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6. Water Out Sensor
The water out sensor is required for proper operation and
is plugged into the freeze sensor jack. Senses output
water temperature and the controller generates a FrE
freeze fault if the temperature drops below 38°F (3.3°C)
in cool mode. DDC generates a HiL high limit fault if the
water temperature rises above 125°F in heat mode. Should
the water out sensor fail, FSn is displayed indicating the
sensor is shorted open. The compressor will shut down
until the fault is cleared or for a minimum time equal to
the staging delay after which the compressor will restart.
The FrE fault will clear when the water temperature rises
above 49°F (9.4°C). The HiL fault will clear when the water
temperature drops below 110°F (43.3°C).
7. High Water Limit Electric Heat Sensor
- Required with Electric Heat
Senses water out temperature and DDC generates a HiL
high limit fault if the water temperature rises above 125°F
(51.7°C) while in the electric heat mode. The electric heater
shuts down for a minimum time equal to the staging delay
or until the water temperature drops below 110°F (43.3°C).
HSn is generated when the sensor is open or shorted and
the heater is shut down until the problem is corrected.
8. Low Freon Pressure Transducer -
Optional
Used to report suction side pressure to the Chilled Water
Master Control (CWMC) for diagnostic use when equipped
with the optional CWMC.
9. High Freon Pressure Transducer -
Optional
Used to report discharge pressure to the Chilled Water
Master Control (CWMC) for diagnostic use when equipped
with the optional CWMC.
System Outputs
1. Compressor
System can be directly connected to compressors up to
two horsepower at 230 VAC; 115 VAC systems can be up
to one horsepower.
DDC hardware includes a set of pilot duty compressor dry
contacts for other starting devices.
2. Chillwater pump
L-2281 Introduction
The Chillwater circulating pump is on when heating or
cooling is selected.
The Chillwater circulating pump output is rated 10 amps @
230 VAC and 15 amps @ 115 VAC.
Note: For resistive loads, see specifications for motor load
ratings.
3. Seawater pump
The seawater pump is on whenever the compressor
is running unless otherwise programmed (see section
"Program Seawater Pump Operation").
The seawater pump output is rated 10 amps @ 230 VAC
and 15 amps @ 115 VAC.
Note: For resistive loads, see specifications for motor load
ratings.
4. Reversing valve
The reversing valve output is pilot duty only and it will be
energized when heating is called for. In addition, the valve
is toggled briefly to the opposite mode when heating or
cooling is required to equalize refrigerant pressures and
reduce the starting load. The valve will only toggle when
heating or cooling is called for and the system has been off
for less than 75 seconds (unless the system is configured
with an electric heater). System should be switched into
heat mode at least once a month to prevent reversing
valve from sticking in cool mode. If reversing valve does
get stuck, use a rubber mallet to very lightly tap it while
switching from cool to heat.
5. Electric heater dry contacts
DDC hardware includes a set of pilot duty dry contacts for
electric heater operation. These contacts will be energized
only when ELECTRIC heating is called for. The reversing
valve relay will also be energized in parallel with this relay
in electric heat mode.
Special Features
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