74
17.0 Maintenance Procedures
17.18 Check Flame Signal
The flame signal can be read from the Boiler
Information screen. It should be a min. 1
μ Α −
DC
.
Check the ignitor for fouling or damaged
insulation if a low flame signal is read.
Check ground wiring and continuity as a cause
for low flame signal. Replace ignitor if condi-
tions are satisfactory.
17.19 Check Combustion Levels
Refer to page 60 of this manual for measuring
combustion levels and burner adjustments.
17.20 Check Flue Gas Temperature
Manually place the boiler into high fire. See
page 60 for procedure.
Navigate to the Boiler Information Menu to
observe the flue gas temperature. See page 50
for procedure.
If the flue gas temperature is more than 54°F
[30°C] above the supply water temperature, shut
the boiler down and follow the heat exchanger
cleaning procedure below.
17.21 Clean Heat Exchanger
Shut down the boiler:
- Follow the instructions on Page 63 "To
Turn Off Gas to Appliance"
- Do not drain the boiler unless the boil-
er will be subject to freezing condi-
tions.
- Do not drain the boiler if freeze protec-
tion fluid is used in the system.
Allow the boiler to cool down to room temper-
ature before servicing.
Disconnect the gas piping and gas valve wire
harness connector.
Disconnect the wiring harness connectors from
the blower and remove the blower clamp.
Remove the blower from the unit.
Remove the mounting nuts securing the burner
plate to the heat exchanger and set aside.
Carefully remove the burner plate assembly
from the heat exchanger. Ensure that the com-
bustion chamber 2-in-1 insulation is not dam-
aged during removal of burner mounting plate
assembly. See WARNING on page 75.
Use compressed air or water to remove any
accumulation from the heat exchanger flue
ways.
Re-assemble the burner plate assembly onto
the heat exchanger. Ensure the combustion
chamber 2-in-1 insulation is in place, posi-
tioned correctly, and not damaged, replace if
necessary. See WARNING on page 75.
Re-assemble the blower onto the burner plate
and reconnect the wiring harness connectors.
Reconnect the gas piping and wire harness to
gas valve. Check for leaks, repair if necessary.
Torque all screws, bolts, and nuts in accor-
dance with specifications in Section 17.24 on
page 75.
Close isolation valves on the boiler water pip-
ing to isolate the boiler from the heating sys-
tem.
Attach a hose to the boiler drain valve and
flush the boiler thoroughly with fresh water by
using the purge valves to allow water to enter
through the make-up water line to the boiler.
Once the boiler has been completely flushed,
return the boiler and system piping back to
operation.
Perform the required startup and checkout pro-
cedures as outlined on pages 56 to 67.
