Start-Up Procedures; General; Prime Condensate Trap With Water; Purge Gas Lines - Carrier 58MSA Installation, Start-Up, And Operating Instructions Manual

4. For approximately 2 sec, short (jumper) the C
on control to the TEST/TWIN 3/16-inch quick-connect termi-
nal on control until the LED goes out. Remover jumper from
terminals. (See Fig. 33.)
NOTE: If TEST/TWIN and C
longer than 2 sec, LED will flash rapidly and ignore component
test request.
Component test sequence is as follows:
a. LED will display previous status code 4 times.
b. Inducer motor starts and continues to run until Step g of
component test sequence.
c. After 7 seconds the hot surface igniter is energized for 15
sec, then off.
d. Blower motor operates on HEAT speed for 10 sec.
e. Blower motor operates on COOL speed for 10 sec.
f. Inducer motor stops.
5. Reconnect R lead to furnace control, remove tape from blower
door switch, and re-install blower door.
6. Operate furnace per instruction on outer door.
7. Verify furnace shut down by lowering thermostat setting
below room temperature.
8. Verify that furnace restarts by raising thermostat setting above
room temperature.

START-UP PROCEDURES

Step 1—General
1. Furnace must have a 115-v power supply properly connected
and grounded. Proper polarity must be maintained for correct
operation.
NOTE: Proper polarity must be maintained for 115-v wiring. If
polarity is incorrect, furnace control fault indicator light will flash
rapidly and furnace will not operate.
2. Thermostat wire connections at terminals R, W, G, and Y
must be made at 24-v terminal block on furnace control center.
3. Natural gas service pressure must not exceed 0.5 psig (14-in.
wc), but must be no less than 0.16 psig (4.5-in. wc).
4. Blower access panel must be in place to complete 115-v
electrical circuit to furnace.
→
These furnaces are equipped with a manual reset limit switch
in burner box. This switch will open and shut off power to gas
control valve if an overheat condition (flame rollout) occurs
in burner enclosure. Correct inadequate combustion-air sup-
ply or improper venting condition and reset switch. DO NOT
jumper this switch. Failure to follow this caution will result in
minor unit operation or performance satisfaction.
Before operating furnace, check flame rollout manual reset switch
for continuity. If necessary, press button to reset switch.
Step 2—Prime Condensate Trap with Water
→
Condensate trap must be PRIMED or proper draining may not
occur. The condensate trap has 2 internal chambers which can
ONLY be primed by pouring water into the inducer drain side
of condensate trap. Failure to follow this caution will result in
minor unit operation or performance satisfaction.
1. Remove upper inducer housing drain connection cap. (See
Fig. 44.)
-24v terminal
OM
-24v terminals are jumpered
OM
2. Connect field-supplied 1/2-in. ID tube to upper inducer
housing drain connection.
3. Insert field-supplied funnel into tube.
4. Pour 1 quart of water into funnel/tube. Water should run
through inducer housing, overfill condensate trap, and flow
into open field drain. (See Fig. 45.)
5. Remove funnel and tube from inducer housing and replace
drain connection cap and clamp.
Step 3—Purge Gas Lines
Never purge a gas line into a combustion chamber. Never test
for gas leaks with an open flame. Use a commercially
available soap solution made specifically for the detection of
leaks to check all connections. Failure to follow this warning
could result in fire, explosion, personal injury, or death.
If not previously done, purge lines after all connections have been
made and check for leaks.
Step 4—Adjustments

SET GAS INPUT RATE

Furnace gas input rate on rating plate is for installations at altitudes
up to 2000 ft.
In the U.S.A., the input ratings for altitudes above 2000 ft must be
reduced by 2 percent for each 1000 ft above sea level.
In Canada, the input ratings must be derated by 5 percent for
altitudes of 2000 ft to 4500 ft above sea level.
Furnace input rate must be within ±2 percent of input on furnace
rating plate adjusted for altitude.
1. Determine natural gas orifice size and manifold pressure for
correct input.
a. Obtain average gas heat value (at installed altitude) from
local gas supplier.
b. Obtain average gas specific gravity from local gas supplier.
c. Verify furnace model. Table 9 can only be used for model
58MSA furnaces.
d. Find installation altitude in Table 9.
NOTE: For Canadian altitudes of 2001 to 4500 ft, use U.S.A.
altitudes of 2001 to 3000 ft in Table 9.
e. Find closest natural gas heat value and specific gravity on
Table 9.
f. Follow heat value and specific gravity lines to point of
intersection to find orifice size and manifold pressure
settings for proper operation.
EXAMPLE: (0—2000 altitude)
Heating value = 1050 Btu/cu ft
Specific gravity = 0.62
Therefore: Orifice No. 45
Manifold pressure 3.6-in. wc
* Furnace is shipped with No. 45 orifices. In this example
all main burner orifices are the correct size and do not need
to be changed to obtain the proper input rate.
Check and verify burner orifice size in furnace. NEVER ASSUME
ORIFICE SIZE; ALWAYS CHECK AND VERIFY.
2. Adjust manifold pressure to obtain input rate.
NOTE: Manifold pressure must always be measured with burner
enclosure front REMOVED. Gas meter must always be clocked
with burner enclosure front INSTALLED.
36