Desert Aire Aura QS Installation And Operation Manual Download Page 47

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VerticalAire™ dehumidifiers may be equipped with a damper box that isolates

the unit when in unoccupied mode. A damper actuator in the box positions the

damper open when occupied. Airflow must be balanced in this mode. If this

option is equipped, operate the unit in occupied mode of operation and

balance according to the DOAS procedure above.

3.3.2.2.1 Damper Box Equipped VerticalAire™ Systems

VerticalAire™ dehumidifiers may be equipped with a damper box

that allows the unit to operate with recirculation air in the

unoccupied mode. Damper actuators in the box position the

dampers in the box to operate in full outdoor air mode or full

recirculation mode. Airflow must be balanced in both modes.

3.3.3 Airflow Balancing for Dedicated Outdoor Air System (DOAS) with

Unoccupied Recirculation

For Aura™ Products

Dehumidifiers designed for dedicated outdoor air operation with unoccupied

recirculation mode have two potential flow paths for supply air: full outdoor air or full

recirculation. The unit may have an energy recovery wheel and an exhaust airstream,

but these paths do not mix in a DOAS unit. A damper is installed on the intake of the

units ordered for outdoor installation; provisions for field installed damper are provided

on units to be installed indoors. A recirculation damper is installed within the unit.

Damper actuator control acts as binary. Outside air damper should be in the fully

closed position during unoccupied mode and fully open in the occupied mode with the

recirculation damper always in the opposite condition. Before starting the balancing

process, check that the ductwork is clear of any obvious restrictions.

Begin in occupied mode. Once the airflow damper is fully open and the recirculation

damper is fully closed, verify that the controller indicates the correct airflow. If too little

airflow is displayed, but the blower control signal is at maximum, there is too much

external static resistance. Evaluate ducts for high restriction. Repeat the process for

unoccupied mode, verifying that the outside air damper is fully closed and the

recirculation damper is fully open. Allow the blower to reach steady state before

verifying that the controller indicates the correct airflow.

For Aura™ units with an external enthalpy wheel, in occupied mode, use a

magnehelic or inclined manometer to measure the air pressure drop of the exhaust

blower. Increase the controller signal up or down until the exhaust air pressure drop

matches the pressure drop indicated on the wheel module label. 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

Summary of Contents for Aura QS

Page 1: ...pplications 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 TotalAire QS Dehumidifier VerticalAire QV Dehumidifiers Aura QS Dehumidifier ...

Page 2: ...2 ...

Page 3: ... 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 Replaced parts are warranted only for the remaining portion of the original warranty period CONDITIONS The warranty is subject to the following conditions 1 The unit must be properly installed a...

Page 4: ...nal injury so the above limitations may not apply to you for certain damages This warranty gives you specific legal rights and you may also have other rights which vary from state to state No person or representative is authorized to make any warranty or assume any liability not strictly in accordance with the aforementioned Inquiries regarding warranty matters should be addressed to Desert Aire C...

Page 5: ...ion D Do not use this appliance if any part has been under water Immediately call a qualified service technician to inspect the appliance and to replace any part of the control system and any gas control that has been under water OPERATING INSTRUCTIONS 1 STOP Read the safety information above on this label 2 Set the thermostat to lowest setting 3 Turn off all electric power to the appliance 4 This...

Page 6: ...jury Indicates an imminently hazardous situation which if not avoided will result in death or serious injury Indicates a potentially hazardous situation which if not avoided could result in death or serious injury Indicates a potentially hazardous situation which if not avoided could result in minor or moderate injury Caution used without the safety alert symbol indicates a potentially hazardous s...

Page 7: ...s Heater Location 30 2 11 Electric Heater Optional 33 2 12 Auxiliary Heat Coil Piping Optional 33 2 13 Smoke Alarm Interlock 34 2 14 Cover Plates if applicable 34 2 15 Roof Curb w Wood Nailer if applicable 35 2 16 Wheel Module Installation Optional for Aura Products 36 3 Start Up Procedures 37 3 1 Preliminary Inspection 37 3 2 Gas Heater Start Up Optional 38 3 2 1 Burner Adjustment 40 3 3 Airflow ...

