2 − Holes are on both sides of the furnace cabinet to facili- tate wiring.
3 − Install a separate (properly sized) disconnect switch near the furnace so that power can be turned off for servicing.
4 − Before connecting the thermostat or the power wiring, check to make sure the wires will be long enough for servicing at a later date. Remove the blower access panel to check the length of the wire.
5 − Complete the wiring connections to the equipment. Use the provided unit wiring diagram and the field wir- ing diagrams shown in table 13 and figure 24. Use 18−gauge wire or larger that is suitable for Class II ra- ting for thermostat connections.
6 − Electrically ground the unit according to local codes or, in the absence of local codes, according to the current National Electric Code (ANSI/NFPA No. 70). A green ground wire is provided in the field make−up box.
NOTE − The SL280DFV furnace contains electronic components that are polarity sensitive. Make sure that the furnace is wired correctly and is properly grounded.
7 − One line voltageade terminal is provided on the furnace integrated control. Any electronic air cleaner or other accessory rated up to one amp can be connected to this terminal with the neutral leg of the cir- cuit being connected to the one of the provided neutral terminals. See figure 25 for control configuration. This terminal is energized when the indoor blower is operat- ing.
8 − An unpowered, normally open (dry) set of contacts with a 1/4" spade terminal
er connections and may be connected to 24V or 120V. Any humidifier rated up to one amp can be connected to these terminals. In 120V humidifier applications the neutral leg of the circuit can be connected to one of the provided neutral terminals. This terminal is energized in the heating mode.
9 − Install the room thermostat according to the instruc- tions provided with the thermostat. See table 13 for field wiring connections in varying applications. If the furnace is being matched with a heat pump, refer to the instruction packaged with the dual fuel thermostat.
Thermostat Selection
CAUTION
Field wiring for both communicating and non−com- municating applications is illustrated in diagrams, which begin on Page 23.
Non−Communicating
In non−communicating applications the SL280DFV is de- signed to operate in a SINGLE−STAGE mode or TWO− STAGE mode using a conventional thermostat.
For optimal performance in non−communicating applica- tions, Lennox recommends use of a ComfortSense® 7000 high quality electronic digital thermostat or any other with adjustable settings for 1st stage / 2nd stage on / off differen- tials and adjustable stage timers.
Lennox recommends the following two−stage thermostat settings:
First heat stage differential set to 1/2 to 1 degree F; second heat stage differential set to 1/2 or 1 degree F; second heat stage upstage timer disabled, or set to maximum (1 hr mini- mum).
Communicating
In communicating applications the icomfort Touch® ther- mostat must be used. Refer to the instructions provided with the thermostat for installation, set−up and operation. In communicating system all unused thermostat wire in the wire bundle needs to be terminated inside and out. The ex- tra wires can terminate on the ’C" terminal of the icomfortt communication terminal strip. (RSBus). Using an addition- al wire come off "C" terminal and wire nut all the extra wires together. Termination on the outdoor control must match the indoor control.
Indoor Blower Speeds
Non−Communicating
1 − When the thermostat is set to AN ON," the indoor blower will run continuously at a field selectable per- centage of the second−stage cooling speed when there is no cooling or heating demand. The factory default setting is 38% of cool speed.
2 − When the SL280DFV is running in the heating mode, the indoor blower will run on the heating speed desig- nated by the positions of DIP switches 11, 12 and 13. First stage heating will run at 91% heat speed.
3 − When there is a cooling demand, the indoor blower will run on the cooling speed designated by the positions of DIP switches 5 and 6. First stage cooling will run at 70% cool speed.
Communicating
NOTE − When the SL280DFV is used with icomfort Touch® thermostat, proper indoor blower speed selec- tions are made by the communicating thermostat.
1 − When the thermostat is set to AN ON," the indoor blower will run at setting determined during system configuration.
2 − When there is a heating demand the fan will run on heating speeds for firing rate.
3 − When there is a cooling demand, the fan will run on the first stage and second stage cooling speed set using the icomfort Touch® thermostat in the installer setup mode. The factory default is based upon 400 CFM a ton.
