MORTEX
PRODUCTS
INC
501
TERMINAL
RD
FORT
WORTH,
TX
76106
Page
14
Table 4: Gas Pipe Capabilities
Note: capabilities up to 14” W.C. (0.50 PSI (3.48 kPa)) Gas Pressure through Schedule 40 Pipe.
Cubic Feet per Hour with a pressure drop of 0.3” W C (0.0075 kPa).
Natural Gas – Specific Gravity – 0.60
Propane Gas – Specific Gravity – 1.50
SECTION V: LINE AND LOW VOLTAGE
WIRING
POWER SUPPLY
The furnace internal wiring is complete except for the power
supply and the thermostat wires. See wiring diagram and/or
Table 5, 6 and 7 for fuse and circuit current. The minimum
circuit breaker dice is 15 amps. A fused switch is recommended
to be mounted on the side of the unit fused for the proper
current. Multiply 1.25 to the current value shown in the tables
below for the proper breaker size. The minimum supply wire
size is 14 gauge and the minimum ground wire size is 14 gauge.
The use of cable connectors on incoming power supply wires to
relieve any strain on wiring is recommended.
The furnace must be electrically grounded in accordance with
local codes or, in absence of local codes, with the National
Electrical Code, ANSI/NFPA 70, and / or the Canadian
Electrical Code CSA22.1, Part 1, if an external electrical source
is utilized.
Proper methods for field installing electrical wiring:
i.
Between the furnace and devices not attached to the
furnace.
ii.
Between the separate devices that are field installed
and located.
iii.
Exterior to the furnace between the burner assembly
and a limit control or a fan control.
Wiring shall conform to the temperature limitations of 63
°
F
(35
°
C) rise.
The furnace shall be installed so the electrical components shall
be protected from water.
Table 5 Ratings & Physical Electrical Data
to 20
1/2
5/8
Natural
to 60
1/2
-
60
to 70
-
3/4
to 40
1/2
-
Propane
to 70
-
5/8
to 80
1/2
-
to 20
-
5/8
to 50
1/2
-
Natural
to 60
-
3/4
70
to 80
3/4
-
to 30
1/2
-
Propane
to 60
-
5/8
to 80
1/2
-
MODEL
G18D
TYPE OF
GAS
LENGTH
(FT)
PIPE SIZE
(IN)
PIPE SIZE
IN OD
to 20
-
5/8
to 50
1/2
-
Natural
to 60
-
3/4
77
to 80
3/4
-
to 30
1/2
-
Propane
to 60
-
5/8
to 80
1/2
-
to 40
1/2
3/4
Natural
to 50
-
3/4
90
to 30
1/2
-
Propane
to 40
-
5/8
to 60
1/2
3/4
PIPE SIZE
(IN)
PIPE SIZE
IN OD
MODEL
G18D
TYPE OF
GAS
LENGTH
(FT)
Input
Output
Cabinet Width
Max. External
Static Pressure,
Duct inwc
AFUE
Air Temp.
Rise Range
60,000
48,000
19.5"
0.30
80%
40-70
70,000
56,000
19.5"
0.30
80%
40-70
77,000
61,600
19.5"
0.30
80%
40-70
90,000
72,000
19.5"
0.30
80%
45-75
Input
Max Outlet
Air Temp
Blower Size
Max. Over-
Circuit Protection
60,000
170
10 x 8
15
70,000
170
10 x 8
15
77,000
170
10 x 8
15
90,000
175
10 x 8
15
Min. Wire Size (AWG)
@ 75 FT One Way
14
14
14
14
USE
COPPER
CONDUCTORS
ONLY.