Page 8: ...arms Readings Above High Pressure Trip Set Point 62 4 4 Low Pressure Alarms Below 97 PSIG Evaporator Coil Icing 63 5 Appendix 65 5 1 Compressor Failure 65 5 1 1 Compressor Replacement 65 5 2 Recommended Duct Design 69 5 3 Recommended Controller Settings 70 5 4 IAQ Sequence of Operation 70 5 4 1 Basic Sequence 70 5 4 2 Blower Operation 71 5 4 3 Dehumidification Operation 72 5 4 3 1 Packaged Units 7...

Page 9: ... claim form from the carrier Promptly fill out and return the form Carriers may deny claims that you have not filled out within a week of delivery Notify Desert Aire of any damage Damaged units must have signed documents at the time of delivery to be eligible for a freight claim 1 3 Rigging 1 Failure to observe rigging instructions may lead to equipment damage personal injury or death 2 Lifting me...

Page 10: ...tion using hand truck equipment dollies or pipe rollers Use caution to not damage the unit with the fork lift or tip the unit over ensuring it is kept as level as possible 20 30 Ton The base is equipped with a built in 12 gauge skid Use a fork lift to move the unit into place Use caution to not damage the unit with the fork lift or tip the unit over ensuring it is kept as level as possible In all ...

Page 11: ...1 Figure 1 Typical Rigging for an IAQ Dehumidifier 1 Do not tip the dehumidifier on its side 2 Avoid dropping the unit down stairways or subjecting it to severe mechanical shock Desert Aire QS QV Manual ...

Page 12: ...12 Desert Aire QS QV Manual ...

Page 13: ...w for proper airflow through the condensing section If three or more walls surround the unit consult the factory for proper unit location to allow for adequate airflow through the condenser section Install the unit on a sturdy level mounting base or platform that will prevent vibration and sound transmission Never install the dehumidifier on a wooden or metal platform without consulting the design...

Page 14: ...s exhaust fans or plumbing vents You can use galvanized sheet metal ducts for most applications However you should use aluminum or stainless steel ducts for extreme applications such as chemical laden environments 2 3 Condensate Drain Piping Condensate drain lines installed in an unconditioned space must be heat taped to prevent freezing Check the heat tape yearly before winter operation The conde...

Page 15: ...ecification 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 Once you have designed and installed the trap follow this sequence 1 Connect the trap to a main drain line with 1 4 of downward pitch per linear foot of run 2 Support the d...

Page 16: ...er Cooled Systems Only As an option the dehumidifier may be equipped with a tower water or a heat pump loop condenser Use industry standard piping practices when connecting to such a dehumidifier Connections are copper stubs Refer to submittal documentation for specific size per model Water Quality and General System Design A 60 mesh or finer strainer must be installed in the water inlet line Flus...

Page 17: ... 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 ...

Page 18: ...e 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: ...emperature range must be pure water between 55 F 95 F Ground source loop temperature range must be 30 glycol between 35 F 105 F Figure 6 Water Flow Rates Glycol Percent 0 5 10 15 20 and up Min Entering Water Temperature F 48 47 45 40 35 Figure 7 Glycol Concentration Requirements 2 6 Remote Condenser Installation Air Cooled Systems Only Important Refer to the separate Air Cooled Condensers Installa...

Page 20: ...des are adhered to when connecting any device to this equipment All electrical connections to units labeled Class 1 Group D Division 2 must be done with a conduit seal Electrical wiring must comply with all national state and local codes Refer to the wiring diagram located inside the electrical section for all wiring connections To connect main power attach the supply wires to the three pole power...

Page 21: ...ing parameters The length capacitance resistance and inductance of the cable used to connect the field wiring of the Intrinsically Safe circuit shall not overload the rating of the Intrinsically Safe barrier The standard Desert Aire IAQ dehumidifiers are controlled by a microprocessor controller This controller is designed for precise monitoring and control of air temperature and relative humidity...

Page 22: ...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 2 9 1 Auxiliary Heating Dry Contact Closure Desert Aire will provide a dry contact closure to interlock with the buil...

Page 23: ...re dehumidifier may be equipped with an optional Category III gas fired heater to provide air heating during the winter months You must read and understand the following guidelines and warnings before you connect the heating section Failure to follow these guidelines can result in improper and unsafe operation of this equipment which can cause severe personal injury death or substantial property d...

Page 24: ...pply system at pressures in excess of 0 5 psig 14 0 wc Copper and brass tubing and fittings except tin lined shall not be used if the gas contains more than a trace 0 3 grains per 100 cubic ft of hydrogen sulfide gas Check with your gas supplier For initial start up of the furnace after installation it may be necessary to purge the air out of the gas line This should be done by a qualified heating...

