Unit Start−Up & Adjustments - Lennox OHR23-105 Installation Instructions Manual

Unit Start−Up & Adjustments
Before starting the unit, make sure the oil tank is adequate-
ly filled with clean No. 1 or No. 2 furnace oil.
NOTE − Water rust or other containments in oil supply sys-
tem will cause malfunction and failure of the internal parts
of the fuel unit.
CAUTION
Never burn garbage or paper in the heating system.
Never leave papers near or around the unit.
Blower door must be in place before start-up.
1. Set thermostat for heating demand and turn on electri-
cal supply to unit.
2. Check initial air adjustment. All units are equipped with
an air adjustment dial on the right side of the burner.
See burner parts arrangement illustration.
3. Turn unit on. Place a can or container under the bleed
port located on the fuel pump. Loosen nut on bleed
port to release air and oil mixture from fuel line. Allow
mixture to escape until a steady stream of oil is emitted
from the port. Drain at least 1/2 pint of oil from the
pump. Retighten nut on bleed port. If lockout occurs,
press reset button and continue with bleed procedure.
NOTE − A two−line fuel system will normally bleed itself
by forcing air back to the tank through the return line.
This type of bleeding procedure is not necessary.
4. If burner fails to start, push reset button on primary
safety control and the burner motor reset button once.
See part arrangement illustration.
CAUTION
Do not push the reset button on the primary control
more than one time.
5. If burner fails to light again, refer to the troubleshooting
section in this manual (beginning on Page 18).
Fuel Pump Pressure
Measure fuel pump pressure with unit off. Attach pressure
gauge to pump outlet. Turn unit on and check pressure and
compare to table 7. Adjust if necessary.
Temperature Rise
To measure temperature rise, place plenum thermometers
in warm air and return air plenums. Locate thermometer in
warm air plenum where thermometer will not see" the heat
exchanger to prevent it from picking up radiant heat. Set
thermostat to its highest setting to start unit. After plenum
thermometers have reached their highest and steadiest
readings, subtract the readings. The difference in temper-
atures in the supply and return air plenums should approxi-
mate the temperature rise range listed in table 7 and the
appliance rating plate. If not, adjust the blower motor pulley
to adjust the blower speed.
Limit Control
Limit Control
Fan Control
The fan on time of 30 seconds is not adjustable. Fan off
time (time that the blower operates after the heat demand
has been satisfied) can be adjusted by moving the delay
switches on the fan control board. Fan off time will affect
comfort and is adjustable to satisfy individual applications.
See figure 20.Set the heat fan off delay switches to either
60, 90, 120, or 150 seconds. The factory setting is 90 sec-
onds.
Delay Off Switch Settings
60 sec
OHR23 Operating Parameters
Fuel Nozzle Size,
Unit Spray Angle, &
Pattern
Type
.65 GPH -.80°, B
for −105 input
−105/
−120
*.75 GPH -.80°, B
for −120 input
.85 GPH - .80°, B
for −140 input
−140/
−154
*1.0 GPH -.80°, B
for −154 input
*Nozzle must be field provided for field conversion to high-
er heating input. Oil burner pump pressure is 140 psi for
each unit.
Burner Adjustment
The following steps are essential to the proper operation of
OHR23 series oil furnaces. To prevent sooting, follow
these instructions in the sequence given.
1. Perform Draft Test
Perform a draft test at the breach between the outlet of
the vent connector and the barometric draft control.
Drill a 1/4" access hole to allow the draft gauge to be
inserted into the vent connector.
A minimum draft of 0.03 inches w.c. must be estab-
lished without the burner in operation. With the burner
in operation, the draft should be 0.04 to 0.05 inches
w.c. This is VERY critical to the flame retention head
burners.
Oil furnace installations also require careful inspection
to make sure the chimney is in good shape and can ac-
commodate the products of combustion. The temper-
ature in the unconditioned space will also affect the
draft if long vent connectors are allowed to get too
cold.
Page 15
Do not adjust from factory setting.
90 sec 120 sec 150 sec
Figure 20
Table 7
Input Output
Rating Rating Head
Btu/Hr Btu/Hr
Type
105,000 85,000
FB3
119,000 97,000
140,000 113,000
FB6
154,000 125,000
Temp. rise
+10° F hrz/
down
70/70
60/70