IBC Technologies VFC 160 Installation And Operating Instructions Manual - page 17
IBC Technologies Inc.
- 17 -
VFC 160
2.3 BLOWER ADJUSTMENT
To ensure a proper gas/air ratio, adjust the
blower using the manometer as shown in
Figure 14.
Figure 14. Blower Adjustment
Connections
Table 7 - Blower Adjustment
1. Once again, ensure that vents are not
obstructed (see Troubleshooting Guide)
2. Connect manometer in the
configuration shown in Fig.14
3. Increase blower speed (using manual
Fan Speed screw as shown in Figure 15)
until 1.20”wc differential is achieved
4. Open gas supply and start boiler
5. Raise thermostat to trigger call-for-heat.
Within 40s, gas valve will open and
boiler will attempt to ignite
6. Once stable combustion has been
achieved, take CO
2
sample at vent
termination
7. Turn Fan adjust screw on enunciator
panel to vary fan speed (and airflow)
until combustion analyzer reading of
9.2% CO
2
is achieved
Ignition Module
Pressure Switch
Operator
Flow Switch
Vent Hi-Limit
Water Hi-Limit
Fan Speed
Fan
Thermostat
24 V
AC
Pump
Set Point
80°F
180°F
H
L
Call for Heat
Power
FXFR
Fan adjust
Figure 15. Fan Adjustment
2.4 CHECK BOILER INPUT
To ensure that the boiler input is correct,
check the boiler input rate using the
following procedure:
Table 8 - Check Boiler Input
1. Start boiler
2. Ensure other gas appliances are not
using the supply gas
3. Observe the number of cubic feet used
by the boiler in 1 minute
4. Consult gas supplier for gas heating
value(typically 1000 BTU/cu. ft.)
5. Verify output by using the formula at
the end of this section
6. If fuel flow is too high or low, check
the orifice plate size. Adjust gas valve
(per Section 2.2) as required to
achieve Rating gas plate input;
recheck flue gas composition at 9.2%
CO
2
if adjustment is made.
Boiler Input Formula
time
=
seconds for 1 cu. ft. of
natural gas through meter
HV
= heating value of gas as
provided by gas supplier
INPUT
= gas input(in BTU/hr)
2.5 SET OPERATOR LIMIT
Adjust operator limit as temperature
demands require.
Table 9 - Operator Setting
Dial Colour
"A" to "E" Temp. Range
Red
130°F - 170°F
Black
100°F - 140°F
INPUT
HV
time
3600
=
×