Air Handling Unit Components 2 | HVAC Forced Air Systems

Air Handling Unit Components 2: Heat - There are many different types and arrangements of heating systems for air handling units and these types of heating systems and arrangements of heating systems vary from commercial to residential. Some air handling units do not have any heat source inside them at all but have remote heat for zoning. The air handling unit provides the airflow and the remote heaters provide heat for zoning.

Sometimes the air handling unit is a VAV air handling unit and other times it is just to provide air for a duct heater whether the duct heater is gas-fired or electric. For air handling units which some have heating systems inside the five main ways of providing heat for air handling units are:

Trane Air Handler Making Dust | HVAC Troubleshooting

Trane Air Handler Making Dust | HVAC Troubleshooting leaking duct work Trane air handler

This is a brand new installation and the ductwork was leaking. Older ductwork definitely leaks and can cause a dusty environment

Trane Air Handler Making Dust | HVAC Troubleshooting - I would appreciate someone in the Trane organization that would please tell me why since installment and still 5 years later my house is nothing but a dust pit. I am not exaggerating. You can wipe dust blankets DAILY off my walls, floors, furniture. I have been, since the installation, asking someone to help me.

My original installer put a filtering system “like used in coal mines” - did not help. I have had independent HVAC inspectors who cannot understand nor have any reasoning for the dust. One thing was that the original TRANE installer did not put sufficient air return duct in my house.


L.E. (more…)

Air Handler Coils | HVAC AHU

Air Handler Coils
The air handler coils should be checked for dirt and debris which may have been sucked into the air handler inadvertently. Some air handlers have filters inside them before the coils. It is a good time to change the filters when making this check.

Any dirt or debris on the coil(s) should be removed immediately as these things will impede airflow through the air handler and throughout the entire system as a whole. Dirty evaporator coils can cause AC problems. Some air handler coils are installed in the air handler cabinet while other coils are installed in the ductwork. (more…)

Air Handler Cabinet | HVAC Components

The air handler cabinet is made of sheet metal and simply acts as a duct to guide the air through and to protect the air handler components and to protect people from the air handler components. Depending on the manufacturer will depend on the color of the unit. Trane air handlers are usually green,

Carrier air handlers are usually gray, Goodman, Janitrol, and York air handlers are usually brown (as many manufacturers use brown). Air handler components are the blower and can have air handler coils installed inside the air handler. Additionally, electrical controls for the air handler components along with dampers to control the airflow.


Air Handler Cabinet | HVAC Components

Commercial Air Handlers

Commercial air handlers are usually unpainted sheet metal especially McQuay but Carrier, York, and Trane will paint their commercial equipment before shipping. It simply depends on the manufacturer and what they decided to use to paint their equipment before shipping.

Hopefully, you can use this as a guide if there is no identifying information on the equipment. Sometimes the identifying information (nomenclature) for air handlers are hidden on the inside of the cabinet but it is not recommended to open the air handler cabinet unless you are a trained HVAC professional.

AHU Cabinet Construction

Air Handler CabinetAll manufacturers paint the air handler cabinets and depending on how they paint the cabinets will depend on the durability of the finish and in some cases the durability of the cabinet itself. Most air handler cabinets are constructed of steel and then a primer paint is applied followed by a final coat of the finished color.

The primer coat is the coat that will bond with the steel and prevent future rusting or corrosion of the cabinet as long as the cabinet is not scratched or the primer coat is not scratched off the cabinet and bare metal is visible.

A few manufacturers use a solid-state process of powder coating the primer coat and powder coating creates a near-permanent bond between the steel and the paint. The bond in powder coating can be down to the molecular level if the process is done correctly so the better cabinets will be ones that are powder coated.

AHU Maintenance | Air Handler Cabinet

In the way of maintenance for air handling units, there is little maintenance needed for AHU cabinets. If the air handler has been exposed to a rough environment and the paint is scratched or is fading as a result of direct sunlight it may be necessary to apply a coat of paint to the air handling unit to protect the metal from rust and corrosion. Some air handlers have doors that are accessed for maintenance purposes such as air filter maintenance or motor and belt maintenance.

Some older air handlers need to have screws removed to access essential parts of the air handler for maintenance and the screws and screw holes become stripped so they do not hold the doors on securely. It is necessary to repair these stripped-out holes and replace the screws so the access doors are held on securely.

This is especially true about rooftop units. These air handler access panels can come to lose either by the wind or by the unit’s vibrations when in operation and the wind can pick these panels up and throw them making them a hazard to people and property.

Air Handler Cabinet

The cabinet protects all the components. It is, therefore important, to ensure it is durable.

High Performance HVAC

Air Handler Cabinet

Air Handler Evaporator Condensation Drain Blower Compartment

Air Handler Blower Compartment and Evaporator Condensation Drain

Air Handler Evaporator Condensation Drain Blower Compartment

This air handler has the access panels removed during the installation process so the HVAC installation technician can make the final connections and adjustments. In clear view is the air handler blower compartment with the air handler blower. The air handler blower is comprised of an electric motor, a blower wheel, and a squirrel cage which holds it all together. Attached to the outside of the squirrel cage is a run capacitor which is a functioning part of the electric motor. All these air handler components combined blows air throughout the entire HVAC system including the evaporator coil. (more…)

Air Handler Components

Air Handler Components. This article will take different types of air handlers and disassemble them part by part. This will give you a good description of each part and hopefully a better understanding of the air handler. Most of the components associated with the air handler are in the air handler. However, there are a few components which are not in the air handler but associated with the air handler.

There are some hot water and cold water coils which are not fixed in the air handler. They are downstream in the ductwork. There are also some gas and electric duct heaters which are mounted in the ductwork. They are completely reliant on the air handler for air flow. These systems will also be covered. Hopefully, this article will offer you a comprehensive look at the air handler, all its parts, and how it functions. (more…)

Air Handler Filter Pressure Sensor

Air Handler Filter Pressure Sensor and Low Static PressureAir Handler Filter Pressure Sensor - This is a pressure sensor. It tells a maintenance technician if the air filters are dirty and clogged. The pressure control is a low static pressure switch to trip the unit if the mixing box drops below the setpoint pressure. The pressure the switch is calibrated to.

In addition, the low static pressure sensor protects the fan and the ductwork including dampers from damage. If the economizer damper and the return air damper would fail closed (or another possible scenario) that would cause the unit to pull negative pressure in the mixing box. (more…)

Water Dripping from Air Conditioner | Condensation Drain Pipe

Water Dripping from Air Conditioner - We have 2 air conditioning units in our house and 2 pipes protrude from the roof. One of the pipes is dripping water. We were told to look for a blockage and to empty the pans. I don’t see where to check for a blockage. Any suggestions?
The air conditioning units we have: Bryant models 373LAV, 376CAV Downflow/Horizontal and 383KAV, 395CAV Upflow Gas Furnace. (more…)

HVAC Duct Work – Air Handling Unit Duct

HVAC Duct Work - Air Handling Unit Duct - Air Handler Duct WorkHVAC Duct Work delivers the conditioned air to the spaces. The Air Handling Duct channels this conditioned air to spaces where it is needed and then a return duct channels the air back to the air handling unit duct for re-conditioning. The return ductwork has a negative pressure while the supply ductwork has positive pressure.

In commercial systems and tight residential homes, it is necessary to add fresh air to this conditioned air so the air remains fresh and healthy for the occupants of the structure. This is required by the mechanical code and often this air comes through ductwork from the outside. (more…)