Desert Aire Aura QS Installation And Operation Manual
  1. Manuals
  2. Brands
  3. Desert Aire Manuals
  4. Dehumidifier
  5. Aura QS
  6. Installation and operation manual

Desert Aire Aura QS Installation And Operation Manual

Indoor air quality
Hide thumbs
Table of Contents

Advertisement

Quick Links

• 100% Outdoor Air
Systems & High
Outdoor Air Systems
• Aura™ (QS), dedicated
outdoor air system,
offers a high quality
dehumidifier with
various options to
cover multiple
applications
• TotalAire™ (QS),
dedicated outdoor air
systems, offers an
optional energy
recovery wheel that
recovers both sensible
and latent heat.
• VerticalAire™ (QV),
dedicated outdoor air
system, is a high-
quality cost-effective
dehumidifier that's
designed for tight
spaces
Indoor Air Quality
Aura™ (QS)
TotalAire™ (QS)
VerticalAire™ (QV)
Installation and Operation Manual
Aura™ (QS)
Dehumidifier
TotalAire™ (QS)
Dehumidifier
VerticalAire™ (QV)
Dehumidifiers

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the Aura QS and is the answer not in the manual?

Questions and answers

Related Manuals for Desert Aire Aura QS

Summary of Contents for Desert Aire Aura QS

  • Page 1 Indoor Air Quality Aura™ (QS) TotalAire™ (QS) VerticalAire™ (QV) Installation and Operation Manual • 100% Outdoor Air Systems & High Outdoor Air Systems • Aura™ (QS), dedicated outdoor air system, TotalAire™ (QS) offers a high quality Dehumidifier dehumidifier with various options to cover multiple applications •...
  • Page 3 TERMS Desert Aire warrants all components (except as noted) for a period of two (2) years from the date of shipment. This warranty shall be limited to the supply of new or rebuilt parts for the part which has failed because of defects in workmanship or material, and does not include the cost for labor, transportation or other costs not herein provided for.
  • Page 4 PH: (262) 946-7400 • FAX: (262) 946-7401 • E-MAIL: service@desert-aire.com Additional copies of this manual can be purchased for a nominal fee from Desert Aire. Desert Aire also posts the most current revision of our I/O Manuals on our website. For a digital copy of the I/O Manual for your unit revision, please submit request to the contact information listed above.
  • Page 5 TO TURN OFF GAS TO APPLIANCE Set thermostat to lowest setting. Turn off all electric power to the appliance if service is to be performed. Turn gas control knob clockwise to "OFF" position. Desert Aire - QS/QV Manual...
  • Page 6 Caution used without the safety alert symbol indicates a potentially hazardous situation which, if not avoided, could result in property damage. Product Warning for the State of California Desert Aire - QS/QV Manual...

  • Page 7: Table Of Contents

    Aura™ and TotalAire™ Units ............3.3.2.2 Airflow Balancing for QV Dehumidifiers .......... 3.3.2.2.1 Damper Box Equipped VerticalAire™ Systems ....3.3.3. Airflow Balancing for Dedicated Outdoor Air Systems (DOAS) with Unoccupied Recirculation ................3.3.4. Airflow Balancing for High Outdoor Air Systems (HOAS) ....... 3.3.4.1 For Units with External Enthalpy Wheel (Aura™) ......3.3.4.2 For Units with CO Control (Aura™) ..........Desert Aire - QS/QV Manual...
  • Page 8 Component Replacement, Charge, Evacuation, & Leak Instructions ......5.6. System Rating Plate ...................... 5.7. Start-Up Supervision Supplemental Information ............5.8. System Start-Up Report ....................Start-Up Request Form ....................Start-Up Report ......................Compressor Replacement Form ................... Desert Aire - QS/QV Manual...

