CONQUEST 80 - Control Responses

CONTROL RESPONSES
1.
POOR EQUIPMENT
GROUNDING
• Results in erratic flame sensing
and nuisance soft lock outs.
Check for poor grounding of the
burners by measuring the
resistance from the common
transformer terminal to the sheet
metal of a burner. There should
be zero/low Ohms resistance.
Check the unit grounding by
measuring the resistance from
the furnace neutral wire to the
furnace ground wire (green or
bare copper).
2. LIMIT SWITCH OR OVER
TEMPERATURE SWITCH
OPENING
• Results in furnace shut down.
The gas valve closes, the
inducer fan and main blower run
until the limit resets. If the control
is not reset, both blowers run
indefinitely.
• When the limit resets, the
inducer fan runs for 5 seconds
and stops. The main blower runs
for its pre-set off delay. After the
main blower stops, the inducer
fan starts and goes through a
normal ignition sequence.
3. HEAT ASSISTED LIMIT
CONTROL (HALC) OPENING
• This shuts down the gas valve.
If the first retry for ignition, after a
burner interruption for any
reason, fails, the IFC
immediately starts the main
blower. The main blower runs for
180 seconds. This should reset
the HALC. After it resets the
main blower stops, the unit goes
into its normal ignition sequence.
4. OPEN PRESSURE SWITCH
• Upon a heat call the control
operates the induced draft
blower for 30 seconds before
starting the ignition sequence.
If the pressure switch contacts
do not close, the induced draft
blower continues to run for up to
60 seconds. After 60 seconds
the control goes into a five-
minute "rest." It retries for ignition
for 60 seconds again after the 5
minute rest. It repeats this cycle
indefinitely.
• If the pressure switch opens for
more than 2 seconds during a
heating cycle, the control closes
the gas valve and starts another
trial for ignition. If the pressure
switch opens for less than 2
seconds the control takes no
action.
5.
PRESSURE SWITCH CLOSED
ON START UP
• If the pressure switch contacts
have welded or remain closed
for some reason, the control
does not attempt to start the
furnace. It waits, with the "OK"
light on, until the pressure switch
contacts reopen.
6.
LOW/NO GAS PRESSURE
• With insufficient gas pressure
to generate a proper flame, the
control loses flame sensing and
goes into soft lock out.
7. IMPROPER POLARITY
• If the control or furnace is
wired improperly the control
lights the burners, but will not
sense flame current. It goes into
soft lock out after 4 trials for
ignition.
8. VOLTAGE SPIKES
• Transient voltage spikes cause
the
controls to respond by
resetting, with the "OK" light
off for 0.5 second,
and then
starts a normal ignition
sequence.
9. VARIATIONS IN 60 HERTZ
FREQUENCY
• The timing of the ignition
sequence changes in proportion
to the frequency variation.
10. MOMENTARY POWER
OUTAGES
• There is no effect if the outage
is less than 0.2 second or more
than 2.5 seconds. The unit
operates normally if the reset is
outside this range.
• The controls are designed so
that momentary power outages
do not cause lock out. The
control waits one to 2.5 seconds
and then restarts the furnace.
11. CAN THE CONTROLS BE
COMBINED FOR TWINNING
• Yes, see the section on
furnace twinning.
r,
• The "OK" light flashes if the
twinning wiring or procedures
are not correct.
12.
HUMIDIFER OPERATION
• The control powers the
humidifier through the "HUM"
terminal 5 seconds after the
blower starts on a heating
speed. It terminates humidifier
operation 30 seconds before the
blower stops.
NOTE: This does not apply to
UTEC 1012-925 controls.
13. INCOMPATIBLE
THERMOSTATS
• If the control is connected to a
"power robbing" thermostat, the
induced draft blower (IDB) tries
to start during the off cycle.
Since this drains so much power
from the thermostat, the I DB
pulsates off and on.
14.
THERMOSTAT SET
r
TO "FAN"
• With the thermostat "FAN"
switch set to the "ON" position,
the control powers the blower
constantly through the "FAN"
terminal on the board. On a call
for heat, the blower stops as the
furnace goes through its ignition
sequence. The blower runs on
its heating speed 20 seconds
after the gas valve opens. It
shifts back to the constant
speed after the heating speed is
timed off.
NOTE: This does not apply to
UTEC 1012-925 controls.
15.
SENSING FLAME DURING
THE "OFF" CYCLE
• If the control senses flame
when a flame should not be
present, the amber "FLAME"
LED flashes rapidly (3 times per
second) with the "OK" and
"PWR" LED's on. The furnace
operates both the main blower
and inducer. It does not allow
fl"
the gas valve to open.
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