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MODELS:

MAA1020H-MAA1024H 

MAA1030H-MAA1036H 

MAA1042H-MAA1048H

MGA1072H

Installation & Operation Manual 

1.5 - 4 & 6 Ton Vertical Wall-Mount Heat Pumps

IMPORTANT

This manual may include information for options and features which may not be 

included on the unit being installed. Refer to the unit data label or Model Identification 

to determine which features and options this unit is equipped with. 

INSTALLER:  

Affix the instructions on the inside of the building adjacent to the thermostat.

END USER:  

Retain this manual for future reference.

Heat Pump Product Manual

Vertical Wall-Mount Heat Pumps

Manufactured By:

A Division of the AIRXCEL

®

 Commercial Group

P.O. Box 400 • Cordele, Georgia 31010 • 156 Seedling Drive • Cordele, Georgia 31015

(229) 273-3636 • Fax (229) 273-5154

E-mail: [email protected] • Internet: www.Marvair.com

The most current version of this manual can be found at www.Marvair.com.

Marvair Wall Mount H/P MAA1020H-1048H/MGA1072H I&O Manual

02/2021 Rev.2

Summary of Contents for MAA1020H-MAA1024H MAA1030H

Page 1: ... equipped with INSTALLER Affix the instructions on the inside of the building adjacent to the thermostat END USER Retain this manual for future reference Heat Pump Product Manual Vertical Wall Mount Heat Pumps Manufactured By A Division of the AIRXCEL Commercial Group P O Box 400 Cordele Georgia 31010 156 Seedling Drive Cordele Georgia 31015 229 273 3636 Fax 229 273 5154 E mail marvairsales airxce...

Page 2: ...y work Failure to follow these rules may result in death serious bodily harm property damage and damage to the equipment Important Safety Precautions 1 USE CARE when LIFTING or TRANSPORTING equipment 2 TRANSPORT the UNIT UPRIGHT Laying it down on its side may cause oil to leave the compressor and breakage or damage to other components 3 TURN ELECTRICAL POWER OFFAT THE breaker or fuse box BEFORE in...

Page 3: ...eat HGR Valve 26 3 4 Ventilation System Set Up 28 Chapter 4 Troubleshooting 4 1 Overview 30 4 2 Failure Symptoms Guide 31 4 3 Compressor Troubleshooting 32 4 4 Electric Heat Control 33 Chapter 5 Electrical Schematics 5 1 Electrical Schematics 34 WARNING If the information in these instructions are not followed exactly a fire may result causing property damage personal injury or loss of life Read a...

Page 4: ...5b Thermostat Connection Diagram 24 Figure 6 Temperature Sensor Wires Modulating HGR Valve 27 Figure 7 Desired Temperature Set Point Modulating HGR Valve 27 Figure 8 Damper Adjustment 28 Figure 9 Damper Air Path 29 Figure 10 Typical Configuration for Single Element Heater 33 Figure 11a Typical 1ø Electrical Schematic Diagram Heat Pump with Manual Outside Air Damper 35 Figure 11b Typical 208 230v 3...

Page 5: ...ing requirements For school classrooms models are available to comply with the ASHRAE 62 1999 standard Ventilation for Acceptable Indoor Air Quality Where cooling is required during cool or cold weather e g telecommunication shelters a factory installed economizer can be used To insure proper operation and optimum performance all outside air ventilation packages and the economizer are non removabl...

Page 6: ...Stat None Special 16 Operating Condition N Hard Start 1 Low Ambient w FCC None Special 17 Indoor Air Quality Features A UV Light K Bi Polar Ionization None Special 18 Air Flow 1 Top Supply Bottom Return Special 19 Compressor Location D Left Hand All 31 2 to 5 ton units E Right Hand All 11 2 to 3 ton units 20 Filter Option A 2 Pleated MERV 8 AC HP C D MERV 11 High Filtration Package E MERV 13 High ...

