Page 4
FLAME
1
5
HSI/CAI
NEUTRALS
L1
ACC
HUM
1 4
3
6
P7
9
1
10
3
12
J2
4
7
W915
2 STAGE
COMPR
W951
HEAT
PUMP
W914
DEHUM
HARMONY
CUT FOR
OPTION
SELECTION
OUTDOOR
SENSO
R
DISCHARG
E
AIR
SENSO
R
1 2 3 4 5 6
10
12
9
11
13
ON
ON
SureLight
W1W2
G
Y2
Y1 C C
DH L O DS
R
W1
W2
G
Y2
Y1
C
C
R
L
DH
7 8
14
15
SENSE
R
I+ I−
C R
I+ I−
C
OUTDOOR EQUIPMENT
I+
I−
INDOOR EQUIPMENT
IG
N
CAI2
CAI1
N
N
J3
S1
S4
S3
DIAGNOSTIC
LED
FIGURE 2
Placing the SL280UHNV furnace into operation:
SL280UHNV units are equipped with a SureLight® igni-
tion system. Do
not
attempt to manually light the burner
on these furnaces. Each time the thermostat calls for heat,
the burner will automatically light.
Operating the Gas Valve (Figure 3)
1 - STOP! Read the safety information at the beginning
of this section.
2 - Set the thermostat to the lowest setting.
3 - Turn off all electrical power to the unit.
4 - This furnace is equipped with an ignition device
which automatically lights the burners. Do not try to
light the burners by hand.
5 - Remove the access panel.
6 - Move switch on gas valve to OFF. Do not force. See
figure 3.
7 - Wait five minutes to clear out any gas. If you then
smell gas, STOP! Immediately call your gas supplier
from a neighbor’s phone. Follow the gas supplier’s
instructions.
8 - If you do not smell gas go to next step.
GAS VALVE
NEGATIVE AIR
PRESSURE PORT
POSITIVE AIR
PRESSURE PORT
MANIFOLD
PRESSURE TAP
INLET
OUTLET
SUPPLY
PRESSURE
TAP
GAS VALVE SHOWN IN THE ON POSITION
FIGURE 3
9 - Replace the upper access panel.
10 - Turn on all electrical power to to the unit.
11 - Set the thermostat to desired setting.
NOTE - When unit is initially started, steps 1 through
11 may need to be repeated to purge air from gas line.
12 -
If the appliance will not operate, follow the
instructions
Turning Off Gas to the Unit
WARNING
If overheating occurs or if gas supply fails to shut off,
shut off the manual gas valve to the appliance before
shutting off electrical supply.
1 - Set the thermostat to the lowest setting.
2 - Turn off all electrical power to the unit if service is to
be performed.
3 - Remove the upper access panel.
4 - Move switch on gas valve to OFF. Do not force. See
figure 3.
5 - Replace the access panel.
WARNING
Do not set thermostat below 60°F (16°C) in heating
mode. Setting thermostat below 60°F (16°C) reduces
the number of heating cycles. Damage to the unit may
occur that is not covered by the warranty.
Filters
All SL280UHNV filters are installed external to the unit.
Filters should be inspected monthly. Clean or replace the
filter( s) when necessary to ensure proper furnace opera-
tion.
A filter must be in place when the unit is operat-
ing
. See table 1 for recommended filter sizes.
NOTE -
Use replacement filters that are similar in size
and efficiency ratings to those originally provided by the
installing contractor. Use of replacement filters with higher
filtration ratings may restrict air flow to the furnace. This
may result in reduced unit efficiency, as well as premature
blower motor failure.
