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Chilled water valve “CLOSING” sequence (Decreasing Temperature)
1. The chilled water valve proportionally closes 10% for each 0.1ºF below the temperature setpoint plus 1ºF.
2. The chilled water valve responds to a change of the return air temperature after each adjustment period. When
a change is made to the setpoint, the chilled water valve will delay its response for fi ve (5) minutes, after which it will
respond after each adjustment period.
3. If the current temperature is lower than the temperature at the last adjustment period, the following sequence will
determine the new valve position:
Current Temperature = Setpoint + 1.0º F = 100% Position Open
Current Temperature = Setpoint + 0.9º F = 90% Position Open
Current Temperature = Setpoint + 0.8º F = 80% Position Open
Current Temperature = Setpoint + 0.7º F = 70% Position Open
Current Temperature = Setpoint + 0.5º F = 50% Position Open
Current Temperature = Setpoint + 0.4º F = 40% Position Open
Current Temperature = Setpoint + 0.3º F = 30% Position Open
Current Temperature = Setpoint + 0.2º F = 20% Position Open
Current Temperature = Setpoint + 0.1º F = 10% Position Open
Current Temperature = Setpoint + 0.0º F = 0% Position Open
4. If the temperature is consistently rising, the valve will open accordingly at each adjustment period. Likewise,
if temperature is consistently falling, the valve will close accordingly at each adjustment period. However, if the
temperature changes directions, then the temperature must change the amount of the deadband before the valve will be
repositioned. The temperature can slowly drift back and forth within a deadband window at any point in the adjustment
period without a valve position change.
ENERGY SAVER and AUXILIARY CHILLED WATER COOLING
1. Energy Saver/Auxiliary Chilled Water Cooling will be available whenever the incoming water (or water/glycol) supply
is below the energy saver chilled water temperature setpoint, menu 2-6.
2. The Energy Saver/Auxiliary Chilled Water Cooling mode will operate only in a two (2) degree range. The range
is between the return air setpoint plus deadband and two (2) degrees. If the temperature rises above this range, the
Energy Saver/Auxiliary Chilled Water Cooling will be inhibited for the amount of time set in sub-menu 3-8, “ENERGY
SAVER LOCK-OUT TIME” and DX (Direct Expansion) cooling will take over. After the amount of time set in sub-menu
3-8, “ENERGY SAVER LOCK-OUT TIME”, it will try Energy Saver/Auxiliary Chilled Water Cooling again.
3. The chilled water valve proportionally opens 10% for each 0.1ºF above the temperature setpoint plus temperature
deadband.
4. The chilled water valve responds to a change of the return air temperature after each adjustment period. When
a change is made to the setpoint, the chilled water valve will delay its response for fi ve (5) minutes, after which it will
respond to each adjustment period.
5. If the temperature is consistently rising, the valve will be opened more at each adjustment period. Likewise, if the
temperature is consistently falling, the valve will be closed more at each adjustment period. However, if the temperature
movement changes directions, then it must change the amount of the deadband before the valve will be repositioned.
The temperature can be slowly drifting back and forth within a deadband window at any point in the adjustment period
and no valve changes will be made.
6. If the current temperature is higher than at the last adjustment period, the following sequence is used to determine
the new valve position:
Current Temperature = Setpoint + Deadband + 0.0º F = 0% Position Open
Current Temperature = Setpoint + Deadband + 0.1º F = 10% Position Open
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