Questions
Answers
How can I find out what tonnage my unit is?
The easiest way to find out the tonnage of a unit is the model number on the nameplate. Tonnage is usually the first and/or second numbers in the model number. The nameplate contains a number of other key pieces of information as well. Nameplate diagrams are shown below.
What piping sizes should be used to connect split air-cooled Data Aire units?
The best way to get this information is to review the Operations and Maintenance Manual that comes with the unit. If you can not locate the Manuals they are also available on this website in the Download Literature section. Connections tables are shown below.
Can I install an Emergency Power Off (EPO) connection, and if so, where is it installed?
Yes, an Emergency power Off (EPO) connection can be installed on your Data Aire unit. First, locate the electrical panel on the Data Aire unit. Terminal blocks can be either vertical or horizontal, see top two photos below. Next locate connections 1 and 2. There will be a jumper between these connections, remove the jumper. Finally, connect your EPO between connections 1 and 2, see bottom two photos below.
Does the Data Aire unit ship with a refrigerant (R-22) charge in the system?
Data Aire units that have a self-contained refrigerant system, such as packaged and water/glycol cooled units, DO ship with a refrigerant charge. Air cooled units DO NOT have a charge, but may have residual refrigerant from factory run testing.
How many pound s of R-22 refrigerant are in my Data Aire unit?
A rule of thumb is to charge each circuit (larger units may have dual circuits) with 3 lbs. of refrigerant per circuit to start. Add more as needed based on pressure and superheat. For more details see the Operation and Maintenance Manual shipped with the unit. These manuals are also available for download from this website. The total charge of split systems will be dependent on several factors, including length of run, line size, and flooded system. Air cooled split systems are shipped without a refrigerant charge.
How much R-22 is needed per receiver tank?
The amount of R-22 in a receiver tank depends on the size of the receiver. Receiver size is determined by the size of the compressor. A small receiver is used for compressors of 6.5 ton or less. Medium receivers are used for compressors between 7.5 ton and 12.5 ton. Large receivers are used for compressors over 15 ton. Keep in mind that if you have a dual circuit machine the compressor tonnage will be half the nominal tonnage of the unit. For example, a DALA-1034 CO D (LCS system 10 ton, three phase, 406V, outdoor condenser with dual circuits) will have 2 5-ton compressors, not a single 10-ton compressor. Receivers are 80% full at the quantities indicted below.
1-6.5 ton compressor, with small receiver...36 lbs. of R-22
7.5-12.5 ton compressor, with medium receiver...62 lbs. of R-22
15 ton, or larger, compressor, with large receiver...94 lbs. of R-22
How much clearance around my Data Aire unit is required for servicing?
Data Aire recommends 36" on the front and two sides of floor mounted units, and on all sides for both ceiling and outdoor units.
What are the typical pressures for discharge and suction?
Discharge pressures range between 215 to 250 PSI. Suction pressures range from 60 to 70 PSI.
What are the typical temperatures for superheat and sub-cooling?
Sub-cooling temperatures range between 10 to 12 degrees F. Superheat temperatures range between 10 to 14 degrees F. with unit return air at 68 to 74 degrees.
Are traps required in refrigerant piping run with air cooled units?
Yes, trapping is required on both the discharge and/or suction lines. Discharge lines, also called hot gas lines, should be trapped at the top (inverted) and bottom, as well as every 15-20 feet of vertical rise as applicable. Suction lines should be trapped in a similar fashion.
How much steam is generated by the Nordec humidifier? Can it be adjusted?
The amount of steam generated depends on the model of humidifier you have in your Data Aire unit. To determine the model number, locate the product description label on the Nortec humidifier. Match the model number to the table below to determine the amount of steam generated. All humidifiers can be adjusted within the range shown. Factory setting is 60% of capacity. Additional details are available in the Operation and Maintenance Manual shipped with the unit.
Is an air vent valve required in the piping when an expansion tank is used?
Air vents must be installed in various locations in the piping system to purge air and for sure at the highest point in the piping system. One of the most common problems in water/glycol systems is the presence of air in the condenser loop. In addition, an expansion tank is recommended on glycol systems. The Operation and Maintenance Manual shipped with the unit, or available for download on this website, illustrates typical field piping for a glycol system.
How are ambient fans on the heat exchanger controlled? Can they be adjusted?
The first condenser fan motor (header end) has a fan speed controller on air cooled units. Secondary and subsequent ambient fans on heat exchangers are controlled by ambient sensing thermostats. These are preset at the factory, but can be adjusted in the field if conditions warrant. To adjust these thermostats, locate he electrical panel on the heat exchanger. The next photo shows the ambient sensing thermostats in the electrical panel. The lower photo is a close-up of an individual thermostat with indication of the adjustment screw.
Factory setting for a two-fan unit is first fan - fan speed controller (FSC), second fan - 25 degrees. A three-fan unit is first fan - FSC, second fan - 75 degrees, third fan - 25 degrees. A four-fan unit is first fan - FSC, second fan - 75 degrees, third fan - 85 degrees, fourth fan - 25 degrees. A five-fan unit is FSC, 65, 85, 75, and 25 degrees respectively.
What pressure in the condenser will cause the condenser fan motors to start?
The condenser fan motor will start when the pressure in the condenser reaches between 190 to 200 PSI fan speed control motor will start modulating.
