Weil-McLain 2 Series Manual page 100

®
SlimFit Series 2
Troubleshooting
Troubleshooting suggestions for SlimFit boilers
Display Condition
IGNITION Boiler went through 5 ignition
FAULT attempts and never detected
flame or flame sense value
never reached minimum
threshold for boiler model.
AIR PRESSURE Occurs when Air Pressure
Switch Open connection is open.
GAS PRESSURE Gas pressure switch is open
SW FAULT
(high or low).
100
COMMERCIAL CONDENSING GAS
(continued)
Diagnostics
Automatically resets after 1 hour
or can be reset by performing
manual reset on boiler.
Reset using Manual Reset
screen on display.
High pressure in the exhaust
pipe or high vacuum in the
boiler intake or cabinet has
caused the air switch to open.
The switch is closed in normal
operating conditions.
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
have an indicator light on.
Switches can be reset by
pushing on plastic
in the middle of the dial as
indicated on the
Control will also need reset
using display after gas pressure
switch has been reset.
- — Boiler Manual
FIRED WATER BOILER
(continued)
Corrective Action(s)
Check condensate trap for blockage allowing condensate to accumulate
inside heat exchanger.
Check ignition cable connection.
Fouled, worn, bent, or faulty igniter.
Fouled igniters can be cleaned for additional use with steel wool.
Worn or badly fouled igniters should be replaced with the proper repair
part.
Igniter rods should be parallel with a 3.5 mm (0.138 in) spark gap.
NOTICE: Thin white deposits on the igniter are typical, but brown or
black deposits could be the result of flue gas recirculation. Thoroughly
inspect the venting system and termination for the possibility of leakage
or flue gas feedback into the air line.
Dirty burner and/or heat exchanger will cause high back pressure and
poor ignition.
Follow procedure in maintenance section of this manual to clean burner
and heat exchanger. Visual inspection of flueways may not be sufficient
to diagnose condition.
Check combustion settings on high and low fire and adjust per setup
instructions if necessary.
Check incoming gas pressure with boiler off and at high fire. Adjust
within limits on rating label.
Verify correct boiler model and altitude is selected in control and correct
elevation must be entered when operating above 2,00 feet.
Check ignition cable resistance. Should measure 1000 Ohms (+/- 50
Ohms).
Check for flue pipe and intake pipe restrictions or blockage.
Check burner fasteners and gaskets.
Check venturi gaskets and proper venturi. (Propane models use different
venturi's).
Check boiler size selected in control against boiler rating label. Correct if
necessary to select the proper boiler size.
Check exhaust and intake pipe for restrictions or blockage.
Check condensate drain for blockage. If condensate is unable to drain
out of the boiler it can begin to block the flow of exhaust gases. Clean
the condensate collection area of the base and condensate trap. Refill
trap with fresh water.
Check the P7 connection as seen on Figures 52, page 48 &
Figure 53, page 50. Check the connections on the pressure switch.
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.
will Low Pressure Switch Setting = 2 inches H2O
High Pressure Switch Setting = 14 inches H2O
cover
switch.
Part number 550-100-180/0917