Commissioning
4-20
750-382
CBT
4.1.15 — Operation check: gas valve, gas pressure switches, and combustion air proving switch
Before initial firing of the burner, the gas valve, Low Gas Pressure Switch (LGPS), High Gas Pressure Switch
(HGPS), and Combustion Air Proving Switch (CAPS) should be checked for proper operation.
• Before proceeding, review Section 4.3 - Control setpoints for initial LGPS, HGPS, and CAPS settings.
Note: Close the downstream manual gas shut-off valve before checking pressure switches and CAPS.
While performing the following safety checks, use the CB Falcon Annunciation screen to monitor the status of
the circuits involved. Press <Annunciation> on the Operation page to access this screen.
LGPS
1. To check the Low Gas Pressure Switch, first close the upstream manual shutoff valve (both manual shutoff
valves should now be closed).
2. Start the burner and wait 10 seconds during purge for CAPS to be made.
3. Turn the LGPS setting to maximum.
4. Open the test cock to bleed the gas line.
5. The controller should lock out. The screen will indicate Lockout 67 ILK OFF.
6. Reset the controller and change the LGPS setting back to minimum to proceed.
CAPS (Interrupted Airflow Switch)
1. Initiate burner sequence.
2. During purge cycle, set Combustion Air Proving Switch to its maximum setting.
3. The CB Falcon should lock out on an airflow failure. The display will show Lockout 65 Interrupted Airflow
Switch OFF.
Note: If the CAPS fails to open even when set to maximum, test by disconnecting the low-pressure line to the
switch and initiating burner sequence. The switch should now break during the purge cycle. Reconnect low-pres-
sure side after a successful CAPS check.
4. Following a successful CAPS check, dial the CAPS back to its minimum setting and reset the CB Falcon.
Note: The CAPS is ignored when the boiler is in “Run” state. A CAPS test must be performed during Purge or
Trial for Ignition.
HGPS and GAS VALVE
1. Open the upstream manual shutoff valve and wait a few moments for gas pressure to rise.
FIGURE 4-14. Annunciation screen
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