Page 7: ...e 4 Refrigerant Charge R410A Ounces Basic Model Special Option TEMPERATURE RANGES Non Economizer Base Unit 20ºF 131ºF 7ºC 55ºC Desert Duty 20ºF 131ºF 7ºC 55ºC Extreme Duty 0ºF 131ºF 18ºC 55ºC Economizer Equipped Base Unit 40ºF 131ºF 29ºC 55ºC Desert Duty 40ºF 131ºF 29ºC 55ºC Extreme Duty 40ºF 131ºF 29ºC 55ºC An Optional FCC switch is required for the cooling Mode Heating mode ratings are 47 F Outd...

Page 8: ...llows When the enthalpy of the outdoor air is below the set point the outdoor air damper is proportionally open and return air damper is proportionally closed to maintain between 50 F and 56 F 10 C to 13 C at the mixed discharge air sensor Integral pressure relief allows the indoor air to exit the shelter through the air conditioner When the enthalpy of the outdoor air is above the set point the o...

Page 9: ... controller or BAS control is required for proper operation of the HGR coil 1 6 Standard Controls PC Board Description of Operation The PC board controls the operation of the indoor blower the compressor and the reversing valve while providing high pressure loss of charge protection with an integral defrost function Upon a call for mechanical cooling or heating the controller will energize the com...

Page 10: ...ff to prevent a short cycle condition Loss of Charge LPS By Pass Timer Thecontrolincludesafixed threeminuteLossofChargeSwitch LPS bypasstimer IftheLossofCharge Switch is open on initial power up or while the compressor is running the control will ignore the fault for three minutes If the fault still exists after three minutes the control will de energize the compressor register a loss of charge fa...

Page 11: ...ric Heat During Defrost EHDD The board provides the option of running the electric heat EH during a defrost cycle There are two options for the EHDD Yes and No If Yes is selected the board will energize the EH terminals during a defrost cycle If No is selected the EH terminals will not be energized during a defrost cycle The factory setting for EHDD is No If the S circuit is in the Yes position th...

Page 12: ...l will ignore the status of the LPS and not recognize a fault for 3 minutes If the LPS is still open after 3 minutes the control will de energize the compressor register the first LPS fault and initiate the 3 minute anti short cycle timer If two LPS faults occur within a one hour period the control will enter a LPS lockout condition and energize the alarm contacts The RED status LED will blink twi...

Page 13: ...erminal is removed the fan will remain energized for the pot settable 10 90 second post purge period When the damper relay option is selected by placing the jumper in the Yes position the control will energize the DRO terminal with every G call to open the damper When the G call is not present the control will energize the DRC terminal to close the damper The default setting for the damper relay o...

Page 14: ... for Dehumidification Control provides simultaneous operation of compressor when in cooling mode and the electric elements to provide dehumidification without over cooling the room The electric element kW must be properly sized for each model for proper operation Factory installed Available on all MAA units Consult factory for details Hot Gas Reheat HGR Marvair heatpumpsequippedwiththeHotGasReheat...

Page 15: ...mixed air sensors The controller is designed to maintain the supply air temperature between 50o to 56o F by mixing warm indoor air with cooler outdoor air On a call for cooling from the wall mounted thermostat if outdoor conditions are suitable the sensor will open the damper and admit outside air i e economizer cooling If the outdoor ambient is too hot or humid the sensor will place the actuator ...

Page 16: ... stand for 24 hours with primary power turned on 2 Attempt to start the compressor after 24 hours 3 If the compressor will not start makes excessive noise or will not operate return the unit to the freight carrier General 1 Inspect unit for completeness Check for missing parts e g hardware Refer to the installation kit information in section 2 3 2 Remove access panels and check for loose wires Tig...

