BURNER PRIMARY (SAFETY) CONTROL
The furnace is equipped with a primary combustion control,
sometimes referred to as the burner relay or burner protector
relay, which uses a light sensing device (cad cell) located in the
burner housing, to monitor and control combustion.
Over time, dust or combustion residuals can build up on the
lens of the cad cell impairing its response to the flame. The
cad cell should be checked for cleanliness and proper align-
ment if the primary control frequently shuts down combus-
tion.
COMBUSTION CHAMBER
This furnace is equipped with a high quality cerafelt combus-
tion chamber. It is held in place by a retaining bracket.
CHECK THE ALIGNMENT OF THE COMBUSTION CHAM-
BER AND OIL BURNER BEFORE FIRING. IT IS POSSIBLE
FOR THE COMBUSTION CHAMBER TO SHIFT IF SUB-
JECTED TO ROUGH HANDLING DURING TRANSIT.
The combustion chamber should be inspected for damage or
carbon build up whenever the oil burner is removed for repairs
or routine maintenance.
WARNING: Do not start the burner unless the blower
access door is secured in place.
CIRCULATING AIR BLOWER
These furnaces (with the exception of model P*LBX20F190
which is belt drive) are equipped with direct drive blower sys-
tems. Direct drive blower speed adjustments are not normally
required in properly sized extended plenum duct systems. The
motor RPM and air CFM delivery will vary automatically to ac-
commodate conditions within the usual range of external static
pressures typical of residential duct systems.
Under-sized duct systems may require a higher blower speed
to obtain a reasonable system temperature rise. Some older
duct systems were not designed to provide static pressure.
They typically feature special reducing fittings at each branch
run and lack block ends on the trunk ducts.
These systems may require modification to provide some re-
sistance to the airflow to prevent over-- amping of the direct
drive blower motor. Selecting a lower blower speed may cor-
rect this problem.
Direct drive blower speeds are adjusted by changing the “hot”
wires to the motor winding connections. Please refer to wiring
diagram on Page 12, or the wiring diagram label affixed to the
furnace. THE NEUTRAL WIRE (normally the white wire) IS
NEVER MOVED TO ADJUST THE BLOWER SPEED.
It is possible and acceptable to use a single blower speed for
both heating and cooling modes. The simplest method to con-
nect the wiring from both modes is to use a “piggy--back con-
nector” accommodating both wires on a single motor tap.
8
Unitary Products Group
035-14289-000 Rev. A (0701)
MODEL
OUTPUT
(BTU/H)
BURNER
MODEL
NOZZLE
PUMP
PRESSURE
FLOW RATE
HEAD
STATIC
PLATE
UPFLOW
P*HBX12F08001
60,000
AF76BO
0.50 / 60
°
A
100 PSIG
0.50 GPH
F0
3-3/8"
78,000
AF76BO
0.65 / 60
°
A
100 PSIG
0.65 GPH
F0
3-3/8"
90,000
AF76XN
0.75 / 60
°
A
100 PSIG
0.75 GPH
F3
2-3/4"
100,000
AF76XN
0.85 / 60° A
100 PSIG
0.85 GPH
F3
2-3/4"
P*HBX16F10001
79,000
AF65XN
0.65 / 80
°
A
100 PSIG
0.65 GPH
F3
2-3/4"
90,000
AF65XN
0.75 / 80
°
A
100 PSIG
0.75 GPH
F3
2-3/4"
101,000
AF65XN
0.85 / 80
°
A
100 PSIG
0.85 GPH
F3
2-3/4"
119,000
AF65XN
1.00 / 80
°
A
100 PSIG
1.00 GPH
F3
2-3/4"
LOWBOY
P*LBX12F08001
60,000
AF63B0PWHS
0.50 / 60
°
A
100 PSIG
0.50 GPH
F0
3-3/8"
78,000-
AF63B0PWHS
0.50 / 60
°
A
100 PSIG
0.65 GPH
F0
3-3/8"
90,000
AF63XNPWH
S
0.75 / 60
°
A
100 PSIG
0.75 GPH
F3
2-3/4"
P*LBX16F12001
79,000
AF76XN
0.65 / 80
°
A
100 PSIG
0.65 GPH
F3
2-3/4"
90,000
AF76XN
0.75 / 80
°
A
100 PSIG
0.75 GPH
F3
2-3/4"
101,000
AF76XN
0.85 / 80
°
A
100 PSIG
0.85 GPH
F3
2-3/4"
117,000
AF76XN
1.00 / 80
°
A
100 PSIG
1.00 GPH
F3
2-3/4"
P*LBX16F14501
130,000
AF76YB
1.10 / 70
°
A
100 PSIG
1.10 GPH
F6
2-3/4"
143,000
AF76YB
1.20 / 60
°
A
100 PSIG
1.20 GPH
F6
2-3/4"
P*LBX20F19001
168,000
AF65XO
1.50 / 70
°
B
100 PSIG
1.50 GPH
F12
2-3/4"
181,000
AF65XO
1.65 / 70
°
B
100 PSIG
1.65 GPH
F12
2-3/4"
DOWNFLOW/HORIZONTAL
P*DHX12F0801
60,000
AF76BO
0.50 / 60
°
A
100 PSIG
0.50 GPH
F0
3-3/8"
78,000
AF76BO
0.65 / 60
°
A
100 PSIG
0.65 GPH
F0
3-3/8"
90,000
AF76XN
0.75 / 60
°
A
100 PSIG
0.75 GPH
F3
2-3/4"
TABLE 4 - BECKETT AF OIL BURNER SET-UP