Blower Heat Off Delay Timings; Comfortnet™ System; Overview; Airflow Consideration - Goodman MVM96 Installation Instructions Manual

B H O D
LOWER EAT FF ELAY
The integrated control module provides a selectable heat off delay
function. The heat off delay period may be set to 90, 120, 150, 180
seconds using the DIP switches or jumper provided on the control
module. The delay is factory shipped at 150 seconds but may be
changed to suit the installation requirements and/or homeowner
preference. Refer to the dip switch chart in the back section of
this manual for switch positions and corresponding delay times.
C N ™ S
OMFORT ET
O
VERVIEW
NOTE: Dip switch #13 MUST be set to match thermostat
type. To use the CTK01AA communicating thermostat, dip
switch #13 must be set to ON position. This is also the cor-
rect setting for a non-communicating 2-stage thermostat. To
use the CTK02AA modulating thermostat, check to make
sure dip switch #13 is in the OFF position (factory position).
This is also the correct position when using a non-communi-
cating single stage thermostat.
The ComfortNet system is a system that includes a ComfortNet
compatible furnace and air conditioner or heat pump with a CTK0*AA
thermostat. A valid ComfortNet system could also be a compat-
ible furnace, CTK0*AA thermostat and non-compatible, single stage
air conditioner. Any other system configurations are considered
invalid ComfortNet systems and must be connected as a tradi-
tional (or non-communicating) system (see Electrical Connec-
tions for wiring connections).
A ComfortNet heating/air conditioning system differs from a non-
communicating/traditional system in the manner in which the in-
door unit, outdoor unit and thermostat interact with one another. In
a traditional system, the thermostat sends commands to the in-
door and outdoor units via analog 24 VAC signals. It is a one-way
communication path in that the indoor and outdoor units typically
do not return information to the thermostat.
The indoor unit, outdoor unit and thermostat comprising a
ComfortNet system "communicate" digitally with one another, cre-
ating a two-way communications path. The thermostat still sends
commands to the indoor and outdoor units. However, the thermo-
stat may also request and receive information from both the indoor
and outdoor units. This information may be displayed on the
ComfortNet thermostat. The indoor and outdoor units also inter-
act with one another. The outdoor unit may send commands to or
request information from the indoor unit. This two-way digital com-
munications between the thermostat and subsystems (indoor/out-
door unit) and between subsystems is the key to unlocking the
benefits and features of the ComfortNet system.
T
IMINGS
YSTEM
Two-way digital communications is accomplished using only two
wires. The thermostat and subsystem controls are powered with
24 VAC. Thus, a maximum of 4 wires between the equipment and
thermostat is all that is required to operate the system.
A C
IRFLOW ONSIDERATIONS
Airflow demands are managed differently in a fully communi-
cating system than they are in a non-communicating wired
system. The system operating mode (as determined by the
thermostat) determines which unit calculates the system air-
flow demand. If the indoor unit is responsible for determining
the airflow demand, it calculates the demand and sends it to
the ECM motor. If the outdoor unit or thermostat is respon-
sible for determining the demand, it calculates the demand
and transmits the demand along with a fan request to the
indoor unit. The indoor unit then sends the demand to the
ECM motor. The table below lists the various ComfortNet
systems, the operating mode, and airflow demand source.
System Operating
System
Air Conditioner +
Furnace
Continuous Fan
Heat Pump Heating
Heat Pump +
Furnace
Auxiliary Heating
Continuous Fan
Furnace + Non-
Comm 1stg Air
Conditioner
Continuous Fan
42
Airflow Demand Source
Mode
Cooling Air Conditioner
Heating Furnace
Thermostat
Cooling Heat Pump
Heat Pump
Only
Furnace
Thermostat
Cooling Furnace
Heating Furnace
Thermostat