DA LCS System Specifications Guide
Computer Room Air Conditioning Units
Basis-of-Design Product: Subject to compliance with requirements, provided product indicated on drawings or comparable product by one of the following:Data Aire, Inc.
Description: The environmental control, Computer Room Air Conditioning, units shall be provided with a high sensible cooling system, self-contained, and shall be capable of humidifying, dehumidifying, and filtering air. Units shall be factory assembled, piped, wired and factory run tested prior to shipment. Provide quantities and configurations as shown on the project drawings.
Cabinet and Frame
The frame shall be constructed of 14 gauge welded tubular steel and coated with a heavy corrosion inhibiting finish. The outer galvanized steel casing shall have removable panels for servicing. The panels shall be insulated with ½” neoprene insulation for protection and sound attenuation. The electrical panel shall be hinged and swing out for servicing. A stainless steel drain pan shall be provided integral to the unit.
Blower Section
The blower section shall be belt driven centrifugal type, double width, double inlet and shall be statically and dynamically balanced at the factory as a complete assembly to maximum vibration level of two mils in any plane. The blower wheel shall be supported by a heavy steel shaft having self-aligning ball bearings rated for an average life of 100,000 hours. The blower shall be driven by a motor mounted on an adjustable slide base. The motor shall be 1750 rpm and have internal overload. The drive shall be belt driven with variable pitch sheave sized for 200% of the fan motor horsepower. The blower shall be located to draw air over the coil to insure even air distribution and maximum coil performance.
Filter Section
The filter chamber shall be an integral part of the system, designed within the frame and cabinet. The filters shall be four inch (4″) pleated type rated MERV 8 (based on ASHRAE Std. 52.2).
Electric Reheat
The reheat shall be of the finned enclosed sheath type, fabricated of a stainless steel core sheath with plated fins to withstand moist conditions. The reheat shall be installed on the leaving air side of the cooling coil and shall be two stage. The total kW shall be 15 to operate on supply of ___ volts, 3 phase, 60 hertz.
Refrigeration Circuit
Air Cooled with Remote Outdoor Condenser – The refrigeration circuit shall be split type with an indoor evaporator section and remote outdoor condenser. The refrigeration circuit shall be a (single/dual) circuit system.
The indoor evaporator section shall include the cooling coil, compressor(s), humidifier, reheat, filters, and controls. The cooling coil shall be constructed with 1/2″ O.D. copper tube with 12 fins per inch of corrugated aluminum for maximum heat transfer. Maximum face velocity shall be less than 500 feet per minute. The expansion valve(s) shall be of the adjustable thermostatic type with external equalization. The compressor(s) shall be hermetic scroll type, with complete overload protection on all three power lines, internal thermostat for winding protection, crankcase heater, sight-glass and low pressure override timer for positive starting at low temperatures. The filter drier shall be of the flare fitting type for non-torch servicing. The circuit(s) shall contain high and low pressure safety switches. The high and low-pressure safety switches shall be installed with Schrader type fittings with valve core.
Each system shall include a low profile, slow speed and direct drive propeller type air cooled condenser. The air discharge shall be vertical to minimize the effects of wind blowing through the coil at low ambient temperatures. The condenser shall be constructed of aluminum and contain a 1/2″ O.D. copper tube coil with corrugated aluminum fins for maximum heat transfer. The condenser shall have fan speed control with transducers to modulate the speed of the first condenser fan motor and provide positive start-up and operation at ambient temperatures to -20° F. Additional condenser fan motors are to be controlled by ambient thermostats. All controls including the fan speed control shall be factory mounted in the air cooled condenser in integral factory wired and tested control panel. The air cooled condenser shall be manufactured by the manufacturer of the indoor unit.
Refrigerant piping and control wiring between the indoor evaporator section and the remote outdoor condenser shall be field provided.
CONTROL SYSTEM
The Mini-dap™4 offers the definite answer for precision environmental control with the fast and most advance controller with 50MHz, 32 bit microprocessor. The system is comprised of two components – a wall-mount display module and a control module. The wall-mount display module includes a backlit liquid crystal display and six buttons for easy programming and remote mounted temperature and humidity sensor. All settings, status and alarm conditions are displayed on the module in easy to read verbiage. The control module is mounted inside the unit and connected to the display module via a special “telephone” like cable.
