Check Safety Controls - Carrier 58GFA Installation, Starting-Up And Operation Manual

e. Canadian installations only—The Canadian ratings are
approved for altitudes up to 2000 ft for natural and propane
gases. High-altitude ratings are from 2001 ft to 4500 ft
above sea level. High-altitude rating includes a 10 percent
derate as required by Canadian standards. (See Table 8.)
PILOT FLAME
MANIFOLD
Fig. 12—Burner Flame
Table 8—Canadian Orifice Size
SEA LEVEL
GAS
0—2000
Natural 44
Propane 54
2. Set temperature rise.
Do not exceed the temperature rise range specified on the unit
rating plate. Determine the air temperature rise as follows:
a. Place duct thermometers in return and supply ducts as near
furnace as possible. Be sure thermometers do not "see" heat
exchangers so that radiant heat will not affect thermometer
readings. This is particularly important with straight-run
ducts.
b. When thermometer readings stabilize, subtract return-air
temperature from supply-air temperature to determine tem-
perature rise.
c. Adjust air temperature rise by adjusting blower speed.
Increase blower speed to reduce temperature rise. Decrease
blower speed to increase temperature rise.
d. To change blower motor speed selections for heating mode,
remove blower motor lead from control board HEAT
terminal. (See Fig. 10) Select desired blower motor speed
lead from 1 of the other terminals and relocate it to HEAT
terminal. See Table 9 for lead color identification. Recon-
nect original lead on SPARE terminal.
Disconnect the electrical power before changing the speed
tap. Failure to follow this warning can cause personal injury.
→
BURNER FLAME
BURNER
A84076
HIGH ALTITUDE
2001—4500 FT
45
55
12
Table 9—Speed Selector
COLOR SPEED
Black
Yellow (When
Medium-High
present)
Blue Medium-Low
Red
White Common
Recheck the temperature rise. It must be within the limits
specified on the unit rating plate. Recommended operation at
midpoint of rise or above.
3. Set thermostat heat anticipator.
The thermostat heat anticipator must be set to match the amp
draw of the electrical components in the R-W circuit. Accurate
amp draw readings can be obtained at thermostat subbase
terminals R and W. Fig. 13 illustrates an easy method of
obtaining the actual amp draw. The amp reading should be
taken after the blower motor has started. See the thermostat
manufacturer's instructions for adjusting the heat anticipator
and for varying the heating cycle length.
NOTE: When using an electronic thermostat, set the cycle rate for
3 cycles per hr.
THERMOSTAT SUBBASE
TERMINALS WITH
THERMOSTAT REMOVED
R Y W G
10 TURNS
FROM UNIT 24-VOLT
TERMINAL BLOCK
EXAMPLE: 5.0 AMPS ON AMMETER
10 TURNS AROUND JAWS
Fig. 13—Amp Draw Check With Ammeter

CHECK SAFETY CONTROLS

1. Check operation of gas shut-off control for 100 percent
shutoff.
NOTE: The furnace pilot must be lit to cause the thermocouple to
energize the thermal magnet circuit of gas valve GV, which
permits gas flow to the remaining portion of the valve. If the pilot
flame is extinguished, the thermocouple will no longer energize
the thermal magnet circuit of the gas valve GV. Gas flow to the
pilot and the main burners will cease until the pilot is manually
relit.
a. With furnace operating, unscrew pilot thermocouple lead
from gas valve. The pilot and main burner gas must shut
off. No gas should flow through valve.
FACTORY
ATTACHED TO
High Cool
Spare
Heat
Low Spare
COM
HOOK-AROUND
VOLT/AMMETER
= 0.5 AMPS FOR THERMOSTAT SETTING
A80201