Purge Gas Lines; Sequence Of Operation - Carrier 58MXA Installation, Start-Up, And Operating Instructions Manual

A99118
Fig. 48--Inducer Housing Drain Tube Cap
3. Insert field=supplied flmnel into tube.
4. Pour 1 quart of water into funnel/robe. Water sho_fld run
through inducer housing, overfill condensate trap, and flow
into open field drain. (See Fig 49.)
5. Remove flmnel and robe from inducer housing and replace
&ain connection cap and clamp.
A99119
Fig. 49--Filling Condensate Trap
37
Step 3--Purge Gas Lines
If not previously done, purge lines after all connections have been
made and check tbr leaks.
iiiii_, 1,
_: iiiiiil,.
FIRE AND EXPLOSION HAZARD
Failure to follow this warning could result in a fire, explosion,
personal it!ire'y, or death.
Never purge a gas line into a combustion chamber. Never test
_br gas leaks with an open flame Use a commercially
available soap solution made specifically _br the detection of
leaks to check all connections.
Step 4--Sequence of Operation
F! RNACE MAY NOT OPERATE
Failure to _bllow this caution may result in flu'nace operation
stopping and water pipes fi'eezing during cold weather
Furnace control must be grounded _br proper operation, or
control will lock out Control is grounded d_rough
green yellow wire connected to gas valve and burner box
screw.
Using schematic diagram, follow sequence of operation through
di_:_krent modes. (See Fig. 30.) Read and follow wiring diagram
carefully.
NOTE: Ifa power interruption occurs during a call [br heat (W),
the control will start a 90=second blower=only ON period two
seconds after power is restored, if the thermostat is still calling _br
gas heating. The Amber status code LED light will flash code 12
during the 90=second period, after which the LED will be ON
continuous, as tong as no faults are detected After the 90=second
period, the fl/mace will respond to the thermostat normally.
The blower door must be installed _br power to be conducted
through the blower door interlock switch ILK to the furnace
contloi CPU, transformer TRAN, inducer motor IDM, blower
motor BLWM, hot=surfitce igniter HSI, and gas valve GV.
HEATING MODE
(See Fig. 27 for thermostat connections.)
The wall thermostat "calls for heat," closing the R to W
circuit. The furnace control performs a self=check, verifies the
pressure switch contacts PRS are open, and starts the inducer
motor IDM.
a. Inducer Prepurge Period= As the inducer motor IDM
comes up to speed, the pressure switch contacts PRS close
to begin a 15-second prepurge period.
b. Igniter '_¥arm-[ p- At the end of the prepurge period, the
Hot-Surface igniter HSI is energized for a 17=second
igniter warm-up period.
c. Trial-Nr-Ignition Sequence- When the igniter warm-up
period is completed the main gas valve relay contacts
GVR-I and -2 close to energize the gas valve GV, the gas
valve opens, and 24 vac power is supplied for a field-
installed humidifier at the HUM terminal. The gas valve
GV permits gas flow to the burners where it is ignited by
the Hot Surfhce Igniter HSI. Five seconds after the GVR=I
closes, a 2-second flame period begins. The HSI igniter
will remain energized until the flame is sensed or until the
2-second flame proving period begins.