The wall-mount display module will allow recall and display of the high and low temperature and high and low humidity for the last 24 hours; current percent of capacity and average percent of capacity for the last hour of operation for cool 1, cool 2, reheat, humidification, dehumidification, component runtimes for fan motor, cooling stages, reheat, humidification, dehumidification and chilled water valve. Programming will have multi-level password and accomplished entirely from the front of the wall mount display module. Programmable functions shall be entered on flash memory to ensure program retention should power fail. The historical database shall be maintained by rechargeable battery backup. Multiple messages shall be displayed by automatically scrolling from each message to the next. Alarm conditions shall be displayed by automatically scrolling from each message to the next. Alarm conditions, in addition to being displayed, shall enunciate an audible alarm. Programmable summary contacts shall be available for remote alarm monitoring. Additional test or service terminal shall not be required for any functions. The control shall include temperature anticipation, moisture level humidity control.
An alarm condition shall continue to be displayed until the malfunction is corrected. Multiple alarms shall be displayed sequentially in order of occurrence and only those alarms, which have not been acknowledged, shall continue to sound an audible alarm. A user accessible diagnostic program shall aid in system component trouble shooting by displaying on the unit LCD screen the name of the controlled item, output number, terminal plug or pin number for each controlled item.
Automatic Control Functions
- Humidity Anticipation
- Start Time Delay
- Energy Saver (Glycol Operation)*
- Dehumidification Lockout
- Sequential Load Activation
- Automatic or Manual Restart mode
- Compressor Short Cycle
Condition and Data Routinely Displayed
- Unit Status
- Unit type
- Current Date and Time
- Unit ID /Zone ID*
- Humidity Setpoint
- Temperature Setpoint
- Current Temperature
- Current Relative Humidity
- Cooling stage 1, 2*
- Dehumidification
- Reheat 1
- Humidification
- Energy Saver On*
- Current Chilled Water Valve Position*
- Chilled Water Temperature*
- Discharge Temperature*
Switching and Control FunctionsFan, Cool 1, Cool 2*, Heat, Humidification, Dehumidification, CW Valve*
Menu Selection Buttons and Switches
- Alarm/Silence Button
- System On/Off/ESC Button
- Select Up/Down Buttons
- Menu Button
- Enter Button
Standard Alarms and Conditions
- High Humidity Warning
- Low Humidity Warning
- High Pressure Compressor
- Compressor Short Cycle
- Humidity Sensor Error
- High Temperature Warning
- Low Temperature Warning
- Firestat Tripped
- Temperature Sensor Error
- Local Alarms
- Power Failure Restart
- Maintenance Required
- High Condensate Water Level
- Person to Contact on Alarm
Optional Alarms**
- Smoke Detector*
- Low Pressure Compressor
- Standby Pump On*
- No Water Flow*
- Dirty filter*
- Fan Motor Overload*
- Custom Message**
- Discharge Sensor Error*
- Chilled Water Sensor Error*
- Unit in standby**
- Humidifier inhibited*
- Reheat Inhibited*
- Reheat and Humidifier inhibited*
Historical Data
- High/Low Temperature Last 24 Hrs
- High/Low Humidity Last 24 Hrs
- Humidifier, and Chilled Water *
- Low Temperature Last 24 Hrs
- Alarm History (Last 100 Alarms)
- Percent of Cap. Utilized in the last hr
- High Humidity Last 24 Hours
- Hourly Average of Duty
Equipment Runtimes for: Blower, Compressor 1, Compressor 2*, Reheat, Dehumidification, Energy Saver*
Programmable Functions
- Temperature Setpoint
- Temperature Deadband
- System Start Delay
- Low Temperature Alarm Limit
- Humidity Deadband
- Humidity Setpoint
- High Humidity Alarm Limit
- Low Humidity Alarm Limit
- Define Password
- Reset Equipment Runtimes
- Audio Alarm Mode
- Humidity Anticipation
- Compressors(s)
- Calibrate Temperature Sensor
- Temperature Scale
- High Temperature Alarm Limit
- Water Valve Voltage Range*
- Firestat Temperature Alarm Limit
- Manual Diagnosis
- No water flow alarm action*
- Remote Alarm contacts
- Calibrate Discharge Air Sensor*
- Person to contact on Alarm
- Dehumidification Mode
- Reheat mode
- Calibrate Humidity
- Humidifier
- Compressor Assists to Energy Saver*
- Network Protocol
- Compressor Lead/Lag Sequence*
- Calibrate Chilled Water Temp. Sensor*
- Scheduled Normal Maintenance
- Power Problem or Restart Mode
- Compressor Short Cycle Alarm
- Low Discharge Temp Alarm Limit*
* Some of the programmable selections, displays or alarms may require additional components or sensors** Note: Two optional alarms are available on DX system and three optional alarms on Chilled water system. In most cases, optional alarm requires optional sensor or detector.
