Nordyne G6RL 90+, G6RC 90+, G6RD 93+ User Manual

Residential Gas Furnaces

Installation Instructions

G6RC Series 90+ Upflow Condensing Furnace
G6RD Series 93+ Upflow Condensing Furnace
G6RL Series 90+ Downflow Condensing Furnace

G6RC 90+, G6RD 93+ Upflow G6RL 90+ Downflow

!

WARNING:

Improper installation, adjustment, al­teration, service, or maintenance can
cause injury or property damage. Re­fer to this manual for assistance. For
additional information consult a quali­fied installer, service agency, or the
gas supplier.

These instructions are primarily intended to
assist qualified individuals experienced in
the proper installation of this appliance.
Some local codes require licensed installa­tion/service personnel for this type of equip­ment. Read all instructions carefully before
starting the installation.

DO NOT DESTROY. PLEASE READ CARE­FULLY AND KEEP IN A SAFE PLACE FOR
FUTURE REFERENCE.

!

FOR YOUR SAFETY:

Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.

!

FOR YOUR SAFETY:

WHAT TO DO IF YOU SMELL GAS:

• Do not try to light any appliance.

• Do not touch any electrical switch; do
not use any phone in your building.

• Immediately call your gas supplier
from a neighbor's phone. Follow the
gas supplier's instructions.

• If you cannot reach your gas supplier,
call the fire department.

• Extinguish any open flame.

Table of Contents

Furnace Specifications ......................................................................................................... ... 4-5

Furnace Airflow Data.......................................................................................................... 6-7

Installation Requirements ...................................................................................................... .... 8

Supply Air Plenum Installation ..................................................................................................9

Installation on a Concrete Slab ............................................................................................. 9

Installation on a Combustible Floor....................................................................................... 9

Circulating Air Supply............................................................................................................... 10

Return Air ............................................................................................................................ 11

Venting and Combustion Air Requirements .......................................................................... 11

Air Requirements for One-Pipe Installation ........................................................................ 13

Installation in An Unconfined Space ................................................................................... 13

Installation in A Confined Space ......................................................................................... 13

• Air From Inside .................................................................................................................. 1 3

• Air Directly Through An Exterior Wall ............................................................................... 14

• Outdoor Air Through Vertical Openings or Ducts ............................................................. 14

• Outdoor Air Through Horizontal Openings or Ducts......................................................... 14

Venting Requirements .............................................................................................................. 1 4

Vent Pipe Material ............................................................................................................... 14

Vent Pipe Length and Diameter .......................................................................................... 14

Vent Pipe Installation ..........................................................................................................15

Pipe Routing & Support....................................................................................................... 15

Location of Outdoor Terminations....................................................................................... 18

Horizontal Venting ............................................................................................................... 19

Vertical Venting ................................................................................................................... 20

Vent Freezing Protection..................................................................................................... 20

Concentric Vent Termination............................................................................................... 20

Drainage of Condensate From Furnace................................................................................. 21

Gas Supply and Piping........................................................................................................ 22

Leak Check.......................................................................................................................... 22

Conversion..................................................................................................................... ...... 23

High Altitude Application ..................................................................................................... 23

Natural Gas High Altitude Conversion ................................................................................ 23

LP/Propane Gas Sea Level and High Altitude Conversion ................................................ 23

Electrical Wiring ........................................................................................................................ 24

Line Voltage Wiring .............................................................................................................24

Low Voltage Wiring ............................................................................................................. 25

Start-up and Adjustments......................................................................................................... 25

Start-Up Procedure..............................................................................................................26

Verifying and Adjusting Firing Rate..................................................................................... 26

Verifying and Adjusting Temperature Rise ......................................................................... 27

Verifying Burner Operation.................................................................................................. 27

Verifying Operation of the Supply Air Limit Switch ............................................................. 29

Description of Components ..................................................................................................... 29

Maintenance ............................................................................................................................... 31

Combustion Air and Vent System ....................................................................................... 31

Air Filter(s) .................................................................................................................. ......... 31

Lubrication ........................................................................................................................... 31

Condensate Drain Assembly............................................................................................... 31

Blower Compartment........................................................................................................... 31

Heat Exchanger and Burner Maintenance.......................................................................... 31

Location of Major Components ........................................................................................... 32

System Operation Information ................................................................................................. 31

Sequence of Operation ....................................................................................................... 33

Furnace Fails to Operate .................................................................................................... 34

Twinning of Two Furnaces .................................................................................................. 34

Installation/Performance Checklist ......................................................................................... 35

4

FURNACE SPECIFICATIONS

Upflow G6RC & G6RD Furnaces

Combustion Air

Inlet

23 1/4"

A

Exhaust Vent

3/4"

3/4"

Figure 1. G6RC, G6RD Unit Dimensions

1 1/2" x 3 1/2" Dia.

