Unitary products group P-HMX12F05701 User manual

CONTENTS
INTRODUCTION....................................... 3
HEATLOSS .......................................... 3
LOCATIONOFUNIT.................................... 3
UPFLOWINSTALLATION................................ 4
HORIZONTALINSTALLATION............................ 4
NON-SUSPENDEDINSTALLATION ....................... 5
SUSPENDEDINSTALLATION............................ 5
AIRCONDITIONINGAPPLICATIONS...................... 5
COMBUSTIONAIR..................................... 5
CHIMNEYVENTING.................................... 5
BAROMETRICDAMPERCONTROL....................... 7
FURNACE CONTROLS ................................. 7
ELECTRICALCONNECTIONS............................8
HUMIDIFIER.......................................... 8
OILTANK ............................................ 8
PIPINGINSTALLATION................................. 9
OILFILTER........................................... 9
OILBURNERNOZZLES................................. 9
COMBUSTIONCHAMBER.............................. 10
BURNER ELECTRODES ............................... 10
OILBURNERSETUP.................................. 10
PREPARATIONS:..................................... 10
PROCEDURE:........................................ 11
STACKTEMPERATURE:............................... 11
CIRCULATING AIR BLOWER............................ 12
MAINTENANCEANDSERVICE.......................... 13
FURNACE INSTALLATION SET UP. ...................... 13
OPERATING INSTRUCTIONS ........................... 14
WIRINGNOTES...................................... 18
CONTINUOUSFANOPERATION: ........................18
ACCESSORIES:...................................... 18
THERMOSTAT HEATING
CONNECTIONS:...................................... 18
R7184 DETAILED SEQUENCE OF OPERATION .............20
R7184 LED DIAGNOSTIC LIGHT. . . ...................... 22
TROUBLESHOOTING ................................. 22
INSTALLATION
INSTRUCTION OIL FIRED WARM AIR FURNACE
P-HMX12F05701 - P-HMX12F08001
(Horizontal or Upflow Model)
P-HMX14F10001 - P-HMX20F12001
(Upflow Only)
Read this complete manual before beginning installation. These
instructions must be kept with the furnace for future reference.
035-17473-000-B-1101
CAUTION: READ ALL SAFETY GUIDES BEFORE
YOU BEGIN TO INSTALL YOUR UNIT.

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IMPROPER INSTALLATION MAY CREATE A CON-
DITION WHERE THE OPERATION OF THE PROD-
UCT COULD CAUSE PERSONAL INJURY OR
PROPERTY DAMAGE.
IMPROPER INSTALLATION, ADJUSTMENT,
ALTERATION, SERVICE OR MAINTENANCE CAN
CAUSEINJURYORPROPERTYDAMAGE.REFER
TO THIS MANUAL FOR ASSISTANCE OR ADDI-
TIONAL INFORMATION, CONSULT A QUALIFIED
INSTALLER, SERVICE AGENCY OR THE GAS
SUPPLIER.
THIS PRODUCT MUST BE INSTALLED IN STRICT
COMPLIANCE WITH THE ENCLOSED INSTALLA-
TION INSTRUCTIONS AND ANY APPLICABLE
LOCAL, STATE, AND NATIONAL CODES INCLUD-
ING BUT NOT LIMITED TO, BUILDING, ELECTRI-
CAL AND MECHANICAL CODES.
The furnace area mustnot be used as a broomcloset
orforanyotherstoragepurposes,asafirehazardbay
be created. Never store items such as the following
on, near or in contact with the furnace.
1. Spray or aerosol cans, rags, brooms, dust mops,
vacuum cleaners or other cleaning tools.
2. Soap powders, bleaches, waxes or other cleaning
compounds; plastic items or containers; gasoline,
kerosene, cigarette lighter fluid, dry cleaning fluids
or other volatile fluid.
3. Paint thinners and other painting compounds.
4. Paper bags, boxes or other paper products
Never operate the furnace with the blower door
removed. To do so could result in serious personal
injury and/or equipment damage.
WARNING
CAUTION
WARNING
INTRODUCTION
Please read these instructions completely and carefully
before installing and operating the furnace.
The furnace must be installed and set up by a qualified
contractor.
P*HMX12F05701 and P*HMX12F08001 are oil fired
forced air multi-positional furnaces, with an output
capacity range of 58,000 BTU/Hr to 79,000 BTU/HR.
These furnaces may be installed in the up-flow posi-
tion, as well as both horizontal left and right positions.
P*HMX14F10001 and P*HMX20F12001 are oil fired
Upflow ONLY furnaces, with an output capacity range
of 100,000 BTU/Hr. to 118,000 BTU/Hr. These furnaces
shall be installed in the up-flow position only.
All model furnaces are listed with the Canadian Stan-
dards Association,(CSA) and comply with both
Canadian and American (U.S.) standards for use with
No. 1 (Stove) and No. 2 (Furnace) Oil. Please refer to
the tables in the appendix for performance and dimen-
sional data.
In Canada, the installation of the furnace and related
equipment shall be installed in accordance with the
regulations of CAN/CSA - B139, Installation Code
For Oil Burning Equipment, as well as in accordance
with local codes.
In the United States of America, the installation of the
furnace and related equipment shall be installed in
accordance with the regulations of NFPA No. 31,
Installation of Oil Burning Equipment,aswellasin
accordance with local codes.
When installation or application questions arise, regu-
lations prescribed in the National Codes and Local
Regulations take precedence over the general instruc-
tions provided with this installation manual. When in
doubt, please consult your local authorities.
All models are shipped assembled and pre-wired. The
furnace should be carefully inspected for damage
when being unpacked.
DO NOT USE GASOLINE, CRANK CASE OIL, OR
ANY OIL CONTAINING GASOLINE.
WARNING

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HEAT LOSS
The maximum hourly heat loss for each heated space
shall be calculated in accordance with the procedures
described in the manuals of the Heating, Refrigera-
tion and Air Conditioning Institute of Canada
(HRAI), or by any other method which is suitable for
local conditions, provided the results obtained are in
substantial agreement with, and not less than those
obtained using the procedure described in their manu-
als.
In the United States, Manual J. titled, "Load Calcula-
tion" published by the Air Conditioning Contractors
of America, describes a suitable procedure for calcu-
lating the maximum hourly heat loss.
LOCATION OF UNIT
The furnace should be located such that the flue con-
nection to the chimney is short, direct and consists of
as few elbows as possible. When possible, the unit
should be centralized with respect to the supply and
return air duct work. A central location minimizes the
trunk duct sizing. All models may be installed on com-
bustible floors.
Minimum installation clearances are listed in Table 1. NOTE: The recommended installation clearances do not take
intoconsiderationtheclearancesnecessarytoreplace
the air filter or perform other routine maintenance.
Table 1: Clearance to Combustibles
Models: P*HMX12F05701 and P*HMX12F08001
Location Up-flow Horizontal
Top 2 in. 2 in.
Bottom 0 in. 1 in.
S/A Plenum 1 in. 1 in.
Rear 1 in. 1 in.
Sides 1 in. 1 in.
Front 9in.19in.1
Flue Pipe 9 in. 9 in.
Enclosure Closet Alcove
124” clearance is required for servicing.
Models: P*HMX14F10001 and P*HMX20F12001
Location Up-flow
Top 1 in.
Bottom 0 in.
S/A Plenum 1 in.
Rear 1 in.
Sides 1 in.
Front 9in.1
Flue Pipe 4in. measured horizontally or below flue pipe.
Flue Pipe 9 in. measured vertically or above flue pipe.
Enclosure Closet
124” clearance is required for servicing.

