15604-6
AUTOMATIC TEMPERATURE CONTROL (ELECTRIC)
Required indicating and control devices shall be installed in the cover.
Terminal strips shall be provided for all electrical connections.
Panels shall be central and/or local as indicated or required.
5. Control Panels shall be provided in accordance to Section 16160.
R. Gauges: Thermometers and pressure indicating gauges shall be provided as shown
on the Drawings and other points throughout the system where the visual indication
of temperature or pressure is required or will prove beneficial to operating personnel
in the operation of the control system. Gauges will not be required on room type
thermostats.
S. Timer/Controller: Repeat Reset Cycle Timers shall be rated 120 volts. The cycle
shall automatically reset to origin upon loss of power. The "ON" timing circuit shall
be continuously adjustable up to a period of 60 minutes. The "OFF" timing circuit
shall be continuously adjustable up to a period of 10 hours. Both circuits shall have
a minimum setting of 3% of range. Setting accuracy shall be 10% of range maximum.
Timer life shall have a warrantee through 10,000,000 operations (no load). An LED
cycle progress annunciator shall be provided with each timing circuit. Contacts shall
be NO and/or NC as detailed on the Drawings, and shall be rated 7 amperes at 125
volts. Repeat, Reset Cycle Timers shall be suitable for recessed panel mounting, and
shall be Automatic Timing Controls 342 series, or equal.
FY
PART 3 - EXECUTION
3.1 DESCRIPTION OF OPERATION
A. Packaged VAV Cooling Air Handling Unit (CRTU-1):
1. | Occupied/unoccupied schedule shall be programmed as provided by the owner.
2. Supply fan:
a. Occupied operation: The fan shall be energized and the integral variable
frequency drive shall modulate the fan speed as necessary to maintain a
0.75” WG static pressure in the supply duct upstream of the VAV terminal
boxes..
b. Unoccupied operation: The fan shall be de-energized.
3. Ventilation:
a. Occupied operation: The outside air damper shall be open to minimum
position and the return air damper open to maximum position to provide
ventilation air.
b. Unoccupied operation: The outside air dampers shall be closed and the
return air damper shall open fully.
c. The exhaust air damper shall be closed at all times unless economizer
operation is available and the outside air damper is open beyond the
required position for ventilation.
4. Cooling: When the temperature rises above 60°F at the outside air temperature
sensor, or when the temperature at the outside air temperature sensor is above
50°F and the outside enthalpy is greater than the indoor enthalpy, CRTU-1 shall
be in cooling mode.
a. Occupied operation: The compressors and hot gas reheat shall
stage/modulate as necessary to maintain a discharge air temperature of
55°F (adj.) at the discharge air temperature sensor.
13089K
