Please read this manual carefully before installation and keep it for future reference. Owner’s Manual Universal™ Series Air Handler | 2-3 Ton Model - MDUI18024/MDUI18036 Thank you for choosing MRCOOL. Please read this manual carefully before installation and keep it for future reference. Copyright © 2020 MRCOOL, LLC | v05.07.
Contents ! Safety Precautions ....................... 2 1 Appliance Overview ..................... 5 1. 2. 3. 4. Introduction ........................................................ 5 Accessories ........................................................ 6 Unit Dimensions ................................................ 7 Main Parts ........................................................... 8 2 Unit Installation ........................... 9 1. Pre-Installation Instructions............................
Safety Precautions Safety Precautions Read Before Installation ! Incorrect installation may cause serious damage or injury. The seriousness of potential damage or injuries is classified as either a WARNING or CAUTION. This symbol indicates ignoring instructions may cause death or serious injury. WARNING This symbol indicates that ignoring instructions may cause moderate injury to your person, damage to your unit, or other property.
Safety Precautions 5. Install the unit in a firm location that can support the unit’s weight. If the installation location cannot support the weight, or the installation is performed improperly, the unit may fall and cause serious injury and/or damage. 6. For all electrical work, follow all appropriate wiring standards, regulations, and the Installation Manual. 7. You must use an independent circuit to supply power. Do not connect other appliances to the same circuit.
Safety Precautions For units that have an auxiliary electric heater, DO NOT install the unit within 3 feet (1 meter) of combustible materials. DO NOT install the unit in a location that may be exposed to combustible gases. If combustible gas accumulates around the unit, it may cause fire. DO NOT operate your air conditioner in a wet room such as a bathroom or laundry room. Too much exposure to water may cause electrical components to short circuit. 1.
Safety Precautions Appliance Overview 1 To Our Customers; Thank you for choosing a MRCOOL home HVAC product. Please read this manual carefully before installation and operation of the Universal™ Series Air Handler to ensure correct use and handling. In addition to the safety precautions in the previous section, please adhere to the following guidelines and note our exceptions to liability. 1.
Appliance Overview The Universal Series™ Air Handler offers the perfect combination of superior product quality, operating efficiency, operating sound levels, and value for money. The condensing unit uses the environmentally friendly refrigerant R410A, which is chlorine-free to help prevent damage to the ozone layer. Unless otherwise stated (as “OPTIONAL”) the air conditioning system includes the following accessories. Use all of the installation parts and accessories to install the air conditioner.
Appliance Overview Unit Dimensions MDUI18024/MDUI18036 A B H Fig. 1.1 W D Unit Dimensions (Inches/MM) Width 21-1/4 in. (540mm) Page 7 Depth Height 21-1/4in. (540)mm 48-1/4in. (1224mm) mrcool.com A 11-5/8in. (295mm) B 20in.
Appliance Overview Main Parts Electric Box Assembly Centrifugal Fan Fan Motor Secondary Drain Pan Evaporator Assembly Fig. 1.2 Primary Drain Pan Model MDUI18024 / MDUI18036 Cooling capacity (ton) 3.0 Optional electric heater (kW) 5-10 Motor @ 230V ～, 60Hz Model MDUI18024 / MDUI18036 HP FLA 1/2 2.1 Unit: inch( mm) Model MDUI18024 / MDUI18036 Filter size 19-5/16×20-5/16× 5/8 (490×516×15) mrcool.
2 Unit Installation The Universal™ Series has 2 installation methods 1. The Conventional Weld Line Set Installation MRCOOL® Preferred Method Instructions can be found on page 11 OR View complete install video by scanning this QR code 2.
Unit Installation 4. Replacement Parts When reporting shortages or damages, or ordering repair parts, give the complete product model and serial numbers as stamped on the product. Replacement parts for this product are available through your contractor or local distributor. Installation Location WARNING • This air handler is designed for indoor installation only. Do not install it outdoors.
Unit Installation - OPTION 1: Conventional Weld / Flare Line Set Conventional Line Set Installation Specification of Connection Pipe External diameter (inch) Model Vapor pipe Liquid pipe 3/4 3/8 MDUI18024 / MDUI18036 Piping Preparation 1. WELD Type Complete Unit Replacement All cut ends are to be round, burr free, and cleaned. Failure to follow this practice increases the chances for refrigerant leakage. Line set size matches service valve connection.