In addition, the Mini dap4 control panel shall support the following network protocols for integration with a Building Management System (BMS) for Computer Room Air Conditioning (CRAC system monitoring and control: Modbus RTU, Modbus TCP/IP, SNMPv1/v2, BACnet IP or BACnet MS/TP and LonTalks. Unit(s) shall be furnished with an optional interface card to communicate directly with the Building Automation System (BAS) through a RS-485, Ethernet or LonTalks port. All alarms, set points, and operating parameters that are accessible from the unit mounted control panel shall also be made available through the BAS.
Options
Energy Saver Coil – Provide an Energy Saver Coil, built into the system to provide total matching capacity. Whenever the incoming water/glycol temperature is below the setpoint of the water sensing changeover thermostat, Energy Saver cooling shall be available. The water sensing changeover thermostat shall be factory set at 45° F/7.2° C. The water sensing changeover thermostat shall be field adjustable. Energy Saver mode shall operate during a need for cooling. Energy Saver mode shall operate in the following range: return air setpoint plus deadband plus 2 degrees. The Energy Saver valve shall open at setpoint plus deadband. The valve shall modulate as long as the space is between setpoint plus deadband plus 2 degrees. When the space temperature falls to setpoint, the valve shall close and the space shall be considered satisfied. While in Energy Saver mode with the valve open, if the incoming water/glycol temperature rises 3° F above the setpoint (of the water sensing changeover thermostat), the Energy Saver valve shall close and DX (mechanical) cooling shall begin. Provide a 3-way pressure control valve on the condenser water circuit, and 3-way valve on the economy coil. Common piping for coil and condensers shall be provided.
Auxiliary Chilled Water Coil – Provide an auxiliary chilled water coil. Units shall operate using the chilled water for cooling. Upon a loss of water flow or an increase in room temperature the system shall bring on compressor (DX) cooling. Separate piping shall be provided for the chilled water coil and refrigeration connections.
Remote Temperature and Humidity Sensors – Provide temperature and humidity sensors for remote wall mounting. Sensors shall be provided in a wall mount plastic case for remote sensing of temperature and humidity. 25 feet of shielded cable shall be provided for field wiring.
Unit Mounted Disconnect – Provide a unit mounted non-automatic disconnect switch installed in the high voltage electrical section. The operating mechanism shall prevent access to the high voltage electrical components until switched to the “OFF” position. The operating mechanism (handle) shall protrude through the exterior unit panel.
Steam Generator Humidifier – Units shall be furnished with an electric steam generator humidifier with “quick change” disposable cylinders and auto-flush cycle. The steam generator humidifier control system shall optimize cylinder life by concentrating incoming water to a predetermined conductivity much higher than that of any entering water. The control system shall continuously monitor the conductivity in the cylinder through its electronics, which shall allow water to be flushed as often as is necessary to maintain the level at this design conductivity. The high design conductivity shall result in a minimum flushing of heated water, which saves energy. The humidifier shall be designed to allow all units at any voltage to produce full rated steam output at an optimum low water level.
Provide a steam generator humidifier with a capacity of __ pounds per hour.
Hot Water Reheat – Provide hot water reheat. The coil shall be designed for 150-psi maximum water pressure and shall include a 2-way valve.
Hot Gas Reheat – Provide hot gas reheat. The hot gas discharge shall be used for reheat and maximum system efficiency.
Hot Gas Bypass – Provide hot gas bypass. Hot gas bypass control on the refrigerant circuit shall maintain minimum suction pressure during low load conditions
3-Way Water Regulating Valve – Provide a 3-way water-regulating valve for pressure control. The 3-way valve shall control the water/glycol flow rate to maintain the required capacity under varying conditions.
Condensate Pump – Provide a factory mounted and wired condensate pump. The condensate pump shall be complete with sump, motor, and automatic control. The pump shall be rated for 130 GPH @ 20 feet maximum or 40 GPH @ 20 feet with check valve.MERV 11 Filters – Provide MERV 11 filters (based on ASHRAE Std. 52.2) shall be 4-inch deep, pleated type.
Extended Compressor Warranty – Provide an extended compressor warranty for a period of two (2) or four (4) years in addition to the standard three (3) year warranty. The warranty shall be for replacement of compressors and does not include labor.
DA LCS System Specifications Guide – DA LCS System Specifications Guide –
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