100
Di
ag
no
sti
cs
TABLE 19 (continued)
R97V FAULT CODES WITH DESCRIPTIONS AND SOLUTIONS
(1) Check the vent system for blockage and proper termination and repair as necessary.
(2) Check the specification sheets and/or installation instructions. Remove excess venting.
STATUS:
This is a critical fault. The furnace will not operate in gas heat modes but all other modes (e.g. cooling) should
function if present simultaneously with a heating call (e.g. defrost call in dual-fuel mode).
DESCRIPTION:
This fault indicates that the low pressure switch is open
when the inducer is energized at low speed
. Since
the furnace only ignites at high fire, this condition should never be seen except after the blower on delay period of the ignition
cycle and only after the furnace attempt to switch to low stage heating. The switch is ignored except in heating modes.
(8) Insure proper termination and determine if high altitude kit may be necessary (see item 4)
(9) Replace the pressure switch.
(6) Loose or faulty wiring.
(9) Faulty pressure switch.
(8) Wind gusts (sporadic).
(7) Disconnected, blocked, split or cut pressure switch hoses.
CAUSE:
(2) The flue vent length and/or number of elbows exceeds the maximum number specified.
(7) Replace hoses as necessary.
(4) Replace control board.
(3) Repair or replace inducer and/or inducer wiring and/or electrical connections.
SOLUTION:
(1) Blockage or improper termination in either the inlet or exhaust vents.
(6) Check wiring and connections. Replace and/or repair as necessary.
(1) Check the vent system for blockage and proper termination and repair as necessary.
(2) Check the specification sheets and/or installation instructions. Remove excess venting.
(5) High altitude kit not installed in areas of high elevation.
(4) Faulty control board (inducer relay).
(3) Faulty or disconnected inducer.
(5) Check elevation of the installation and consult the specifications for the furnace to determine if a high altitude kit is needed.
Install proper kit as necessary.
(6) Replace hoses as necessary.
(7) Insure proper termination and determine if high altitude kit may be necessary (see item 4)
(8) Replace the pressure switch.
(7) Wind gusts (sporadic).
(8) Faulty pressure switch.
SOLUTION:
(3) Repair or replace inducer and/or inducer wiring and/or electrical connections.
(4) Replace control board.
(5) Check wiring and connections. Replace and/or repair as necessary.
(3) Faulty or disconnected inducer.
(4) Faulty control board (inducer relay).
(5) Loose or faulty wiring.
(6) Disconnected, blocked, split or cut pressure switch hoses.
45
EXPECTED OPERATION:
(1) DISPLAYED
BEFORE
HEAT IS ESTABLISHED: The IBM (Indoor Blower Motor) will not be
energized. The fault code will not be displayed until the IDM (Induced Draft Motor) has been energized for a minimum of ten
seconds. The IDM will remain energized at the high speed (high speed is default pre-purge speed) for a period of five minutes
after the beginning of the pre-purge attempt. After five minutes, the IDM is de-energized and second attempt at pre-purge is
made (as long as the heat call is still present). This cycle is repeated indefinately until either the pressure switch closes or the
heat call is lost. (2) DISPLAYED
AFTER
HEAT IS ESTABLISHED - If this fault is displayed
after
heat is established, the gas
valve will be de-energized, the IBM will be energized (if not already energized) at the correct heat speed (determined by the
firing rate required by the thermostat) and the IDM will remain energized at high speed. The IBM will complete a 90 second
blower off-delay and the IDM will complete a 20 second post-purge (at high speed). After these delays, a new attempt at ignition
will be made provided the call for heat is still present.
CAUSE:
(1) Blockage or improper termination in either the inlet or exhaust vents.
(2) The flue vent length and/or number of elbows exceeds the maximum number specified.
46
LOW PRESSURE SWITCH OPEN, INDUCER ON LOW SPEED
STATUS:
This is a critical fault. The furnace will not operate in gas heat modes but all other modes (e.g. cooling) should
function if present simultaneously with a heating call (e.g. defrost call in dual-fuel mode).
DESCRIPTION:
This fault indicates that the low pressure switch is open
when the inducer is energized at high speed
. The
switch must close after the inducer is energized and before the ignition sequence can begin. The switch is ignored except in
heating modes.
LOW PRESSURE SWITCH OPEN, INDUCER ON HIGH SPEED
EXPECTED OPERATION:
This fault is displayed only after heat is established and switched to low fire with the IBM (Indoor
Blower Motor) energized at low speed. When this fault is displayed the gas valve will be de-energized, the IBM will remain
energized at the low heat speed and the IDM (Induced Draft Motor) will remain energized at the low speed. The IBM will
complete the user-selected blower off-delay (at low speed) and the IDM will complete a 20 second post-purge (at low speed).
After these delays, a new attempt at ignition will be made provided the call for heat is still present.