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NOTE: Over-fire draft for all models is -0.02 in Water column. Static Plate Diameter: 3-3/8 inch for AF76BO and 2-
3/4 inc. for AF76XN.
UPFLOW INSTALLATION
These furnace models have been assembled for instal-
lation in the up-flow position. Maintain all clearances to
combustibles as outlined in Table 1 on page 3.
Suggestion; as a measure to prevent fuel oil from accu-
mulating in locations other than the combustion cham-
ber, as could be the case in the event of nozzle drip,
install the furnace with an approximate 2 degree slope
from the oil burner casing towards the combustion
chamber. Use shims made of noncombustible material.
HORIZONTAL INSTALLATION
The 057 & 080 BTU output model furnaces are assem-
bled and shipped ready for installation in the upflow
position. The furnace may be installed in either of the
horizontal positions; warm air discharging left or warm
air discharging right by following these steps:
1. Rotate the furnace 90° to the desired position.
2. Remove the three nut and washer sets fastening the oil
burner assembly to the furnace. Rotate the oil burner
assembly to be in the upright position. (Ignition trans-
former and / or oil primary control control should be on
top).
3. Re-align the oil burner assembly to the combustion
chamber (fire-pot), then secure into place with the three
nut and washer sets.
Table 2: General Specifications
MODEL INPUT OUTPUT NOZZLE BECKETT AF BURNER AIR
P*HMX U.S. GPH BTU/Hr. Delavan BURNER MODEL BURNER HEAD FILTER
P*HMX12F05701 0.50 58,000 0.50 / 70°A AF76BO F0 16 x 25 x 1
P*HMX12F08001 0.70 79,000 0.70 / 70°A AF76BO F0 16 x 25 x 1
P*HMX14F10001 0.85 100,000 0.85 / 70°A AF76XN F3 16 x 25 x 1
P*HMX20F12001 1.00 118,000 1.00 / 70° A AF76XN F3 16 x 25 x 1
FIGURE 1 : TYPICAL SUSPENDED OPERATION

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NON-SUSPENDED INSTALLATION
Maintain clearances to combustibles as outlined in
Table 1. Installation on a combustible floor requires a
clearance of 1 inch. This can be done by using non-
combustible materials such as one inch thick channel
iron or similar material. The furnace must be supported
in such a way as to not allow twisting or sagging of the
cabinet. Suggestion; as a measure to prevent fuel oil
from accumulating in locations other than the fire pot,
as could be the case in the event of nozzle drip, install
the furnace with an approximate 2 degree slope from
the oil burner casing towards the fire pot. Use shims
made of noncombustible material.
SUSPENDED INSTALLATION
Refer to Figure 1. Maintain clearances to combustibles
as outlined in Table 1. Remove the four circular knock-
outs on the top panel, and similarly, the four circular
knock-outs on the bottom panel. The removed knock-
outs allow 3/8 inch treaded road to be inserted through
the interior of the furnace. Use care when inserting
rods, since the foil backed insulation can be easily
ripped and torn away from the panel surfaces. Secure
the furnace with 2 inch minimum slotted angle or equiv-
alent, as shown in Figure 4. The furnace must be sup-
ported in such a way as to not allow twisting or sagging
of the cabinet. Suggestion; as a measure to prevent
fuel oil from accumulating in locations other than the
fire pot, as could be the case in the event of nozzle
drip, install the furnace with an approximate 2 degree
slope from the oil burner casing towards the fire pot.
AIR CONDITIONING APPLICATIONS
If the furnace is used in conjunction with air condition-
ing, the furnace shall be installed in parallel with or with
the evaporator coil upstream from the furnace to avoid
condensation in the heat exchanger. In a parallel instal-
lation, the dampers or air controlling means must pre-
vent chilled air from entering the furnace. If the
dampers are manually operated, there must be a
means of control to prevent the operation of either sys-
tem unless the dampers are in the full heat or full cool
position. The air heated by the furnace shall not pass
through a refrigeration unit unless the unit is specifi-
cally approved for such service.
The blower speed must be checked and adjusted to
compensate for the pressure drop caused by the evap-
orator coil. Refer to Appendix B for recommended wir-
ing and electrical connections of the air conditioning
controls.
COMBUSTION AIR
If the furnace is installed in a closet or utility room, two
ventilation openings must be provided connecting to a
well ventilated space (full basement, living room or
other room opening thereto, but not a bedroom or bath-
room). One opening shall be located 6” from the top
and bottom of the enclosure at the front of the furnace.
Each opening shall have a minimum free area of 1½
square inches per 1,000 Btu/h of total input rating of all
appliances installed in the room.
For furnaces located in buildings of unusually tight con-
struction, such as those with high quality weather strip-
ping, caulking, windows and doors, or storm sashed
windows, or where basement windows are well sealed,
a permanent opening communicating with a well venti-
lated attic or with the outdoors shall be provided, using
a duct if necessary. The duct opening shall have a free
area of 1½ square inches per 1,000 Btu/h of total input
rating of all appliances to be installed. When a furnace
is installed in a full basement, infiltration is normally
adequate to provide air for combustion and draft opera-
tion. Furnace rooms under 65m³ (700 ft³) should auto-
matically be treated as confined space.
The Model CAS-2B-90E Furnace Boot manufactured
byFieldControls,Inc.maybeusedwiththefurnaceto
obtain combustion air directly from outdoors. Use of
this device does not alter the need for ventilation air;
however, it does provide a good direct source of com-
bustion air and is connected directly to the oil burner.
CHIMNEY VENTING
The chimney must be sized correctly and be in good
repair. If the chimney is oversized, there is a high risk of
the flue gases condensing resulting in damage to the
chimney and other venting parts. This problem may be
corrected by the use of an appropriately sized chimney
liner.
If the chimney serves the furnace only, the vent should
be sized at 4 inch minimum, 5 inch maximum. If the fur-
nace is to be co-vented with other appliances, refer to
CAN/CSA B139,Installation Code For Oil Burning
Equipment or NFPA 211,Standard for Chimneys, Fire-
places, Vents, and Solid Fuel-Burning Appliances for
correct sizing information.

