66 • dap4 User Manual
Compressor “OFF” sequence (Decreasing Temperature)
Cool 4 OFF at Temperature Se 3y°F
Cool 3 OFF at Temperature Se 2y°F
Cool 2 OFF at Temperature Se y°F
Cool 1 OFF at Temperature Setpoint
Note: y = “stage to stage” which can be changed in MenuB-Setpoints; default value is 0.3
5. If the temperature drops below the setpoint during an adjustment period, all compressors turn
OFF at once.
CHILLED WATER COOLING
Chilled water valve “opening” sequence (Increasing Temperature)
1. The chilled water valve proportionally opens 10% for each 0.1°F above the temperature set
point plus temperature deadband.
2. The chilled water valve responds to a change of the return air temperature after each adjust-
ment period.
If the current temperature is higher than the temperature at the last adjustment period, the follow-
ing sequence will determine the new valve position:
Current Temperature = Se De 0.0°F = 0% Position Open
Current Temperature = Se De 0.1°F = 10% Position Open
Current Temperature = Se De 0.2°F = 20% Position Open
Current Temperature = Se De 0.3°F = 30% Position Open
Current Temperature = Se De 0.4°F = 40% Position Open
Current Temperature = Se De 0.5°F = 50% Position Open
Current Temperature = Se De 0.6°F = 60% Position Open
Current Temperature = Se De 0.7°F = 70% Position Open
Current Temperature = Se De 0.8°F = 80% Position Open
Current Temperature = Se De 0.9°F = 90% Position Open
Current Temperature = Se De 1.0°F = 100% Position Open
Chilled water valve “closing” sequence (Decreasing Temperature)
1. The chilled water valve proportionally closes 10% for each 0.1°F below the temperature set
point plus 1.0°F.
2. The chilled water valve responds to a change of the return air temperature after each adjust-
ment period.
3. If the current temperature is lower than the temperature at the last adjustment period, the fol-
lowing sequence will determine the new valve position:
Current Temperature = Se 1.0°F = 100% Position Open
Current Temperature = Se 0.9°F = 90% Position Open
Current Temperature = Se 0.8°F = 80% Position Open
