50
Units with Complete C or Deluxe D Controls
STANDBY
The Y and W terminals are not active in Standby mode; however,
the O and G terminals may be active, depending on the applica
-
tion. The compressor will be off.
COOLING
Y and O terminals are active in Cooling mode. After power up, the
first call to the compressor will initiate a 270 to 300 second ran
-
dom start delay and a 5-minute anti-short cycle protection time de
-
lay. After both delays are complete, the compressor is energized.
NOTE: On all subsequent compressor calls the random start delay
is omitted.
HEATING STAGE 1
Terminal Y is active in heating stage 1. After power up, the first
call to the compressor will initiate a 270 to 300 second random
start delay and a 5-minute anti-short cycle protection time delay.
After both delays are complete, the compressor is energized.
NOTE: On all subsequent compressor calls the random start delay
is omitted.
HOT GAS REHEAT (OPTIONAL FOR COMPLETE C OR
DELUXE D CONTROLS)
Terminal H is active in dehumidification mode with hot gas re
-
heat. After a call for H, the reversing valve (O), compressor (Y),
and fan (G) are also enabled.
NOTE: Any call for cooling (Y), heating (Y or W), or reversing
valve (O) will override dehumidification mode (H).
WATERSIDE ECONOMIZER (OPTIONAL FOR COMPLETE
C OR DELUXE D CONTROLS)
Y and O terminals are active in Cooling mode. When the enter
-
ing water temperature drops below the entering water tempera
-
ture set point on the waterside economizer aquastat, the com
-
pressor and reversing valve are disabled and the waterside econ
-
omizer is enabled. The waterside economizer three way control
valve will divert water to the economizer coil for free cooling.
When the entering water temperature rises above the aquastat set
point, the waterside economizer is disabled and the compressor
and reversing valve are enabled.
TWO WAY WATER FLOW CONTROL VALVE (OPTIONAL)
The two way water flow control valve is enabled anytime there is
a call for cooling (Y), heating (Y), or dehumidification (H) and al
-
lows water to flow through the unit. When there is no call for cool
-
ing, heating, or dehumidification, the water flow control valve is
disabled, stopping flow through the unit.
BOILERLESS HEAT (DELUXE D ONLY)
When the entering water temperature is below the boilerless heat
aquastat entering water temperature set point and there is a call for
heating (Y), the compressor is disabled and the auxiliary heat out
-
put is enabled. When the entering water temperature is above the
aquastat set point, the auxiliary heat output is disabled and the
compressor is enabled.
PUMP/VALVE RELAY (DELUXE D ONLY)
The pump/valve relay is enabled anytime there is a call for cooling
(Y), heating (Y), or dehumidification (H) and can be used to en
-
able/disable field installed flow control valves or circulator
pumps. When there is no call for cooling, heating, or dehumidifi
-
cation, pump/valve relay is disabled.
Units with WSHP Open Controls
Units with WSHP Open still feature a UPM board for unit opera
-
tion, so the operation will be similar to the sequence for the other
control packages. WSHP Open does feature advanced functional
-
ity, such as automatic fan speed control and intelligent alarming,
which will differ from the other control packages. Below is an
overview of the different features for the WSHP Open controls.
For more details of the WHSP Open operation, please refer to the
WSHP Open Integration Guide and the WSHP Points/Properties
Manual. See Fig. 40 for WSHP Open Control Board overview.
COOLING
The control will operate one or two stages of compression to
maintain the desired cooling set point. To improve dehumidifica
-
tion and reduce noise, the control operates the fan at the lowest
speed possible to satisfy the load conditions. If cooling is active
and should the SAT approach the minimum SAT limit, the fan will
be indexed to the next higher speed. Should this be insufficient
and if the SAT falls further (equal to the minimum SAT limit), the
fan will be indexed to the maximum speed. If the SAT still contin
-
ues to falls 5 degrees below the minimum SAT limit, all cooling
stages will be disabled.
During Cooling, the reversing valve output will be held in the
cooling position (either B or O type as configured) even after the
compressor is stopped. The valve will not switch position until the
opposite mode is required.
REVERSE CYCLE HEATING
The control will operate one or two stages of compression to
maintain the desired heating set point. To reduce noise, the control
operates the fan at the lowest speed possible. If the heating is ac
-
tive and should the SAT approach the maximum SAT limit, the fan
will be indexed to the next higher speed. Should this be insuffi
-
cient, then if the SAT rises further and reaches the Maximum
Heating SAT limit, the fan will be indexed to the maximum speed.
If the SAT still continues to rise 5°F above the maximum limit, all
heating stages will be disabled.
During Heating, the reversing valve output will be held in the
heating position (either B or O type as configured) even after the
compressor is stopped. The valve will not switch position until the
opposite mode is required.
TWO POSITION OA DAMPER
The control can be configured to operate a 2-position ventilation
damper to provide the minimum ventilation requirements during
occupied periods.
MODULATING OA DAMPER WITH DCV
The control can be configured to operate a modulating ventilation
damper during occupied periods that responds to changing CO
2
levels from an optional sensor. The control monitors the CO
2
level
and compares it to the configured set points and adjusts the venti
-
lation rate as required. The control provides proportional ventila
-
tion to meet the requirements of ASHRAE specifications by pro
-
viding a base ventilation rate and then increasing the rate as the
CO
2
level increases. The control has three user adjustable set
points; start ventilation maximum ventilation and maximum
damper position. The control will begin to proportionally increase
ventilation when the CO
2
level rises above the start ventilation set
point and will reach the full ventilation rate (maximum damper
position) when the CO
2
level is at or above maximum set point. A
user configurable minimum damper position ensures that proper
base ventilation is delivered when occupants are not present.
AUXILIARY MODULATING HOT WATER / STEAM
HEATING REHEAT
The control can modulate a hot water or steam valve connected to
a coil on the discharge side of the unit and supplied by a boiler in
order to maintain the desired heating set point should the compres
-
sor capacity be insufficient or a compressor failure occurs. Unless
the compressor fails, the valve will only operate to supplement the
heat provided by the compressor if the space temperature falls two
degrees or more below the desired heating set point. The valve
will be controlled so the SAT will not exceed the Maximum Heat
-
ing SAT limit.
Summary of Contents for AQUAZONE 50PSH
Page 17: ...17 Fig 15 PSC Motor Single Phase Single Stage WSHP Open Control ...
Page 20: ...20 Fig 18 Constant Torque Motor Single Phase Single Stage WSHP Open Control ...
Page 23: ...23 Fig 21 Constant Airflow Single Phase WSHP Open ...
Page 26: ...26 Fig 24 PSC Motor Three Phase Single Stage WSHP Open ...
Page 29: ...29 Fig 27 Constant Torque Motor Three Phase Single Stage WSHP Open ...
Page 32: ...32 Fig 30 Constant Airflow Motor Three Phase Single Stage WSHP Open ...
