UTEC 1012-925 CONTROLS
INTRODUCTION
This Integrated Furnace control
comes on the "J" series furnaces.
This control has the Factory part
number of 62-24268-01 and carries
the UTEC part number of 1012-925.
The most obvious difference is this
control has only two LED's.
OPERATION
The control has most of the same
functions as current three-light
controls. If it detects a problem, the
control attempts to restart the
furnace. If it cannot, it goes into a
"Soft Lock Out."
Soft lock out causes
1. Not detecting flame after four
ignition trials.
2. Four flame failures during one
heat call.
3. A software irregularity in the
microprocessor.
A soft lock out can be reset at the
thermostat or main power
disconnect. This only interrupts
furnace operation. Cooling calls
through the "Y" and "G" terminals
operate normally. It resets
automatically after one hour.
FIGURE 81
UTEC 1012-925 FURNACE CONTROL
"Self Healing"
The control also has a "self healing"
feature, which is activated after the
second failed ignition trial. The
control operates the main blower for
180 seconds in an attempt to cool
and reset a possible open heat
assisted limit control (HALC).
All other furnace operations are
locked out until after the blower runs.
Sequence of Operation
The control's sequence of operation
is virtually the same as current
controls; however, some timings are
different. The correct sequence
follows.
Prepurge -
1. Thermostat calls for heat.
2. Inducer starts.
3. Pressure switch closes.
4. Inducer runs for 5 seconds.
5. Igniter heats for 30 seconds
and the inducer continues
operating.
Ignition Trial -
1. Gas valve opens.
2. Igniter remains energized for
ONLY 7 seconds after gas
valve opens.
3. Burners ignite.
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Flame Recognition -
1. Igniter de-energizes during
eighth second.
2. Flame sensor recognizes
ignition during
EIGHTH
SECOND.
Operation -
1. Main blower starts 22 seconds
after gas valve opens.
2. Inducer and burners operate.
Shutdown -
1. Thermostat call ends.
2. Gas valve closes and burners
go out.
3.
Inducer runs for a 5 second
postpurge.
4. Main blower operates until timed
off by the control board.
There are other similarities. If the
burners don't light, the inducer
operates for
30 seconds between
trials for ignition. The control delays
the blower for
one second after the
cooling equipment starts.
It keeps
the main blower operating for
45
seconds after the cooling call
ends.
Even though its function is the same r
as current controls, there are some
differences.
1. Screw connections for
thermostat wires.
2. Twinning requires a special kit
(RXGP - F03).
3. No humidifier connection
terminal.
4. No "FAN" and "HEAT/COOL"
connections.
5. There are only two indicator
lights.
6. The "OK" light blinks to indicate
a problem.
78
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