What is the factory setting for the water-regulating valve?
Standard factory setting is between 215 and 250 PSI discharge pressure.
What is the GPM requirement for my Data Aire chilled water unit?
Chilled water equipment can have varying water flows, but a reasonable rule of thumb would be 2.5 GPM per ton. Under typical operating conditions, such as 72 degrees with 45 degree entering water temperature (EWT), this will yield a water temperature differential of about 10 degrees (LWT equals 55 degrees) For instance, model DACU 1834 is a nominal 18 ton unit so a water flow of 2.5 x 18 equals 45 GPM, can be calculated.
What is the factory setting of the thermal expansion valve (TXV)?
The factory setting for the TXV valve is the mid-range of the valve adjustment stem. The table below shows the settings per valve model. The model number is stamped on the valve body, or in some cases labeled on the top.
What is the anticipated difference in temperature from water-in and water-out for a chilled water unit?
The typical differential should be in the range of 10 to 12 degrees.
What is the anticipated difference in temperature from water-in and water-out for a water-cooled unit?
The temperature differential can range from 10 to 50 degrees depending on water temperature and flow.
Where is the location to pipe in a check valve on air-cooled split systems, per circuit?
A check valve is recommended and should be located 6' to 10' from the compressor on the discharge line.
Is the external static pressure (ESP) listed in the catalog external or total ESP?
All the external static pressure (ESP) listing in Data Aire's product catalogs are total ESP.
What are the low and high-pressure switch settings?
The low-pressure switch is set to 28 PSI. The high-pressure switch is set at 400 PSI.
What is the pressure setting for hot gas by-pass?
The factory/standard setting is to begin opening when the suction pressure falls below 60 PSI.
What is the pressure drop across the coils of Data Aire unit and/or the unit itself?
There are a number of factors that can affect these results as well as the configuration of the unit. In general the pressure drop across the coil is .3" to .5", and for the entire unit the pressure drop will range between 1.5" and 2.5". For more specific information on a particular unit contact the Engineering Department.
What are the pressure drops across components such as: plate and fin heat exchanger, regulating valve, coaxial coil and the units piping?
Pressure drops for individual components are not published because they vary from unit to unit. Heat exchangers, whether plate and fin, or coaxial, typically represent approximately 45% of the total loss. Regulating valves also represent approximately 45% of the total unit loss. The remaining 10% is the loss caused by internal piping. Exact breakdowns of these component values for specific models can be obtained by contacting Data Aire's Engineering Department. Please provide the unit's model and serial number.
What is the control logic between the energy saver and auxiliary cooling coils and the compressor(s)?
Energy Saver/Auxiliary Chilled Water Cooling will be available whenever the incoming water supply is below the setpoint of the Water Sensing Changeover Thermostat.
The Energy Saver/Auxiliary Chilled Water mode will operate only in a two (2) degree range. The range is between the return air setpoint plus deadband and two (2) degrees above this. If the temperature rises above this range, Energy Saver/Auxiliary Chilled Water Cooling will be inhibited for one (1) hour and DX cooling only will be available. After one (1) hour, it will try Energy Saver/Auxiliary Chilled Cooling again.
The chilled water valve proportionally opens 10% for each 0.1º F above the Temperature Setpoint plus Temperature Deadband.
The chilled water valve responds to a change of the return air temperature after each adjustment period. Then a change is made to the setpoint, the chilled water valve will delay its response for five (5) minutes, then will respond after each adjustment period.
If the temperature is consistently rising, then the valve will be opened more at each adjustment period. Likewise, if the temperature is consistently falling, then the valve will be closed more at each adjustment period. However, if the temperature movement changes directions, then it must change the amount of the deadband before the valve will be repositioned. The temperature can be slowly drifting back and forth within a deadband window at any point in the adjustment period and no valve changes will be made.
If the current temperature is higher than at the last adjustment period, the following sequence is used to determine the new valve position.
Current Temperature = Setpoint + Deadband + 0.0º F = 0% Position
Current Temperature = Setpoint + Deadband + 0.1º F = 10% Position
Current Temperature = Setpoint + Deadband + 0.2º F = 20% Position
Current Temperature = Setpoint + Deadband + 0.3º F = 30% Position
Current Temperature = Setpoint + Deadband + 0.4º F = 40% Position
Current Temperature = Setpoint + Deadband + 0.5º F = 50% Position
Current Temperature = Setpoint + Deadband + 0.6º F = 60% Position
Current Temperature = Setpoint + Deadband + 0.7º F = 70% Position
Current Temperature = Setpoint + Deadband + 0.8º F = 80% Position
Current Temperature = Setpoint + Deadband + 0.9º F = 90% Position
Current Temperature = Setpoint + Deadband + 1.0º F = 100% Position
Where is the low voltage wiring connected between the evaporator and the condenser or fluid cooler heat exchangers?
FLOOR UNITS - First locate the electrical box in the indoor unit and then the terminal block within the electrical panel. See photos below. On the indoor unit, terminal block connections 42 and 43 connect to the indoor evaporator. On the outdoor unit, 39 and 40 should be connected to the outdoor condenser.
CEILING UNITS - First locate the electrical box in the indoor unit and then the terminal block within the electrical panel. On the indoor unit terminal block connections 39 and 40 connect to the indoor evaporator. On the outdoor unit, 39 and 40 should be connected to the outdoor condenser.
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