•The IAQ sensor reading is greater than the DCV start control set point.
The control has four user adjustable set points: DCV start control set point, DCV maximum control set point, minimum damper position, and DCV maximum damper position.
Two-Position OA Damper — The control can be configured to operate a ventilation damper in a two-position ventilation mode to provide the minimum ventilation requirements during occupied periods.
WATERSIDE ECONOMIZER — The WSHP Open control- ler has the capability of providing modulating or two-position water economizer operation (for a field-installed economizer coil mounted to the entering air side of the unit and connected to the condenser water loop) in order to provide free cooling (or preheating) when water conditions are optimal. Water econ- omizer settings can be accessed through the equipment status screen. The following conditions must be true for economizer operation:
•SAT reading is available.
•LWT reading is available.
•If occupied, the SPT is greater than the occupied cooling set point or less than the occupied heating set point and the condenser water is suitable.
•Space temperature reading is valid.
•If unoccupied, the SPT is greater than the unoccupied cooling set point or less than the unoccupied heating set point and the condenser water is suitable.
Modulating Water Economizer Control — The control has the capability to modulate a water valve to control condenser water flowing through a coil on the entering air side of the unit.
Cooling — The purpose is to provide an economizer cooling function by using the water loop when the entering water loop temperature is suitable (at least 5° F below space temperature). If the water loop conditions are suitable, then the valve will modulate open as required to maintain a supply-air temperature that meets the load conditions. Should the economizer coil ca- pacity alone be insufficient for a period greater than 5 minutes, or should a high humidity condition occur, then the compressor will also be started to satisfy the load. Should the SAT ap- proach the minimum cooling SAT limit, the economizer valve will modulate closed during compressor operation.
Heating — Additionally, the control will modulate the water valve should the entering water loop temperature be suitable for heating (at least 5° F above space temperature) and heat is required. The valve will be controlled in a similar manner ex- cept to satisfy the heating requirement. Should the economizer coil capacity alone be insufficient to satisfy the space load con- ditions for more than 5 minutes, then the compressor will be started to satisfy the load. Should the SAT approach the maxi- mum heating SAT limit, the economizer valve will modulate closed during compressor operation.
Two-Position Water Economizer Control — The control has the capability to control a NO or NC, two-position water valve to control condenser water flow through a coil on the entering air side of the unit.
Cooling — The purpose is to provide a cooling economizer function directly from the condenser water loop when the en- tering water loop temperature is suitable (at least 5° F below space temperature). If the optional coil is provided and the wa- ter loop conditions are suitable, then the valve will open to pro- vide cooling to the space when required. Should the capacity be insufficient for a period greater than 5 minutes, or should a high humidity condition occur, then the compressor will be started to satisfy the load. Should the SAT reach the minimum cooling SAT limit, the economizer valve will close during compressor operation.
Heating — Additionally, the economizer control will open the water valve should the entering water loop temperature be suit- able for heating (at least 5° F above space temperature) and
heat is required. The valve will be controlled in a similar man- ner except to satisfy the heating requirement. Should the coil capacity be insufficient to satisfy the space load for more than 5 minutes, then the compressor will be started to satisfy the load. Should the SAT reach the maximum heating SAT limit, the economizer valve will close during compressor operation.
DEMAND LIMIT — The WSHP Open controller has the ability to accept three levels of demand limit from the network. In response to a demand limit, the unit will decrease its heating set point and increase its cooling set point to widen the range in order to immediately lower the electrical demand. The amount of temperature adjustment in response is user adjustable for both heating and cooling and for each demand level. The re- sponse to a particular demand level may also be set to zero.
CONDENSER WATER LINKAGE — The control pro- vides optimized water loop operation using an universal con- troller (UC) open loop controller. Loop pump operation is auto- matically controlled by WSHP equipment occupancy sched- ules, unoccupied demand and tenant override conditions. Positive pump status feedback prevents nuisance fault trips. The condenser water linkage operates when a request for con- denser water pump operation is sent from each WSHP to the loop controller. This request is generated whenever any WSHP is scheduled to be occupied, is starting during optimal start (for warm-up or pull down prior to occupancy), there is an unoccu- pied heating or cooling demand, or a tenant pushbutton over- ride. At each WSHP, the water loop temperature and the loop pump status is given. The WSHP will NOT start a compressor until the loop pumps are running or will shutdown the com- pressors should the pumps stop. This prevents the WSHP from operating without water flow and thus tripping out on refriger- ant pressure, causing a lockout condition. The WSHP Open controller control will prevent this from occurring. Also, the loop controller can be configured to start the pumps only after a configurable number of WSHPs are requesting operation (from 1-"N"). This can be used to prevent starting the entire loop op- eration for only one WSHP. Meanwhile, the WSHPs will not operate if the loop pump status is off and therefore the WSHP compressor will not run.
COMPLETE C AND DELUXE D BOARD
SYSTEM TEST
System testing provides the ability to check the control operation. The control enters a 20-minute Test mode by momentarily shorting the test pins. All time delays are in- creased 15 times. See Fig. 13-17.
Test Mode — To enter Test mode on Complete C or Deluxe D controls, cycle the fan 3 times within 60 seconds. The LED (light-emitting diode) will flash a code representing the last fault when entering the Test mode. The alarm relay will also power on and off during Test mode. See Tables 29-31. To exit Test mode, short the terminals for 3 seconds or cycle the fan 3 times within 60 seconds.
NOTE: Deluxe D control has a flashing code and alarm relay cycling code that will both have the same numerical label. For example, flashing code 1 will have an alarm relay cycling code 1. Code 1 indicates the control has not faulted since the last power off to power on sequence.
WSHP Open Test Mode — To enter WSHP Open test mode, navigate from the BACview6 home screen to the config- uration screen. Choose the service screen and enable unit test. The controller will then test the following:
FAN TEST — Tests all fan speeds, sequences fan from low to high, and operates each speed for one minute. Resets to disable on completion.
COMPRESSOR TEST — Tests compressor cooling and heating operation. Sequences cooling stage 1 then cooling
