Start-Up, Adjustment, And Safety Check; General; Sequence Of Operation - Carrier 58UHV Installation, Start-Up, And Operating Instructions Manual

SETUP
SWITCH NO.
SW-1
Only High-Gas Heat
SW-2
Low-Gas Heat (Adaptive Mode)
SW-3 and SW4
Step 9—Start-Up, Adjustment, and Safety Check

GENERAL

The furnace must have a 115-v power supply properly connected
and grounded. Correct polarity must be maintained to enable gas
heating operation.
The gas service pressure must not exceed 0.5 psig (14-in. wc), and
no less than 0.16 psig (4.5-in. wc).
Thermostat wire connections at R and W/W1 are the minimum
required for gas heating operation. W2 must be connected for
2-stage heating thermostats. Y/Y2 and G are required to be
connected to the furnace for cooling and heat pumps. G is required
for continuous-fan. C 24V is required for some clock thermo-
OM
stats. These connections must be made at the 24-v terminal block
on the furnace control. (See Fig. 13.) O is required for heat pumps
only. Y1 is required for 2-stage cooling and 2-stage heat pumps.
The O and Y1 connectors must be made to the ICM2+ furnace's
orange and blue leads, flagged "O" and "Y1," respectively.
This furnace can be installed with either a single-stage heating or
a 2-stage heating thermostat.
For single-stage thermostats, connect thermostat R to W/W1 at the
furnace control terminal block. (See Fig. 11.) For single-stage
thermostats, the control will determine, based on length of previ-
ous heating on and off cycles, when to operate in low- and
high-stage for optimum comfort. Setup switch-2 (SW-2) must be
in the factory-shipped OFF position. See Fig. 14 and Tables 6 and
7 for setup switch information.
BLOWER-
OFF
DELAY
LOW
HEAT
(ADAPTIVE
ALGORITHM)
HIGH
HEAT
ONLY
Fig. 14—Setup Switches on Furnace Control
(Factory Settings)
Table 6—Setup Switch Description
NORMAL
POSITION
OFF (Staged Gas Heat)
OFF (Single-Stage Thermostat)
ON, OFF
ON OFF
4
3
2
1
A93377
Turn switch on to obtain only high-gas-heat operation on any call
for heat regardless of whether R-W/W1, or R-W/W1, -W2 is
closed. SW-1 overrides SW-2.
Turn switch off for installations with single-stage thermostats; con-
trol selects low-gas-heat or high-gas-heat operation based on pre-
vious cycles. Turn switch on for installations with 2-stage thermo-
stats to permit only low-gas-heat operation in response to closing
R-W/W1. High-gas heat is supplied only when R to W/W1 and W2
are closed.
Switches control gas heating mode blower-off delay. (See Table
7.)
Table 7—Blower-Off Delay Setup
Switch (SW) Position
DESIRED HEATING
MODE BLOWER-OFF
DELAY (SEC)
90
135
180
225
If a 2-stage heating thermostat is to be used, move SW-2 to the ON
position at the end of the furnace installation. This overrides the
built-in control process for selecting high- and low-stage and
allows the 2-stage thermostat to select gas heating modes. The W2
from the thermostat must be connected to W2 on the control
terminal block. (See Fig. 12.)
This furnace is equipped with a manual reset limit switch in
the gas control area. The switch will open and shut off power
to the gas valve if a flame rollout or overheating condition
occurs in the gas control area. DO NOT bypass the switch.
Correct inadequate combustion-air supply, component fail-
ure, or restricted flue gas passageway before resetting the
switch.
Before operating the furnace, check each manual reset switch for
continuity. If necessary, press and release the button to reset the
switch.

SEQUENCE OF OPERATION

Using the schematic diagram in Fig. 16, follow the sequence of
operation through the different modes. Read and follow the
diagram very carefully.
NOTE: The GE ICM2+ BLWM speeds are infinitely variable
from 300 to 1400 rpm and are dynamically controlled to precisely
control airflow rate (CFM). The ICM2+ motor ramps to speed at
a controlled rate to reduce start-up noise perception (4 to 11 sec,
depending on the target CFM). The ICM2+ motor ramps down
slowly to a stop in the same time as the ramp-up time. ICM2+
ramp-up and ramp-down times are additive to blower-on and -off
delays, respectively. The ICM2+ is 115-v energized whenever
power is available at the furnace control, but operates only when
the 24-v motor control input(s) are on.
NOTE: If a power interruption occurs during a call for heat
(W/W1 or W/W1 and W2) and if the thermostat is still calling for
gas heating, the control will start a 90-sec blower only on period
2 sec after power is restored. The red LED will flash code 12
during the 90-sec period, after which the LED will be on
continuously as long as no faults are detected. The ICM2+ motor
will operate at low-gas heat CFM after a power interruption in
11
DESCRIPTION
OF USE
SETUP SWITCH
SW-3
OFF
OFF
ON
ON
SW-4
OFF
ON
OFF
ON