Carrier F96CTN, Installation, Start-Up, Operating, Service And Maintenance Instructions

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F96CTN and G96CTN (Series A): Installation, Start-up, Operating, Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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7. Replace orifice with correct size, if required as shown in Table 20 .
Use only factory-supplied orifices. See EXAMPLE 1.
Example 1
EXAMPLE: 0 - 2000 ft. (0 - 609.6M) altitude
Heating value = 1050 Btu/cu ft.
Specific gravity = 0.62
Therefore: Orifice No. 44
(Furnace is shipped with No. 44 orifices. In this example, all main
burner orifices are the correct size and do not need to be changed to
obtain proper input rate.)
Manifold pressure: 3.4-in. w.c. (847 Pa) for high heat, 1.4-in. w.c. (349
Pa) for low heat
NOTE: To convert gas manifold table pressures to Pascals, multiply the
in. w.c. value by 249.1 Pa/in. w.c. (1 in. w.c. = 249.1 Pa).
Check Inlet Gas Pressure
The inlet gas pressure must be checked with the furnace operating in
maximum heat. This is necessary to make sure the inlet gas pressure
does not fall below the minimum pressure of 4.5 in. w.c. for natural gas.
The maximum inlet gas pressure is 13.6 in. of water column. If the inlet
pressure is too low, you will not be able to adjust the manifold pressure
to obtain the proper input rate. To check the inlet gas pressure:
1. Make sure the gas supply is turned off to the furnace and at the
electric switch on the gas valve.
2. Loosen set screw on inlet tower pressure tap no more than one full
turn with a 3/32-in. hex wrench, or remove the 1/8 in. NPT plug
from the inlet pressure tap on the gas valve.
3. Connect a manometer to the inlet pressure tap on gas valve.
4. Turn on furnace power supply.
5. Turn gas supply manual shutoff valve to ON position.
6. Turn furnace gas valve switch to ON position.
7. Jumper the R to W/W1 and W2 thermostat connections at the
furnace control board.
8. When main burners ignite, confirm inlet gas pressure is Between
4.5 in. w.c. and 13.6 in. w.c.
9. Remove jumper across thermostat connections to terminate call for
heat. Wait until the blower off delay is completed.
10. Turn furnace gas valve electric switch to OFF position.
11. Turn gas supply manual shutoff valve to OFF position.
12. Turn off furnace power supply.
13. Remove manometer from the inlet pressure tap of the gas valve.
14. Tighten set screw on inlet tower pressure tap with 3/32-in. hex
wrench, or if ⅛ -in. NPT plug was removed, apply pipe dope
sparingly to end of plug and re-install in the gas valve.
Adjust Manifold Pressure
1. Adjust manifold pressure to obtain low fire input rate. See Fig. 63 .
a. Turn gas valve ON/OFF switch to OFF.
b. Loosen set screw on manifold tower pressure tap with 3/32-in.
hex wrench, or remove the 1/8 inch NPT plug from the manifold
pressure tap on the gas valve.
c. Connect a water column manometer or similar device to
manifold pressure tap.
d. Turn gas valve ON/OFF switch to ON.
e. Move setup SW1-2 on furnace control to ON position to lock
furnace in low-heat operation. See Fig. 62 and Fig. 38 .
f. Manually close blower door switch.
g. Jumper R and W/W1 thermostat connections on control to start
furnace. See Fig. 38 .
h. Remove regulator adjustment cap from low heat gas valve
pressure regulator and turn low-heat adjusting screw (3/16 or
smaller flat-tipped screwdriver) counterclockwise (out) to
decrease input rate or clockwise (in) to increase input rate. See
Fig. 63 .
A170117
Fig. 63 – Gas Valve with Tower Pressure Ports
i. Install low-heat regulator adjustment cap.
j. Move setup switch SW1-2 to OFF position after completing
low-heat adjustment.
k. Leave manometer or similar device connected and proceed to
Step 2.
2. Adjust manifold pressure to obtain high fire input rate. See Fig. 63 .
a. Jumper R to W/W1 and W2 thermostat connections on furnace
control. This keeps furnace locked in high-heat operation.
b. Remove regulator adjustment cap from high-heat gas valve
pressure regulator and turn high heat adjusting screw (3/16-in. or
smaller flat-tipped screwdriver) counterclockwise (out) to
decrease input rate or clockwise (in) to increase input rate. See
Fig. 63 .
c. When correct input is obtained, replace caps that conceal gas
valve regulator adjustment screws. Main burner flame should be
clear blue, almost transparent. See Fig. 64 .
d. Remove jumpers R to W/W1 and R to W2.
NOTICE
!
If orifice hole appears damaged or it is suspected to have been redrilled,
check orifice hole with a numbered drill bit of correct size. Never
redrill an orifice. A burr-free and squarely aligned orifice hole is
essential for proper flame characteristics.
WARNING
!
FIRE HAZARD
Failure to follow this warning could result in personal injury, death,
and/or property damage.
Inlet pressure tap set screw must be tightened and ⅛ -in. NPT pipe plug
must be installed to prevent gas leaks.
NOTICE
!
DO NOT set low-heat manifold pressure less than 1.3-in. w.c. (324 Pa)
or more than 1.7 in. w.c. (423 Pa) for natural gas. If required manifold
pressure is outside this range, change main burner orifices to obtain
manifold pressure in this range.
NOTICE
!
DO NOT set high-heat manifold pressure less than 3.2-in. w.c. (797 Pa)
or more than 3.8 in. w.c. (947 Pa) for natural gas. If required manifold
pressure is outside this range, change main burner orifices to obtain
manifold pressure in this range.