43"

15"

1"

22 1/2"

19 3/4"

25 1/8"

Opening for

Gas Connection

7/8" Dia. Electric

Connection

25 1/4"

8"

Return Air Opening

(Side)

Combustion Air
Vent
(See Fig. 15
for sizes)

+

20 1/2"

33"

3/4"

B

C

Return Air Opening

(Bottom)

D

2 1/4"

3/4"

2" PVC
Exhaust
Vent
(See Fig. 15
for sizes)

30 1/4"

25 1/4"

27 5/8"

1 1/2" x 3 1/2" Dia.
Opening for
Gas Connection

7/8" Dia. Electric
Connection

+

8"

25 5/8"

1 1/4"

23"

28"

Condensate Drain Outlets

23"

Bottom Return Opening

Downflow G6RL Furnace

Combustion Air Inlet

24 1/2"

Exhaust Vent

3/4"

22 1/2"

Exhaust

Vent

2"

3/4"

A

B

3/4"

27 7/8"

3/4"

Figure 2. G6RL Unit Dimensions

24 7/8"

7/8" Dia. Electric

43"

1 1/2" x 3 1/2" Dia.

Gas Connection

1"

Connection

21 7/8"

Opening for

21 1/4"

8"

21 1/2"

15 1/2"

Condensate
Drain
Outlet

C

C

L

Bottom Supply Air Opening

(Side)

D

2 1/2"

Combusting

Vent

(3" for 80/100

2" for 40/60)

21 1/2"

Condensate

Drain

Outlet

24 7/8"

7/8" Dia.
Electric

Connection

1 1/2" x 2 1/2"

Knockout

For Gas

Connection

21 7/8"

10 1/4"

19 3/4"

Bottom Opening

5

6

1170

1060

1160

1050

1310

1080

1630

1400

1250

1700

1480

1320

1140

1650

1480

1320

1140

2070

1760

1470

1280

1030

gh*G6RC040C-08

g

G6RC040C-12

gh*G6RC060C-12

gh*G6RC080C-12

gh*G6RC080C-16

Med-High

g

G6RC100C-16

gh*G6RC120C-16

g

G6RC120C-20

Med-High

gh*G6RD040C-10

gh*G6RD060C-10

Model Input Motor Motor

Number (Btuh) Speed HP

Table 1. Furnace Airflow Data

Heating

40,000 Medium 1/5

40,000 Medium 1/3

60,000 Medium 1/3

80,000 Medium 1/3

80,000

100,000 Med-High** 1/2

120,000 Med-High** 1/2

120,000

40,000 Medium 1/3

60,000 Medium** 1/3

Hi

Low**

Hi

h*

Low**

Hi

Low**

Hi

Low**

Hi

Med-Low**

Low

h*

Hi

Med-Low

Low

Hi

Med-Low

Low

h*

Hi

Med-Low**

Low

Hi

Low**

Hi

Low

Ex ternal Static Pressure (Inches W ater Column)

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

CFM Rise CFM Rise CFM Rise CFM Rise CFM Rise CFM Rise CFM Rise CFM Rise

950 36 920 38 890 39 850 41 800 43 750 46 690 50 630 55
740 47 710 49 680 51 650 53 600 58 550 63 490 - 430 -

620 56 590 59 560 62 520 - 470 - 410 - 350 - 290 ­1330 - 1280 - 1230 ­1190 - 1160 - 1110 -

830 42 810 43 780 44 760 46 720 48 670 52 610 57 550 63
1310 - 1260 - 1210 ­1160 45 1120 46 1080 48

800 65 780 67 760 68 740 70 710 73 680 - 650 - 620 ­1490 46 1450 48 1390 50
1230 56 1200 58 1150 60

780 - 750 - 720 - 680 - 630 - 570 - 510 - 440 ­1840 - 1780 - 1700 41
1600 43 1560 44 1470 47

1/2

1380 50 1350 51 1300 53
1100 - 1050 - 1000 - 950 - 900 - 850 - 800 - 750 ­1910 45 1860 47 1780 49
1640 53 1620 53 1540 56
1440 60 1410 61 1370 63
1230 - 1210 - 1180 ­1860 56 1800 58 1730 60
1650 63 1610 65 1550 67
1440 72 1410 74 1380 75
1230 - 1210 - 1180 ­2260 - 2200 - 2140 -

3/4

1870 56 1840 56 1790 58
1540 67 1530 68 1510 69
1360 - 1330 - 1310 ­1050 - 1005 - 960 - 915 - 855 - 800 - 730 48 670 53

990 - 950 - 905 - 860 - 810 - 760 46 700 50 650 54

770 46 740 48 700 50 660 53 625 56 580 61 540 65 500 70
1175 45 1125 47 1075 49
1075 49 1040 51 995 53 950 56 900 59 840 63 790 67 720 73

800 66 770 69 745 71 710 74 670 - 630 - 580 - 530 -

- 1120 - 1030 - 940 37 850 41

- 1010 - 910 38 820 42 720 48

45 1100 47 1040 50 980 53 920 56
49 990 52 940 55 890 58 830 63

53 1210 57 1100 63 980 - 830 ­64 1010 69 910 - 810 - 680 -

42 1550 45 1470 47 1380 50 1290 54
49 1350 51 1280 54 1210 57 1150 60
55 1190 58 1120 62 1040 67 960 -

51 1620 53 1520 57 1420 61 1310 66
58 1420 61 1340 65 1250 69 1150 75
66 1270 68 1210 72 1140 - 1060 -

