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272357-UUM-A-0407

4

Unitary Products Group

Every time the filters are changed the following items should be visually
inspected:

Check vent pipe for blockage or leakage.

Check all components to be sure they are in good condition and
that there are no obvious signs of deterioration.

Check for dirt or lint on any surfaces or on components. Do not try
to clean any of the surfaces or components. Cleaning of the fur-
nace and its components must be done by a qualified service pro-
fessional.

If, during the inspection of your furnace, you find any of the following
conditions:

Excessive amounts of dust and lint on components.

Damaged or deteriorated components or surfaces.

Leaks or blockage in the vent pipe passages.

Water on any surface inside or outside of the furnace.

Do not operate the furnace, call a certified dealer / servicing contractor
to check and / or clean your furnace, or for more information if you have
questions about the operation of your furnace.

If all components appear to be in good operating condition, replace the
front panels. Turn ON the gas and electrical power supplies to the fur-
nace, and set thermostat to the desired temperature.

Air Filters

Dirty filters greatly restrict the flow of air and may cause damage to the
moving parts of the furnace. If the filters become clogged the heat
exchangers and blower motor could overheat resulting in a potentially
dangerous situation.The filters should be checked every 3 months. On
new construction, check the filters every week for the first four weeks
and every three weeks after that, especially if the indoor fan is running
continuously. When replacing the filter(s) you must use filters that are
the same size as those recommended in Table 1. use the following pro-
cedure to determine the filter size. Never operate your furnace without a
suitable air filter.

Removing Filters

Externally Mounted Air Filters

Some installations may have the air filter in a rack attached to the cas-
ing of the furnace or placed in the return air duct. You can gain access
to the filter by pulling on the door or unscrewing the retaining screw,
then slide the filter(s) out of its channel. Replace throw away filter(s)
with the same size new filter(s). Throw away filter(s) may be replaced
with cleanable filter(s) at this time. Cleanable filter(s) may be cleaned as
described in the manufacturer instructions or as described below and
then re-installed.

To replace the filter after cleaning you must do the following:

1.

Slide filter into place.

2.

Snap the door on or place the door in position and tighten the
retaining screws, if provided.

3.

Make sure the door is secure to the end of the filter rack.

How to Clean your Filter

High-velocity filters may be cleaned with a vacuum cleaner or washed
with a garden hose. Be sure to shake off excess water and allow filter to
completely dry before re-installing the filter.

Blower Care

Even with good filters properly in place, blower wheels and motors will
become dust laden after long months of operation. The entire blower
assembly should be inspected annually. If the motor and wheel are
heavily coated with dust, they can be brushed and cleaned with a vac-
uum cleaner. If the blower cannot be properly cleaned without removing
it from the furnace, then this service must be performed by a qualified
service agency.

Motor Lubrication

The motors in these furnaces are permanently lubricated, and do not
require periodic oiling.

SECTION II: SERVICE AND MAINTENANCE 

MANUAL

SAFETY SECTION

The following safety rules must be followed when servicing the
furnace.

FURNACE MAINTENANCE SECTION

The furnace should be cleaned and adjusted by a certified dealer or
qualified service contractor once a year or before the start of every
heating season. The following items must be cleaned and serviced or
replaced if there are signs of deterioration.

1.

The vent terminal screen (if applicable).

2.

The furnace vent and combustion air intake passageways. Should
it be necessary to service the vent/air intake system, the manufac-
turer recommends this service be conducted by a qualified service
agency. The operation of this appliance requires the reassembly
and resealing of the vent/air intake system.

3.

The furnace burners, ignitor and flame sensor.

FURNACE CLEANING SECTION

NOTE: 

The cleaning operations listed below must be performed only by

a qualified service agency.

Burner Removal/Cleaning

The main burners should be checked periodically for dirt accumulation.
If cleaning is required, follow this procedure:

1.

Turn off the electrical power to the unit.

2.

