IBC SL 28-160 Installation And Operating Instructions Manual page 53

Control wire plug
Air pressure sensor
Do not blow into sensor ports
Water pressure sensor
TROUBLESHOOTING
SL 28-160 MODULATING GAS BOILER
5.2.2 Fan/Blower
Operating power is provided by means of a separate 120 VAC connector at the
bottom of the fan (white/black/green). Control of the fan is provided via a four
lead connector at the top of the fan. This connector feeds a PWM control signal
(black wire) from the controller and provides a tachometer signal (white wire)
back from the fan. Unplugging the control connector will cause the fan to go to
high speed and trigger a "Blocked Vent Error" within 6 seconds if the boiler is
operating.
LEAD COLOR FUNCTION
35 VDC Positive power
Red
terminal
35 VDC Negative power
Blue
terminal
Black Signal from controller
White Fan tach.
Table 10: Fan Operation
5.2.3 Differential Air Pressure Sensor
Do not blow into the ports of the sensor, this is not a switch and "does not
click when closed". Excessive pressure will damage the sensor thus requiring
replacement. The sensor values are located in the advanced diagnostics section
of the controller. In general, the Fan Pressure and the Required Pressure
should be very close to each other while the boiler is in operation. If the required
pressure is higher than the actual pressure there are several possible causes.
•
Exhaust and/or Air Intake piping installed longer that allowed
•
Improper grading of the Exhaust and/or Air Intake piping allowing condensate
to be trapped in the piping
•
Re-Ingestion of flue gasses has caused the Venturi and/or Fan Impeller to
erode, becoming ineffective.
•
Air Pressure Sensor tubing not correctly attached.
If the Differential Air Pressure Sensor replacement is required, Ensure the
replacement sensor is marked for use on the SL 28-160 model boiler. Use of any
other differential air pressure sensor is forbidden.
5.2.4 Water Pressure Sensor
The water pressure sensor ensures there is adequate pressure in the heating
system for safe operation. The pressure is displayed in PSI as the default. If the
system pressure should drop below 8PSI the firing rate of the boiler is reduced.
If the pressure drops to 4PSI or lower, the boiler will not fire.
Check operation of the sensor by isolating the boiler from its system piping,
closing the system fill valve then cracking the pressure relief valve; the pressure
displayed should reflect declining pressure. If it remains "fixed", drain boiler and
replace sensor, or dislodge any blocking debris from sensor inlet channel and
reinsert.
TROUBLESHOOTING
Fan will only operate at max.
speed if disconnected.
Fan will only operate at max.
speed if disconnected.
Fan will only operate at max.
speed if disconnected.
2 pulses/rev (freq x 30=rpm)
5-3