Carrier 58PAV - Manual (Page 13)

Table 9—Speed Selector
SPEED TAP NO.*
Common C
High 1
Med-High 2
Med-Low 3
Low 4t
* White wire from control box to oommon; blaok wire from oontrol box to oooiing
speed seiection; red wire from control box to heating and constant fan speed
seiection.
t Speed tap No. 4 is not used on 045-08 and 070-08 units.
A CAUTION
Recheck the temperature rise. It must be within the limits
specified on the unit rating plate. Recommended operation is
at midpoint of rise or above.
3. Set thermostat heat anticipator.
The thermostat heat anticipation 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 instmctions 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.
CHECK SAFETY CONTROLS — The flame sensor, gas valve,
and pressure switch were all checked in the Start-up section as part
of normal operation.
1. Check primary limit control.
Fig. 13—Amp Draw Check With Ammeter
This control shuts off the combustion control system and
energizes the circulating-air blower motor if the furnace
overheats.
The preferred method of checking the limit control is to
gradually block off the return air after the furnace has been
operating for a period of at least 5 minutes. As soon as the
limit has shut off the burners, the return-air opening should be
unblocked. By using this method to check the limit control, it
can be established that the limit is functioning properly and
will operate if there is a motor failure.
2. Check draft safeguard switch.
The purpose of this control is to permit the safe shutdown of
the furnace during certain blocked vent conditions.
a. Disconnect power to furnace and remove vent connector
from furnace outlet collar. Be sure to allow time for vent
pipe to cool down before removing.
b. Restore power to furnace and set room thermostat above
room temperature.
c. After normal start-up, allow furnace to operate for 2
minutes, then block (100 percent) flue outlet. Furnace
should cycle off within 2 minutes.
d. Remove blockage and reconnect vent pipe to furnace outlet
collar.
e. Wait 5 minutes and then reset draft safeguard switch.
3. Check pressure switch.
This control proves operation of draft inducer blower.
a. Turn off 115-v power to furnace.
b. Remove control door and disconnect inducer motor lead
wires from wire harness.
c. Turn on 115-v power to furnace.
d. Close thermostat switch as if making normal furnace start.
If the hot surface ignitor does not glow, then the pressure
switch is functioning properly.
e. Turn off 115-v power to furnace.
f. Reconnect inducer motor wires, replace control door, and
turn on 115-v power.
CHECKLIST
1. Put away tools, instruments, and clean up debris.
2. Verify manual reset switches have continuity.
3. Ensure blower and control access doors are properly installed.
4. Cycle test furnace with room thermostat.
5. Chenk operation of accessories per manufacturer’s instrac-"
tions.
6. Review User’s Manual with owner.
7. Leave literature packet near furnace.
13