44 seconds after FD fan starts
75 seconds after FD fan starts
47 seconds after pre-purge
60 seconds after FD fan starts
10 seconds after pilot extinguishes
A nozzle and vane assembly
Number of cams and switches
Immediately after completion of the pilot flame trial.
Prior to pre-purging.
After the automatic main burner fuel valve opens.
At the same time as the automatic main burner fuel valve.
After pre-purging and just prior to pilot ignition.
Must be manually ignited.
Ignites before the main burner ignites, and is extinguished when the main burner is extinguished.
Is one that has been extinguished by an inadequate flame signal.
Ignites, is proven stable and extinguishes after the main flame is established.
Burns continuously, like that in a home furnace.
A post-purge begins.
The timer motor stops.
Operation control switch contacts close.
The main flame trial ends.
Flame failure switch contacts open.
Energizes the ignition transformer
Ends the ignition trial
Opens the main fuel valve
Closes the pilot valve
High steam pressure limit switch tripped.
Igniter transformer failure.
Pilot flame trial failure.
An interlock, such as the combustion air proving switch, has failed.
Main flame trial failure.
If the trial for ignition period has lasted approximately 15 to 30 seconds.
After the flame relay de-energizes.
Within 4 or 5 seconds.
After the main burner flame ignites.
Can be opened before the flame scanner sees a flame.
Can be opened any time during the start-up sequence.
Should be opened as soon as the pilot valve opens.
Must be opened before the ignition transformer energizes.
Must be closed before pilot ignition.
So that the operator has time to check the fuel and water systems.
So that combustibles are fully removed prior to ignition.
To cool the hot refractory.
So that the programmer has time to verify permissiveness.
So that combustion gases are fully removed prior to ignition.
Rapidly process large amounts of data.
Act as a networking switch.
Produce hypothetical solutions to problems.
Evaluate systems by comparison.
Perform only a specific dedicated task.
A laptop computer
A mainframe computer
A netbook computer
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