  • Page 9: Introduction

    Use moving equipment whenever possible. 1.3.1. Rigging the Dehumidifier Depending upon the unit type, various rigging methods are used to best lift the equipment. Please reference the applicable sections below: Desert Aire - QS/QV Manual...
  • Page 10 • All Products (QV and QS) Personnel should avoid stepping on the top of the unit. Desert Aire dehumidifiers are not designed to support the weight of a person on all portions of the roof. Damage incurred through caved or distorted top panels will not be covered under warranty. If you must walk on the top panels, carefully walk on the edges where structural integrity is greatest.
  • Page 11 Figure 1 - Typical Rigging for an IAQ Dehumidifier Do not tip the dehumidifier on its side. Avoid dropping the unit down stairways or subjecting it to severe mechanical shock. Desert Aire - QS/QV Manual...
  • Page 12 Desert Aire - QS/QV Manual...

  • Page 13: Installation

    Precautions should be taken for indoor units located within unconditioned spaces to prevent damage resulting from condensation. Do not install an indoor-rated dehumidifier in an outdoor or a wet environment. If you must install a dehumidifier outside you must use an outdoor-rated dehumidifier. Desert Aire seals and weatherproofs outdoor dehumidifiers to help prevent water infiltration. You can determine whether your dehumidifier is outdoor-rated by inspecting the unit rating plate. See section 5.6 for details. Desert Aire - QS/QV Manual...

  • Page 14: Duct Installation

    Note: Dehumidifiers with gas heating option may have condensate form inside the furnace heat exchanger since it is located downstream from the cooling coil. On indoor units, you must also connect the heater’s drain line (if present) to your field-installed condensate drainage plumbing. Note: While the supply blower runs, the drain pan area inside the dehumidifier operates at a negative pressure. Your unit requires a p-trap in the condensate drain pipe to prevent condensate from being drawn into the cabinet of the dehumidifier. Desert Aire - QS/QV Manual...
  • Page 15 Trap the condensate as shown in Figure 3. The P-trap dimensions in Figure 3 are sized for a maximum return air static of 2.0” of water. If your return air static exceeds this specification, consult Desert Aire for help in resizing the P-trap. You may also need to install a cleanout tee or plug near the trap. Note that the drain opening in the drain pan is off-center to simplify its cleaning and servicing.

  • Page 16: Auxiliary Heat Coil Piping

    6.0. Do not use water with high concentration of sulfur, chlorine, or sodium chloride. A dedicated circulating pump must be used unless the main pump can develop enough head to overcome the combined resistance of the water condenser and the piping connected to it. See specific Flow Rate section for the required water flow rate and head for your application. Desert Aire - QS/QV Manual...
  • Page 17 Do not exceed these guidelines as excessive flow rates will erode the condenser and piping. Aura™ Products Flow Rate The flow rate and antifreeze concentration (if used) will depend on the application. Please refer to Figure 4 and 5 for the required flow rate and temperature limits for the given application and unit type. If the application deviates from these conditions, please contact Desert Aire Service at 262-946-7400 for further review. Unit Size Fluid Flow Rate Fluid Pressure Drop (Nom.
  • Page 18 Figure 5 - Aura™ Q-Pump Minimum Water Temperature TotalAire™ and VerticalAire™ Products Flow Rate The flow rate and antifreeze concentration (if used) will depend on the application. Please refer to Figure 6 and 7 for the required flow rate and temperature limits for the given application and unit type as well as the glycol concentration requirements. If the application exceeds these conditions, please contact Desert Aire Service at 262-946-7400 for further review. Desert Aire - QS/QV Manual...

  • Page 19: Remote Condenser Installation (Air-Cooled Systems Only)

    Figure 7 - Glycol Concentration Requirements Remote Condenser Installation (Air-Cooled Systems Only) Important: Refer to the separate Air Cooled Condensers Installation and Operation manual for additional details on line design, traps, clamping, and other condenser installation requirements. Desert Aire - QS/QV Manual...

  • Page 20: High Voltage Wiring

    On three phase units the power supply must have 4 connections (3 power and 1 ground). Connect the power supply wires to the main power block located in the upper section of the electrical compartment. Desert Aire - QS/QV Manual...

  • Page 21: Wire And Fuse Sizing

    (RDT), in cases where the controller mounted display or IDT would prove hard to view or use. See the controller manual for details on wiring and environmental limits. Desert Aire - QS/QV Manual...

