33
feature and the furnace operates on high
fire only. All of the burners will operate on a
call for heat and the variable speed blower
will operate at a higher speed.
3.
Low fire only configuration – For this instal-
lation, the high terminal is disconnected
(See Figure 26c). This defeats the staging
feature and the furnace operates on low fire
only. The furnace will run at reduced firing
rate and the variable speed blower will
operate at a lower speed.
4.
Outdoor ambient dependent configuration
– For this installation, low and high terminals
are connected in parallel with an outdoor
thermostat (open on rise style) in series
with the high terminal (See Figure 26d).
CAUTION:
DO NOT CONNECT W2 from
outdoor thermostat to the furnace wiring
when using the outdoor ambient dependent
configuration. When the outdoor tempera-
ture is above the set point, the outdoor
thermostat opens keeping the high terminal
open. The furnace operates in the low fire
mode at a lower blower speed. When the
outdoor thermostat closes, the high fire on
gas valve opens and the furnace operates
in the high fire mode at higher blower speed.
5.
Timed staging configuration – For this in-
stallation, the low and high fire on the gas
valves are connected in parallel with a delay
on make timer (two wire style) in series with
the secondary gas valve (See Figure 26e).
CAUTION:
DO NOT CONNECT W2 from
thermostat to the furnace wiring when using
timed stage configuration. When the low fire
on the gas valve is energized, the furnace
operates in the low fire mode at a lower
blower speed and the timer begins its delay
function. If the room thermostat is not sat-
isfied before the timer activates, the fur-
nace will stage to high fire and the blower will
operate at a higher speed until the room
thermostat is satisfied.
6.
Two Stage Cooling – The furnace is sup-
plied with the yellow “Y1” and blue “Y2”
connections attached to the control board.
Connect a field supplied wire from the
yellow “Y1” to the thermostat and the con-
densing unit, and another wire connected
from “Y2” on the thermostat to “Y2” on the
condenser. (See Figure 27.)
Install the thermostat per the manufacturer's
instructions. The low voltage (24 volt) connec-
tions from the thermostat are made at the
terminal strip on the control board in the fur-
nace. See Figures 26a-26e for the proper
connections for heating only (four wire) and
heating/cooling (five wire) applications. The
recommended minimum wire gauge for ther-
mostat wiring is shown in Table 11.
The thermostat must not be installed on an
outside wall or any other location where its
operation may be adversely affected. Adverse
affects include radiant loading from fireplaces,
sunlight, or lighting fixtures, and convective load-
ing from warm air registers or electrical appli-
ances.
To check the heat anticipator setting either:
1.
Add the current draw of the system compo-
nents; or
2.
Measure the current flow on the thermostat
R-W circuit after the circulating blower
motor has started.
Set the heat anticipator according to the thermo-
stat manufacturer's instructions for heat antici-
pator settings.
START-UP AND ADJUSTMENTS
Prior to start-up, verify that:
1.
The line voltage power leads are securely
connected, that the polarity of the connec-
tions is correct, and that the furnace is
properly grounded.
Figure 27. Two Stage Condensing Unit
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Y2
Y1
THERMOSTAT
Two Stage Condensing Unit
Y2
Y1
YELLOW
Y1
BLUE
Y2
CONDENSING
UNIT
REMOVE BLUE
WIRE FROM
Y TERMINAL
OF
FURNACE
BOARD
Summary of Contents for TC060
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