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P/N 42-9470 11/07 Copyright 2007 Mestek, Inc.
Cast iron condensing boiler
Cast iron condensing boiler
— Installation and operation manual
Starting the boiler
(continued)
Figure 32
Throttle adjustment and fl ame window
Measure fl ame current
Electrical shock hazard
— Th e electrical box contains line-voltage
wiring and contacts. Use caution when working in the electrical box to
avoid contact with line-voltage elements. Power must be on to measure
fl ame current.
With the boiler operating at
low fi re
(low-fi re jumper in place), measure the fl ame
current.
Remove the upper electrical panel cover (upper right side of boiler).
Att ach microammeter leads to the fl ame current test pins of the Fenwal ignition
module as in Figure 32.
Th e fl ame current should be approximately 6 microamps, and never less than 1 mi-
croamp. Record the fl ame current value on the back page of this manual.
If fl ame current is acceptable, continue with setup. If fl ame current is too low, check
the ignition electrode/fl ame rod assembly following the instructions in the Main-
tenance section of this manual.
Check boiler modulation
Remove the low-fi re jumper from the electrical connection panel (see Figure 28).
Th e boiler fi ring rate should change to meet demand. Th e SmartCycle control dis-
play will show the percentage of maximum fi ring rate (between 20% and 100%).
Test fl ame failure modes
Flame loss
With the boiler running in normal operation, close the manual gas valve on the
incoming gas line.
Within 0.8 second aft er the fl ame goes out, the boiler gas valve should shut off .
Th e SmartCycle control will restart operation with prepurge, then continue
through a normal start cycle.
With the manual gas valve closed, the boiler should att empt ignition three times,
then lockout, as described below.
Ignition failure
Make sure there is a call for heat.
Turn the boiler on/off switch
OFF
.
Close the manual gas valve on the gas supply line.
Turn the boiler on/off switch
ON
.
Th e boiler should start a regular cycle.
When the boiler att empts ignition, no fl ame will occur. Within 4 seconds of igni-
tion start, the control will close the boiler gas valve and att empt another start.
Aft er three failed ignition att empts, the Fenwal control will lockout.
Th
e boiler will shut off and the SmartCycle control display will show “LOCKOUT.”
Open the manual gas valve.
Reset the controls by turning the boiler on/off switch off , then on again.
Th e boiler should restart and operate normally.
Test control & interlock operation
Test SmartCycle operating limit function
Allow the boiler to fi re until the supply temperature reaches the upper end of the
control band.
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Th e boiler should gradually cycle to minimum input (fi ring
rate = 20%), then turn off .
Test external controls
Lower the sett ing of external limit controls below the sup-
ply water temperature. Verify that the controls shut down
as required.
Test operation of low water cut-off s, fl ow switches and other
external devices.
Test external gas pressure interlocks, if used.
Test/verify operation of combustion air dampers and end
switches, if used.
DHW applications
For DHW applications, verify that the boiler operates on demand
from the indirect water heater and shuts off as required.
Fill out the installation certifi cate
Complete the checklist and installation certifi cate on the
back page of this manual.
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