  • Page 22: Duct-Mount Sensor

    Auxiliary Heating Control Wiring Note: You must use the Desert Aire control system to control or interlock with the room heating system. This prevents wide fluctuations in room air temperature. It also prevents the heater from trying to heat the room while the dehumidifier is running in cooling.

  • Page 23: Gas Heater (Optional)

    “neutral” 24 VAC input and the “negative” signal input. You must follow the instructions included with the valve cut sheet. Observe the proper polarity, or you may damage both the valve and the Desert Aire controller. See the unit wiring schematic for information on signal wire connection points.

  • Page 24: Gas Piping

    LP gas is especially dangerous because it is heavier than air and may accumulate to a dangerous concentration at the floor level. 2.10.2 Gas Piping Gas supply piping installation should conform with good practice and to national and local codes. The orifice for the burners are sized for either natural gas (having a heating valve of 1025 BTU per cubic foot and a specific gravity of 0.60) or for liquefied propane gas (with a heating value of 2500 BTU per cubic foot and a specific gravity of 1.53). If the gas at the installation does not meet this specification, consult the factory for proper orificing. Desert Aire - QS/QV Manual...
  • Page 25 Use the table below as a guide to capacity. Note that each gas heat module in a TotalAire™ unit will have an independent connection. Aura™ units have a single gas heat connection. Ensure that any branch connection is also properly sized for a minimal pressure drop. Desert Aire - QS/QV Manual...
  • Page 26 Note: When sizing supply lines, consider possibilities of future expansion and increased requirements. Refer to National Fuel Gas Code for additional information on line sizing. Figure 9 - Gas Pipe Capacity in Cubic Feet per Hour Desert Aire - QS/QV Manual...
  • Page 27 Piping from the LP tank to the furnace must follow the recommendations of the gas supplier. • A readily accessible, certified manual shut off valve with a non-displaceable rotor member should be installed within six feet of the gas equipment it serves. Desert Aire - QS/QV Manual...
  • Page 28 Second Stage L. P. Gas NFPA-54 And NFPA-58 Regulator Tank 11"-14" Water Column Pressure At All Times. (Check Pressure At Burner) Typical 2-Stage L. P. Gas Piping Figure 11 - Recommended LP Gas Piping Method Desert Aire - QS/QV Manual...
  • Page 29 11” wc. Aura™ units – maximum supply pressure for liquefied petroleum (LP) gas is 13.5” wc and minimum supply for purpose of input adjustment is 11” wc. Before attempting to measure or adjust high fire manifold gas pressure, the inlet (supply) pressure must be within the specified range for the gas being both used when the heater is in operation and on standby. Incorrect inlet pressure could cause excessive manifold gas Desert Aire - QS/QV Manual...

  • Page 30: Gas Heater Location

    • Indoor units only: The dehumidifier must be located on a level, dry surface in an area which is free from and protected from excessive drafts or wind. It must be installed so that the electrical components are protected from water. If the area becomes wet or damp at times, the dehumidifier should be raised above the floor using concrete blocks or steel dunnage. Desert Aire - QS/QV Manual...
  • Page 31 Remember, chlorine is heavier than air. This fact should be kept in mind when determining installation location of these heaters and building exhaust systems. Desert Aire - QS/QV Manual...
  • Page 32 Desert Aire units are not designed or approved for use in atmospheres containing flammable vapors or atmospheres highly laden with chlorinated vapors. The following requirements must be followed when connecting this furnace to a vent system: • The connection of this burner to the vent system shall be in accordance with the local building codes, the vent manufacturer’s instructions and Part 7,...

  • Page 33: Electric Heater (Optional)

    Install swing joints in the connection piping to prevent damage to the coil header from thermal expansion. • Use a backup wrench on the pipe stubs when attaching connections to prevent damage to the header. Desert Aire - QS/QV Manual...

  • Page 34: Smoke Alarm Interlock

    Align the cover plate with the channel stiffener as shown in Figure 13. Place the cover plate on the channel stiffener, ensuring that the holes in the cover plate coincide with the four blank holes in the stiffener. Desert Aire - QS/QV Manual...

