Despatch LFD Series with Protocol Plus User Manual
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Note that in a Class A oven, the heater can not be energized until the forced exhaust
system has brought in a minimum amount of fresh air into the chamber. The purge
timer provided prevents the heater from energizing until the oven has had enough time
to bring in the amount of fresh air required. The purge timer is energized by the airflow
switch which closes when the exhaust system is running.
The pre-determined purge time is two minutes for the LFD1-42 and LFD2-24 and three
minutes for the LFD2-11.