71
IX. System Start-up
(continued)
Refer to Figure 36 for location of offset screw.
Verify CO is less than 100 ppm.
3. Reinstall flue temperature sensor
with silicone
cap into two-pipe vent adapter.
4. Return boiler
to normal operating mode by
pressing “Auto”.
M. Checking / Adjusting Gas Input Rate
1. Turn
off gas supply to all appliances other than
gas-fired boiler.
2. Lock the boiler in high fire,
following Step 3a
in Paragraph L.
3. Clock gas meter
for at least 2 revolutions of
the dial, typically labeled ½ or 1 cubic foot per
revolution on the gas meter.
4. Determine gas flow rate
in cubic feet per hour
based on elapsed time for 2 revolutions.
Example:
Using a meter with dial labeled 1 cubic foot per
revolution, measured time is 72 seconds for 2
Revolutions, i.e. 36 seconds per 1 cubic foot.
Calculate hourly gas flow rate:
3600 sec/hr ÷ 36 sec/cu ft = 100 cu ft/hr
5. Obtain gas-heating value
(BTU per cubic foot)
from gas supplier.
6. Multiply
hourly gas flow rate by gas heating value
to determine the boiler input rate, BTU/hr
Example:
Natural gas heating value provided by local gas
utility is 1050 BTU per cubic foot.
Measured and calculated hourly gas flow rate is 100
cu ft/hr.
Measured boiler input rate is:
100 cu ft/hr * 1050 BTU/ cu ft = 105, 000 BTU/hr
7. Verify measured input rate
is within 88% to
100% of the max. input listed on the boiler rating
label.
8. If measured input is too high,
reduce maximum
modulation fan speed (either central heat or
domestic hot water, depending on source of call for
heat) in increments of 50 RPM and check the input
rate after each adjustment. Follow instructions in
Section X. “Operation” to adjust the maximum
modulation fan speed.
9. If measured input is too low,
increase maximum
modulation fan speed (either central heat or
domestic hot water, depending on source of call for
heat) in increments of 50 RPM and check the input
rate after each adjustment. Follow instructions
in Section X “Operation” to adjust the maximum
modulation fan speed.
10. Return boiler to normal operating mode
by
pressing “Auto”.
11. Return
other gas-fired appliances to previous
condition of use.
N. Test Safety Limits Controls
1. Test the ignition system safety shut-off
by
disconnecting the flame sensor connector (black
plug with orange wire) from the flame ionization
electrode. See Figure 27. The boiler must shut
down and must not start with the flame sensor
disconnected.
2. Test the flow switch
by disabling the primary
loop circulator. The boiler must not start if flow is
not present.
3. Test any other external limits
or other controls
in accordance with the manufacturer’s instructions.
O. Check Thermostat Operation
Verify that the boiler starts and stops in response to
calls for heat from the heating thermostat and indirect
water heater thermostat. Make sure that the appropriate
circulators also start and stop in response to the
thermostats.
P. Adjust Supply Water Temperature
As shipped, the heating set point supply temperature
is set to 180°F (82.2°C) and, indirect water heater set
point supply temperature is set to 170°F (76.7°C). If
necessary, adjust these to the appropriate settings for the
type of system to which this boiler is connected. See
Section X “Operation” (parameter table on page 91)
of this manual for information on how to adjust supply
setpoint.
Q. Adjust Thermostats
Adjust the heating and indirect water heater thermostats
to their final set points.
R. Field Conversion From Natural Gas to LP
Gas
Apex models APX425 and APX525 are factory shipped
as natural gas builds and can be field converted to
LP gas. Follow steps below for field conversion from
natural gas to LP Gas.
Models APX625, APX725 and APX825 are factory
shipped as either natural gas build or LP gas build.
Field conversions of models APX625, APX725 and
APX825 are not permitted.
1. Conversion
of Apex models APX425 and APX525
from one fuel to another is accomplished using
the throttle screw on the gas valve. Figure 36 “Gas
Valve Detail” shows the location of the throttle
screw on the valve. Locate the throttle screw on the
boiler being converted.
Summary of Contents for APEX
Page 57: ...57 VIII Electrical continued Figure 26 Ladder Diagram ...
Page 58: ...58 VIII Electrical continued ...
Page 59: ...59 Figure 27 Wiring Connections Diagram VIII Electrical continued ...
Page 105: ...105 ...
Page 109: ...109 XIII Repair Parts continued APX625 APX725 and APX825 APX825 shown ...
Page 112: ...112 XIII Repair Parts continued APX425 and APX525 ...
Page 114: ...114 XIII Repair Parts continued APX625 APX725 and APX825 ...
Page 122: ...122 ...
Page 123: ...123 ...
