Sunlife Enterprises SUNLINE DM180 - Manual (Page 51)

356214-XIM-A-0108
Johnson Controls Unitary Products 51
10. If the blower motor runs with the fan switch in the
“ON” position but does not run shortly after the fur-
nace has ignited when the fan switch is in the
“AUTO” position, check the room thermostat for
contact between R and G during “W1” calls.
On calls for heating, the supply air blower operates but
the draft motor does not (the room thermostat fan
switch is in the “AUTO” position).
1. The draft motor has inherent protection. If the
motor shell is hot to the touch, wait for the internal
overload to reset.
2. If the motor shell is cold with the room thermostat
calling for heat, check for line voltage at the
motor's Mate-N-Lok connector attached to the
evaporator partition. If line voltage is present,
replace the draft motor.
3. If line voltage is not present, check for line voltage
at the heat relay (RW1) contacts in the main con-
trol box and check to see if the (RW1) is pulled in.
4. If the (RW1) relay is pulled in, check for a loose line
voltage connection.
5. If the (RW1) relay is not pulled in, check for 24 volts
at the (RW1) coil. If 24 volts is present, replace the
(RW1) relay. If 24 volts is not present, check for a
loose 24 volt connection back to the relay board
and check the connections from the room thermo-
stat to the relay board. If all connections are cor-
rect, replace the relay board.
The draft motor runs but the furnace does not light and
the sparker does not spark.
1. The ignition control (IC1, IC2) may be locked out
due to either a flame roll out or 100% shut off.
These safety features are described above. If lock-
out has occurred, 24V must be removed from the
ignition controls. This is done at the unit or by
resetting the room thermostat. After resetting 24V,
check for proper furnace operation. If lock-out con-
tinues to occur, locate the source of the problem
and correct.
2. Check all 24 volt connections from the relay board
to and in the gas heat section. Check low voltage
connections to the (ETD) located in the control
box.
3. If the furnace is hot, it may be out on an over-tem-
perature condition, wait for limit reset.
4. If the furnace is cold, check for 24 volts at wire 241
attached to the electrical time delay (ETD) located
in the main control box. If 24 volts is not found,
replace the ETD.
5. 24 volts is found at wire 241, remove the wires
attached to the (TDR) and with a VOM, check for
continuity across contacts 1 and 2. If none is found,
the (TDR) is open and must be replaced. If there is
continuity, re-attach the wires.With the draft motor
running, check for 24 volts at terminal 4 of (RW1-2)
and (RW2-1). If 24 volts is not present, the centrifu-
gal switch (CS) has not closed or has gone bad.
Check the line voltage to the unit - if it is correct,
replace the draft motor. If line voltage is low, call
the power company.
6. Check for 24V at terminal 2 of (RW1-2 and RW2-
1). If 24V is not present, check for 24V at (RW1
and RW2) relay coils. If these relays are pulled in,
then check for a loose connection at terminal 2 and
terminal 4 of each relay. If no problem is found,
then replace (RW1 and/or RW2) as required.
7. If 24 volts is present at the ignitor controls, check
all control wiring at the ignitor controls and the high
tension wire to the ignitors. Check that the ground
wires from the ignitor controls, the gas valves and
pilot burners are all intact and making good electri-
cal connection. Check to make sure that the
ceramic insulator on the pilot ignitors or sensors is
not broken or cracked, if all are intact, replace the
ignition control IC1 or IC2.
The draft motor runs and the ignitor sparks at the pilot
burner but the pilot does not ignite and a gas odor is
not detected at the draft motor outlet.
1. Check to make sure gas is being supplied to the
unit. Make sure that the gas pressure to the unit is
within the proper limits as described in the “POST
START CHECK LIST” page 43 and that the pilot
adjust screw is allowing some flow of gas as
described in “PILOT CHECKOUT” page 44.
2. Check all wiring between the ignitor control and the
gas valve. Check to make sure the ground connec-
tions are intact.
3. If the wiring is intact, check for 24 volts across ter-
minals “PV” and “COMMON” on the ignitor control.
If 24 volts is not present, replace the ignitor control.