Frequently Asked Questions (FAQ) about Air Conditioning Air Handling Units (AHU)

Monday, August 30, 2021

An air handler is also called the “inside unit” of a split-system air conditioner. Here’s links to a collection of our articles about them:

 What is the requirement for a service receptacle outlet for heating, air conditioning, and refrigeration (HACR) equipment?

 What is the required clearance for access and working space in front of a furnace or air handler?

 Will installing a special ultraviolet (UV) light in the air conditioning system kill mold? 

 What is the small pipe sticking out of the eaves/soffit under the roof overhang? 

 Why can't I use my home's central air conditioning system to cool the garage? 

 Does the condenser (outdoor unit) SEER rating determine the SEER of an air conditioning system? 

 What is a FanRecycler and AirCycler? 

 What are the Florida Building Code Energy Conservation Code requirements for installing an air handler in the attic? 

 Why does it take so long to cool a house when an air conditioner has been off for a while? 

 What is a return air plenum for a furnace or air conditioning system?

 Why is there a wall switch next to the furnace or indoor unit of the air conditioner in the garage?

 Is it acceptable for an air conditioning condensate drain line to terminate under the house?

 Why does the air conditioner condensate drain line need a trap in it?

 What is the average lifespan of an air conditioner? 

 Why is my air conditioner running constantly? 

 What is a TX valve or TXV for an air conditioner or heat pump system?

 My air conditioner won't come on after changing the air filter. What's wrong?

 What does an ultraviolet air treatment system do? 

• When is an auxiliary drain pan required under an air conditioner indoor unit air handler? 

• What are the building code requirements for installing a heat pump air handler (indoor unit) in the attic? 

• Can a water heater and air conditioner use the same drain? 

• What is an electric heat lock out on a heat pump? 

• Can the disconnect for an air handler be inside it? 

• Can an air conditioning condensate drain pipe connect to a sink drain?

• How can I make my Florida air conditioner last longer? 

• What is the difference between an upflow, downflow, and horizontal air handler or furnace? 

• What is the difference between a fan coil unit (FCU) and an air handling unit (AHU)?

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