Installation Requirements for Air Handling Units (AHUs)

Foundation Acceptance: The acceptance of the equipment foundation shall comply with the following regulations: The location, geometric dimensions, and elevation of the equipment foundation must meet the design requirements. If the design does not specify otherwise, the foundation for floor-mounted AHUs should be 150mm higher than the building floor level. The surface of the equipment foundation must be cleaned and leveled.

Assembly & Sealing: For on-site assembled modular AHUs and heat recovery units, functional sections should be bonded with sealing strips and then connected internally at the four corners using connecting plates, bolts, and nuts. The connections must be airtight, and heat-resistant sealing strips shall be used for sections connected to the heating section. Inspection doors and frames must be flat, firm, and airtight, with flexible operation. The condensate drain pipe (trough) must be unobstructed, and the condensate discharge pipe must be equipped with a water seal (P-trap) with a height complying with the equipment technical documentation. The unit must be cleaned, and the interior must be free of debris, trash, and dust.

Vibration Isolation: When rubber vibration isolators are used for various types of equipment, the textures of each layer of isolators should be staggered, with a steel plate of no less than 4mm thickness placed in between. When the contact surface of the equipment base is smaller than the area of the vibration isolator, a steel plate should be placed on the upper surface of the isolator to ensure uniform load distribution. AHUs shall use rubber vibration isolators, and the equipment base shall be connected to the foundation bolts.

Piping & Duct Support: Air handling equipment shall not bear the weight of external piping or ductwork; all inlet and outlet ducts must have independent supports and hangers. Flexible connections should be used between the inlet/outlet and the ductwork. The length of the flexible connector is generally 150~200mm. Installation should be moderately tight with no obvious twisting, and the connection must be airtight and firm.

Grounding: The AHU equipment body must be properly grounded.

Split & Packaged Units: The installation and fixation of the outdoor unit of split-type air conditioners and air-cooled packaged air conditioners must be firm and reliable, meeting the spatial requirements for natural cooling airflow intake. The indoor unit of split-type air conditioners must be correctly positioned, kept level, and ensure smooth condensate drainage. Wall penetrations for piping must be well-sealed to prevent rainwater infiltration.

Piping for Modular AHUs: Piping for modular AHUs shall comply with the following: Flexible rubber joints should be used for water pipe connections to the unit, and pipes must have independent supports and hangers. Drain valves should be installed at the lowest point of the unit's piping, and air vent valves at the highest point. Valves and instruments must be fully installed with correct specifications and positions; damper opening directions must align with the airflow direction. Condensate water seals must be set up according to the product technical documentation. When used in winter, measures must be taken to prevent the coils and pipelines from freezing. When flexible short ducts are used to connect the unit and ductwork, the thermal insulation performance of the flexible short ducts must meet the requirements of the duct system.

Suzhou Pharma Machinery Co.,Ltd.

2026/07/03

Gino