Page 25: ...ate gas with minimal pressure drop 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: ... 98 92 79 73 67 61 Capacity of Piping Cubic Feet per Hour based on 0 3 w c Pressure Drop Specific Gravity for Natural Gas 0 6 Natural Gas 1000BTU Cubic Ft Specific Gravity for Propane Gas 1 6 Propane Gas 2550BTU Cubic Ft Length of Pipe 20 30 40 50 60 70 80 90 100 125 150 175 200 Natural 730 590 500 440 400 370 350 320 305 275 250 225 210 Diameter of Piping Propane 445 360 305 268 244 226 214 195 1...

Page 27: ...pically 6 Install a ground joint union and manual shutoff valve in an accessible position close to the equipment Ensure that the pipe and fittings are free from chips and debris Make sure that the threads are clean and properly cut Seal pipe threads with pipe dope or a suitable joint compound that is compatible with the gas you are using Do not use Teflon tape to seal gas pipe joints Support gas p...

Page 28: ...he valve must be a minimum 5 wc or as noted on the rating plate and maximum of 14 wc for natural gas Note Always check the rating plate for minimum gas supply pressure Minimum supply pressure requirements vary based on size of burner and gas control option Most units require a minimum of 5 wc as stated above but Sizes 350 and 400 with electronic modulation require a minimum of 6 wc natural gas sup...

Page 29: ...s copper tubing may only be used with gases that are not corrosive to it See the note below to check with your LP gas supplier before using copper Seamless copper tubing must comply with standard type K or L for seamless copper water tube ASTM B 88 or seamless copper tube for air conditioning field service ASTM B 280 LP Only Copper and brass tubing and fittings except tin lined shall not be used i...

Page 30: ...in this manual and should be followed accordingly In the absence of local codes installation must conform to these instructions regulations of the National Fire Protection Association provisions of National Electrical Code ANSI NFPA70 latest edition and the National Fuel Gas Code ANSI Z223 1 latest edition Indoor units only The dehumidifier should be located as near the vent terminal as practical ...

Page 31: ...in this manual are the only venting combustion air systems approved for these separated combustion units Do not use this concentric adapter box with any other product Do not use an existing venting system This heater REQUIRES installation of the combustion air vent system supplied with the unit Installation should be done by a qualified agency in accordance with these instructions The qualified se...

Page 32: ...arances and to prevent physical damage The vent pipe must slope upward 1 4 minimum for each foot of horizontal run away from the furnace Vent connectors used in connecting the furnace to the vent cannot be channeled through floors ceilings and walls without the proper protective construction This construction must be in accordance with the requirements of the National Fuel Gas Code ANSI Z223 1 lat...

Page 33: ...l For Aura Products In order to keep the controls of the electrical heater cool there are two openings in the panel adjacent to the heater The hoods for rain protection of these openings are shipped with the unit and the mounting hardware is already in place Mount the hoods over the heater cooling openings using this hardware 2 12 Auxiliary Heat Coil Piping Optional The Desert Aire dehumidifier ma...

Page 34: ...igure 13 Cover Plate Installation 1 The Packet should contain items as shown in the Table below for various Plate Sub Assemblies The Plate Sub Assembly to be used will depend upon size of the Unit Please check the packet for correctness of items and quantities Sub Assembly TA RAIL PLT 4 2 TA RAIL PLT 4 4 TA RAIL PLT 4 6 TA RAIL PLT 6 2 TA RAIL PLT 6 4 TA RAIL PLT 6 6 TA RAIL PLT 6 8 Cover Plates Q...

Page 35: ...r 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 ...

Page 36: ...on to the wheel are provided within the wheelmodule behind the door adjacent to the connection Flexible conduit is also provided Insert the flexible conduit into the flexible conduit fittings on the unit and the module Tighten the fittings Thread the power cable through the cable gland on the inside rear of the module and into the main unit Continue threading the cable through each gland up to the...

Page 37: ...hipping restraining brackets on supply and or exhaust blower equipped with a spring isolation base if applicable Make sure that the unit is level and securely mounted so that it cannot shift or transmit vibration to the building Verify that the incoming power supply matches the rating plate of the dehumidifier The available power supply voltage must be within 10 of the voltage printed on the ratin...

