Fantech ATMO Series, Installation And Operation Manual

17

TROUBLESHOOTING

Problem

Causes

Solutions

Air is too dry

Dehumidistat control is set too low

Increase the desired level of humidity. Change ventilation mode from 
continuous mode to standby.

FAA out of balance

Have contractor balance FAA airflows

Air is too humid

Dehumidistat control is set too high

Reduce the desired level of humidity. Combine this with the use of continuous 
exchange mode.

Sudden change in temperature

Wait until outside temperature stabilizes (winter). Heating will also improve 
situation.

Storing too much wood for heating

Store a majority of your wood outside. Even dried, a cord of wood contains 
more than 20 gallons of water.

Dryer vent exhaust is inside home

Make sure the dryer vent is exhausting outside.

Poor air circulation near windows

Open curtains or blinds.

FAA out of balance

Have contractor balance FAA airflows

Well sealed basement door is closed

Open the door or install a grill on the door.

Failed damper system may be stuck in recirculation 

mode

Check defrost damper. If damper is always blocking incoming fresh air, have 
contractor verify damper system.

Persistent condensation
on window

Improper adjustment of dehumidistat control

Reduce the desired level of humidity. Combine this step with use of continuous 
exchange mode.

FAA out of balance

Have contractor balance FAA

Poor air circulation near windows

Open curtains or blinds.

Poor Air Flows

1/4" (6mm) mesh on the outside hoods is plugged

Clean exterior hoods or vents

Filters plugged

Remove and clean filter

Core obstructed

Remove and clean core

Indoor grilles closed or blocked

Check and open grilles

Inadequate power supply at site

Have electrician check supply voltage

Ductwork is restricting airflow

Check duct installation

Improper speed control setting

Increase the speed of the FAA (i.e. change unit control from REDUCED to NORMAL 

speed)

FAA airflow improperly balanced

Have contractor balance FAA airflows

Ducting has fallen down or been disconnected from FAA

Have contractor reconnect ducting

Supply air feels cold

Poor location of supply grilles, the airflow may irritate 

the occupant

Locate the grilles high on the walls or under the baseboards, install ceiling
mounted diffuser or grilles so as not to directly spill the supply air on the 
occupant (eg. Over a sofa) 
Turn down the FAA supply speed. A small duct heater (1kw) could be used to 
temper the supply air
Placement of furniture or closed doors is restricting the movement of air in 
the home

Outdoor temperature extremely cold

If supply air is ducted into furnace return, the furnace fan may need to run 
continuously to distribute ventilation air comfortably

FAA and/or Ducts frosting up

FAA air flows are improperly balanced

Have HVAC contractor balance the FAA airflows

Malfunction of the FAA defrost system

Note: minimal frost build-up is expected on the core before unit initiates 

defrost cycle functions

Condensation or Ice Build Up in 
Insulated Duct to the Outside

Incomplete vapor barrier around insulated duct

Tape and seal all joints

A hole or tear in outer duct covering

Tape any holes or tears made in the outer duct covering 
Ensure that the vapor barrier is completely sealed.

LED is flashing

Everything is in good operations

LED is not flashing

No Power is being transmitted to the Control Board

Make sure unit is plugged.
Transformer may need replacing.

Note:

 It is best to get the unit checked by a certified HVAC Contractor/Technician.