  • Page 35: Roof Curb W/ Wood Nailer (If Applicable)

    Roof Curb w/ Wood Nailer (if applicable) Certain options for curbs shipped with the Aura™ units include a treated wood nailer and flashing installed on the side of the curb. This allows for draining of the pan installed under the condenser section. The nailer and flashing should be carefully inspected on final installation of the roof material. Any separation of the flashing from the curb due to transportation and lifting will cause water to penetrate behind the flashing and past the roof materials. Re-caulk as required to close any gaps that may have occurred. Figure 15 - Wood Nailer Desert Aire - QS/QV Manual...

  • Page 36: Wheel Module Installation (Optional For Aura™ Products)

    Land the wires in the open terminals of the power block per the wiring diagrams. Repeat the above process for the communication cable, landing the leads in the appropriate terminal block per the wiring diagram. For outdoor units, an exhaust hood will be shipped inside the unit to be field installed. Install the hood using the hardware provided. Align the hood by the fastening locations on the side of the hood first, and the top last. Desert Aire - QS/QV Manual...

  • Page 37: Start-Up Procedures

    Energize any external auxiliary heaters before start-up so that the air is at the design temperature. Preliminary Inspection Verify that all contractors have completed their work. Find the Desert Aire Start-Up Report for QS/QV Models, which is near the end of this manual. You must fill out the start-up report to validate the dehumidifier warranty. Check the following items: •...

  • Page 38: Gas Heater Start-Up (Optional)

    Check the rubber tubing to the inducer fan pressure switch to make sure it is pushed firmly onto the pressure tap. • Indoor units only: Check all venting connections for tightness and to make sure there is no blockage. Desert Aire - QS/QV Manual...
  • Page 39 Remove the 1/8” threaded pipe plug located on the top right side of the gas valve. Use a U tube manometer or a pressure gauge to measure the pressure. To adjust the pressure, remove the screw from the regulator on the outlet side of the gas valve. Turn the Desert Aire - QS/QV Manual...

  • Page 40: Burner Adjustment

    85°F. If the outlet or supply duct temperature is too high, you must balance the supply airflow. Airflow Balancing To ensure code compliance and long equipment service life, proper airflow must be verified by a qualified air balancer. Shut off the compressor to prevent the refrigeration from running while you balance the air. If the unit is equipped with a Supply Fan Variable Frequency Drive (VFD) then the blower speed will be modified at the VFD. Unit airflow rate is specified at the time of order. The flow rate each unit has been designed for is indicated on a label near the air balance ports. A pressure differential across a fixed set of components that corresponds with the flow rate is shown on the label as well. This is a convenient method of setting and checking the flow. Alternatively, external test and balance may be completed with velometer, anemometer, flow hood, or other testing devices. In all cases the flow rate should be set according to the label to ensure appropriate operation and system reliability. Desert Aire - QS/QV Manual...

  • Page 41: Blower Adjustment Procedure

    If issues persist, consult the Desert Aire Service Department 262-946-7400. Prior to any calls to the Desert Aire Service Department please have the unit serial number and model number available.

  • Page 42: Unit With A Vfd

    If this happens, consult the Desert Aire Service Department 262-946-7400. Prior to any calls to the Desert Aire Service Department please have the unit serial number and model number. 3.3.1.3 Unit with a VFD The usage of the VFD controlled blowers allows for a simple way to achieve the correct speed required for proper air balancing.

  • Page 43: Aura™ And Totalaire™ Units

    Aura™ units have convenient ports located in the electrical system compartment. Figure 19- QS side view showing location of Air Balance Ports Figure 20- Aura™ side view showing location of Air Balance Ports Desert Aire - QS/QV Manual...

