BTU XT-70 - Page 100

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XT-70 Control Panel 100
Purge Cycles During Cure with a CO2 Sensor:
Sweet potatos initially will give off a large amount of CO2. A typical setpoint would be 85 de-
grees during cure. If the product is brought in cooler than 85 degrees and the outside air is
less than 85, heat will be needed. During this time of heating, the CO2 will need to be
purged. If a CO2 sensor is being used, purge config 7 would be the ideal purge cycle.
If the system is running in Cooling and the CO2 level exceeds the CO2 Setpoint, the fresh air
doors will be pulsed open to the Max door setting. If during this opening of the fresh air
doors, the plenum temperature drops below the Low Dev setting, the doors will be closed 5%
until the plenum rises.
If the system is running in Warming and the CO2 level exceeds the CO2 Setpoint, the fresh
air doors will be pulsed open to the Max door setting. During this operation, the plenum tem-
perature will be monitored. If the Plenum temperature rises above the High Dev setting the
doors will be closed 5% every update until the temperature goes below. If the Heat switch is
on the heat will come on if the plenum temperature drops below the SP minus the heat
diff. This purge would typically be used without heat.
Cold Purge
Mode =
Cooling
Mode =
Warming
yes
no
Low Dev
no
Pulse Fresh Air
Door to Max position
Return
CO2 > CO2 SP
yes
no
CO2 <
CO2 SP-Diff
no
yes
no
Pulse Fresh Air
Door to Max position
High Dev
yes
no
Return
Mode =
Time
no
Mode =
Refrig
yes
yes
yes
no
ARL Purge 7
yes
Purge Off Clear MCR Timer
Close door 5%
Close door 5%