Unit Installation - OPTION 2: No-Vac® Quick Connect® Line Set INSTRUCTIONS FOR USE WITH NO-VAC™ QUICK CONNECT® LINE SET SOLD SEPARATELY KINK RESISTANT, PRECHARGED, SIMPLE SECURE QUICK CONNECT, 100% CONNECTION GUARANTEE Please read and follow the instructions and diagram below� : Connections must be made exactly as specified to avoid system leaks and /or damage 1. Take out matching male connectors M1 and M2. 2.
Unit Installation IMPORTANT The cutoff valves on the air handlers must be opened AFTER connecting the lines and BEFORE turning on the unit. Otherwise, operation can cause leakage and/or damage to the unit. Condensate Removal 1. DO NOT connect the condensate drain pipe into the waste pipe or other pipelines that are likely to produce corrosive or peculiar smells. This will prevent odors from entering indoors or corrupting the unit. 2. DO NOT connect the condensate drain pipe into the rain pipe.
Unit Installation Ductwork This air handler is designed for a complete supply and return ductwork system. WARNING DO NOT operate the unit without all ductwork completed and attached. • Inadequate ductwork that restricts airflow can result in improper performance and compressor or heater failure. • Ductwork is to be constructed in a manner that limits restrictions and maintains suitable air velocity. • Ductwork is to be sealed to the unit in a manner that will prevent leakage.
Unit Installation CAUTION 1. Ensure that all power supply is disconnected prior to installing the heater kit. 2. A means of strain relief and conductor protection must be provided at the supply wire entrance into 3. 4. 5. 6. cabinet. Only use copper conductors. Installation must follow national electric code and other applicable codes.
Unit Installation Air Handler Field Conversion Converting Unit From 3 Ton to 2 Ton Follow these instructions during unit installation in order to enable a Universal Series 3 ton condenser and air handler split system to operate at 2 ton capacity. 1. DO NOT attempt this conversion while the unit is powered on. 2. Locate the capacity dip switch on the air handler main board. The capacity dip switch is circled on the photo below. 3.
Unit Installation Electrical Connection Vacuum Lines Electrical Regulations WARNING Before performing electrical work, read the following regulations 1. Electrical installation must be conducted by professionals in compliance with local laws, regulations and this installation manual. Never artificially extend the length of a power cord. The electric circuit must be equipped with a circuit breaker and air switch. Both must have sufficient capacity. 2.
Unit Installation Electrical Connection Electrical Parameters Outdoor Unit Model MDUI18024/MDUI18036 Power Supply 208/230V 60Hz Min. Circuit Ampacity 5 amps Max. Overcurrent Protection (A) 15 amps 1. The fuse is located on the main board. 2. Install a circuit breaker at every power terminal near the units (indoor unit and temperature controller) with at least 0.12in (3mm) contact gap. Both units must reach the plug. 3.
Unit Installation Electrical Connection Connecting the Power Cord & Communication Wire For solid wires (Refer to Fig. 2.10 A): 1. Use wire cutters to cut off the wire end and then peel away about 25mm of the insulation layer. 2. Use a screwdriver to unscrew the terminal screw on the terminal board. 3. Use nippers to bend the solid wire into a ring that fits the terminal screw. 4. Form a proper ring and attach to the terminal board. Use a screwdriver to tighten the terminal screw.
Unit Installation Electrical Connection Connecting the Power Cord & Communication Wire WARNING 1. Before work begins, please check to ensure the unit is powered OFF. 2. Match the terminal numbers and wire colors with the colors indicated in the indoor unit. 3. Wrong wire connection may burn the electrical components. 4. Connect the wires firmly to the wiring box. Incomplete installation may lead to a fire hazard. 5. Please use wire clamps to secure the external covers of connecting wires.
Unit Installation Screw with Special Fastener Round Terminal Terminal Board Fig. 2.11 Wire For all terminal wiring (Refer to Fig. 2.13 on the next page): Lead the connection wire and power cord through the insulation tube. Then secure the wires with wire clamps (as shown in Fig. 2.12). Insulation Tube Cord Clamp Fig. 2.12 Page 21 mrcool.