  • Page 44: Airflow Balancing For Qv Dehumidifiers

    Refer to the mechanical equipment schedule or other indication from the building designer for required flow rates. 3.3.2.2 Airflow Balancing for QV Dehumidifiers The total airflow of a Desert Aire VerticalAire™ QV system can be checked by measuring the static pressure drop across the reheat condenser and the dry evaporator coil for models 4-15 tons. For QV units 20-30 tons, the airflow may be checked by measuring the airflow across the reheat coil. The dehumidifier features an adjustable blower sheave to simplify air balancing. Desert Aire - QS/QV Manual...
  • Page 45 Always measure the current draw of the blower motor after you make any changes to the airflow quantity. If the motor draws more than its FLA rating but the total airflow is still low, check the resistance of the ductwork. Verify that all grilles and dampers have been opened and that there are no sudden turns or restrictions in the ductwork. Desert Aire - QS/QV Manual...
  • Page 46 Always measure the current draw of the blower motor after you make any changes to the airflow quantity. If the motor draws more than its FLA rating but the total airflow is still low, check the resistance of the ductwork. Verify that all grilles and dampers have been opened and that there are no sudden turns or restrictions in the ductwork. Desert Aire - QS/QV Manual...

  • Page 47: Damper Box Equipped Verticalaire™ Systems

    DOAS units do not have automatic control of the exhaust blowers. Verify that, in unoccupied mode, the exhaust blower shuts down. For TotalAire™ and VerticalAire™ Products Dehumidifiers designed for dedicated outdoor air operation with unoccupied Desert Aire - QS/QV Manual...

  • Page 48: Airflow Balancing For High Outdoor Air Systems (Hoas)

    Verify the blower is maintaining design airflow; it should maintain the design airflow throughout balancing so long as damper position changes are done slowly. Use the controller to adjust the recirculation damper to a more open position. Check Desert Aire - QS/QV Manual...

  • Page 49: For Units With External Enthalpy Wheel (Aura™)

    A separate damper and actuator are installed between the return air and outside air streams prior to the exhaust air entering the enthalpy wheel. Controls may be set to allow for a mixed air condition during occupancy and/or full recirculation air during unoccupied mode. Airflow must be balanced in both modes. Desert Aire - QS/QV Manual...

  • Page 50: Recirculation Mode (Totalaire™)

    Pressure differential across several components within the systems are measured. All of these devices are connected to the unit controller which takes the inputs from these pressure transducers and controls the fan speed accordingly. Desert Aire - QS/QV Manual...

  • Page 51: Unoccupied Mode With Recirculation (When Specified) (Totalaire™)

    (less than 200 PPM). An offset should be placed in the controller input to reduce the indoor sensor reading. If the reading is supplied by the BMS network, it is recommended that this reading be overridden at the BMS control. Desert Aire - QS/QV Manual...

  • Page 52: Occupied Mode Maximum Outdoor Air (Totalaire™)

    Operate the unit in unoccupied mode of operation. Typically the outdoor air damper will be set to 0% open position. Adjust the recirculation damper position to meet the required flow rate according to static pressure differential per the balance label or independent test and balance measurements. The airflow should be in the static pressure differential range or within +/- 10% of the specified airflow. Should the flow rate be too high or too low, note the static pressure in the mixing box and compare to the value measured during the occupied mode. Duct static pressures that are significantly different will affect airflow during the shifting of modes. Dampers or grille adjustments will be needed to create similar static pressure drops in each mode. Evaluate the system and adjust the dampers accordingly. Desert Aire - QS/QV Manual...

  • Page 53: Refrigeration Testing

    Some Desert Aire systems are shipped in sections to allow for installation of some of the sections in a location much different than another. An example is a unit with a remote condenser ready circuit. The dehumidifier may be installed indoors near the conditioned space while the remote condenser used to reject waste heat is located outdoors. The piping of the condenser is completed in the field before the unit is commissioned. The...

  • Page 54: Dehumidification / Cooling Mode

    (about 30 seconds) in order to ensure proper oil return. This will not substantially affect leaving air conditions and the unit will return to steady state within a few minutes. Desert Aire - QS/QV Manual...

  • Page 55: Heat Pump Mode

    10°F. See the Controller IO Manual for instructions on setting the supply air temperature set point. Note the original setting. Once the set point is adjusted, switch the unit to occupied mode. Desert Aire - QS/QV Manual...
  • Page 56 It can take up to 15 minutes for the unit to reach steady state. While in steady state operation, record the data required for the start-up report. If the supply air temperature set point was adjusted, return it to its original value. Desert Aire - QS/QV Manual...