Page 38: ...heat exchangers Check the drain pan and the condensate piping Test the drain and prime the p trap by pouring water into the drain pan Verify that all service valves in the refrigeration lines are fully open 3 2 Gas Heater Start Up Optional This optional furnace does not have a pilot It is equipped with an igniter that automatically lights the burner Do not attempt to light the burner by hand Check...

Page 39: ...e approach is to assume a value of 1025 BTU ft3 which is the national average With all other gas appliances turned off operate the burner for at least ten minutes After the equipment has warmed up use a stop watch to clock the time required for the small dial on the gas meter to make one full revolution A label on the meter will state how many cubic feet have flowed per revolution usually one two ...

Page 40: ...eration for 15 minutes close the air shutters observing the flame for yellow tipping Open the shutters until the yellow disappears A limited amount of yellow tipping is permissible for liquefied petroleum gases Natural gas should not display any yellow tipping When making the adjustment close the air shutters no more than is necessary to eliminate the problem condition After 15 20 minutes of conti...

Page 41: ...nit and reduce it until it is equal to or less than the design condition indicated on the rating plate 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 3 3 1 2 Unit without a VFD Change the blower speed by adjusting the motor pulley To adjust the variable ...

Page 42: ... frequency should be recorded near the VFD for future reference Once the airflow is adjusted review the motor current draw If the current draw is in excess of the current rating listed on the unit nameplate or the drive is unable to achieve the airflow at the maximum 75 Hz setting consult the Desert Aire Service Department 262 946 7400 Prior to any calls to the Desert Aire Service Department pleas...

Page 43: ...n the reheat condenser the evaporator coil or the enthalpy wheel The dehumidifier features an adjustable blower sheave to simplify air balancing To measure airflow of Aura units measure the pressure drop across both the reheat condenser and dry evaporator Aura units have convenient ports located in the electrical system compartment Figure 19 QS side view showing location of Air Balance Ports Figur...

Page 44: ...or inclined manometer to measure the air pressure drop across the reheat and dry evaporator Compare this value to the value printed on the airflow label on the side of the dehumidifier 6 Change the airflow if necessary by adjusting the motor pulley or any balancing dampers in the field installed ductwork Always measure the current draw of the blower motor after you make any changes to the airflow ...

Page 45: ...and reheat coil ports 1 and 2 Note Ensure test is performed with refrigeration off and evaporator coil dry See Figure 21 Compare this value to the value printed on the airflow label on the side of the dehumidifier 6 Change the airflow if necessary by adjusting the motor pulley or any balancing dampers in the field installed ductwork Always measure the current draw of the blower motor after you mak...

Page 46: ... or inclined manometer to measure the air pressure drop across the reheat coil See Figure 22 Note Port 1 is measuring the internal cabinet pressure downstream of the fan high side and port 2 is added in the discharge duct in the field downstream of the reheat coil low side Always measure the current draw of the blower motor after you make any changes to the airflow quantity If the motor draws more...

Page 47: ...per is installed within the unit Damper actuator control acts as binary Outside air damper should be in the fully closed position during unoccupied mode and fully open in the occupied mode with the recirculation damper always in the opposite condition Before starting the balancing process check that the ductwork is clear of any obvious restrictions Begin in occupied mode Once the airflow damper is...

Page 48: ...ired per blower adjustment procedure Note if total static pressure does not match in both modes of operation and one mode has higher airflow it may be necessary to induce additional static pressure in one mode to reduce the airflow for that mode To accomplish this a maximum damper opening percentage may be set within the controller 3 3 4 Airflow Balancing for High Outdoor Air Systems HOAS For Aura...

Page 49: ...ust blower adjustment did not alter supply air operation If the adjustment has altered supply air operation repeat the supply air balancing and then the exhaust air adjustment until all airstreams are within specifications Verify that in unoccupied mode the exhaust blower shuts down 3 3 4 2 For Units with CO2 Control Aura Dehumidifiers designed for CO2 control can have mixed airflow composed of a ...

Page 50: ...airflow may be significantly higher than the specification in this mode when this is the case If this occurs use the controller to adjust the outdoor air damper maximum open position to limit the stroke of the actuator to a less open position during this mode Adjust the return air damper to the close position and outdoor air damper to the open position until the desired ratio and total specified a...

