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271002-UUM-A-0407

4

Unitary Products Group

FURNACE USER MAINTENANCE

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.

Before proceeding, be sure the area is well ventilated. Turn
the thermostat OFF. If the blower is running, wait until it
stops automatically. Turn OFF the gas and electrical power
supplies to the furnace. Check all metal parts and surfaces
to be sure they have cooled to room temperature before
you begin.

TABLE 1: 

Filter Sizes

Cabinet

Size

Side (in)

Side (cm)

Bottom (in) Bottom (cm)

A

16 x 25

4.06 x 6.35

14 x 25

3.56 x 6.35

B

16 x 25

4.06 x 6.35

16 x 25

4.06 x 6.35

C

(2) 16 x 25 (2) 4.06 x 6.35

20 x 25

5.08 x 6.35

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 AHV8 UH Series

Page 1: ...t 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 not store or use gasoline or other f...

Page 2: ...he 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...

Page 3: ...s 1 STOP Read the safety information above 2 Set the thermostat to the lowest setting 3 Turn off all electric power to the appliance 4 Remove burner door 5 Move gas control switch to the OFF position...

Page 4: ...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 y...

Page 5: ...et Remove this screw before proceeding 3 Unplug the vent motor wires and ground wire Remove the pres sure switch tubing at the tap on the vent motor housing NOTE It is recommended that replacement gas...

Page 6: ...e Y2 circuit for high cooling CONTROL BOARD Variable speed motors will adjust the motor speed in order to maintain the indoor fan CFM The control board is used to control the blower speed thus the CFM...

Page 7: ...higher speed will take 30 seconds and any ramp down to a lower speed or off will take 60 seconds Tap D is the normal profile best suited for most of the country where neither excessive humidity nor ex...

Page 8: ...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 9: ...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 10: ...271002 UUM A 0407 10 Unitary Products Group SECTION III REPLACEMENT PARTS LIST 39 29 38 43 21 25 35 31 27 23 22 20 24 30 44 26 53 42 28 18 2 4 11 6 9 5 17 16 12 7 8 3 12A 7 36 25 37 12 20 11...

Page 11: ...ITER 22 DECK BLOWER Rear 23 DECK FRONT 24 HEAT EXCHANGER ASS Y 25 MANIFOLD GAS 26 PANEL UPPER ACCESS Burner Magnet FABRICATED PARTS Continued 27 PAN BASE 28 PANEL BLOWER ACCESS Magnet 29 PANEL TOP 30...

Page 12: ...1BR0121 BOTTOM RETURN FILTER KIT 1 FILTER 21 CABINETS 1BR0221 BOTTOM RETURN FILTER KIT 1 4 FILTER 21 CABINETS 1BR0124 BOTTOM RETURN FILTER KIT 1 FILTER 24 1 2 CABINETS 1BR0224 BOTTOM RETURN FILTER KIT...

Page 13: ...271002 UUM A 0407 Unitary Products Group 13 SECTION IV WIRING DIAGRAM FIGURE 9 Wiring Diagram...

Page 14: ...271002 UUM A 0407 14 Unitary Products Group NOTES...

Page 15: ...271002 UUM A 0407 Unitary Products Group 15 NOTES...

Page 16: ...to products installed 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...

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