  • Page 57: General Testing

    Check the temperature and humidity readings displayed on the controller. If you think the values are incorrect, check the sensor or its field-installed wiring for damage. • Check the operation of the auxiliary heaters by temporarily raising the air temperature set point on the Desert Aire controller. The duct heater(s) or heating valve should energize. Routine Maintenance Schedule 3.6.1 Service Every Month •...

  • Page 58: Service Every Six Months

    Vacuum or blow out any excess moisture from the wheel, dry off the base pans, and return the equipment to operation. The moving airflow will evaporate any moisture remaining within the wheel. Note that equipment used to dehumidify smoking areas or dusty industrial environments should be inspected and cleaned every two to three months to Desert Aire - QS/QV Manual...

  • Page 59: Gas Heater (Optional)

    Note: Please have the following information available if you need to call the Desert Aire Service Department: • Model Number • Serial Number • Room Temperature • Relative Humidity • Operating Refrigeration Pressures • Water Temperature • Compressor Amperage • Blower Motor Amperage(s) Desert Aire - QS/QV Manual...
  • Page 60 Desert Aire - QS/QV Manual...

  • Page 61: Troubleshooting

    Damper is stuck or frozen, preventing the defective actuator end switch from closing Correct cause and reset overload Blower overload has tripped Faulty control wiring Check for loose or incorrect wires on system and controller Desert Aire - QS/QV Manual...

  • Page 62: The Compressor(S) Do Not Run

    Excessive pressure drop in line sets Properly evacuate and recharge refrigeration Non-condensables in refrigeration system system Note: When the remote condenser is active and the outdoor temperature is above 95°F, normal head pressure can be as high as 480 PSIG. Desert Aire - QS/QV Manual...

  • Page 63: Low Pressure Alarms (Below 97 Psig) Evaporator Coil Icing

    Evaluate filter pressure drop and replace if Restricted refrigerant filter-drier necessary Evaluate expansion valve performance and Defective expansion valve replace if necessary Check coil for kinks in tubing and check for Restriction in refrigeration piping debris in distributor Desert Aire - QS/QV Manual...
  • Page 64 Desert Aire - QS/QV Manual...

  • Page 65: Appendix

    High current draw may be related to a bearing issue or a motor winding issue. The initial inspection must be combined with a final analysis of the machine when returned to working order to confirm diagnosis. Specific items should be noted before the replacement to give the best indications of the failure and complete the diagnosis as the new compressor is installed. Desert Aire - QS/QV Manual...
  • Page 66 The following procedures must be used depending on the results of the test above: Any Compressor Service • A new filter dryer must be installed when the system has been opened. If there is no acid or particulates indicated, the new compressor can be installed and run. Proceed to Testing and Final Diagnosis. Desert Aire - QS/QV Manual...
  • Page 67 Other compounds may be present in additives as carriers. Long-term effects of specific additives or compounds with a particular system or design are unknown without significant controlled testing. Particulate Indicated • Install a replaceable core liquid line filter shell. Note that larger Desert Aire systems will have replaceable core liquid line filter shells installed from the factory. The pressure drop levels will be monitored and several core changes may be required. Install ball valves on either side of the filter shell to facilitate these changes. • Install a secondary filter such as Sporlan FS-series or equivalent 20 micron filter in a replaceable core. • Ensure there are access fittings directly upstream and downstream of the liquid filter. There is typically one fitting installed on the filter shell. There is Desert Aire - QS/QV Manual...
  • Page 68 It is possible that there was an internal defect in the compressor or normal mechanical wear occurred over time. Compressors longevity generally is a function of load, lubrication, electrical input conditions, and temperatures. Desert Aire - QS/QV Manual...

  • Page 69: Recommended Duct Design

    Recommended Duct Design You must use proper duct design to ensure that the dehumidifier operates efficiently and without problems. Undersized or restrictive ducts reduce the system airflow, which can cause premature compressor failure. Use the following diagrams as a guide when you design the duct system. Figure 24 - Recommended Duct Designs for Desert Aire Dehumidifiers Desert Aire - QS/QV Manual...

