CAUTION: Fan/limit control location is critical in the
P*DHX12F08001 horizontal positions. To operate ef-
fectively as a high limit control, the fan / limit control
must be installed in the upper position. See Figure 3.
CHIMNEY VENTING
The flue pipe should be as short as possible with horizontal
pipes sloping upward toward the chimney at a rate of one quar-
ter inch to the foot. The flue pipe should not be smaller in cross
sectional area than the flue collar on the furnace.
The flue pipe should connect to the chimney such that the flue
pipe extends into, and terminates flush with the inside surface
of the chimney liner. Seal the joint between the pipe and the lin-
ing.
The chimney outlet should be at least two feet above the high-
est point of a peaked roof. All unused chimney openings should
be closed.
Chimneys must conform to local, provincial or state codes, or in
the absence of local regulations, to the requirements of NFPA
2.11 (latest edition) Chimney, Fireplaces, Vents and Solid Fuel
Burning Appliances (in Canada CSA B139)..
NOTE: All furnace models are approved for use with
Type L vent or equivalent.
CAUTION: The furnace must be connected to a flue
having sufficient draft at all times to ensure safe and
proper operation of the appliance.
NOTE: The recommended flue draft pressure is --
0.02 in. W.C. (as measured upstream of the baromet-
ric draft regulator).
The flue pipe must not pass through any floor or ceiling, but
may pass through a wall where suitable fire protection provi-
sions have been installed. Refer to the latest edition of ANSI
NFPA 31 (in the United States, or CAN/CSA B--139 in Canada)
for regulations governing the installation of oil burning equip-
ment.
See Table 4 for burner set-up.
BAROMETRIC DAMPER CONTROL
This device must be used with all chimney and Type L vent sys-
tems. This control (or draft regulator) automatically maintains a
constant negative pressure in the furnace to obtain maximum
efficiency. It ensures that proper pressures are not exceeded.
If the chimney does not develop sufficient draft, the draft control
cannot function properly. The draft regulator, when installed
should be in the same room or enclosure as the furnace and
should not interfere with the combustion air supplied to the
burner.
The control should also be located near the furnace flue outlet
and installed according to the instructions supplied with the
regulator. The flue outlet pressure (measured between the fur-
nace and draft regulator) should be set to --0.02 in. w.c.
FAN AND LIMIT CONTROL
Upflow & Lowboy Models
The L6064A temperature sensitive fan switch is actuated by a
helical bi--metal sensing element enclosed in a metal guard,
and controls the circulating air blower. This provides a delay
between the burner ignition and blower start up to eliminate ex-
cessive flow of cold air when the blower comes on. Blower
shutdown is also delayed to remove any residual heat from the
heat exchanger and improve the annual efficiency of the fur-
nace. Fan settings of 120
°
F to 130
°
F (50
°
C to 55
°
C) and fan
settings of 90
°
F to 100
°
F (32
°
C to 37
°
C) will usually be satis-
factory.
Downflow /Horizontal Models
The L4064W temperature sensitive fan switch contains a
heater--wrapped bi--metal to actuate the fan switch independ-
ent of the temperature at the helical sensing element. The time
from ignition, to the blower on function is approximately 30 sec-
onds. If after 1 minute, the blower has not come on, replace-
ment of the control may be necessary. The blower shutdown is
the same as noted for the L6064A control.
The limit switch performs a safety function and breaks power to
the oil burner primary control, which shuts off the burner if the
furnace over--heats. The limit control is thermally operated and
automatically resets. The limit control is factory installed, pre--
set and is not adjustable.
The limit control and fan control are incorporated in the same
housing and are operated by the same thermal element.
The downflow furnace utilizes an additional auxiliary limit con-
trol which is an automatic reset type.
ELECTRICAL CONNECTIONS
The furnace is listed by the Canadian Standards Association
under the NRTL (North American) Standard. It is factory wired
and requires minimal field wiring. All field wiring should con-
form to the following standards or by local codes, where they
prevail and by In the United States, refer to the National Fire
Protection Association NFPA--70, National Electrical Code
(latest edition), or in Canada, CAN/CSA C22.1 Canadian Elec-
trical Code, Part 1, and with local codes and regulations.
The furnace should be wired to a separate and dedicated cir-
cuit in the main electrical panel; however, accessory equip-
ment such as electronic air cleaners and humidifiers may be
included on the furnace circuit. Although a suitably located cir-
cuit breaker can be used as a service switch, a separate serv-
ice switch is advisable. The service switch is necessary if
reaching the circuit breaker involves becoming close to the fur-
nace, or if the furnace is located between the circuit breaker
and the means of entry to the furnace room.
6
Unitary Products Group
035-14289-000 Rev. A (0701)
AIR FLOW
FAN & LIMIT LOCATION
AIR FLOW
LEFT HORIZONTAL APPLICATION
RIGHT HORIZONTAL APPLICATION
FAN & LIMIT LOCATION
FIGURE 3 - HORIZONTAL APPLICATION
FAN/LIMIT LOCATION
