Nu-Air Enerboss 400C Series, Specifications, Installation, Operation And Maintenance Manual

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HRV Outside Air (Fresh Air from Outside) 

1.6.5

At the top, right, front of the fan coil a 5” diameter collar is provided.  The outside air 
collar can be specified when ordering to be top or side and can be changed in the field by 
swapping the cover plate and collar plate. 
 

2 

COMMISSIONING

Supply Air Balancing 

2.1

The supply air motor is an ECM operating in constant cfm mode.  Adding static will not 
significantly reduce the total air flow as you would expect with a psc motor.  On ducted 
systems the amount of air at each grille can be regulated with dampers. 

HRV Balancing 

2.2

The HRV 

exhaust air

 can be adjusted in low and high speed using the control board and 

the procedure that follows.  The amount of outside air is adjusted using dampers.  The 
damper in the return air grille can be closed (partially) to increase outside air flow or 
opened to decrease outside air flow.  If outside air needs to be further reduced, a sliding 
damper located in the HRV outside air compartment should be used. 
 
When balancing the HRV: 
-Close all windows, doors and 
fireplace dampers. 
-Turn off any exhaust systems 
such as bathroom fans, range 
hoods, central vacuums or 
dryers. 
 

There are three modes of 
operation in which the HRV 
needs to be balanced.

1) High speed (High ventilation 
switch).  
2) Low speed (thermostat fan 
ON, no heat or cool calls).  
3) Low ventilation with a call for heat or cooling. 
 
Balancing Sequence: 
High Speed Balancing – set supply and exhaust to the specified flows 
Low speed balancing – Fan On.  Reduce the higher flow to match the lower 
Low speed with heat/cool call on – using the throttling damper, match the outside air 
flow to that of the exhaust air. 
 
 
 
 
 

Exhaust air 
measuring 
port 

Fresh Air 
measuring 
port