  • Page 70: Recommended Controller Settings

    Desert Aire refers to this point as the Intake Air, or IA. This sensing point provides for stable unit operation and ensures that air delivered to the supply is less than the design dewpoint. In the case of QS units with energy recovery components upstream of the evaporator, sensing the IA at this point also provides the advantage of disabling the compressors periodically.

  • Page 71: Blower Operation

    OCCUPIED mode, except when a compressor is commanded ON and a low suction pressure condition exists. If the unit is in the UN-OCCUPIED mode, the blower will run on a call for unoccupied dehumidification, cooling or heating (not economizer mode), except if a compressor is commanded ON and a low suction pressure condition exists. Desert Aire - QS/QV Manual...

  • Page 72: Dehumidification Operation

    In this case, energizing the second stage compressor allows the unit to work as a relatively effective heat pump, converting the Desert Aire - QS/QV Manual...

  • Page 73: Cooling Operation

    The standard IAQ controller allows for predictive operation of compressor stages. While compressor operation is allowed at IA temperatures above 70°F, the use of a predictive calculation based on airflow will be used to determine the number of compressor stages required to meet the supply air temperature set point. Compressor capacity can be accurately predicted based on the unit nominal capacity and the airflow. In contrast to the dehumidification staging where enthalpy is used to calculate the compressor stages, the cooling can be accomplished based on dry bulb temperature alone since no dehumidification is required. Desert Aire - QS/QV Manual...

  • Page 74: Heating Operation

    Heating Operation 5.4.5.1 Water Source Heat Pump For Aura™ Products For water source heat pump units, Desert Aire does not use a reversing valve in the refrigeration circuit. Instead, Desert Aire uses solenoid valves which direct the refrigerant flow such that it always travels counter to the water flow in the coaxial heat exchanger. Heating operation is enabled when the intake air temperature (air entering the DX evaporator, downstream of the enthalpy wheel, if equipped) is below the supply air temperature set point and the supply air temperature dewpoint.

  • Page 75: Auxiliary Heat

    5.4.7 Compressor Rotation For any unit with more than one compressor, the compressors rotate based upon the last compressor to start, not the run hours. For units with 4 compressors, the refrigeration circuits Desert Aire - QS/QV Manual...

  • Page 76: Operation

    Also, restarting after an unoccupied cold soak condition needs to be addressed. Desert Aire - QS/QV Manual...

  • Page 77: Enthalpy Wheel Operation

    New dryer should be the same capacity as the original or larger. Recovery When there has not been a major refrigeration system leak, the system will contain refrigerant. This refrigerant must be either recovered to separate cylinders appropriate for the refrigerant type or isolated Desert Aire - QS/QV Manual...
  • Page 78 When this is not possible due to proximity of cabinet structure or other components, a tubing cutter can be used to remove sections of piping. Where new tube is required for replacement, use dehydrated tube where possible. Use the same type of fittings as original. Route the pipe in the exact manner as originally routed. Desert Aire - QS/QV Manual...
  • Page 79 Evacuation • Carefully inspect pump and related equipment before connecting to system. Ensuring gaskets are in good condition and pump is capable of low vacuum levels can save time. Connect pump(s) to as many locations as possible ensuring all locations are well sealed. If a field charge will be required, Desert Aire - QS/QV Manual...
  • Page 80 Purge system with nitrogen to atmospheric pressure (0 gauge pressure). Ensure all portions of systems are at this pressure. Seal system and wait 10 minutes. Start vacuum pump and draw system to 500 microns. Seal system. System may rise to higher level, Desert Aire - QS/QV Manual...
  • Page 81 Test component replaced and function of the system. Many times a separate component in the system may have set a condition that causes a failure of another. Thoroughly test systems to ensure repeat failures do not occur. Note: Compressors supplied with an oil sight glass should be viewed and filled to 50% capacity. Desert Aire - QS/QV Manual...

  • Page 82: System Rating Plate

    System Rating Plate The system rating plate is attached near the electrical enclosure of the dehumidifier. Figure 25 - System Rating Plate Desert Aire - QS/QV Manual...

