Owner’s Manual
MGD-B SERIES GAS FURNACE
Heat Controller, Inc.
G18D Series Gas Furnace
OWNER’S MANUAL
Mortex Products Inc. / Fort Worth, TX 76106
G18D Owner’s Manual
5
IF FURNACE FAILS TO OPERATE PROPERLY
1. Check setting of the wall thermostat and position of
the heat/cool switch if air conditioning is installed.
2. Check to see that electrical power is “ON”.
3. Check to see that system switch is “ON”.
4. Check to see that lever on gas valve is in the “ON”
position.
5. Make sure that air filters are clean, supply registers
are open and return air grilles are not obstructed.
6. Be sure that furnace flue and inlet air pipes are open
and unobstructed.
7. Observe the Diagnostic Light. This light is visible
through a slot on the control panel cover and flashes
when there is a service problem. The diagnostic
codes are:
Steady On:
Normal Operation
One Flash:
Ignition Failure
Two Flashes:
Pressure switch stuck closed.
Three Flashes:
Pressure switch failed to close.
Five Flashes:
Gas valve energized or flame sensed at flame
sensor with no call for heat.
Six or Rapid Flash:
Reversed polarity.
If the cause for failure to operate properly is not an
electrical switch, thermostat switch or gas valve switch
in the off position; call a qualified service technician or
your gas supplier.
DO NOT ATTEMPT TO REPAIR THE
APPLIANCE
YOURSELF.
Four Flashes:
Limit switch is open.
THE FURNACE CONTROLS AND THEIR FUNCTION
•
Auto Ignition Units with “ON-OFF” System Switch -
The switch is on the right side of the furnace control
box and turns electrical power to the furnace on or
off. It must be “ON” for the furnace to operate.
•
Limit Switch -
All furnace models are protected by
two (2) temperature limit safety switches. The lower
limit switch (inside furnace control box) is an
automatic reset type. Press the red button on the top
of the limit to reset. If burner starts but the blower
does not start do not press the red button again. Call
a qualified service technician for service. The limit
switch by the furnace
blower is a manual reset type.
•
Fan Switch -
Furnaces have a temperature sensing
device that turns on the blower when sufficient heat
has built up inside the furnace.
•
Gas Valve -
The gas valve for all models are 100%
shut-off type and will fail safe if for some reason the
gas is turned off .
INSPECTION AND MAINTENANCE
BY THE HOMEOWNER
•
Make a visual inspection of the furnace every 30
days. Do the following:
•
Filters-
Clean filters at least every (3) months and
replace as needed. Size; 16”x20”x1”
•
Motor Lubrication-
None: The combustion and air
circulator motors are permanently lubricated.
•
Return Air -
On some closet installations, the return
air opening may be in the floor. DO NOT cover or
obstruct these floor openings or any other return air
opening to the closet.
•
Heat Exchanger -
under normal conditions, no
cleaning is needed. If cleaning becomes necessary,
only a service technician should do so. Chemicals
should not be used to clean the heat exchanger.
•
Furnace Vestibule -
periodically remove furnace
panels and clean the vestibule area to remove dust
and lint. Shut off all electrical power to the unit
before cleaning.
•
When you’re away -
The furnace has safety controls
to shut the unit down if there is a malfunction.
Therefore do not assume it can operate unattended
for prolonged time periods. There is a damage
possibility to your home in freezing weather, have a
neighbor or family member check your home daily.
INSPECTION AND MAINTENANCE BY A SERVICE
TECHNICIAN
Annual furnace maintenance and Inspection is
recommended.
•
Replace air
and clean dust
and lint from
furnace and area.
•
Remove blower assembly and clean blower wheel
and motor.
•
Inspect the combustion chamber,
collar and roof
jack.
•
Check the gas valve and gas line connections for
leaks.
•
Make adjustments as needed for good operation.
SEASONAL SERVICE INFORMATION
In regions where there is heavy snow accumulation, a
roof jack crown extension is recommended to prevent
blockage of the roof jack combustion air openings.
During extreme cold weather, ice may form on the
furnace roof jack. Small amounts of ice on the roof jack
will present no problem to proper furnace operation.
Excessive ice formation could restrict the combustion air
supply to the burner causing inefficient burner operation.
If excessive ice has formed on the inlet or exhaust
portions of the roof jack, it must be carefully removed.
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