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IMPORTANT: The chimney must be capable of provid-
ing sufficient draft at all times for the safe removal of
the products of combustion.
The chimney should be tested under “winter” condi-
tions; doors and windows closed, all other fossil fuel
burning appliances on, clothes dryer on, bathroom fans
on, etc. If the chimney cannot overcome the competi-
tion for air, it will be necessary to access the reason for
it, and take corrective action. If the chimney is found to
be sized correctly and in good repair, it will probably be
necessary to re-evaluate the availability of combustion
and ventilation air, and take corrective action.
NOTE: These furnaces are approved for use with L-
Vent.
NOTE: Maximum Temperature for L-Vent is
575° F(300°C).
The flue pipe should be as short as possible with hori-
zontal pipes sloping upward toward the chimney at a
rate of one quarter inch per foot. The flue pipe should
not be smaller in cross section area than the flue collar
on the furnace. The flue pipe should connect to the
chimney such that the flue pipe extends into, and termi-
nates flush with the inside surface of the chimney liner.
Seal the joint between the pipe and the lining. The
chimney outlet should be at least two feet above the
highest 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 the National
Building Code.
See Figure 2 and Table 4 for common chimney prob-
lems and their remedies.
Table 3: Min. Chimney Base Temperatures (°F)
Model Chimney Height (ft.)
11 20 28 36
Chimneys with Thermal Resistance less than R6
P-HMX12F05701 300 400 535 725
P-HMX12F08001 270 330 405 505
P-HMX14F10001 250 300 355 430
P-HMX12F12001 225 300 365 430
Chimneys with Thermal Resistance greater than R6
P-HMX12F5701 185 200 220 250
P-HMX12F08001 175 185 195 215
P-HMX14F10001 165 185 195 205
P-HMX12F12001 165 185 195 205
Table 4: Common Chimney Problems
Key Trouble Diagnostic Remedy
A Top of chimney lower
than surrounding
objects
Observation Extend chimney
above all surround-
ing objects within 30
feet.
B Chimney Cap or ven-
tilator. Observation Remove
C Coping restricts
opening. Observation Make opening as large as inside of
chimney.
Key Trouble Diagnostic Remedy
D Obstruction in chim-
ney Can be found by light and mirror reflecting
conditions in chim-
ney.
Useweighttobreak
and dislodge.
E Joist protruding into
chimney. Lowering a light on an extension cord. Must be handled by competent masonry
contractor.
F Break in chimney lin-
ing. Smoke test - build smudge fire blocking
off other opening,
watching for smoke
to escape.
Must be handled by
competent masonry
contractor.
G Collection of soot at
narrow space in flue
opening.
Lower light on exten-
sion cord. Clean out with weighted brush or
bag of loose gravel
on end of line.
H Offset Lower light on exten-
sion cord. Change to straight or to long offset.
I Two or more open-
ings to the same
chimney.
Found by inspection
from basement. The least important opening must be
closed, using some
other chimney flue.
J Loose-seatedpipein
flue opening. Smoke test. Leaks should be eliminated by
cementing all pipe
openings.
K Smoke pipe extends
into chimney. Measurementof pipe from within or obser-
vation of pipe by
means of a lowered
light.
Length of pipe must
be reduced to allow
endofpipetobe
flush with inside of
tile.
L Failure to extend the
length of flue parti-
tion to the floor.
By inspection or
smoke test. Extend partition to floor level.
M Loose-fitted clean-
out door. Smoke test. Close all leaks with cement.
FIGURE 2 : COMMON CHIMNEY PROBLEMS

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The flue pipe must not be routed through concealed
space, because it must be visually checked for signs of
deterioration during the annual inspection and servic-
ing. The flue pipe must not pass through any floor or
ceiling, but may pass through a wall where suitable fire
protection provisions have been installed. Refer to the
latest edition of CAN/CSA B-139 for rules governing
the installation of oil burning equipment. In the United
States, refer to the latest edition of NFPA 31 for regula-
tions governing the installation of oil burning equip-
ment.
BAROMETRIC DAMPER CONTROL
This device is used in conjunction with conventional
chimney venting. This control (or draft regulator) auto-
matically 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 can-
not function properly. The draft regulator, must be
installed within the same room or enclosure as the fur-
nace, and should not interfere with the combustion air
supplied to the burner. The control should be located a
minimum of 3 flue pipe diameters (18”) from the fur-
nace breaching and installed in accordance to the
instructions supplied with the regulator. The flue outlet
pressure (measured between the furnace and draft
regulator) should be set to - 0.02 in. w.c.
FURNACE CONTROLS
The furnace is controlled by the ST9103 ELECTRONIC
FAN TIMER (EFT) combined with an R7184 Oil Pri-
mary Control.
These controls provide for add-on air conditioning. The
ST9103 EFT is located in a control box mounted to the
blower support rails. The R7184 primary control
mounts to a 4x4 junction box connected to the oil
burner, contains the safety circuits and provides input
voltage for the separately mounted ignition transformer
on top of the oil burner.
The circulating fan is controlled by the ST9103 EFT.
The heat delay-on time is fixed at 30 seconds. This
provides a delay between the start of the burner and
the start of the circulating fan to reduce the amount of
ambient unheated air flowing through the ductwork.
The end of the circulating fan cycle is also delayed to
remove residual heat from the furnace. There are four
delay-off choices, 60, 90, 120 and 150 seconds, which
are field adjustable by manipulating the DIP switches
on the ST9103 EFT Board.
The cooling delay-on and delay-off times are fixed at
30 seconds each.
The furnace is protected against over-heating by fixed
high temperature limits. These controls are factory set
and are not field adjustable. If an over temperature
condition is detected, one or both limit switches will
interrupt power to the oil primary control, which will shut
off the oil burner. The circulating fan will continue to
operate. The high limit switches will automatically reset
when the furnace returns to a safe temperature.
Thefurnacemustbeconnectedtoafluehavingsuffi-
cient draft at alltimes toensuresafe and proper oper-
ation of the appliance.
CAUTION
FIGURE 3 : R7184 OIL PRIMARY CONTROL
FIGURE 4 : ST9103 EFT