Page 51: ...haust fan and turn off the wheel Confirm that the exhaust air gravity damper is shut Supply air fan will modulate to maintain the programmed pressure differential over the reheat coil in the unit maintaining the supply air flow rate Check the pressure drop according to the airflow label on the side of the unit It is possible if the static pressures are higher than specified that the flow rate may ...

Page 52: ...he speed For VerticalAire Products VerticalAire dehumidifiers may be equipped with a mixing box that allows the unit to operate with recirculation air in the unoccupied mode and or mixing of airstreams during occupied mode Two independent actuators allow positioning of the dampers to the appropriate settings Airflow must be balanced in all modes If option is equipped first operate the unit in occu...

Page 53: ...e life of the product that requires opening of the hermetic refrigeration system Special care must be taken to ensure that the system is returned to service without contamination Whenever servicing Desert Aire equipment observe the following Use only equipment rated for the pressures of the refrigerant being serviced Use only equipment dedicated to service the refrigerant in the system Do not use ...

Page 54: ...utdoor air temperature condition prevents the unit from running long enough to take data note this on a startup report and proceed to heat pump mode During the first Preventative Maintenance visit that is recommended during spring and fall the service contractor should complete the Dehumidification Cooling Mode section of the startup report To perform start up checks on the compressor the supply a...

Page 55: ...he compressor the supply air dewpoint set point should be lower than the incoming dewpoint by at least 10 F See the Controller IO Manual for instructions on setting the dewpoint set point Note the original setting Once the set point is adjusted switch the unit to occupied mode It can take up to 15 minutes for the unit to reach steady state While in steady state operation record the data required f...

Page 56: ...ts original value For TotalAire and VerticalAire Products In order to test the unit in heat pump mode the air temperature entering the reheat condenser must be approximately 90 F or lower If the condition entering the condenser is higher the unit may run elevated head pressures and a high discharge pressure alarm may occur If a high outdoor air temperature condition prevents the unit from running ...

Page 57: ...imed with water Verify that it drains freely with no leaks If the drain is outside or in an unconditioned space make sure it has been heat traced If you installed a condensate pump make sure it operates properly Check the operation of the remote condenser on units equipped with this option Make sure that the fans cycling switches which are mounted on the condenser are correctly piped and have been...

Page 58: ...e the blower bearings Suggested Grease Brands and Types FINA SHELL ESSO MOBIL Type Marson HTL 3 Alvania Fett 3 Beacon 3 Mobilux EP3 Supplier Base Lithium Lithium Lithium Lithium Range temperature min max 30 C 120 C 20 C 130 C 20 C 130 C 30 C 130 C 3 6 3 Service Every Year 3 6 3 1 Energy Recovery Wheel Optional Dehumidifiers equipped with the optional energy recovery wheel must be inspected regular...

Page 59: ...ged sections of the vent Inspect the pressure switch tubing connections Verify that the inducer fan is free of corrosion warp age deterioration and carbon buildup If necessary clean the housing and the blower wheel with a damp cloth Vacuum any lint or dust from the inducer motor assembly See the separate gas heater manual for detailed service information Note Please have the following information ...

Page 60: ...60 Desert Aire QS QV Manual ...

Page 61: ...es at the jobsite You may need to consult with other contractors who have worked on different portions of this project The following list will help you diagnose some of the most obvious symptoms of a system which does not work properly 4 1 The Blower Does Not Run POSSIBLE CAUSES Occupied switch is in the open position Loss of main power Damper is stuck or frozen preventing the actuator end switch ...

Page 62: ...flow at remote condenser On units with air cooled condensers Remote condenser blower does not run Lack of adequate water flow on units with tower condensers Excessive incoming water temperature on units with tower condensers Excessive air in condenser water lines on units with tower condenser Overload tripped 3 phase only Contactor faulty Blower cycling on internal overload single phase only Servi...

Page 63: ... Defective expansion valve Restriction in refrigeration piping REMEDY Set hot gas valve to maintain 30 F suction 97 PSIG or replace if defective Assure coil is clean and belts are tight Re evaluate system charge Evaluate filter pressure drop and replace if necessary Evaluate expansion valve performance and replace if necessary Check coil for kinks in tubing and check for debris in distributor Dese...

Page 64: ...64 Desert Aire QS QV Manual ...