Unit Installation Electrical Connection Connecting the Power Cord & Communication Wire WARNING 1. High and low voltage wires should be led through different rubber rings of the electric box cover. 2. Do not bundle the temperature controller wires or lay them side by side, otherwise errors will occur. 3. High and low voltage wires should be secured separately. Secure the former ones with large clamps and the latter ones with small clamps. 4.
Refrigerant Piping Connection Post Installation Checks 3 Before Test Run Only perform test run after you have completed the following steps: • Electrical Safety Checks – Confirm that the electrical system is safe and operating properly • Gas Leak Checks – Check all flare nut connections and confirm that the system is not leaking • Confirm that gas and liquid (high and low pressure) valves are fully open List of Checks to Perform Possible Malfunctions Is the main body installed securely? The unit may fall
Post Installation Checks Test Run Preparation Before Connecting The Power: 1. Power must not be connected if the installation work is not completed. 2. Verify the control circuit is correct and all the wires are firmly connected. Valves on the vapor and liquid line should be completely open. 3. Remove any scattered objects, especially metal filing, thrum, and clip. 4. Ensure the unit’s appearance and piping system has not been damaged during transportation or handling. 5.
Outdoor Unit Installation Troubleshooting Maintenance 44 (1) If your air conditioner fails to function normally, check the following items before conducting maintenance: Problem The unit will not activate. The unit operates but stops immediately. Abnormal cooling or heating. Cause Corrective Measure The unit isn’t connected to a power supply. Connect to power supply. Low voltage. Check the circuit voltage is within rated scope. Fuse broken or circuit breaker trips off.
Troubleshooting (2) The following situations are not operation failures. Problem Unit doesn’t run. Time of Occurrence Cause When unit is started immediately after it is just turned off. Overload protection switch causes a 3 minute delay. When power is turned on. Start up could be delayed up to 1 minute. If the unit is running under high humidity, the wet air in the room will be quickly cooled down. Mist comes from the During operation. unit. Slight cracking sound is heard when unit is turned on.
Troubleshooting Error Code WARNING 1) When abnormalities occur, stop the unit immediately and disconnect power. Contact MRCOOL. If the unit continues to run abnormally, it may damage the unit and cause an electric shock or a fire hazard. 2) DO NOT attempt repairs to the appliance yourself. Improper repair and maintenance can create electric shock and fire hazards. Please contact MRCOOL Tech Support for further guidance or a qualified professional for repairs.
Troubleshooting Number Error Code Error 22 P5 Over-current protection 23 P6 Master control and driver communication error 24 25 26 27 P7 P8 P9 PA Driver module sensor error Driver module high temperature protection Zero-crossing protection AC current protection 28 29 30 Pc Pd PE Driver current error Sensor connection protection Temperature drift protection 31 PL Bus low-voltage protection 32 33 34 PH PU PP Bus high-voltage protection Charge loop error Input voltage error 35 ee Driver m
Maintenance and Care Regular check, maintenance, and care should be performed by professional personnel, which will prolong the life span of the unit. 5 Drain Pipe Regularly check the drain pipe for clogs in order to ensure smooth condensate drainage. Notice Before Seasonal Use 1. 2. 3. 4. Check if the inlet/outlet of the indoor unit is clogged. Check if the ground wire is earthed reliably. Check if the filter screen has been set soundly. Check if the unit is installed firmly.
Refrigerant Piping Connection EU Disposal Guidelines 6 This appliance contains refrigerant and other potentially hazardous materials. When disposing of this appliance, the law requires special collection and treatment. DO NOT dispose of this product as household waste or unsorted municipal waste. When disposing of this appliance, you have the following options: • Dispose of the appliance at a designated municipal electronic waste collection facility.
Universal™ Series ELECTRICIAN and/or HVAC TECHNICIAN: LICENSE #: INSTALLATION DATE: INSTALLATION LOCATION: SERIAL NUMBER: The design and specifications of this product and/or manual are subject to change without prior notice. Consult with the sales agency or manufacturer for details. Copyright © 2020 MRCOOL, LLC.
