Rheem 97MDV060 Series Installation Instructions Manual page 68

b. Post-Purge after Non-Calibration Heat Call:
Post-purge after any heat sequence which is not a calibra-
tion sequence shall take place at the same inducer speed
that the system was at when the heat call ended and shall
be a period of 10 seconds.
Blower Off Delay
The blower off delay is to always begin after the gas valve
is de-energized or when detected error conditions that
have been cleared require blower to be energized and
then de-energized. It is user-selectable per dipswitch
SW17 or, for communicating systems, the value selected
at the Econet control center. The blower off delay will take
place at the same CFM demand that the blower was at the
time of the gas valve de-energizing or at CFM matching
100% firing rate if the blower was off.
If a compressor call becomes present during the heat
blower "off" delay, the IFC will immediately switch the
blower output to the greater of the cool call and heat call
CFM until the end of the blower "off" delay. At the end of
the blower off delay, the blower CFM shall be set to the
cool or HP CFM.
1. P1 (8-Pin), P2 (6-Pin) and P7 (5-Pin)
Low-VoltageInternal Wiring Connections – Connect
main twist-lockwire harness to these connections.
Pre-wired from the factory.
2. RJ-14 CONNECTOR (J1)
This connector is used to program the furnace control
at the factory. It may also be connected in the field to
certain Econet devices. It should never be connected
to a telephone line or a telephone. Doing so could
damage the furnace control or the telephone (or
telephone lines) or both.
DO NOT CONNECT A TELEPHONE OR PHONE LINE
TO THE CONNECTOR (JACK) AT POSITION J-1.
DOING SO COULD CAUSE IRREPARABLE DAMAGE
TO EITHER THE FURNACE CONTROL (I.F.C.) OR
THE TELEPHONE (OR TELEPHONE LINE) OR
BOTH.
3. SPARK IGNITION TRANSFORMER (T1)
The spark ignition transformer resides on the furnace
control. The transformer provides spark energy at
approximately 60 hz frequency and a minimum of
12KV.
4. BIAS / TERMINATION (S4)
For current installations, all three of the
dipswitches in bank SW4 must be in the "OFF"
position. If not, the system may not be able to
communicate.
5. COMMUNICATIONS LED'S (CR36 & CR38)
Two LED's are provided to indicate the status of
communications. A red LED (labeled TX) is provided
68
for transmit and a green LED (labeled RX) is provided
for receive. These LED's will be lit in an undefined
pattern when other communicating components are
attached and communicating with the furnace control.
6. LINE VOLTAGE CONNECTIONS (120VAC, L1)
Four ¼" spade terminals are provided for internal
connections and accessories.
7. INDUCED DRAFT MOTOR (INDUCER) OUTPUT(P3)
This three-pin Mate-n-Lok style connector provides
power to the inducer.
8. NEUTRAL TERMINALS (NEUTRAL)
Four ¼" spade terminals are provided for internal
connections and accessories.
9. ELECTRONIC AIR CLEANER (EAC.) OUTPUT (T3)
This output is used to energize an electronic air
cleaner. The output will provide up to 1.0 amp at 115
VAC.This output is energized any time the blower
motor is above the airflow CFM values specified
below. Airflow below these values is not considered to
be enough for a typical electronic air cleaner to
perform properly.
For ½ HP motors - Electronic air cleaner is energized
any time the blower is above 500 CFM
For ¾ HP motors - Electronic air cleaner is energized
any time the blower is above 600 CFM
Continuous fan speeds are selectable and some lower
fan speeds may not deliver enough airflow to operate
an electronic air cleaner. The IFC determines the
minimum airflow necessary to operate an electronic
aircleaner and will not turn on the electronic air
cleaner unless the airflow is high enough for the EAC.
10. HUMIDIFICATION (T3) AND DEHUMIDIFICATION
HUMIDIFIER – The humidifier contacts (labeled
"HUM" (2)) are "dry" contacts on the I.F.C. This means
that the terminals are connected directly to the
contacts of a board-mounted relay. The coil of the
relay is controlled by the microprocessor of the IFC.
The coil is engaged any time the heat speed blower is
engaged and (1) 24VAC is present on the thermostat
terminal of the IFC labeled "HUM STAT" or (2) a
communicating thermostat with humidification and
dehumidification capability is installed with call for
humidification present. (See Figure 48 for location of
humidification/dehumidification inputs on furnace
control.)
An optional 24VAC humidistat can be installed as shown
in Figures 49 thru 52. With the optional humidistat, two
separate conditions must be met before humidification can
begin
1.) There must be a call for heat and the blower must be
engaged and