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ELECTRICAL CONNECTIONS
The furnace is listed by the Canadian Standards
Association (CSA). It is factory wired and requires
minimal field wiring. In Canada, all field wiring should
conform to CAN/CSA C22.1 Canadian Electrical
Code, Part 1, and by local codes, where they prevail.
In the United States, the wiring must be in accordance
with the National Fire Protection Association NFPA-
70,National Electrical Code, and with local codes
and regulations.
Thefurnaceshouldbewiredtoaseparateanddedi-
cated circuit in the main electrical panel; however,
accessory equipment such as electronic air cleaners
and humidifiers may be included on the furnace circuit.
Although a suitably located circuit breaker can be used
as a service switch, a separate service switch is advis-
able. The service switch is necessary if reaching the
circuit breaker involves becoming close to the furnace,
or if the furnace is located between the circuit breaker
and the means of entry to the furnace room. The fur-
nace switch (service switch) should be clearly marked,
installedinaneasilyaccessibleareabetweenthefur-
nace and furnace room entry, and be located in such a
manner to reduce the likelihood that it would be mis-
taken as a light switch or similar device.
The power requirement for the P-HMX Series model is:
120 VAC, 1 ∅,60Hz.,12A.
Accessories requiring 120 VAC power sources such as
electronic air cleaners and humidifier transformers may
be powered from the ST9103 EFT. Do not use the
direct drive motor connections as a power source,
since there is a high risk of damaging the accessories
by exposure to high voltage from the auto-generating
windings of the direct drive motor.
Thermostat wiring connections and air conditioning
contactor low voltage connections are shown in the wir-
ing diagram. Some micro-electronic thermostats
require additional controls and wiring. Refer to the ther-
mostat manufacturer's instructions.
The thermostat should be located approximately 5 feet
above the floor, on an inside wall where there is good
natural air circulation, and where the thermostat will be
exposed to average room temperatures. Avoid loca-
tions where the thermostat will be exposed to cold
drafts, heat from nearby lamps and appliances, expo-
sure to sunlight, heat from inside wall stacks, etc.
For thermostats with heat anticipators, the heat antici-
pator should be adjusted to the amperage draw of the
heating control circuit as measured between the "R"
and "W" terminals of the thermostat. To reduce the risk
of damaging the heat anticipator, do not measure cir-
cuit without first removing one of the two wires. To
determine the heating circuit amperage draw:
1. Note and disconnect the wires from the “R” and “W” ther-
mostat terminals.
2. Connect an ammeter between the two disconnected
wires from the thermostat.
3. Note the amperage reading.
4. Re-connect the thermostat wires. If the thermostat is
serving a combination heating and air conditioning sys-
tem, pay particular attention to polarity.
5. When the thermostat is reconnected and re-plumbed,
adjust the heat anticipator setting to match the observed
amperage reading.
HUMIDIFIER
A humidifier is an optional accessory available through
most heating supplies outlets. Installation should be
carried out in accordance with the humidifier manufac-
turer's installation instructions. Water or water droplets
from the humidifier should not be allowed to come into
contact with the furnace heat exchanger. Terminals
(115 v) are provided on the ST9103 EFT control. Do
not use direct drive motor connections as a source of
power for 120 VAC humidifiers and humidifier trans-
formers.
OIL TANK
Oil storage tanks must be selected and installed in
compliance with applicable codes; in Canada, CAN/
CSA-B139,Installation Code for Oil Burning Equip-
ment, Section 6 and in the United States, NFPA 31,
Standard for the Installation of Oil Burning Equipment,
Chapter 2. Observe all local codes and by-laws.
In general, the oil tank must be properly supported and
remain stable in both empty and full condition. The oil
tank must be fitted with vent and supply pipes to the
outdoors. Refer to the above mentioned codes for siz-
ing. The vent pipe must be no less than 1¼ inches
I.P.S., and terminate with an appropriate vent cap in a
location where it will not be blocked. The fill pipe must
be no less than 2 inches I.P.S., and terminate with an
appropriate cap in a location where debris will not enter
the fill pipe during oil delivery.
If located indoors, the tank should normally be in the
lowest level, (cellar, basement, etc.). It must be
equipped with a shut-off valve at the tank outlet used
for the oil supply. The oil tank must be located as to not
block the furnace / room exit pathway. Observe all
clearances specified in the above mentioned codes.

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PIPING INSTALLATION
In Canada, the entire fuel system should be installed in
accordance with the requirements of CAN/CSA B-139,
and local regulations. Use only approved fuel oil tanks
piping, fittings and oil filters.
In the United States the installation must be in accor-
dance with the requirements of NFPA No. 31 and local
codes and regulations.
Ensure that all fittings used in a copper oil line system
are high quality flare fittings. Do not use compression
fittings.
Pressurized or gravity feed installations must not
exceed 3 PSIG. A pressure greater than 10 PSIG may
cause damage to the shaft seal. If the height of the oil
stored in a tank above the oil burner exceeds 11-1/2
feet, it may be necessary to use a pressure-regulating
device approved for this purpose.
The P*HMX series furnace may be installed with a one
pipe system with gravity feed or lift. The maximum
allowableliftonasinglelinesystemis8feet.Lift
should be measured from the bottom (outlet) of the
tank, to the inlet of the burner. Sizing a single line sys-
tem is complex because of the difficulty estimating the
pressure drop through each fitting, bend and compo-
nent in the line. In general, keep single line systems
short as possible. If the furnace is to be installed in a
suspended position, a two pipe system may be the bet-
ter alternative. Two-stage oil pumps are not available
for oil burners featuring the Beckett Clean Cut Fuel
Unit. Table 5 shows the allowable line lengths (horizon-
tal + vertical) for single and two stage oil pumps. All dis-
tances are in feet.
In retrofit applications, where an existing oil line system
is in place, a vacuum check will help determine
whether a 2-stage oil pump is necessary. The vacuum
in a system featuring a single stage oil pump should
not exceed 6” Hg. The vacuum in a system featuring a
2-stage oil pump should not exceed 15” Hg. (inches of
mercury.
For additional information, see the installation informa-
tion sheet affixed to the oil burner).
OIL FILTER
All fuel systems should include an oil filter between the
fuel oil storage tank and the oil burner. For best results,
install the oil filter as close to the burner as possible.
When using an indoor oil tank, the oil filter may be
installed at the tank downstream from the shut-off
valve. If firing the furnace under the 0.65 gph rate, a 7
to 10 micron line filter should be installed as close to
the oil burner as possible.
OIL BURNER NOZZLES
The P-HMX Series furnace is certified for multiple firing
rates, ranging from 58,000 to 120,000 BTU/Hr. By
manipulating the oil burner nozzle, flame retention
head, and temperature rise, the furnace may be fired at
an ideal rate for a wide range of structures.
Table 5: Oil Lines
Copper Tubing Oil Line Lengths
Single Stage 2-Stage
Lift
(feet) 3/8”O.D. Tubing 1/2”O.D. Tubing 3/8”O.D. Tubing 1/2”O.D. Tubing
0 53 100 68 100
1 49 100 65 100
2 45 100 63 100
3 41 100 60 100
4 37 100 58 100
5 33 100 55 100
6 29 100 53 100
7 25 99 50 100
8 21 83 48 100
9 17 68 45 100
10 13 52 42 100
12 - - - - - - 37 100
14 - - - - - - 32 100
16 - - - - - - 27 100
18 - - - - - - 22 88
Table 6: Nozzles
MODEL NOZZLE (Delavan)
STD ALT HEAD
P*HMX12F05701 0.50 / 70° A 0.50 / 80° A F0
P*HMX12F08001 0.70 / 70° A ) 0.70 / 80° A ) F0
P*HMX14F10001 0.80 / 70° A 0.80 / 80° A F3
P*HMX20F12001 1.00 / 70° A) 1.00 / 80° A) F3

