Instruction manual

25
60
Second
Delay
12
ON
OFF
B1
B2
B3
B4
90
Second
Delay
12
ON
OFF
B1
B2
B3
B4
120
Second
Delay
12
ON
OFF
B1
B2
B3
B4
180
Second
Delay
12
ON
OFF
B1
B2
B3
B4
Style A
Style B
Switches viewed in an upflow installation.
Figure 29 - Heating Fan Off Adjustments
XIII. OPERAXIII. OPERA
XIII. OPERAXIII. OPERA
XIII. OPERA
TITI
TITI
TI
OO
OO
O
NAL CHECKNAL CHECK
NAL CHECKNAL CHECK
NAL CHECK
SS
SS
S
WARNING
T
O AVOID PERSONAL INJURY OR DEATH, DO NOT REMOVE ANY INTERNAL
COMPARTMENT COVERS OR ATTEMPT ANY ADJUSTMENT.
E
LECTRICAL
COMPONENTS ARE CONTAINED IN BOTH COMPARTMENTS.
C
ONTACT A
QUALIFIED SERVICE AGENT AT ONCE IF AN ABNORMAL FLAME APPEARANCE
SHOULD DEVELOP.
BURNER FLAME
The burner flames should be inspected with the burner compart-
ment door installed. Flames should be stable, quiet, soft, and blue
(dust may cause orange tips but they must not be yellow). Flames
should extend directly outward from the burners without curling, float-
ing, or lifting off. Flames must not impinge on the sides of the heat
exchanger firing tubes.
Check the burner flames for:
1. Good adjustment
2. Stable, soft and blue
3. Not curling, floating, or lifting off.
Figure 30 - Burner Flame
AUXILIARY LIMIT CONTROL
A manual reset limits are located on or near the blower. To access
this auxiliary limit, disconnect the electrical power and remove the
blower door. If the limit control opens, the air circulation blower will
run continuously. The diagnostic light will flash four times. These
symptoms are identical to a trip of the primary limit control.
The auxiliary limit control is designed to prevent furnace operation in
case of main blower failure on horizontal and counterflow installa-
tions. It may also open if the power supply is interrupted while the
furnace is firing.
The auxiliary limit control is suitable for both horizontal right and
horizontal left installations. Regardless of airflow direction, it does
not need to be relocated.
WARNING
T
O AVOID PERSONAL INJURY OR DEATH, DO NOT REMOVE ANY INTERNAL
COMPARTMENT COVERS OR ATTEMPT ANY ADJUSTMENT.
E
LECTRICAL
COMPONENTS ARE CONTAINED IN BOTH COMPARTMENTS.
C
ONTACT A
QUALIFIED SERVICE AGENT AT ONCE IF AN ABNORMAL FLAME APPEARANCE
PREVENT PROPERTY DAMAGE, PERSONAL INJURY OR DEATH DUE TO FIRE,
FOLLOW THESE DIRECTIONS FOR THE AUXILIARY LIMIT CONTROL. IF THE
AUXILIARY LIMIT CONTROL OPENS, IT MAY BE RESET ONE TIME ONLY.
(SERVICER’S NOTE: If it becomes necessary to slide the blower
assembly out of the furnace, the auxiliary limit control should be re-
moved first. After the blower assembly is reinstalled, the auxiliary
limit must be reinstalled.)
PRIMARY LIMIT
The primary limit control guards against overheating resulting from
insufficient conditioned air passing over the heat exchanger. If the
primary limit control does not function during this test, the cause
must be determined and corrected. Function of this control should
be verified by gradually blocking the furnace return air after the fur-
nace has been operating (burners firing) for approximately ten min-
utes. Check the control as follows:
1. Allow the furnace to operate with burners firing continuously
for approximately ten minutes.
2. Gradually block the return air to furnace. Remove airflow
blockage when limit control is activated and turns off burners.
Airflow blockage causes unit overheating and will produce
the following reactions:
• The gas valve to close and extinguish flame,
• The induced draft blower to be de-energized after a fifteen
second postpurge, and
• The circulator blower to remain energized continuously until
limit control resets.
3. Remove the return air blockage to clear overheating condition.
After an acceptable temperature is reached during the cool
down period, the limit control will reset and allow the furnace
to resume normal operation.
WARNING
T
O PREVENT PREMATURE FAILURE OF HEAT EXCHANGER, PROPERTY DAMAGE,
PERSONAL INJURY OR DEATH, DO NOT ADJUST THE LIMIT CONTROL (FACTORY
SET).
Primary Limit Control
Figure 31 - Primary Limit Control
IMPORTANT NOTE: This unit must not be used as a construction
heater during the finishing phases of construction of a new struc-
ture. This type of use may result in premature failure due to extremely
low return air temperatures and exposure to corrosive or very dirty
atmospheres.
These checks establish that the primary limit control is functioning
and will respond to a restriction in the return air, or a circulator blower
failure. If the primary limit control does not function during this test,
the cause must be determined and corrected.