Johnson Controls M Series Owner's Manual
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Johnson Controls M Series Owner's Manual

Johnson Controls M Series Owner's Manual

24k multi zone system cassette type indoor unit
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See also: Installation and Maintenance Manual
"M" and "W" Series
24K Multi Zone System
Cassette Type Indoor Unit
Owner's Manual
Air Conditioning Unit
Model:
DHMW24NKB21S
Please read this Installation and Operation manual
carefully before installation and operation and retain it for
future reference.

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Summary of Contents for Johnson Controls M Series

  • Page 1 "M" and "W" Series 24K Multi Zone System Cassette Type Indoor Unit Owner's Manual Air Conditioning Unit Model: DHMW24NKB21S Please read this Installation and Operation manual carefully before installation and operation and retain it for future reference.
  • Page 2 Important Notice ● Johnson Controls, Inc. pursues a policy of continuing improvement in design and performance in its products. As such, Johnson Controls, Inc. reserves the right to make changes at any time without prior notice. ● Johnson Controls, Inc. cannot anticipate every possible circumstance that might involve a potential hazard.

  • Page 3: Table Of Contents

    Table of Contents Introduction and Safety Information..............i 1 Additional Usage Information................1 2 Installation of Cassette Type Indoor Unit ............2 2.1 Schematic Diagram of Installation Spaces ............2 2.2 Installation Location of the Indoor Unit ..............2 2.3 Important Notice..................... 3 2.4 Dimensions of Ceiling Opening and Location of Threaded Mounting Rod ....
  • Page 4 Never bypass or jump-out any safety device or switch. ● Johnson Controls, Inc. will not assume any liability for injuries or damage caused by not following steps outlined or described in this manual. Unauthorized modifications to Johnson Controls products are prohibited as they…...
  • Page 5 Take the following precautions to reduce the risk of property damage. ● Be careful that moisture, dust, or variant refrigerant compounds not enter the refrigerant cycle during installation work. Foreign matter could damage internal components or cause blockages. ● If air filters are required on this unit, do not operate the unit without the air filter set in place. If the air filter is not installed, dust may accumulate and breakdown may result.
  • Page 6 Controls uses only refrigerants that have been approved for use in the unit’s intended home country or market. Johnson Controls distributors similarly are only authorized to provide refrigerants that have been approved for use in the countries or markets they serve. The refrigerant used in this unit is identified on the unit’s faceplate and/or in the associated manuals.
  • Page 7 under pressure and never open pressurized system parts. ● Before installation is complete, make sure that the refrigerant leak test has been performed. If refrigerant gases escape into the air, turn OFF the main switch, extinguish any open flames and contact your service contractor.
  • Page 8 ● Communication cabling shall be a minimum of 18-Gauge, 2-Conductor, Stranded Copper. Shielded cable must be considered for applications and routing in areas of high EMI and other sources of potentially excessive electrical noise to reduce the potential for communication errors. When shielded cabling is applied, proper bonding and termination of the cable shield is required as per Johnson Controls guidelines.

  • Page 9: Additional Usage Information

    Additional Usage Information ◆ When purchasing or installing multi-zone DFS systems, the combination ratio must not exceed 150% of outdoor unit capacity. If the connecting indoor units exceed the recommended combination ratio then capacity will be greatly reduced and may damage the system. ◆...

  • Page 10: Installation Of Cassette Type Indoor Unit

    2 Installation of Cassette Indoor Unit 2.1 Schematic Diagram of Installation Spaces Wall surface Wall Wall surface surface Model unit:mm DHMW24NKB21S Ground surface Fig.1 2.2 Installation Location of the Indoor Unit (1). There should be no obstructions near the intake or outlet of the indoor unit as this may restrict airflow.

  • Page 11: Important Notice

    2.3 Important Notice: ◆ To ensure good performance and longevity, the unit must be installed by certified technicians according to these instructions. 2.4 Dimensions of Ceiling Opening and Location of Threaded Mounting Rod Refrigerant pipe Threaded mounting rod (X4) 26-3/4" (Gaps between hoisting screw rods) 33"...

  • Page 12: Installation Of Cassette Chassis

    2.5 Installation of Cassette Chassis (1). The primary steps for installing the indoor unit. ◆ When attaching the mounting bracket onto the threaded rod, use the appropriate bolts and washers capable of supporting the weight of the chassis. The use of field supplied mounting cleats to supplement the chassis mounting brackets will provide additional support and prevent possible damage or breakage of the washers.