Turn off the gas supply at the external manual shut-off valve and
loosen the ground union joint.

TABLE 1: 

Filter Sizes

Cabinet Size

Top Return (in)

Top Return (cm)

A

(2) 14 x 20

(2) 35.6 x 50.8

B

(2) 14 x 20

(2) 35.6 x 50.8

C

(2) 14 x 20

(2) 35.6 x 50.8

Make sure you DO NOT move the clip on weight on the
indoor fan wheel when cleaning the wheel. This weight is
used to balance the wheel. Moving the weight will cause
the fan wheel to vibrate.

ELECTRIC SHOCK, FIRE OR EXPLOSION HAZARD
Failure to follow safety warnings exactly could result in
dangerous operation, serious injury, death or property
damage.
Improper servicing could result in dangerous operation,
serious injury, and death or property damage.

Before servicing, disconnect all electrical power to the fur-
nace. 

When servicing controls, label all wires prior to disconnect-
ing. Reconnect wires correctly. 

Verify proper operation after servicing.

Summary of Contents for PT8 DH Series

Page 1: ...s electrical parts that have been wet or the furnace if deemed necessary FIRE OR EXPLOSION HAZARD Failure to follow safety warnings exactly could result in serious injury death or prop erty damage Do...

Page 2: ...e ducts ter minate outside the space containing the furnace 4 Examine the furnace casing making sure the physical support is sound without sagging cracks or gaps Examine the furnace base making sure i...

Page 3: ...electric power to the appliance 4 Remove burner access panel 5 Move gas control switch to the OFF position Do not force See Figure 4 6 Wait five 5 minutes to clear out any gas If you then smell gas ST...

Page 4: ...secure to the end of the filter rack How to Clean your Filter High velocity filters may be cleaned with a vacuum cleaner or washed with a garden hose Be sure to shake off excess water and allow filte...

Page 5: ...th the top and bottom The brush must pass around the rear heat exchanger tubes Vacuum loose scale and dirt from each tube 7 Clean Replace all components in reverse order Re gasket all surfaces which r...

Page 6: ...st be long enough to adequately cool the furnace but not so long that cold air is blown into the living space The blower on delay is fixed at 30 seconds and cannot be adjusted Continuous Blower Operat...

Page 7: ...out Low gas pressure faulty gas valve faulty hot surface ignitor or burner problem may cause this The furnace will lock out for one hour and then restart 8 RED FLASHES This fault is indicated if the f...

Page 8: ...DUCER LOW STAGE PRESSURE SWITCH HSI 1ST STAGE MAIN VALVE FLAME SENSE LOW CIRCULATOR HEAT SPEED 1ST STAGE LOW PRESSURE SWITCH CLOSE RECOGNITION HSI WARM UP 17 SEC IGNITION ACTIVATION PERIOD 4 SEC TRIAL...

Page 9: ...25 37 7 TABLE 2 Field Installed Accessories Non Electrical FIELD INSTALLED ACCESSORIES NON ELECTRICAL MODEL NO DESCRIPTION USED WITH 1NP0347 PROPANE LP CONVERSION KIT ALL MODELS 1PS0313 HIGH ALTITUDE...

Page 10: ...GROMMET 1 2 DIA 36 BRACKET ROLL OUT SWITCH 37 ORIFICE BURNER Natural 45 38 PLATE RESTRICTOR 39 COLLAR FLUE 40 BAFFLE BLOWER 41 GASKET RESTRICTOR PLATE 42 TUBING SILICONE 43 WIRING DIAGRAM 44 WIRING HA...

Page 11: ...272357 UUM A 0407 Unitary Products Group 11 SECTION IV WIRING DIAGRAM FIGURE 8 Wiring Diagram...

Page 12: ...alled in the United States and Canada EXCLUSIONS This warranty does not cover any 1 Shipping labor or material charges 2 Damages resulting from transportation installation or servicing 3 Damages resul...

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