Page 17: ...d for proper operation and service Tables 4a 4b below MODEL Min Clearance From the Front Min Clearance Around Sides Single Unit Min Clearance Between Sides Two Units Min Space Above Unit 1020H 1024H 42 inches 30 inches 18 inches 24 inches 1030H 1036H 42 inches 30 inches 18 inches 24 inches 1042H 1048H 42 inches 30 inches 30 inches 24 inches 1072H 42 inches 30 inches 30 inches 24 inches Table 6 Min...

Page 18: ...ump The humidity controller controls the heat pump system when cooling or heating requirements are satisfied and the need exists to dehumidify the conditioned space When cooling or heating is required the thermostat controls the heat pump system operation 50092 Thermostat Guard For use with the 50107 and the 50252 Grilles Description Size Marvair P N For the MAA1020H 1024H Double Deflection Alumin...

Page 19: ...h codes of all governmental authorities have jurisdiction The information contained in this manual is intended for use by a qualified service agency that is experienced in such work is familiar with all precautions and safety procedures required in such work and is equipped with the proper tools and test instruments General Information Note The following instructions are for general guidance only ...

Page 20: ... a minimum thickness of 019 Ductwork must be firmly attached secured and sealed to prevent air leakage Do not use duct liner on inside of supply duct within four feet of the unit Galvanized metal duct extensions should be used to simplify connections to duct work and grilles Use fabric boots to prevent the transmission of vibration through the duct system The fabric must be U L rated UL 181 to a m...

Page 21: ... side of the mounting brackets on the Heat Pump Circle the mounting holes with the silicone bead 3 Using an appropriate and safe lifting device set the Heat Pump on the bottom support bracket mounted on the wall You must stabilize the unit on the bracket with the lifting device or by some other means the bracket alone is not sufficient 4 Make sure that the duct flanges are properly aligned with th...

Page 22: ...prior to starting the compressor High Voltage Wiring The power supply should have the proper voltage phase and ampacity for the selected model 1 Refer to the electrical data on the data sticker on the unit for field wiring requirements of the unit Size the incoming power supply lines and the fuse s or HACR breaker s according to requirements described in the National Electric Code Run the power co...

Page 23: ...s than one hour However after several minutes of operation the compressor s internal protector will trip The compressor will then cycle on the protector until the phasing is corrected Reverse operation for longer than one hour may have a negative impact on the bearings To change the rotation turn off power to the unit and reverse L1 L2 at the disconnect 4 Install the ground wire on the ground lug ...

Page 24: ...24 Marvair Wall Mount H P MAA1020H 1048H MGA1072H I O Manual 02 2021 Rev 2 Figure 5a Humidity Control Wiring Detail Heat Pumps Figure 5b Thermostat Connection Diagram ...

Page 25: ...ermostat Slowlylowerthethermostatcoolingsetpointtemperature Once the indoor fan turns on allow approximately three minutes for the compressor and outdoor fan to start For units equipped with the low ambient control note that the outdoor fan may not come on immediately because it is cycled by refrigerant pressures Some units have a time delay module which prevents the compressor from restarting imm...

Page 26: ...ir heat pumps with an economizer and optional on all other Marvair units has cycled 3 Move the system switch to the Off position All functions should stop The Blower Timed Delay Relay BTR keeps the blower running for 90 seconds after the unit shuts off Note The damper blade should remain closed during the heating cycle unless the minimum position potentiometer has been set for constant ventilation...

Page 27: ...emperature ºF Insert the probes of the meter into the negative black and positive red set point test terminals on the board Carefully and in small increments turn the blue knob on the potentiometer until the volt meter displays the desired milliamp voltage temperature Airxcel Commercial Group recommends 70ºF and no lower than 68ºF and no higher than 78ºF Allow the refrigerant system to stabilize f...

Page 28: ...m Subtract the return air from the supply air The difference is the amount of fresh air c Loosen the set screw that holds the collar onto the rod connected to the damper Move the collar and tighten the set screw Rod Set Screw Figure 8 Damper Adjustment d Repeat steps a b and c until the desired amount of fresh air is being introduced into the room Important Note Since Configuration Y does not have...