035-17473-000-B-1101
10 UnitaryProductsGroup
COMBUSTION CHAMBER
This furnace is equipped with an efficient cerafelt com-
bustion chamber. It is held in place by a retaining
bracket.
The cerafelt combustion chamber is quite soft initially.
After firing, it becomes very brittle. Be sure to do all
alignment and positioning adjustments before the first
firing.
The combustion chamber should be inspected for dam-
age or carbon build-up whenever the oil burner is
removed for repairs or routine maintenance.
BURNER ELECTRODES
Correct positioning of the electrode tips with respect to
each other, to the fuel oil nozzle, and to the rest of the
burners is essential for smooth light ups and proper
operation.
The electrode tips should be adjusted to a gap of 5/32”,
1/16” ahead of the nozzle, 7/16” above the centerline of
the nozzle. The “Z” dimension (front edge of the burner
head to the front face) of the nozzle is 1-1/8 inches.
The electrode porcelains should be free of cracks, the
electrode tips should be tapered and free of burrs, and
the contact rods must be clean and be in firm contact
with the ignition transformer contact springs. The elec-
trodes must not come into contact with the burner
head.
OIL BURNER SET UP
The burner air supply is adjusted to maintain the fuel to
air ratio to obtain ideal combustion conditions. A lack
of air causes "soft" and "sooty" flames, resulting in soot
build-up throughout the heat exchanger passages.
Excess combustion air causes a bright roaring fire and
high stack temperatures resulting in poor fuel effi-
ciency.
PREPARATIONS:
Drill a ¼” test port in the venting, ideally at least 2 diam-
eters (12”) away from the furnace breaching, if venting
horizontally from the furnace, or from the flue pipe
elbow if venting vertically before reaching the furnace.
(see Figures 6 and 7).
Note A: Locate hole at least 6 inches on the furnace
side of the draft control.
Note B: Ideally, hole should be at least 12 inches from
breeching or elbow.
CHECK THE ALIGNMENT OF THE COMBUSTION
CHAMBERANDOILBURNERBEFOREFIRING.IT IS
POSSIBLE FOR THE COMBUSTION CHAMBER TO
SHIFT IS SUBJECTED TO ROUGH HANDLING DUR-
ING TRANSIT.
Before operating the furnace check burner alignment
with combustion chamber. The end cone of the air
tubemustbecenteredtotheaccommodatingringpro-
videdinthedesignofthecombustion chamber.Adjust
as necesssary before first firing.
WARNING
CAUTION
FIGURE 5 : TEST PORT LOCATION FOR SMOKE
TEST VERTICAL
FIGURE 6 : TEST PORT LOCATION FOR SMOKE
TEST HORIZONTAL.

035-17473-000-B-1101
Unitary Products Group 11
The test port will allow flue gas samples to be taken
and stack temperatures to be measured.
Before starting the burner, check the burner alignment
with the combustion chamber (fire pot), check that the
correct nozzle is tightened into place, and that the
burner electrodes are properly positioned.
PROCEDURE:
Start the burner and allow it to run at least ten minutes.
Set the air shutter to give a good flame visually. The air
supply to the burner is controlled by the air shutter on
the left side of the burner, and the bulk air band. To
adjust, loosen the bolt on the movable shutter. Move
the shutter gradually until a good flame (visually) has
been achieved. Re-snug the bolt.
Check the initial draft setting as the furnace warms up.
Thedraftmaybemeasuredatthetestport.Inmost
cases, the pressure drop between the test port and the
oil burner is negligible. The test port draft reading may
be interpreted as the “over fire draft” reading. The draft
should be set to - 0.02 inches w.c.
Check the oil pump pressure. All P-HMX furnaces are
designed to be operated at 100 PSIG.
After reaching steady state, take a smoke test. If not
indicating a trace, set the combustion air controls to
provide a trace.
When the trace smoke has been established, measure
the CO2or O2in the flue gas. Typically, the CO2read-
ing will range between 11.5% to 13.5% or the O2read-
ing approximately 3.3%.
Open the end air shutter (or open the bulk air band if
necessary) until the CO2readingdrops1or2percent-
age points, or, if measuring O2content, until the O2
reading increases 2 or 3 percentage points.
Take another smoke test; it should now be zero smoke.
If the smoke test reads zero, tighten up the end air
shutter, and bulk air band.
Re-test the draft, and the CO2or O2to be certain that
the settings have not shifted.
SMOKE TEST NOTE:
If oily or yellow smoke spots are found on the smoke
test filter paper, it is usually a sign of unburned fuel.
This indicates poor combustion. This type of problem
may be caused by excess draft, excess air, or contami-
nated fuel. Do not ignore this indicator.
STACK TEMPERATURE:
Stack temperature will vary depending on fuel input,
circulating air blower speed, and burner set up, etc. In
general, stack temperature should range between
350°F to 450°F, but could be as high as 550°F, assum-
ing that the combustion air is approximately room tem-
perature (65°F - 70°F). In general, lower stack
temperature indicates greater efficiency; however,
excessively low stack temperature can lead to conden-
sation forming in the chimney and / or venting. Sulphur
and similar contaminants in the fuel oil will mix with
condensation to form acids. Acids and resultant chemi-
cal salts will cause rapid deterioration of the chimney
and venting components, and may attack the furnace.
If the flue gases are below the range, it may be neces-
sary to slow down the blower fan. If the flue gases are
above the range, the blower fan may require speeding
up. Stack temperature varies directly with the system
temperature rise. System temperature rise is the differ-
ence between the furnace outlet temperature and fur-
nace inlet temperature as measured in the vicinity of
the connection between the plenum take-offs and the
trunk ducts. Typical temperature rise values range
between 65°F and 85°F.
If the venting from the furnace to the chimney is long,
or exposed to cold ambient temperatures, it is advis-
able to insulate the venting with a removable, non-com-
bustible, wrap-around type insulation to reduce stack
temperature loss. The venting should be inspected
annually to ensure that it is intact.
IF THE FURNACE FAILS TO IGNITE, CHECK THE
OIL TANK FUEL GAUGE. IF THE FUEL GAUGE
SHOWS THAT OIL IS PRESENT, PRESS THE
RESET BUTTON ONCE ONLY. IF THE BURNER
FAILS TO IGNITE, CONTACT YOUR SERVICE
CONTRACTOR.
ALL FURNACE CONTROLS ARE SENSITIVE AND
SHOULD NOT BE SUBJECTED TO TAMPERING. IF
PROBLEMSPERSIST,CALLYOURSERVICECON-
TRACTOR.
WARNING
CAUTION