  • Page 13: Condensate Hose

    ◆ When completing the flare connections, start the flare nuts by hand; then use the two wrenches as described above to properly tighten. ◆ Refer to Table 1 below if the torque setting is too high then the flare nut may be damaged or the flare may crack causing leaks.
  • Page 14 ◆ If gravity fall cannot be achieved due to obstructions or install limits, then a riser will need to be installed to allow proper sloping of the drain line. ◆ To prevent bending or warping of the drain line, the supporting brackets should be installed in 3'-5' spans as needed.

  • Page 15: Electrical Wiring

    Condensate hose(accessory) Fig. 9 ◆ Please install the condensate hose according to the following process if several drain hoses join together. Above 4" The specs of the joined condensate hoses should fit the running capacity of the unit. Fig. 10 (2).
  • Page 16 System wiring and connections ◆ Communication wiring: ① The communication wire should be connected to the #2 terminal at both the indoor and outdoor units. ② Wiring according to the indoor side circuit diagram. ◆ Secure the impact fastener after connection. ◆...

  • Page 17: Grille Installation

    DHW42CMB21S POWER 2.9 Grille Installation 1. Install the grille onto the indoor unit body by matching the position of the swing flap motor of the panel to the piping position of the panel to the piping position of the cassette shown in Fig.13.
  • Page 18 (3). Partially tighten the (four) screws in the corners to secure panel to chassis. (4). Tighten the screws incrementally so that the grille rises in a level manner until the grille meets the finished ceiling. (5). Once the grille is in place and tightened the sealing gasket of the grille should be compressed to approximately 1/4 to 1/8 of an inch.
  • Page 19 Air leak Air leak from ceiling Water condensatation, water drop Fig.14 If a gap still exists between the ceiling and the cassette grille, and these cannot be ② . eliminated with the corner screw adjustments, then the cassette chassis needs to be adjusted lower for proper sealing of grille to chassis Corner adjustment(s) to lower the chassis if needed.

  • Page 20: Nomenclature Of Cassette Type Indoor Unit

    3 Nomenclature of Cassette Type Indoor Unit Drainage equipment (inside type) Discharge condensate water from indoor unit when cooling Drainage hose Guide louver (placed in air outlet vent) Air outlet vent Connecting pipe Air filter, purifier (in air inlet grille) Air inlet grille Fig.17 DHMW24NKB21S...

  • Page 21: Working Temperature Range

    4 Working Temperature Range Working Temperature Range Indoor side state ℉（℃） Outdoor side state ℉（℃） Dry bulb Wet bulb Dry bulb Wet bulb temp. ℉（℃） temp. ℉ （℃） temp. ℉ （℃） temp. ℉ （℃） Rated. Cooling 80.0(26.7) 67.0(19.4) 95.0(35.0) 75.0(23.9) Max.

  • Page 22: Troubleshooting Malfunctions

    5 Troubleshooting Malfunctions Warning! ◆ Disconnect power immediately if there is a strong burning smell or if abnormal noises are coming from the indoor or outdoor units. Contact the installing contractor or service provider to have the system evaluated. ★ Check the following items before contacting service provider Event Possible Causes Possible Solutions...
  • Page 23 ★ The following circumstances are considered normal (based on mechanical and environmental factors) “Operation” Reason Built-in delay in system prevents Unit is turned off, then immediately restarting until pressures equalize - back on about 3 minutes. Air conditioning unit doesn’t run Delay at the outdoor unit when When first turned on indoor is first turned on.

  • Page 24: Maintenance Methods

    6 Maintenance Methods When the air conditioning unit won’t be used for a long time, please turn off the main power supply of the air conditioning unit. Warning! off the unit and off the main power supply when cleaning the air condition ◆...

  • Page 25: Cleaning Air Inlet Grille

    Fig. 20 Fig. 21 6.2 Cleaning Air Inlet Grille (1). Open the air inlet grille (Refer to the first step of "Clean Air Filter" above.) (2). Take out the air filter (Refer to the second step of "Clean Air Filter" above.) (3).

  • Page 26: Cleaning Of Surfaces And Louvers

    Function and usage period for air purifying ◆ Could absorb CO, CO , benzene, aldehydes and odor of gasoline etc. ◆ Could absorb unhealthy material such as dust, pollen, bacteria, or virus. ◆ Usage period is six months to one year. Replacement purifier should be ordered through your installer or service provider.
  • Page 28 Product improvement, specifications and appearance in this manual are subject to change without prior notice. © Johnson Controls, Inc. USA LIT - 12012209...

This manual is also suitable for:

W seriesDhmw24nkb21s

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