10
Check flame and combustion (continued)
4.Place the boiler into the active position by pressing the SHUTDOWN button on the display board (FIG.
5.Locate the pinhole button above the “T” in the Knight XL logo on the display board (FIG.
6.Insert the probe from a combustion analyzer into the hole left by the removal of the flue temperature sensor.
7.Once the boiler has modulated up to full fire, measure the combustion. The values should be in the range listed in Table 10A below. The CO levels should be less than 150 ppm for a properly installed unit.
If the combustion is not within the specified range, reference the Troubleshooting Section of the Knight XL Service Manual for possible causes and corrective actions.
Table 10A Flue Products Chart
Natural Gas | Propane | ||
|
|
|
|
CO2 | O2 | CO2 | O2 |
8.0% - 10% | 3.0% - 6.5% | 9.0% - 11% | 4.1% - 6.9% |
|
|
|
|
8.Once the combustion analysis is complete, test the safety shutoff device by turning the manual shutoff valve to the OFF position and ensuring that the boiler shuts down and registers an alarm. Open the manual shutoff valve, reset the control, and return to Service Mode.
9.Turn the main power off to the boiler and replace the flue temperature sensor into the flue pipe connection.
10.Place the boiler back into normal operation.
WARNING You must replace the flue gas temperature sensor to prevent flue gas
spillage into the room. Failure to comply could result in severe personal injury, death, or substantial property damage.
54 
Installation & Operation Manual
Set space heating operation
Determine controlling sensor
For space heating systems, the temperature control can be based on one of three sensors; the inlet, outlet, or system supply sensor. The SMART SYSTEM control is programmed at the factory to control the temperature of the outlet sensor. The control will automatically switch to the system supply sensor once it is connected. If it is desired to base the temperature control on the inlet sensor, the appropriate parameter must be changed in the control. See the Knight XL Service Manual for a detailed explanation of this procedure.
Verify space heat circulator mode
The Space Heating Mode controls both the system (primary) pump (if connected), and the boiler (secondary) pump. When the SMART SYSTEM control receives a space heating call for heat, it turns on the system pump. If the boiler is not heating an indirect DHW (Domestic Hot Water) tank, it also turns on the boiler pump. After the space heating call for heat ends, the system pump continues to run for a short period of time. If the boiler pump was running, it continues to run for a short period of time as well. These pump delays are factory set to 30 seconds. If different delays are desired, the appropriate parameters in the control must be changed. See the Knight XL Service Manual for a detailed explanation of this procedure.
Set space heating set point temperature
The UP and DOWN keys may be used during normal operation to adjust the space heating set point temperature. Once the desired temperature is displayed, press the ENTER/RESET key to save the new setting. If the ENTER/RESET key is not pressed, the new setting will be used for the current heating cycle only. The old setting will become active after the current heating cycle ends.
