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BTU VENTILATION CORPORATION
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OFFICE 888-884-8070
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FAX 218-346-7485
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www.btucorp.com
XT-70 Control Panel
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at 85%. Once the purge is over the fans will go to the previous setting.
If the XT panel is in Refrigeration or a Timed run the XT would pulse the fresh air doors open
to the Max Door setting for the length of the purge.
If the XT panel is in Cooling and the Heat Switch is in Auto, the XT panel will turn the Return
air heaters on for the duration of the purge.
To use this configuration, set the following E2 parameters:
Purge_Cnfg = 1
Purge_cnfg = 2
ARL: (Ambient Reverse Loading) This purge cycle uses the fresh air doors to false load the
refrigeration when you have minimum loading and the refrigeration wants to cycle on and off.
When the Refrigeration output drops below the minimum Refrig_Level setting, the XT panel
will slowly pulse the Fresh Air doors in a Heat PID mode to bring in warm fresh air to keep the
Refrigeration system running. The Refrigeration system will run at the minimum setting and
the doors will modulate in a heat mode to control temperature. The doors can only open to
the Max Door Setting. The ARL mode will not only keep the refrigeration running, but will
purge the storage by bringing in fresh air after long runs of refrigeration. The ARL function is
primarily used in the spring when the refrigeration load is light.
The Outside air temperature must be above the start temperature for the ARL to become ac-
tive. Under some conditions it may be necessary to raise the start temperature to ensure the
outside air is warm enough. This can be done using the OSA Diff setting. To protect against
the OSA not being warm enough, the parameter LC (low cutout) is used. This is in 1/10ths of
a degree and would have a default of 5.
To use this configuration, set the following E2 parameters:
Purge_Cnfg = 2
Ref_Level (ROL) default setting = 30%
ROL_Diff
default setting = 5%
Low_Cutout
default setting = 5 tenths of a degree
Max_Door
default setting = 20%