Page 29: ...d value of the Tmix equals the calculated or desired value of Tmix The motorized damper Configuration B can be controlled by an optional relay that allows additional external control with a choice of 24 120 or 240V coils to regulate fresh air ventilation in response to a control located remote from the Marvair heat pump GreenWheel ERV Configuration H Setting the correct air flow for the GreenWheel...

Page 30: ...it MarvairHeatPumpsarethoroughlytestedbeforetheyareshippedfromthefactory However itispossible that a defect may escape undetected or damage may have occurred during transportation However the great majority of problems result from installation errors If you experience difficulties with the Heat Pump please review the installation steps in Chapter 2 Much time can be saved by taking a thoughtful and...

Page 31: ...proper operation 4 Check air filter s Check blower operation Remove airflow restriction C Unit cycles on high pressure or loss of charge 1 Loss or restriction of airflow 2 Restriction in refrigerant circuit 3 Refrigerant overcharge following field service 4 Defective high pressure control or loss of charge switch 1 Check blower assembly for proper opera tion Look for airflow restrictions e g the a...

Page 32: ...r component failures before condemning the compressor The following electrical tests will aid diagnosis on single phase units 1 Start Up Voltage Measure the voltage at the compressor contactor during start up The voltage must exceed the minimum shown in Table 8 section 2 2 or compressor failure is likely A low voltage condition must be corrected 2 Running Amperage Connect a clip on type ammeter to...

Page 33: ... circuit to the heater assembly the switch will have to be replaced by qualified service personnel after the source of the overheat problem is resolved In addition to the thermal cut out switch described above there is a single function thermal cut out switch P N 70005 mounted on the heater frame This switch controls the 24V AC control current to the heater contactor s which powers all the heating...

Page 34: ...ower is available The heater drives liquid refrigerant from the crankcase and prevents loss of lubrication caused be oil dilution Power must be applied to the unit for 24 hours before starting the compressor Note Heat pumps with scroll compressors generally do not require crankcase heaters The indoor evaporator fan motor is cycled by the blower timed delay relay See Figure 9 Due to the large numbe...

Page 35: ...35 Marvair Wall Mount H P MAA1020H 1048H MGA1072H I O Manual 02 2021 Rev 2 Figure 11a Typical 1ø Electrical Schematic Diagram Heat Pump Models MAA with Manual Outside Air Damper ...

Page 36: ...36 Marvair Wall Mount H P MAA1020H 1048H MGA1072H I O Manual 02 2021 Rev 2 Figure 11b Typical 208 230v 3ø Electrical Schematic Diagram Heat Pump Models MAA ...

Page 37: ...37 Marvair Wall Mount H P MAA1020H 1048H MGA1072H I O Manual 02 2021 Rev 2 Figure 11c Typical 460v 3ø Electrical Schematic Diagram Heat Pumps Models MAA with the PC Control Board ...

Page 38: ...f the electrical components Be sure the unit has dried before restarting Use a fin comb of the correct spacing to straighten mashed or bent fins Outdoor Coil Periodically inspect the outdoor coil and the cabinet air reliefs for dirt or obstructions Remove foreign objects such as leaves paper etc If the coil is dirty it may be washed off with a commercial solvent intended for this purpose TURN OFF ...

Page 39: ...material charges 2 Damages caused by shipping accident abuse negligence misuse fire flood or Acts of God 3 Damages caused by operating or staging the unit in a corrosive environment 4 Damages caused by improper application of the product 5 Damages caused by failing to perform proper routine maintenance 6 Expenses incurred for erecting disconnecting or dismantling the product or installing the repl...

