44 Questions
What is the first step in the typical sequence of operation for most programming controllers mentioned in the text?
Pre-ignition Interlocks
When does the BMS start the draft fan according to the sequence of operation outlined in the text?
After Pre-ignition Interlocks and High airflow
What initiates the increase in fan speed or combustion air damper position to high-fire position as per the text?
High airflow
What marks the completion of the purge process as per the typical sequence of operation discussed in the text?
Low airflow
When does the BMS ignite the pilot flame based on the sequence of operation detailed in the text?
After Low airflow
What is the purpose of waiting up to 10 seconds after starting the igniter according to the text?
To stabilize the pilot flame
What happens when the steam pressure or hot water temperature rises above the set point of the operating control?
The programming controller de-energizes the SSOVs
What occurs during the programming controller's post-purge phase?
The flame is extinguished
What does the programming controller do during standby mode?
Allows time for SSOV proof-of-closure switches to close
If the SSOV proof-of-closure switches do not close during standby, what does the programming controller do?
Remains in standby mode until corrected
When a call for heat is received and all permissives are satisfied, what does the programming controller do?
Repeats the startup sequence
What will the BMS do if the pilot is too small to reliably light off the main burner?
Shut the pilot SSOV and lockout the burner system
During the main flame trial for ignition period, what happens if the main flame is not established within 10 seconds?
A safety shutdown and lockout occurs
What initiates the Safe Start stage in the operating sequence chart?
Power quality evaluation
What happens if a flame is detected during the safe start check according to the text?
Controller returns to standby mode
During the Pilot Trial for Ignition period, what is expected if the pilot flame is not proven within 10 seconds?
Safety shutdown will occur
What does the BMS do if a permissive switch opens during the run period?
Shuts off SSOVs and conducts a post-purge of the furnace
What happens if a flame is not detected during safe start check?
The controller begins the purge.
Which component must be at the proper pressure to satisfy the low atomizing medium cut-off switch for an oil-fired boiler?
Atomizing medium
What must be running to satisfy the low fuel pressure cut-off switch for an oil-fired boiler?
Oil pumps
In a dual fuel boiler, what must be placed on either oil or gas depending on the fuel used?
Fuel selector switch
What is required to initiate the boiler ignition sequence according to the text?
Closing the main electrical disconnect switch
What does closing the on-off switch during initial startup lead to?
Initiating the firing sequence
What is needed for the programming controller to move from standby mode to safe start check mode?
'On-off' and 'operating control' switches closed
What happens if the pilot fails to light within 15 to 90 seconds?
The primary controller will go into safety shutdown and lockout.
If the main flame goes out during the run period, what action does the burner take?
Goes into safety shutdown and lockout.
What does the primary controller do in case of a second failed attempt to establish a pilot?
Goes into safety shutdown and lockout.
What action is taken if the number of main flame failures in a call for heat cycle reaches 5?
A 5-minute natural draft purge is performed before attempting to establish a pilot.
What must the operator do if there is an ignition failure during boiler startup?
Correct the problem and reset the control.
What are the conditions that must be satisfied before a boiler can be started by its programming controller?
The pressure should be above the cut-in setting.
What does the programming controller do if permissives and pre-ignition interlocks are not satisfied?
Purges the furnace first.
What happens if there is a main burner failure during operation?
The programming control will lock out.
What happens if there is an ignition failure during boiler startup?
The operator must manually ignite the burner.
What happens in case of a main flame failure during operation?
The operator must correct the issue and reset the control.
What happens when a safety shutdown and lockout occurs during the PILOT TRIAL-FOR-IGNITION PERIOD (PTFI)?
There is no pilot flame present at the end of the PTFI period
When does the burner restart automatically in an automatically fired boiler?
When the operating control closes
Which component of a natural draft gas-fired boiler is energized to light the pilot flame?
Ignition transformer and pilot SSOV
What is a requirement for all fuel-fired boilers?
Built-in self-diagnostics
What is indicated directly on the controller during a safety shutdown and lockout?
An ALARM light
What happens during a safety shutdown if an SSOV proof-of-closure switch opens during the RUN period?
There is no flame present
Which condition is likely to trigger a safety shutdown and lockout during the INITIATE period?
AC line power error occurred
What occurs when an operating control opens in an automatically fired boiler?
'Call for heat' condition initiates
'Shutdown without Lockout' occurs in an automatically fired boiler when:
'Call for heat' condition is initiated by pressuretrol
'Safety Shutdown and Lockout' closes all SSOVs and locks itself out when:
'Pilot is intermittent, pilot SSOV is NOT energized'
Test your knowledge on the primary control system of a boiler, including the functions of the pilot SSOV, main burner, operating control, and programming control. Understand how the system operates to maintain the desired steam pressure or water temperature.
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