Carrier 070-08/024070 Installation, Start-Up, Operating And Service And Maintenance Instructions page 36

%
BURNER J
ORIFICE
Table 9--Speed Selection
COLOR SPEED AS SHIPPED
White Common BLW
Black High COOL
Yellowt Med-High SPARE
Blue Med-Low HEAT
Red Low* SPARE
* Continuous-blower speed-as shipped default
t Not available on 1/5 HP motors.
A93059
Fig. 53--Orifice Hole
a. Place theru]ou]eters in return and supply ducts as close to
l_lrnace as possible. Be sure thermometers do not see
radiant heat from heat exchangers. Radiant heat aflccts
teu]perature rise readings. This practice is particularly
important with straight-run ducts.
b. When thermon]eter readings stabilize, subtract return-air
teu]perulure from supply-air temperature to determine air
teu]perulure rise.
NOTI::: Blower access door umst be installed %r proper teu]pera-
ture rise u]eusureu]eBt.
NOTF:: If the teu]perature rise is outside this range, first check:
1.) Gas input Ik>r heating operation.
2.) Derate lbr altitude il applicable.
3.) Return and supply ducts lbr excessive restrictions causing static
pressures greater than 0.50-in. we.
4.)Dirty filter.
ELECTRICAL SHOCK HAZARD
Failure to lollow this warning could result in personal inju W
or death.
Disconnect 115-v electrical power beik>re changing speed tap.
c. Adjust air ten]perature rise by adjusting blower speed.
Increase blower speed to reduce teu]perature rise. Decrease
blower speed to increase temperature rise.
d. Turn thermostat down below teen] teu]perumre and re-
move blower access door.
e. To change u]otor speed selection lot heating, ren]ove
blower n]otor lead fi'on] control HEAT ten]dnal (See Fig.
24.) Select desired blower u]otor speed lead l]'on] one of the
other ten]]inals and relocate it to the HEAT tem]inul (See
Table 9 Ik_r lead color identification). Reconnect original
lead to SPARE teru]inal.
f. Repeat steps a through e.
g. When correct input rate and temperature rise is achieved,
turn gas valve ON/OFF switch to OFF.
h. Reu]ove munon]eter or similar device l]*om gas valve.
i. Reinstall muniik_ld pressure tap plug in gas valve.
FIRE HAZARD
Failure to %llow this warning coiuld result in personal injury,
death, and/or property damage.
Reinstall mani%ld pressure tap plug in gas valve to prevent
gas leak.
k. Turn gas valve ON/OFF switch to ON.
FURNACE OVERHEATING HAZARD
Failure to this caution u]ay result in 17educed l_.trnace lilk:.
Recheck ten]perature rise. It nmst be within liudts specified
on the rating plate. Reconnnended operation is at the mid-
point of rise range or slightly above
6. Set theru]ostal heat anticipator.
a. Mechanical thern]ostat Set thermostat heat anticipator to
match the an]p draw of the electrical components in the
R-W circuit. Accurate amp draw readings can be obtained
at the wires normally connected to thern]ostat subbase
terlninals, R and W. The therlnostat anticipator should
NOT be in the circuit while measuring current.
(1.) Remove thermostat fl'om subbase or from wall.
(2.) Connect an amp meter as shown in Fig. 54 across the
R and W subbase terminals or R and W wires at wall.
(3.) Record amp draw across terminals when lurnace is in
heating and after blower starts.
(4.) Set heal anticipator on thermostat per thermostat
instructions and install on subbase or wall.
b. Electronic thermostat: Set cycle rate %r 4 cycles per hr.
7. Adjust blower oK delay
The blower off delay has 4 adjustable settings l]'om 90 sec to
180 sec. The blower off delay jumpers arc located on the
l?lrnace control board. (See Fig. 24.)
To change the blower off delay setting, move the jumper from
one set of pins on the control to the pins used liar the selected
blower off delay. Factory off delay setting is 120 sec.
8. Set airflow CFM lbr cooling
Select the desired blower n]otor speed lead %r cooling
airflow. See Table 5-Air Delivery-CFM (With Filter). See
Table 9 %r lead color identification.
Step 4--Check Safety Controls
The flame sensor, gas valve, and pressure switch were all checked
in the Start-up procedure section as part of noru]al operation.
1. Check Main Limit Switch(es)
This control shuts off combustion control system and ener-
gizes air-circulating blower motor, if furnace overheas. By
using this u]ethod to check liudt control, it can be established
that limit is limctioning properly and will operate if there is a
restricted duct systeu] or n]otor faihn'c. If lindt control does
not function during this test, cause must be detemdned and
corrected.
a. Run furnace liar at least 5 n]inutes.
b. Gradually block off return air with a piece of cardboard or
sheet u]etal until the liu]it trips.
j. Reinstall blower access door if reu]oved.
36