035-17473-000-B-1101
12 UnitaryProductsGroup
CIRCULATING AIR BLOWER
These furnaces are equipped with direct drive blower
systems. Direct drive blower speed adjustments are
not normally required in properly sized extended ple-
num duct systems. The motor RPM and air CFM deliv-
ery will vary automatically to accommodate conditions
within the usual range of external static pressures typi-
cal of residential duct systems. Under-sized duct sys-
tems 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 resistance to the airflow to prevent over- amping
of the direct drive blower motor. Selecting a lower
blower speed may correct this problem.
Direct drive blower speeds are adjusted by changing
the "hot" wires to the motor winding connections.
Please refer to wiring diagram in Figure 9 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 sim-
plest method to connect the wiring from both modes is
to use a "piggy-back connector" accommodating both
wires on a single motor tap. It is also acceptable to con-
nect the selected motor speed with a pig tail joined to
both heating and cooling speed wires with a wire nut.
As a safety precaution against accidental disconnec-
tion of the wires by vibration, it is advisable to secure
the wire nut and wires with a few wraps of electricians
tape.
If the joining of the blower speed wiring is done in the
furnace junction box, tape off both ends of the unused
wire.
The circulating fan start-up is delayed 30 seconds in
the heating mode.
The circulating fan start-up is delayed 30 seconds in
the cooling mode. The “fan off” is delayed 30 seconds
in the cooling mode.
The “fan off” heating delay may be field adjusted by
manipulating the dip switches. See Figure 7.
Do not use the blower speed wires as a source of
power to accessories as electronic air cleaners and
humidifier transformers. The unused motor taps auto-
generate sufficiently high voltages and may damage
accessory equipment. Use the terminals provided on
the ST9103 EFT.
FIGURE 7 : HEATING MODE “BLOWER OFF”
TIMINGS, ST9103
DO NOT CONNECT POWER LEADS BETWEEN
MOTOR SPEEDS. THE NEUTRAL WIRE MUST
ALWAYSBECONNECTEDTOTHEMOTOR'SDES-
IGNATED NEUTRAL TERMINAL.
DISCONNECTTHEPOWERSUPPLYTOTHEFUR-
NACE BEFORE OPENING THE BLOWER ACCESS
DOOR TO SERVICE THE AIR FILTER, FAN AND
MOTOR. FAILURE TO SHUT OFF POWER COULD
ALLOW THE BLOWER TO START UNEXPECT-
EDLY, CREATING A RISK OF DEATH OR PER-
SONAL INJURY.
WARNING
CAUTION

035-17473-000-B-1101
Unitary Products Group 13
MAINTENANCE AND SERVICE
Routine Maintenance By Home Owner
Other than remembering to arrange for the annual pro-
fessional servicing of the furnace by the service or
installation contractor, the most important routine ser-
vice performed by the home owner is to maintain the
air filter or filters. A dirty filter can cause the furnace to
over-heat, fail to maintain indoor temperature during
cold weather, increase fuel consumption and cause
component failure.
The furnace filter(s) should be inspected, cleaned or
replaced monthly. The furnace is factory equipped with
a semi-permanent type filter. If the filter is damaged,
replace with filters of the same size and type.
During the routine service, inspect the general condi-
tion of the furnace watching for signs of oil leaks in the
vicinity of the oil burner, soot forming on any external
part of the furnace, soot forming around the joints in the
vent pipe, etc. If any of these conditions are present,
please advice your service or installation contractor.
Annual Service By Contractor
The heat exchanger should be inspected periodically
and cleaned if necessary. if cleaning is necessary,
SHUT OFF POWER TO THE FURNACE and remove
the burner. Using a stiff brush with a wire handle, brush
off scale and soot from inside the drum and flue pipe.
To clean the radiator, remove the round covers on the
inner radiator access pipes located on the front panel
between the oil burner and the flue pipe.
Awirebrushcanbeusedtoloosendirtanddebrison
the inside surfaces of the radiator. Clean out all accu-
mulated dirt, soot and debris with a wire handled brush
and an industrial vacuum cleaner. Replace the clean-
out covers.
Most direct drive blower motors are permanently lubri-
cated by the motor manufacturer. These motors will
have no oil ports. If the blower motor does contain oil
ports, under normal operating conditions it will not
require oiling for the first two years. Oil sparingly (a few
drops) in each oil port with SAE 20 non-detergent oil.
Oiling is most easily done with a "tele-spout" oilier. This
oilier has a long flexible plastic spout. DO NOT OVER-
LUBRICATE. Excess oil causes premature electric
motor failure.
Inspect the blower fan. Clean it if necessary.
Oil Burner Maintenance: Follow the instructions of the
oil burner manufacturer. (See oil burner manufacturer's
instructions supplied with furnace). The oil burner noz-
zle should be replaced annually. We recommend that
the oil filter be changed on an annual basis.
The venting system should be cleaned and inspected
for signs of deterioration. Replace pitted or perforated
vent pipe and fittings. The barometric damper should
open and close freely.
All electrical connections should be checked to ensure
tight connections. Safety controls such as the high limit
controls should be tested for functionality. The fan con-
trol functions should be checked to ensure that all fan
speeds are operating properly.
FURNACE INSTALLATION SET UP
The furnace must be set up as the final step in the
installation.
A. THE OIL BURNER MUST BE SET UP FOL-
LOWING THE PROCEDURES OUTLINED IN
OIL BURNER SET UP ON PAGE 11.
B. THE P-HMX12F057011 AND P-HMX12F08001
SHOULD OPERATE WITHIN A TEMPERA-
TURE RISE OF 50°F TO 85°F; THE
P-HMX14F10001 AND P-HMX20F1201
SHOULD OPERATE WITHIN A TEMPERA-
TURE RISE OF 65°F TO 80°F. TO DETERMINE
THE TEMPERATURE RISE, MEASURE THE
SUPPLY AIR AND RETURN AIR TEMPERA-
TURES WHEN THE FURNACE HAS REACHED
STEADY STATE CONDITIONS. THIS IS THE
POINT AT WHICH THE SUPPLY AIR TEMPER-
ATURE STOPS INCREASING RELATIVE TO
THE RETURN AIR TEMPERATURE. THE FUR-
NACE MAY HAVE TO RUN 10 TO 15 MINUTES
TO REACH STEADY STATE CONDITIONS.
THE MEASUREMENTS MAY BE MADE WITH
DUCT THERMOMETERS OR THERMOCOU-
PLES USED IN CONJUNCTION WITH MULTI-
METERS WITH TEMPERATURE MEASURE-
MENT CAPABILITIES.
Do not start the burner or blower fan unless the
blower access door is securely in place.
The combustion chamber is fragile. use care when
inspecting and cleaning this area.
CAUTION
CAUTION