Page 65: ...conditioning and dehumidification applications due to their ability to cope with occasional periods of liquid refrigerant return There are fewer moving parts in a scroll compressor subject to wear compared to alternative compressor designs Nonetheless there are still many mechanical and electrical parts with close tolerances Replacement of the compressor may be required during the normal service l...

Page 66: ...t Refrigeration oil must be tested for acid and particulate during any compressor replacement For the initial testing the compressor sump should be used to sample the oil Oil can be recovered through the Schrader port on the low point compressor shell or through the suction line connection after the compressor has been removed Use Virginia KMP New Calgon Phase III Sporlan Test All or equivalent oi...

Page 67: ...o Schrader fittings Ensure there are access fittings directly upstream and downstream of the suction filter There is typically one fitting installed on the suction filter There may be a bulkhead fitting attached to the compressor suction side Do not use acid neutralizing additives or other chemicals for acid removal The refrigeration system must contain only oil and refrigerant Precipitates of add...

Page 68: ... acid is found replace with activated charcoal cores and test at 24 hour intervals until acids are at acceptable levels Once acid is no longer detected replace cores with standard filter elements Remove outlet screens if they were required by filter manufacturer If the pressure differential across the liquid line filter is 5 PSI or greater replace cores and secondary filter with new components and...

Page 69: ...oid repeat compressor damage 5 2 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...

Page 70: ...ill provide a detailed description of the unit controls and also explain the heat pump design All Desert Aire IAQ products sense the temperature and relative humidity of the air entering the evaporator and use this data as the process variable to determine the unit mode of operation On IAQ units without an energy recovery device enthalpy wheel the sensing point is downstream of the filter rack On ...

Page 71: ...een the heating and cooling set point and dehumidification is not required un conditioned air will be provided to the space This condition is commonly referred to as an Economizer Mode 5 4 2 Blower Operation The following is the blower control sequence for the standard IAQ control system In all cases the blower will not run in an alarm condition If the blower cycles off the blower will remain off ...

Page 72: ...nner Short cycling will not occur since intake air conditions do not change rapidly For TotalAire and VerticalAire Products Dehumidification operation is enabled when the IA dewpoint is greater than the dewpoint set point The standard IAQ controller allows for a wide range of operating conditions through the use of predictive capacity equations embedded in the controller Based on the unit size air...

Page 73: ... design dew point will also provide more sensible capacity dehumidification stages will take precedence over cooling stages 5 4 4 2 Q Pump Inverter Units When cooling but no dehumidification is needed the supply air set point is achieved by varying the speed of the compressor for more or less capacity based on the temperature of the supply air As more capacity is required the compressor speed will...

Page 74: ...s above the set point a bypass valve will open to prevent overheating of the space Should auxiliary heating be installed a modulating output will activate when the capacity of the heat pump is insufficient to heat the air to the desired leaving air temperature Use of the modulating output is determined when the reheat valves reach 100 for a set period of time capability is available should there b...

Page 75: ...temperature falls the SAT set point is raised to provide warmer air to the space The Zone Reset is accomplished by a second PID control loop the output of which is the SAT set point This control loop also allows for setting the maximum and minimum SAT set point limits Up to four of these sensors can be used providing multi zone control Multiple sensors may be set to either average the zone reading...

Page 76: ...ut of the PID control loop will be the P2 set point and will vary from a low limit to a high limit Both of the low and high limits and the 700 ppm CO2 set point are user adjustable This varying set point is used to control the modulating damper actuator A control loop has been added to control the damper actuator positions The outside air damper will vary from a minimum to a maximum based upon the...

Page 77: ...e to start This will be allowed for 90 seconds adjustable and then the calculated suction pressure cutout value will be used to cycle the compressors This cycling will not be indicated as an alarm or recorded in the alarm history If the low suction pressure cycle occurs 3 adjustable times in a 1 adjustable hour time period then an alarm will be indicated and recorded in the alarm history as a mult...

Page 78: ...s will have isolation valves located inside the unit cabinet near the area where the connections are made The compressor can be used to move refrigerant to the system components that will be used to temporarily hold the charge Note that cooling a condenser by running as many fans as possible and or cooling the coil surface with a stream of water can assist in storing charge The low side pressure s...

Page 79: ...erant and oil The particulate can move throughout the system and cause contamination on valves and other critical components System filters may become fouled Flowing nitrogen into the system and ensuring that the inside of the tube is significantly free from oxygen while brazing ensures that oxides do not form As the last joints of a system are made additional thought must be made on the location ...

