BTU XT Micro, Руководство пользователя

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XT-Micro Control Panel 23
CO2 CONTROL:
Theory
CO2 build up happens primarily during two different conditions. First when the system is in
Cooling and the outside air temperature is very cold. This will cause the fresh air doors to be
closed most of the time. During this period when little fresh air is being introduced in the stor-
age CO2 build can happen fairly rapidly. The best way to purge the CO2 under these condi-
tions is to turn on the return air heaters. The return air heaters will force the return tempera-
ture to climb by three degrees. This will cause the fresh air doors to open to maintain plenum
temperature and the CO2 will be purged out the exhaust doors. During this time the fan
speed may be increased to aid in purging the CO2. This second condition for CO2 build up
can occur during long refrigeration runs with the fresh air doors closed. If the refrigeration has
enough capacity the fresh air doors can be slowly opened to 20% until the CO2 is purged out
of the building and then the doors will close.
The best scenario is to activate the purge cycle using a CO2 sensor. If a sensor is not avail-
able then a purge cycle for cooling or refrigeration can be activated using the programmable
time clock.
The type of CO2 purge is controlled using the Purge_cnfg variable. This variable can be set
to the following applications:
0 = No Purge cycles.
1 = CO2 Time Purge using Time Clock only
2 = CO2 purge during Cooling or Refrigeration mode with CO2 sensor.
3 = Force Purge
Purge_cnfg = 0
No purge: Fresh air doors only open in the Cooling mode to control temperature. Set the
Purge_cnfg equal to zero.
Purge_cnfg = 1
CO2 Time Purge using Time Clock only: This mode will activate a time purge without using a
CO2 sensor. The operator must choose the desire time for the purge on one of the schedule
clocks. The purge schedule should be the set on the last used of the four schedule clocks.
This schedule clock should be set for mode 6 or purge. Choose the desired start and stop
times for the purge. The highest used schedule clock has priority over previous schedule
clocks. Example Schedule clock 1 could be set to run 24 hours in Cooling. Schedule clock 2
could be set for a 20 minute purge from 3am to 3:20am. Schedule clock 2 would have priority
over schedule 1. If the system was in the Cooling Mode and the schedule clock 2 was active
the system would continue to Cooling using the fresh air doors and the return air heater would
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