035-17473-000-B-1101
14 UnitaryProductsGroup
The return air should be measured at a point where the
thermometer will be well within the air stream near the
furnace return air inlet.. Actual location is not particu-
larly critical; however, avoid locations where the tem-
perature readings could be affected by humidifier
bypass ducts, the inside radius of elbows, etc.
The supply air temperature should be measured at a
point where the thermometer will be well within the air
stream near the furnace supply air outlet. Usually, the
side mid-point of the supply air plenum take-off is ideal,
providing it is out of the line of sight to the heat
exchanger. If the thermometer is within the line of sight
of the heat exchanger, the supply air readings may be
skewed by radiant heat from the heat exchanger. If the
plenum take-off is unsuitable, the supply air tempera-
ture may be measured within the first 18 inches of the
first segment of supply air trunk duct.
If the temperature rise is outside the recommended
range, it may be adjusted by selecting alternate circula-
tion fan motor speeds. If the temperature rise is too
high, speed the fan up. If the temperature rise is too
low, slow the fan down.
C. Keep in mind that the stack temperature varies
directly with the temperature rise. The higher the
temperature rise, the higher the stack tempera-
ture will be, resulting in lower efficiency. The
lower the temperature rise, the lower the stack
temperature will be, which, in some cases, may
allow condensation to form in the chimney and
other vent parts.
D. Test the high limit control to ensure that it is oper-
ating correctly. This may be done by temporarily
removing the circulator fan heating wire or neu-
tral wire. Turn of electrical power to the furnace
before working with the motor wires. Be sure to
protect any removed wires from shorting out on
metal furnace parts. If the high limit test is suc-
cessful, shut off the electrical power to the fur-
nace, restore the proper motor wiring. Then
restore power to the furnace.
E. Operate the furnace through a minimum of three
full heating cycles. During this time, check for
fuel oil leaks, gross air leakage from the supply
air ductwork, unusual noises originating any-
where within the heating system which may
cause some concern or annoyance to the home
owner, etc.
F. Be sure that the home owner is familiar with the
furnace. The home owner should be aware of the
location of electrical circuit breaker or fuse, the
location of any electrical switches controlling the
furnace, the location of the oil tank shut-off valve
and how to operate the valve. The home owner
should know where the oil tank gauge is located
and how to read it.
It would be beneficial to review safety issues with the
home owner, such as the danger of storing combusti-
bles too close to the furnace, hanging anything on the
furnace vent pipe, and especially the dangers of indis-
criminately pressing the burner reset button.
IMPORTANT: Be sure that the home owner knows
where the burner reset switch is located, and is aware
that the reset switch is not to be activated more than
once without a look for the cause of the problem, (lack
of fuel, etc.). Be sure that the homeowner knows when
to quit trying to start the furnace during these condi-
tions and who to call for emergency service.
OPERATING INSTRUCTIONS
Before Lighting
• Open all supply and return air registers and grilles.
• Open all valves in oil pipes.
• Turn on electric power supply.
To Light Unit
• Set the thermostat above room temperature to call
for heat. The burner will start. NOTE: If the furnace
has been off for an extended period of time, it may
be necessary to press the RESET button on the
primary combustion control relay, (once only). If
pressing the reset button does not start the fur-
nace, refer to Appendix C, Troubleshooting.
• After 30 seconds , as the furnace becomes warm,
circulation fan will start.
• The furnace will continue to run until the thermostat
call for heat is satisfied.
• Set the thermostat below room temperature. The
oil burner will stop.
• The air circulation blower will continue to run for
60, 90, 120 or 150 seconds after the oil burner has
stopped, depending on the dip switch settings.
To Shut Down Unit
• Set the thermostat to the lowest possible setting.
• Set the manual switch (if installed) in the Electrical
Power Supply Line to "OFF".
NOTE: Ifthefurnaceistobeshutdownforan
extended period of time, close the oil supply
valve to the oil burner.

035-17473-000-B-1101
Unitary Products Group 15
In the United States, the R. W. Beckett “AF” Burner may be equipped with Beckett’s “Inlet Air Shut-Off”,
Beckett Part No. AF/A 5861, to increase efficiency. It reduces the amount of air passing through the oil
burner, combustion chamber, breaching, etc. up the chimney between burner cycles.
NOTE: THE USE OF THIS CONTROL CAN OCCASIONALLY CAUSE POST COMBUSTION
NOZZLE DRIP.
Tip: These formulae will assist with the design of the duct work
donotattempttostarttheburnerwhenexcessoil
has accumulated, when the furnace is full of
vapour, orwhen the combustion chamber isvery
hot. never burn garbage or paper in the furnace,
and never leave paper or rags around the unit.
WARNING
Table 7: Becket AF Oil Burner Set-Up
BECKETT AF SERIES OIL BURNERS
FURNACE
MODEL OUTPUT BTUH BURNER MODEL NOZZLE PUMP PRESSURE FLOW RATE HEAD STATIC PLATE
P-HMX12F05701 58,000 AF76BO 0.50 / 70° A 100 PSIG 0.50 GPH F0 3-3/8 in.
P-HMX12F08001 79,000 AF76BO 0.70 / 70° A 100 PSIG 0.70 GPH F0 3-3/8 in.
P-HMX14F10001 100,000 AF76XN 0.85 / 70° A 100 PSIG 0.85 GPH F3 2-3/4 in.
P-HMX20F12001 118,000 AF76XN 1.00 / 70° A 100 PSIG 1.00 GPH F3 2-3/4 in.
Table 8: Blower Performance Table
Furnace
Model Motor HP Blower Temp.
Rise
( ∆T)
Motor
FLA Speed
CFM
External Static Pressure - Inches w.c.
0.20 0.30 0.40 0.50 0.60 0.70
P-HMX12F05701
P-HMX12F08001 1/2 G10 - DD 55°-85°F 77
High 1368 1298 1223 1144 1046 938
Medium - High 1318 1256 1178 1108 1007 909
Medium - Low 1173 1132 1071 993 909 816
Low 856 833 791 748 692 610
P-HMX14F10001 1/2 G10 - DD 55°-85°F 7.7
High 1593 1493 1410 1321 1226 1110
Medium - High 1485 1410 1341 1258 1146 1035
Medium - Low 1182 1158 1135 1074 996 896
Low 810 802 785 750 703 633
P-HMX20F12001 3/4 G12 - 10 DD 45°-75°F 12.5
High 2008 1977 1915 1867 1801 1715
Medium - High 1819 1802 1759 1724 1662 1588
Medium - Low 1734 1698 1680 1644 1588 1510
Low 1501 1491 1470 1428 1385 1319
()() CFMxOutputBonnet
RiseeTemperaturSystem
RiseeTemperaturSystemxOutputBonnet
CFM 085.1085.1 ==

