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Allied Furnace: Return air connection and sealing

Updated · by Aurora Star Tech Inc.

Return air connection and sealing on a Allied furnace: Improper return connections can allow combustion products into the living space.

Homeowner with a furnace problem? Call (647) 657-2977 or book a service call — licensed technicians across Vaughan and the GTA.

Applies to: Upflow and horizontal installations with return air

Common causes of return air connection and sealing

  • Return ducts connected to the back of the furnace
  • Gaps or leaks in the base or platform
  • Return air shared with a fireplace or stove

How to fix return air connection and sealing: step by step

  1. Do not connect return air ducts to the back of the furnace.
  2. Seal the return air system to the furnace with sheet metal screws and joint tape.
  3. Seal the furnace airtight to the return plenum in platform installs.
  4. Do not use a door as part of the return air duct system.
  5. Make sure the base gives stable support with no sagging, cracks or gaps.
  6. Do not connect return or supply ducts to other heating devices such as a fireplace or stove.
  7. For side return, cut only within the cabinet markings and keep the opening within the stated dimensions.
Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.

If the unit shows an error code, look it up: Allied Furnace codes

Source: Allied 92G1UH installation instructions manual, p. 10, 14. Written in our own words as a summary; always check the original manual.

General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.

Emergency Furnace Repair

647-657-2977