There are new blower motor speed
terminals. One is marked
"FAN"
to operate the blower constantly.
The other is marked
"HEAT/
COOL"
to operate both heating
and cooling on the same speed.
Always connect the "Y"
thermostat wire to the "Y"
control board terminal. DO NOT
SIMPL V WIRE NUT THIS WIRE
TO THE WIRE GOING TO THE
CONDENSING UNIT. If not
connected to the control board
the unit does not go into the
cooling blower speed.
After the cooling call ends the
blower continues for a 45-second
off delay.
UTEC 1012-925 CONTROLS
INTRODUCTION
This Integrated Furnace control
comes on the (-)GRJ and (-)GTJ
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.
"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.
FIGURE 92
UTEC 1012-925 FURNACE CONTROL
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.
Ignition Trial -
1.
Gas valve opens.
2.
Igniter remains energized for
ONL V 7 seconds after gas
valve opens.
3. Burners ignite.
Flame Recognition -
1. Igniter de-energizes during
eighth second.
2. Flame sensor recognizes
ignition during
EIGHTH
SECOND.
Operation-
1. Main blower starts 20 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
as current controls, there are some
differences.
1. Screw connections for
thermostat wires.
2. Twinning requires a special kit
(RXGP - F03).
,
"
~
41
78
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