035-17473-000-B-1101
16 UnitaryProductsGroup
.
FIGURE 8 : GENERAL DIMENSIONS (P-HMX SERIES)
Table 9: general dimensions (inches)
Cabinet Plenum Openings Flue Filter Ship
Supply Air
DxE
Return Air (perm) Weight
Width
ADepth BHeight CSide FxG Bottom Diam. Height
H(lb.)
P*HMX12F05701 & P*HMX12F08001
22 31 49½ 20½ x 20 14 x 22 14 x 22 5 42 16 x 25 x 1 190
P*HMX14F10001 & P*HMX20F12001
22 31 58-1/8 20½ x 20 14 x 22 n / a 6 46½ 16 x 25 x 1 250
C
H
14,000
22,000
31,000
22.125
Flue
Pipe
20,000
20,500

035-17473-000-B-1101
Unitary Products Group 17
FIGURE 9 : WIRING DIAGRAM - OIL FURNACE WITH ST9103A EFT & R7184A CONTROL

035-17473-000-B-1101
18 UnitaryProductsGroup
WIRING NOTES:P-HMX SERIES OIL FURNACE
CONTINUOUS FAN OPERATION:
The ST9103 EFT has provisions to run the blower
motor continuously on a speed lower than the cooling
or heating speeds. On a call for cooling, the fan motor
will switch to cooling speed, and on a call for cooling,
the fan will switch to heating speed, each over-riding
the continuous low speed fan.
To obtain continuous low speed fan, route a 16 gauge
stranded, type TEW, 105°C wire from the CONT Termi-
nal on the ST9103 EFT to the low speed or medium
low speed motor terminal. Both wire ends will require ¼
inch quick connects, (also known as “Faston” connec-
tors or ¼” spade connectors). For additional control
over the continuous low speed fan circuit, an SPST
toggle switch may be wired in series between the
motor terminal and the ST9103 EFT terminal. The con-
tinuous low speed fan operation operates at 115 vac.
Use appropriate wiring methods to prevent electrical
shock.
ACCESSORIES:
The ST9103 EFT has provisions for supplying 115 volt
power to an electronic air cleaner (EAC) as well as 115
volts to a line voltage humidifier or humidifier step down
transformer. Both sets of terminals are ¼ inch quick
connect type, rated at 1 A each.
TheEACterminalsprovidepowertoanelectronicair
cleaner whenever the heating or cooling speeds are
activated. Power is not provided when the continuous
speed is activated. If the electronic air cleaner must run
during continuous low speed fan operation, wire the
EAC into the furnace L1 terminal.
The HUM terminals provide power to a line voltage
humidifier or humidifier step down transformer when
the oil burner motor is operating.
THERMOSTAT HEATING CONNECTIONS:
The thermostat connections “R” and “W”, or “Rh” and
“W” connect to the “R” and “W” screw terminals shown
on the left hand side of Figure 10, on the ST9103 EFT
located in the control box mounted to the blower
mounting rails
NOTE: All thermostat wires for both heating and cool-
ing connect to the furnace at this point. A factory
installed wiring harness connects the heating control
functions to the R7184A oil primary control.
Figure 7,on page 12, shows the detail of the timed
“Blower Off” dip switch settings. Figure 10 shows the
dip switch location along the bottom edge of the control
board, just above the “Honeywell” label.
NOTE: The Honeywell R8184G may be used in place
of the R7184A. The R8184G is an intermittent ignition
control whereas the R7184A is an interrupted ignition
control. the R8184G continues to provide a spark dur-
ing the entire burner cycle whereas the R7184A dis-
continues the spark after the flame has been proved.
The R8184G does not have the diagnostic led features
found on the R7184A oil primary controls.
TURN OFF ELECTRICAL POWER TO THE FUR-
NACE WHEN SERVICING OR ALTERING FUR-
NACE WIRING.
FAILURETODOSOMAYRESULTINSEVEREPER-
SONAL INJURY, PROPERTY DAMAGE OR DEATH.
WARNING
FIGURE 10 : THERMOSTAT CONNECTIONS
ST9103A

035-17473-000-B-1101
Unitary Products Group 19
R7184 DETAILED SEQUENCE OF OPERATION
A. SAFETY CHECK IS MADE FOR FLAME (4 SECOND
DELAY).
1. When flame is not present, the R7184 will apply
power to the burner motor and ignition trans-
former.
2. When flame is present, the control remains in the
idle state.
B. CONTROL ENTERS THE TRIAL FOR
IGNITION STATE.
C. CONTROL MONITORS THE BURNER FLAME.
1. When flame is present, the control enters ignition
carryover state. (Continues to spark for 10-30
seconds).
a Provides continuous spark after flame is
sensed to assure that burner remains lit.
b Turns on LED diagnostic light.
c Starts carryover timer.
•Flame and call for heat are monitored.
Ιf flame is lost and lockout timer has not expired,
R7184 will return to trial for ignition state.
•If flame is lost and lockout timer has expired,
R7997 will enter the recycle state.
•Recycle timer starts.
•Burner motor and igniter are turned off.
•LED diagnostic light flashes slow.
•Returns to idle state when recycle timer
expires (60 seconds).
•Carryover timer expires.
•Enters run state.
•Igniter turns off.
Combustion continues until thermostat is satisfied or
R7184 detects a loss of flame and enters into Recycle
Mode.
Thermostat is satisfied - call for heat is terminated:
•R7184 shuts off burner motor.
•LED diagnostic light is off.
•R7184 returns to idle state.

035-17473-000-B-1101
20 UnitaryProductsGroup
FIGURE 11 : SEQUENCE OF OPERATION
IDLE STATE
THERMOSTAT CALLS FOR HEAT
SAFETY CHECK FOR FLAME
BURNER MOTOR STARTS
TRIAL FOR IGNITION
FLAME
NO FLAME
BURNER FLAME MONITORED
CARRYOVER STATE
•Provides Continuous Spark
•LED Diagnostic Light On
•Start Carryover Timer
NO FLAME
FLAME
FLAME
FLAME
FLAME LOST
FLAME LOST
CARRYOVER TIMER EXPIRES
RUN STATE
•Ignitor Turns Off
THERMOSTAT SATISFIED
R7997 SHUTS OFF:
•Burner Motor
•LED Diagnostic Light
RETURNS TO IDLE STATE
REMAINS IN IDLE STATE
LOCKOUT STATE
R7997:
•Shuts off burner motor
•Shuts off ignitor
•Fast Flashes LED
diagnostic light.
TO EXIT LOCKOUT
PRESS RESET
R7997:
•Shuts off burner motor
•Shuts off ignitor
•Slow Flashes LED
diagnostic light.
RECYCLE TIMER STARTS
RECYCLE TIMER EXPIRES
(60 SECONDS)
R7997
SEQUENCE
of
OPERATION
R7184
R7184
R7184
R7184 SHUTS OFF