Energy Recovery Ventilator (Erv); Heat Recovery Ventilator (Hrv); Fresh Air Damper; Zoning Application - Lennox iComfort S30 Installation And Setup Manual

Thermostat ventilation CFM parameters are to be adjusted only after the HRV/
ERV set up is completed and the CFMs are known. Once the thermostat's
CFMs are adjusted they are used with the thermostat's timer algorithm to
determine how long to run the HRV/ERV and to change from low to high speed
if a 2-stage HRV/ERVs.

Energy Recovery Ventilator (ERV)

The ERV unit is equipped with an enthalpic core. This device is designed
for use in warm, humid climates with heavy air conditioning loads. The ERV
unit transfers both sensible (temperature) and latent (moisture) heat from
incoming fresh air to the stale air as it is being exhausted; thus, reducing the
air conditioning load.

Heat Recovery Ventilator (HRV)

The HRV unit is equipped with an aluminum core. The device uses the stale
air that is being exhausted to condition the fresh air as it is being brought in.
Lennox models are all non-communicating equipment and can be added during
the commissioning procedure (see "Commissioning (Using the HD Display)"
on page 19).
Parameter settings and descriptions are listed in "Table 6. Smart Hub
Parameters" on page 23. The table below list which parameters are available
for the Fresh Air Damper, ERV and HRV equipment.

Fresh Air Damper

This option is used to control a damper connecting outside air to the return
plenum of the system. When a fresh air damper style of ventilation is added
to the system, and ventilation is required, the ventilation demand is serviced
by energizing one relay to close or open the relay contacts connected to the
fresh air damper and commanding the blower to run at a rate of at least the
continuous fan speed.
The parameter Fresh Air Damper Ventilation CFM represents the CFM of the
air drawn through the fresh air damper while the system runs the indoor blower
at the continuous fan speed for non-zoned systems, and the lowest zone CFM
(continuous fan, heating, or cooling) for zoned applications. All calculations
used to determine the ventilation volume requirement and the amount of
ventilation air delivered use this number regardless of the actual fan speed.

Zoning Application

• When ventilation is demanded in zoned applications without conditioning
calls, the fresh air damper will open and the blower will run at the lowest set
zone CFM referred to above.
• Ventilation while a zone is being conditioned is serviced simply by opening
the fresh air damper while the zone system conditions the zone.
• The system keeps track of the amount of ventilation delivered in the same
manner as any single speed HRV or ERV.
• When the time required to satisfy the ventilation time requirement using the
fresh air damper ventilation rate is greater than or equal to the time remaining
in the ventilation time block, then ventilation is initiated and continues until
the ventilation time requirement is satisfied.

Operation of Fresh Air Dampers with Environmental Overrides

• When the Non-ASHRAE Compliant mode is selected (Timed), the system
first checks for the outdoor temperature and dew point to be within the set
parameter range before allowing ventilation to occur.
• When the ventilation changes states (on/off) due to an environmental
override, it will remain in that state for a minimum of 10 minutes before again
changing states due to an environmental override.
• Operation is otherwise the same as the ASHRAE compliant method.

Wiring

Wiring connections are listed in "Figure 13. iComfort S30 with Ventilation
(Fresh Air Damper, ERV and HRV)" on page 13.

Ventilation Control Modes

Thermostat ventilation CFM parameters are to be adjusted only after the HRV/
ERV set up is completed and the CFMs are known. Once the thermostat's
CFMs are adjusted they are used with the thermostat's timer algorithm to
determine how long to run the HRV/ERV and to change from low to high speed
if a 2-stage HRV/ERVs.
Table 17. Ventilation Control Modes
Ventilation Control Mode
Ventilation Minutes Per Hour
(0 to 60 min., default is 20 min.)
Ventilation Rate
(20 to 500 cfm, default is 130 cfm)
(Shown only for single speed ERV or HRV)
Ventilation Rate for Low Speed
(10 to 200 cfm, default is 50 cfm)
(Shown only for two speed ERV or HRV)
46
1 2 1
Fresh Air
Speed Speed Speed
Damper
HRV HRV ERV
Timed
X X X X
X X X
X
2
Speed
ERV
X
X