Fantech ATMO Series, Installation And Operation Manual

7

INSTALLATION EXAMPLES 

(CONT'D)

DIRECT CONNECTION of both the FAA SUPPLY AIR STREAM and EXHAUST AIR STREAM 
to the FURNACE COLD AIR RETURN

SIMPLIFIED INSTALLATION

(GOOD)

(RETURN/RETURN METHOD)

Suggested installation for:

• When bathroom and kitchen 

already have local exhaust 
system

• May be suitable for 

retrofitting

Benefits: 

Least expensive 

installation type

1.  Furnace blower must operate when ventilation from FAA is required. The furnace should 

be set to run continuously or interlocked with FAA. 

See furnace electrical connection 

on page 16.

2.  A minimum separation of 1m (39’’) is recommended between the two direct 

connections.

3.  In order to prevent exhausting any fresh air, the FAA's exhaust air connection should be 

upstream of the FAA's supply air connection when ducting to the furnace’s cold air return.

4.  Due to the difference in pressure between the FAA and the equipment it is being 

connected to the FAA's airflow must be balanced on site, using the procedure found in the 
section “AIRFLOW BALANCING”

* In the case of a multi-zone system, please contact Fantech customer 

service prior to installing any installation type requiring the use of the 

furnace interlock"

Air from inside

* Unit air flow should be balanced while FAA is on "Normal" speed and 
furnace blower is running.

1 m (3' 3") 

min.  

recommended

Cold air 

return

* Ductwork layout may dif-
fer depending on model

FAA/Furnace ducting for Simplified Installation - Option 1

Stale air to

outside

Fresh air from

outside

Fresh air to
living areas

Fantech fresh air appliances (FAA) that use a supply fan shutdown for frost prevention do 

not include an outdoor air motorized damper. If you are using a simplified installation, i.e. 

connecting the FAA supply air duct to a furnace's return air duct, the FAA must operate 

continuously. When the FAA is turned off, no warm exhaust air will flow through the FAA 

but the furnace's fan will continue to draw in outdoor air directly into the furnace.  If it's 

cold outside, cold air will be introduced, without re-heating, directly into the furnace.

If the FAA is installed such that the homeowner may turn off the FAA during the winter, we 

recommend installing a motorized damper between the FAA's supply air and the furnace's 

return air duct that closes when the FAA is not operating. See wiring diagram (figure 1). 

You may also choose to use a Fantech FAA that uses a recirculation defrost that incorpo-

rates an outdoor air damper. 

Damper 
Motor

24 VAC Transformer

COM

NO

ERV Furnace interlock
See page 16.

24V

120V

Figure 1

*Transformer and Damper motor not included

Motorized 
damper

1 m (3' 3") 

min.  

recommended

Air return