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Bosch 80% AFUE Gas Furnace
User's Information Manual
06.2018
|
Bosch Thermotechnology Corp.
Data subject to change
5 Routine Maintenance
5.1 Annual Inspection
WARNING:
The furnace must be inspected by a qualifi ed installer or
service agency at least once per year.
Homeowners: Homeowners may only clean and replace fi lters
and replace fuses as required by basic maintenance. All other
operations, including installation, repair, and service must be
performed by a qualifi ed installer, service agency, or the gas
supplier.
Service Reminder:
Call your service technician if the unit will not operate. Before calling,
always check the following to be sure service is required:
1. Check that electrical disconnect switches are
ON
.
2. Check room thermostat for proper setting.
3. Replace any blown fuses or reset circuit breakers.
4. Gas valve should be
ON
.
5. Air fi lter should not be clogged/dirty, which will limit air fl ow.
6. Is gas turned on at the meter?
7. Is manual main shut-off valve open?
Record the model and serial number of the furnace. These numbers are
available on the warning label located on the blower access panel.
Serial Number: __________________________________________
Model Number: __________________________________________
Your qualifi ed service professional must perform the following checks at the
beginning of the heating season. This will ensure that all furnace components are in
proper working order and that the heating system functions appropriately.
1.
The Venting System
a.
All fl ue gas carrying areas external to the furnace (i.e. chimney, vent
connector, vent pipe) are clear and free of obstructions.
b.
Inspect heat exchangers and blowers for corrosion, deterioration, or
deposits of debris. Remove any obstructions.
c.
The vent connector is in place, slopes upward and is physically
sound without holes or excessive corrosion.
d.
The return-air duct connection(s) is physically sound, is sealed to
the furnace casing, and terminates outside the space containing the
furnace.
e.
The physical support of the furnace is sound without sagging,
cracks, gaps, etc. around the base so as to provide a seal between
the support and the base.
f. There are no obvious signs of deterioration of the furnace.
g.
The burner fl ames are in good adjustment (by comparison with
pictorial sketches or drawings of the main burner fl ame. Refer
to the Installation, Operation, and Maintenance Manual for more
information).
h.
In applications which include a cooling coil, the condensate drain
and trap should be checked for leaks and cracks. The trap must be
fi lled with water and the drain and trap should be cleaned.
2. The
Blower
The bearings in the induced draft blower and circulator blower motors
are permanently lubricated by the manufacturer. No further lubrication is
required. Check motor windings for accumulation of dust which may cause
overheating. Clean as necessary.
3.
The Flame Sensor
Under some conditions the fuel or air supply can create a nearly invisible
coating on the fl ame sensor. This coating acts as an insulator causing a drop
in the fl ame sense signal. If the fl ame sense signal drops too low. The furnace
will not sense fl ame and will lock out. The fl ame sensor should be carefully
cleaned by a qualifi ed servicer using emery cloth or steel wool. Following
cleaning the fl ame sense signal should be 1 to 6 microamps at 115 volts.
4.
The Heat Exchanger
Inspect the heat exchanger for excessive rust, cracks, or holes. Visual
inspection is always best, but requires training and practice. There are tools
(fi eld supplied) available to assist, such as inspection cameras and dye
penetration inspection systems. Inspect the metal fl ue for rust or holes, and
make sure it’s supported properly.
If the heat exchangers get a heavy accumulation of soot and carbon, they
must be replaced rather than cleaning them. A heavy build-up of soot and
carbon indicates that a problem exists which needs to be corrected, such
as improper adjustment of manifold pressure, insuffi cient or poor quality
combustion air, incorrect size or damaged manifold orifi ce(s), improper
gas, or a restricted heat exchanger. In these scenarios, the heat exchanger
must be replaced.
5.2 Filters
A return air fi lter is not supplied with this furnace; however the installer will supply
fi lter(s) at the time of installation. Filters are installed external to the unit. Have your
installer instruct you on how to access your fi lters for routine maintenance.
Filter Maintenance
Improper fi lter maintenance is the most common cause of inadequate heating or
cooling performance. Inspect fi lters every month and clean (permanent) or replace
(disposable) as required. When replacing a fi lter, it must be replaced with a fi lter
of the same type and size. Become familiar with fi lter location and procedures for
removal cleaning and replacing them. If help is needed, contact the installer of the
furnace or a qualifi ed service agency.
Filter Removal Procedure
1.
Turn OFF electrical power to the furnace.
2.
Remove fi lter cabinet door.
3.
Slide out fi lter.
4.
If the fi lter is damaged, replace it with a new one.
5.
For reusable fi lters, use cold tap water and mild liquid detergent (if needed)
to rinse the fi lter.
6.
Once dry, reinstall fi lter.
7.
Replace fi lter cabinet door.
8.
Turn ON electrical power to furnace.