Page 40: ...of the supply outlet duct flange on the unit The 1 25 4 mm clearance must extend on all sides of the supply duct for the first 3 feet 1 meter from the unit IMPORTANT Marvair requires a minimum of 1 25 4 mm from the surface of any supply ducts to combustible material for the first 3 feet 1 meter of the duct Ducting Extensions should be cut flush with the inside wall for applications without duct wo...

Page 41: ...r all other heaters 6 Install the two No 10 screws in the heater assembly plate 7 Install wire harness in hole provided in drain pan and then through filter bracket and then into control box 8 Wire the heater as shown in the wiring diagram provided with the heater kit the insulated terminal ends are to be connected at the heater 9 Install pop tie in appropriate hole in back panel to secure wire 10...

Page 42: ...42 Marvair Wall Mount H P MAA1020H 1048H MGA1072H I O Manual 02 2021 Rev 2 ...

Page 43: ...o _________________________________________________________ Compressor Serial No _________________________________________________________ D Pre Start Up Is there shipping damage Yes No If so describe ________________________________________________________________ _____________________________________________________________________________ Will this damage prevent starting the unit Yes No Incomi...

Page 44: ...Yes No Average Voltage L1 L2 L1 L3 L2 L3 3 _______________V Deviation Difference Average Voltage Maximum Deviation ______________V Voltage Imbalance Deviation Difference x 100 Average Voltage ___________ A Voltage Imbalance greater than 2 with the unit running must be addressed and corrected Excess Line to Line Voltage Imbalance can cause the compressor to overheat and cause premature failure Exam...

Page 45: ... An incoming voltage that is Not between the Minimum and Maximum listed on the unit Data Label Must be addressed and corrected before starting unit Improper voltage can cause the compressor to overheat and cause premature failure Measured Line to Line Balance Is incoming voltage properly balanced use formula below to calculate balance Yes No Average Voltage L1 L2 L1 L3 L2 L3 3 ___________ V Deviat...

Page 46: ...idistat Control been installed wired to the Dehumidification input Yes No Has the Humidistat Control been properly setup for dehumidification Yes No Adjust the cooling setpoint so there is No demand for cooling Adjust the Humidity setpoint so there is No demand for dehumidification The unit will not be running Electric Reheat Start Adjust the Humidity setpoint to approximately ten percent below th...

Page 47: ...he Economizer Control Board been properly wired to the Control Yes No Has the Economizer Control Board Ambient selections been properly setup Yes No Has the Economizer Control Board Minimum Opening selection been properly setup Yes No Are ambient conditions suitable for Economizer Cooling If not skip this section Yes No Economizer Cooling Start If using a standard thermostat Set the Control to ON ...

Page 48: ...l Heating Heat Pump Check and Record Readings After about 10 minutes of operating in the heating mode check and record the following data points Inside Temperature IAT ºF Outside Temperature OAT ºF Entering Condenser Air Temperature Should be same temp as OAT ºF Leaving Condenser Air Temperature Acceptable Range 15º 20º below OAT ºF Return Air Temperature RAT db Should be same temp as IAT ºF Retur...

Page 49: ...e indoor blower motor IBM On Yes No Is the Compressor Off Yes No Is the Condenser Fan CFM Off Yes No Is the Heater On Clamp an AmpProbe on one leg of the heater contactor to verify Yes No Heating Check and Record Readings After about 10 minutes of operating in the heating mode check and record the following data points Inside Temperature IAT ºF Outside Temperature OAT ºF Return Air Temperature RAT...

Page 50: ...ge of the Outdoor Thermostat is 0ºF to 50ºF Is the indoor blower motor IBM On Yes No Is the Compressor On Yes No Is the Condenser Fan CFM On Ambient conditions may be delay CFM Yes No Is the Heater Off Clamp an AmpProbe on one leg of the heater contactor to verify Yes No Heating Mode Stop Mechanical Heating Heat Pump Adjust the heating setpoint to approximately two degrees below the current indoor...

Page 51: ..._____________ ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ ______________________________________________...

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