Carrier 58VLR Installation, Start-Up & Operating Instructions Download Page 10

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The variable-speed oil-fired unit will detect the humidistat
contacts opening on increasing humidity and reduce its airflow
to approximately 85 percent of nominal cooling mode airflow.
This reduction will increase the system latent capacity until
the humidity falls to a level which causes the humidistat
contacts to close. When the contacts close, the airflow will
return to 100 percent of the selected cooling airflow. To
activate this mode, remove the Jumper between DH and R of
the electronic board and wire in a standard humidistat.

Step 9—Filters

FIRE, CARBON MONOXIDE AND POISONING
HAZARD
Failure to follow this warning could result in fire, personal
injury, or death.
Never operate unit without a filter or with filter access door
removed.

An internal filter rack is provided as standard equipment with
furnace and is located in blower compartment. A sufficient
clearance should be provided for air filter access. Refer to Table 8
for filter rack flange dimensions for return air duct.

STARTUP, ADJUSTMENT, AND SAFETY CHECKOUT

Step 1—Operational Checkout

Installation of furnace is now complete. Run through the following
checkout and ensure each item has been performed.

1. Correct nozzle size has been selected for desired input rate.

2. Electrical wiring is completed according to Fig. 4.

3. Blower wheel support is removed.

4. Blower access door is secured in place.

5. Valve on oil supply line is open.

6. RESET BUTTON on primary control is pushed down.

7. Flame observation door is closed.

8. Thermostat is set for heating mode and set above room

temperature.

If all of the above items have been performed, set main electrical
switch to ON position and burner should start. When burner starts,
proceed to Combustion Check section.

Step 2—Sequence of Operation

Using schematic diagram in Fig. 4 follow the sequence of
operation through the different modes. Read and follow diagram
very carefully.

NOTE:

The GE ICM2 + blower motor speeds are infinitely

variable control airflow rate (CFM). The ICM2+ motor ramps to
speed at a controlled rate to reduce start-up noise perception. The
ICM2+ motor ramps down slowly to a stop in the same time as
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 furnace control, but
operates only when 24-v motor control input(s) are on.

OIL-FIRED HEATING MODE

1. The thermostat closes R to W.

2. Burner motor starts. The burner motor fan pre-purges the

combustion chamber and vent for 10 seconds, establishing the
combustion air pattern. During this time the solenoid valve
holding oil pressure will be approximately 100 psig. Solenoid
valve opens, allowing oil to flow through nozzle. At the same
time, the burner motor’s ignition coil produces spark.

3. Spark ignites oil droplets.

4. Cad cell senses flame and burner continues to fire. Ignition

transformer ceases sparking.

5. After the

″

Pre-Run

″

ON-delay time, the circulating air blower

starts.

6. The circulating air blower and burner motor remain ON until

the thermostat is satisfied. The solenoid valve remains open
(R40-F)

7. Thermostat is satisfied.

8. The solenoid valve closes and the burner fan motor shuts

down.

9. The furnace blower motor continues operating at 38 percent of

the heating airflow for an additional 3 min.

COOLING MODE

a. Single-Speed Cooling Outdoor Unit (See Fig. 5 for ther-

mostat connections.)

(1.) The thermostat closes R to G-and-Y circuits. The

R-Y/Y2 circuit starts outdoor unit, and R to G-and-
Y/Y2 circuits start the furnace BLWM on cooling
speed.

(2.) When thermostat is satisfied, the R to G-and-Y/Y2

circuits are opened. The outdoor unit stops, and
furnace BLWM continues operating at 50 percent of
the cooling airflow for an additional 180 sec.

b. Two-Speed Cooling Outdoor Unit (see Fig. 17 for thermo-

stat connections.)

(1.) The thermostat closes the R to G-and-Y1 circuits for

low cooling or closes the R to G-and Y1-and-Y/Y2
circuits for high cooling. The R to Y1 circuit operates
the outdoor unit on low-cooling speed. The R to
G-and-Y1 circuit operates the furnace BLWM at
low-cooling airflow 55 percent of single-speed cool-
ing airflow. The R to Y1-and-Y2 circuits operate the
outdoor unit on high-cooling speed, and the R to
G-and-Y/Y2-and-Y1 circuits operate furnace BLWM
at high-cooling airflow.

NOTE:

Y1 is found in the furnace and in the outdoor unit. The

furnace control CPU controls BLWM airflow by sensing only
G-and-Y1 for low-cooling airflow and G-and-Y1-and-Y/Y2-for
high-cooling airflow.

(2.) When the thermostat is satisfied, the R to G-and-Y1 or

R to G-and-Y1-andY/Y2 circuits open. The outdoor
unit stops, the furnace blower continues operating at
50 percent of the cooling airflow for an additional 3
min.

CONTINUOUS-BLOWER MODE

a. When R to G circuit is closed by the thermostat, BLWM

operates at 64 percent, 75 percent, or 86 percent of
single-speed cooling airflow; depend on dipswitch setting
(See Tables 13 and 14.)

b. During a call for heat, the BLWM will keep continuous-

blower speed until the end of

″

Short run

″

delay period.

Table 8—Filter Size (In.) and Quantity

UNIT

SIZE