  • Page 83: Start-Up Supervision Supplemental Information

    Start-Up Supervision Supplemental Information A Desert Aire factory start-up is an option which is normally purchased with the equipment. A factory start-up includes several key services: • The expertise of an accomplished, factory-trained mechanic who will supervise the commissioning of the equipment.

  • Page 84: Start-Up Request Form

    Factory Assisted Start-Up is not an installation bid & therefore the system must be ready to run before scheduling. CST Start-Up is performed by a local Certified Service Technician who has been trained by Desert Aire. The CST performs all duties listed above.
  • Page 85 Controls Company Name: ______________________________________________________________ Controls Contact: ________________________________ Cell# ___________________________ Test and Balance Company: _____________________________________________________________ Contact: _______________________________________ Cell# ___________________________ Factory use only – To be filled out by Desert Aire Scheduled Start-up Date: __________________ Unit Controls Protocol: JCI Metasys JCI FX Carel...

  • Page 86: Start-Up Report

    • Before continuing, read the Installation and Operations manual. If you do not fully understand the manual contact the Desert Aire Service Department. Please be prepared with the model and serial numbers located on the rating plate of the unit.
  • Page 87 Additional Oil Added Fan Cycle Controller Settings* This pertains to units with Remote Outdoor Condensers. Refer to Installation and operation manual for instructions. SENS SN-1 SN-2 SN-3 OUTR SENS OUTR SENS OUTR SENS OUTR SENS Desert Aire - QS/QV Manual...
  • Page 88 Suction Pressure Psig Psig Refrigerant Sight Glass Clear Superheat °F °F Subcooling °F °F Compressor Oil Level Sight Glass* ½ ¾ ½ ¾ (level should be at least 3/4 full at completion of the start up) Desert Aire - QS/QV Manual...
  • Page 89 Electric Heater °F Building Management System Information* Communication Type BACnet MS/TP BACnet Ethernet - Modbus (circle one) Device Instance BACnet MS/TP MAC Address Baud Rate IP Address BACnet Ethernet Netmask Gateway Baud Rate Modbus Address Desert Aire - QS/QV Manual...
  • Page 90 Additional Comments: Desert Aire - QS/QV Manual...

  • Page 91: Compressor Replacement Form

      Runs without pumping: Pressures:  _____  / _____  Other (describe):   Continuity (0 resistance) to Ground on one or more legs    Compressor drawing higher current than design    Continuity (0 resistance) between two or more legs     Compressor drawing locked rotor current    (3 phase units)      Runs without pumping: Pressures:  _____  / _____  Other (describe):   Final Determination of Failure Liquid Floodback    Low Superheat Debris Defective Expansion Valve Low Sump Oil Insufficient Motor Cooling Other (Describe): Diagnostic/Corrective Action Summary Describe what corrective action was taken to prevent a repeat failure.  _________________________________________________________________________________________________ _________________________________________________________________________________________________ _________________________________________________________________________________________________ ________________________________________________________________________________________________ Desert Aire - QS/QV Manual...
  • Page 92 PSIG  PSIG (At access fitting nearest TXV)  Suction Pressure  PSIG PSIG PSIG  PSIG (At compressor)  Liquid Line Temperature  °F °F °F  °F (At access fitting nearest TXV)  Suction Temperature  °F °F °F  °F (At Compressor)  Refrigerant Sight Glass Condition             (Clear, Intermittent Vapor, Flashing) Comp. Oil Level Sight Glass  ½       ¾       F  ½       ¾       F  ½       ¾       F  ½       ¾       F  (Shut down comps., wait 5 minutes)    Desert Aire - QS/QV Manual...
  • Page 93 Desert Aire - QS/QV Manual...
  • Page 94 PTIMIZING OLUTIONS HROUGH UPERIOR EHUMIDIFICATION ECHNOLOGY N120 W18485 Freistadt Road • Germantown, WI 53022 • E-mail: info@desert-aire.com Ph: (262) 946-7400 • Fax: (262) 946-7401 • Website: www.desert-aire.com 058 2018/12...

This manual is also suitable for:

Totalaire qsVerticalaire qv

Table of Contents