VAV unit sensor option B - Johnson Controls - LIT-12011950 - Building automation software - Smart Equipment Controller - 5.0

Smart Equipment Controls Sequence of Operation Technical Bulletin

Product name
Smart Equipment Controller
Document type
Technical Bulletin
Document number
LIT-12011950
Version
5.0
Revision date
2024-06-06
Product status
Active

When free cooling available and the SAT is greater than the operating VAV SAT setpoint, the dampers modulate to control the operating VAV SAT setpoint +/-0.5°F.

If the economizer position remains at 100% for 10 consecutive minutes and the SAT is greater than the operating VAV SAT setpoint +5°F, the first compressor output energizes. If the economizer position remains at 100% for another 5 minutes and the SAT is greater than the operating VAV SAT setpoint +5°F, the second compressor output energizes. If the economizer position remains at 100%, the process repeats every 5 minutes until all the compressors energize.

If the economizer position drops below 100% and does not reach the minimum position then returns to 100%, remains at 100% for 5 minutes, and the SAT is greater than the operating VAV SAT setpoint +5°F, the next available compressor energizes. If the economizer position remains at 100%, the process repeats every 5 minutes until all the compressors energize.

Any time the economizer remains at the minimum position for 5 consecutive minutes or the SAT is lower than the operating VAV SAT setpoint -5°F, the last energized compressor turns off. If it remains at the minimum position or the SAT remains lower than the operating VAV SAT setpoint -5°F, the compressors de-energize every 5 minutes until all the compressors are off.

If all compressor outputs de-engerize, the economizer modulates to control to operating VAV SAT Setpoint+/-0.5°F.

When the cooling demand ends the compressors de-energize immediately and the dampers return to operating minimum position.