Adjusting Or Checking Furnace Input; Condensate Drain; Wiring; Power Supply - Trane Oxbox 14 Seer Series Installation Instructions Manual

4.3 ADJUSTING OR CHECKING FURNACE INPUT

- Natural Gas Inlet Pressure 5" -10.5" W.C.
- LP Gas Inlet Pressure 11" -13" W.C.
- Natural Gas Outlet Pressure 3.5" W.C.
- LP Gas Outlet Pressure 10" W.C.
Supply and manifold pressure taps are located on the gas valve body
1/8" N.P.T.
Use a properly calibrated manometer gauge for accurate gas
pressure readings.
Only small variations in the gas flow should be made by means of the
pressure regulator adjustment. Furnaces functioning on LP gas must
be set by means of the tank or branch supply regulators. The furnace
outlet pressure should be set at 10" W.C. at the gas control valve.
To adjust the pressure regulator, remove the regulator cap and turn
the adjustment screw clockwise to increase pressure or counter-
clockwise to decrease pressure. Then replace the regulator cap
securely.
Any necessary major changes in the gas flow rate should be made by
changing the size of the burner orifices. To change orifice spuds, shut
off the manual main gas valve and remove the gas manifold.
For elevations up to 2000 feet, rating plate input rating apply. For high
altitudes (elevations over 2000 feet), see conversion kit index for
derating and orifice spud sizes.
Check of input is important to prevent over-firing of the furnace
beyond its designated input, NEVER SET INPUT ABOVE THAT
SHOWN ON THE RATING PLATE. Use the following formula to
determine input rate.
Heating value of gas (BTU/Cubic Ft) ×3600
C.F.H. Required=
Time of Seconds (for 1 Cubic Ft.) of gas
Start the furnace and measure the time required to burn on cubic foot
of gas. Prior to checking the furnace input, make certain that all other
gas appliances are shut off, with the exception of pilot burners. Time
the meter with only the furnace in operation.
IMPORTANT NOTE FOR ALL ALTITUDES ABOVE 2000 FEET: The
main burner orifices in your furnace and in these kits are sized for the
nameplate input and intended for installations at elevations up to
2000 feet in the USA or Canada, or for elevations of 2000-4500 feet in
Canada if the unit has been derated at the factory. For elevations
above 2000 feet IN THE USA ONLY (see ANSI-Z223.1), the burner
orifices must be sized to reduce the input 4% for each 1000 feet
above sea level.
NOTICE: Derating of the heating input for high altitude in the field is
unlawful in Canada (refer to CAN/CGA 2.17). Units installed in
altitudes greater than 2000 feet must be shipped from the factory or
from a factory authorized conversion station with the heating input
derated by 10% so as to operate properly in altitudes from 2000-4500
feet.

4.4 CONDENSATE DRAIN

The evaporator coil condensate drain ends with a threaded 3/4"
nominal PVC stub. A trap is built in for proper condensate drainage
and to prevent debris from being drawn into the unit. Do not connect
the drain to a closed sewer line. It is recommended that a PVC
cement not be used so that the drain line can be easily cleaned in the
future.
IMPORTANT: Do not install an external trap. Doing so can cause
improper drainage of the condensate and result in flooding within the
unit.

5.0 WIRING

5.1 POWER SUPPLY

WARNING
Turn off the main electrical power at the branch circuit disconnect
closest to the unit before attempting any wiring. Failure to do so
can cause electrical shock resulting in personal injury or death.
1. All wiring should be made in accordance with the National Electrical
Code. Consult the local power company to determine the
availability of sufficient power to operate the unit. Check the
voltage at power supply to make sure it corresponds to the unit's
rated voltage requirement. Install a branch circuit disconnect near
the rooftop, in accordance with the N.E.C., C.E.C. or local codes.
installation & owner's manual
18
2. It is important that proper electrical power is available at the unit.
Voltage should not vary more than 10% from that stamped on the
unit nameplate. On three phase units, phases must be balanced
within 3%.
3. For branch circuit wiring (main power supply to unit disconnect), the
minimum wire size for the length of run can be determined from
Table 5-1 using the circuit ampacity found on the unit rating plate.
Use the smallest wire size allowable in Table 5-1 from the
disconnect to unit. The disconnect must be in sight and readily
accessible of the unit.
Table 5-1: Branch circuit copper wire size (in.)
15 20
200 6 4
150 8 6
Supply wire
length (Ft.)
100 10 8
50 14 12
NOTES:
1. Wire size based on 60°C rated wire insulation and 30°C Ambient
Temp.
2. For more than 3 conductors in a raceway or cable, see the N.E.C.
for derating the ampacity of each conductor. When installed, the
unit must be electrically grounded in accordance with local codes
or, in the absence of local codes, with the National Electrical Code,
ANSI/NFPA 70, if an external electrical source is utilized.
IMPORTANT: This unit is approved for use with copper
conductors only connected to unit contactor. Warranty may be
jeopardized if aluminum wire is connected to unit contactor.
Special instructions apply
conductors: Warranty is void if connections are not made per
instructions.
Attach a length (6" or more) of recommended size copper wire to the
unit contactor terminals L1 and L3 for single phase.
Select the equivalent aluminum wire size from the tabulation below:
Splice copper wire pigtails to aluminum wire with U.L. recognized
connectors for copper-aluminum splices. Please exercise the follow
ing instructions very carefully to obtain a positive and lasting
connection:
1. Strip insulation from aluminum conductor.
2. Coat the stripped end of the aluminum wire with the recommended
inhibitor, and wire brush the aluminum surface through inhibitor.
INHIBITORS: Brundy-Pentex "A"; Alcoa-No. 2EJC; T & B-KPOR
Shield.
3. Clean and recoat aluminum conductor with inhibitor.
4. Make the splice using the below listed wire nuts or split bolt
connectors.
5. Coat the entire connection with inhibitor and wrap with electrical
insulating tape.
AWG Copper AWG Aluminum
Wire Size Wire Size
#12 #10
#10 #8
#8 #6
#6 #4
#4 #2

5.2 HOOK-UP

To wire unit, refer to the following Fig. 5-1.
Wiring to be done in the field between the unit and devices not
attached to the unit, or between separate devices which are field
installed and located, shall conform with the temperature limitation for
Type T wire [63°F rise] when installed in accordance with the
manufacturer's instructions.
Branch circuit ampacity
25 30 35 40 45
4 4 3 3 2
6 4 4 4 3
8 6 6 6 4
10 10 8 8 6
for power wiring aluminum
Connector Type and Size
(or equivalent)
T & B Wire Nut PT2
T & B Wire Nut PT3
Sherman Split Bolt TSP6
Sherman Split Bolt TSP4
Sherman Split Bolt TSP2
50
2
3
4
6