P/N 42-9450 8/08 Copyright 2008 Hydrotherm
Page 40 KN INSTALLATION AND OPERATION INSTRUCTIONS
Starting the boiler (continued)
Figure 32 Throttle adjustment and ame window
Measure ame current
Electrical shock hazard 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
ame current.
With the boiler operating at low re (low- re jumper in place), measure the ame
current.
Remove the upper electrical panel cover (upper right side of boiler).
A ach microammeter leads to the ame current test pins of the Fenwal ignition
module as in Figure 32.
e ame current should be approximately 6 microamps, and never less than
1 microamp. Record the ame current value on the back page of this manual.
If ame current is acceptable, continue with setup. If ame current is too low,
check the ignition electrode/ ame rod assembly following the instructions in the
Maintenance section of this manual.
Check boiler modulation
Remove the low- re jumper from the electrical connection panel (see Figure 28).
e boiler ring rate should change to meet demand. e HeatNet control display
will show the percentage of maximum ring rate (between 20% and 100%).
Test 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 a er the ame goes out, the boiler gas valve should shut o .
e HeatNet control will restart operation with prepurge, then continue through
a normal start cycle.
With the manual gas valve closed, the boiler should a empt ignition three times,
then lockout, as described below.
Ignition failure
Make sure there is a call for heat.
Turn the boiler on/o switch OFF.
Close the manual gas valve on the gas supply line.
Turn the boiler on/o switch ON.
e boiler should start a regular cycle.
When the boiler a empts ignition, no ame will occur. Within 4 seconds of
ignition start, the control will close the boiler gas valve and a empt another start.
A er three failed ignition a empts, the Fenwal control will lockout.
e boiler will shut o and the HeatNet control display will show “LOCKOUT.”
Open the manual gas valve.
Reset the controls by turning the boiler on/o switch o , then on again.
e boiler should restart and operate normally.
Test control & interlock operation
Test HeatNet operating limit function
Allow the boiler to re until the supply temperature reaches the upper end of the
control band.
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e boiler should gradually cycle to minimum input ( ring
rate = 20%), then turn o .
Test external controls
Lower the se ing of external limit controls below the supply
water temperature. Verify that the controls shut down as
required.
Test operation of low water cut-o s, 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 o as
required.
Fill out the installation certi cate
Complete the checklist and installation certi cate on the
back page of this manual.
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