Page 80: ...r a minimum of 10 minutes Alternative Evacuation Specified by Process After components have been repaired or replace evacuation procedure should take place Very small amounts of refrigerant may still be mixed with the oil in the system Out gassing of this refrigerant may interfere with the evacuation and vacuum decay testing IF AND ONLY IF a unit has been previously charged with refrigerant and st...

Page 81: ...the unit is equipped with an accumulator the charge needs to be added to the port upstream of this location The bulkhead fittings on the side of the unit should not be used for charge addition Monitor superheat at the compressor suction inlet using the bulkhead fitting and a temperature sensor on the suction line near the compressor Superheat should not drop below 10 degrees during the process of ...

Page 82: ...82 5 6 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: ...the installing contractor is confident the system will be ready he should contact the Desert Aire Sales representative to schedule the start up Please call at least two weeks before the desired start up date to help prevent scheduling conflicts 5 8 System Start Up Report A copy of the system Start Up Report can be found on the following pages This report needs to be filled out thoroughly by a qual...

Page 84: ...t and the condenser if applicable All field controls sensors and actuators installed and circuits verified that they are wired correctly If you have questions contact Desert Aire for instructions 800 443 5276 Units with heat pump option verify water flow and design temperature See unit labeling for details if applicable Inspect all water lines for leaks and purge air from lines If applicable Verif...

Page 85: ...rols 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 Honeywell Oth...

Page 86: ...ent High voltage electrical components and refrigeration under pressure are present 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 Use one start up report per unit Print or type all information If there is n...

Page 87: ...LBS LBS Additional Oil Added OZS OZS 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 OUTR1 ON1 OFF1 ONT1 OFT1 SNF1 SENS1 OUTR2 ON2 OFF2 ONT2 OFT2 SNF2 SENS2 OUTR3 ON3 OFF3 ONT3 OFT3 SNF3 SENS3 OUTR4 ON4 OFF4 ONT4 OFT4 SNF4 SENS4 Proper Installation Checklist Installation manual read ...

Page 88: ...e Drop wc Return Duct Static Pressure wc Exhaust Duct Static Pressure wc Motor Information Supply Blower Exhaust Blower Ehthalpy Wheel Motor FLA off Nameplate Amps Amps Amps Amperage at Design Airflow L1 L1 L1 L2 L2 L2 L3 L3 L3 Compressors and Refrigeration in Cooling Dehumidification Mode Airside Evaporator Coil Active Circuit A Circuit B Motor RLA off nameplate amps amps amps amps Amperage L1 L1...

Page 89: ...rmation Signal L1 Amps L2 Amps L3 Amps Discharge Air Temp Electric Heater F Auxiliary Water Steam Coil Information Signal Inlet Temp Outlet Temp Discharge Air Temp Water Coil F F F Steam Coil F F F Compressors and Refrigeration in Heat Pump Mode Chiller Barrel Active Circuit A Circuit B Head Pressure Psig Psig Suction Pressure Psig Psig Refrigerant Sight Glass Clear Yes No Yes No Superheat F F Sub...

Page 90: ...90 Additional Comments Desert Aire QS QV Manual ...

Page 91: ...or more legs Compressor drawing higher current than design Continuity 0 resistance between two or more legs 3 phase units Compressor drawing locked rotor current Other describe Runs without pumping Pressures _____ _____ Final Determination of Failure Liquid Floodback Low Superheat Debris Defective Expansion Valve Low Sump Oil Insufficient Motor Cooling Other Describe Diagnostic Corrective Action S...

Page 92: ... Circuit B Use both sides for tandem set Motor See wiring schematic for details Discharge Pressure PSIG PSIG PSIG PSIG Liquid Line Pressure At access fitting nearest TXV PSIG PSIG PSIG PSIG Suction Pressure At compressor PSIG PSIG PSIG PSIG Liquid Line Temperature At access fitting nearest TXV F F F F Suction Temperature At Compressor F F F F Refrigerant Sight Glass Condition Clear Intermittent Va...

Page 93: ...93 Desert Aire QS QV Manual ...

Page 94: ...MIZING SOLUTIONS THROUGH SUPERIOR DEHUMIDIFICATION TECHNOLOGY 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 ...

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Desert Aire Aura QS, Installation And Operation Manual

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