 and 3 are open
Soft lockout for 3 ½ minutes
boiler retries. Each consecutive
failure adds 1 minute to lockout
time, up to 6 ½ minutes
maximum.
None – Check jumper on correct pins and secure connection.
Flow switch attached – Check correct pump is on, check wiring to flow
switch, and check switch is closing.
CAD – Check voltage to damper. Check damper is opening.
OUTDOOR
SENSOR ERROR
Outdoor temperature sensor
short or OPEN.
Will automatically reset if the
condition clears.
Warning only. Supply Max is
targeted until ODT is restored, if
used for target adjustment.
Determine which sensors are suspect and measure their resistance
value and compare it to the values shown in Figure 83, page 97. 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.
&LUE4EMP
4OO(IGH
Occurs if flue temperature
sensor exceeds 210°F
(Warning) or 220°F (Lockout).
Automatic reset occurs if
temperature drops below 210°F
for 2 ½ minutes.
Manual reset is required if the
temperature rises above 220°F.
Reset using manual reset screen
on display.
Follow procedure above for SHORT and OPEN sensor conditions
to properly diagnose sensor. In addition inspect heat exchanger
combustion chamber and flue-ways for abnormal wear and buildup.
Inspect vent system for abnormal wear or damage.
Contact Weil-McLain Technical Support.
&IGURE
Troubleshooting suggestions for SlimFit boilers
(continued)
Troubleshooting
(continued)