- 1090 - 1030 - 960 - 880 ­63 1570 66 1480 70 1380 75 1270 82
70 1410 74 1320 79 1230 84 1120 ­79 1280 81 1220 85 1150 - 1080 -

- 1090 - 1030 - 960 - 880 -

- 1990 - 1910 - 1810 57 1710 61
59 1710 61 1660 63 1610 65 1560 67
71 1430 73 1370 76 1300 80 1220 85

- 1250 - 1220 - 1190 - 1150 -

51 970 54 920 57 860 61 800 66

CAPACITIES —Furnace Airflow Data

Heating

g

Med-High

g

g

g

g

g

Med-High

1430

1295

1145

1000

1425

1265

1130

1500

1350

1195

1040

1945

1800

1540

1360

Model Input Motor Motor

Number (Btuh) Speed HP

G6RD080C-14 80,000

G6RD100C-14 100,000 Med-Hi

Table 2. Furnace Airflow Data

G6RD120C-14 120,000 Med-Hi

G6RD120C-19 120,000

G6RL040C-12 40,000 Medium 1/3

G6RL060C-12 60,000 Medium 1/3

G6RL080C-16 80,000 Med-High 1/2

G6RL100C-16 100,000 Med-High** 1/2

Hi

Med-Low**

Hi

Med-Low

Hi

Med-Low

Hi

Med-Low**

High*

Low**

High*

Low**

High*

Med-Low**

High*

Med-Low

h*

Low

h*

Low

h*

Low

h*

Low

Low

Low

1/2

h** 1/2

h** 1/2

3/4

Ex ternal Static Pressure (Inches W ater Column)

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

CFM Rise CFM Rise CFM Rise CFM Rise CFM Rise CFM Rise CFM Rise CFM Rise

1620 - 1560 45 1490 47
1450 49 1400 50 1350 52
1255 56 1225 57 1180 60
1080 65 1055 67 1030 68
1620 54 1555 57 1485 59
1430 62 1375 64 1330 66
1260 70 1220 72 1170 75
1085 - 1050 - 1015 - 970 - 935 - 890 - 850 - 800 ­1700 62 1635 65 1565 67
1510 70 1455 73 1405 75
1330 79 1280 - 1240 ­1140 - 1110 - 1075 ­2140 - 2070 - 2010 ­1955 - 1900 56 1850 57
1660 64 1620 65 1575 67
1450 73 1430 74 1400 75

1280 - 1210 - 1180 - 1140 - 1090 - 1070 - 1030 - 990 ­1140 - 1090 - 1060 - 1030 - 980 35 950 36 910 37 870 39

875 39 835 41 820 41 805 42 780 43 770 44 760 45 750 45
1260 40 1190 43 1155 44 1120 45 1075 47 1030 49 980 52 940 54
1120 45 1070 48 1040 49 1010 50 960 53 930 55 890 57 850 60

855 59 815 62 800 64 780 65 760 67 730 70 710 - 690 ­1635 - 1585 - 1525 - 1460 46 1400 48 1330 51 1260 54 1180 57
1435 47 1395 49 1350 50 1300 52 1255 54 1200 56 1150 59 1090 62
1230 55 1200 56 1165 58 1130 60 1090 62 1050 65 1000 68 960 71
1050 - 1035 - 1010 - 980 - 950 - 910 - 870 - 820 ­1600 53 1555 54 1500 56 1445 59 1380 61 1310 65 1240 68 1160 73
1475 57 1435 59 1385 61 1335 63 1290 66 1240 68 1190 71 1130 75
1320 - 1290 - 1250 - 1215 - 1170 - 1120 - 1070 - 1020 ­1150 - 1130 - 1110 - 1075 - 1040 - 1000 - 950 - 890 -

49 1365 52 1300 54 1240 57 1170 60
54 1240 57 1180 60 1120 63 1060 66
61 1105 64 1060 66 1020 69 980 72
70 960 73 920 - 870 - 820 ­62 1355 65 1290 68 1220 72 1160 ­70 1210 73 1150 - 1080 - 1010 -

- 1070 - 1010 - 950 - 890 -

70 1435 74 1370 77 1310 - 1240 ­78 1290 - 1230 - 1170 - 1100 -

- 1145 - 1100 - 1050 - 1000 -

- 1010 - 980 - 940 - 910 -

- 1870 56 1800 59 1730 61 1650 64
59 1740 61 1690 62 1630 65 1570 67
69 1495 71 1460 72 1410 75 1370 77
78 1340 79 1300 81 1270 83 1230 -

** Factory Set Cooling Speed
** Factory Set Heating Speed

- Not Recommended

NOTES: 1. Airflow rates of 1800 CFM or more require two return air connections. Data is for operation with filter(s).

2. Temperature rises in the table are approximate. Actual temperature rises may vary.

3. Temperature rises and airflows for external static pressures greater than 0.5 are for reference only.
These conditions are not recommended.

7

INSTALLATION REQUIREMENTS

(

)

Requirements and Codes

This furnace must be installed in accordance
with these instructions, all applicable local build­ing codes, and the current revision of the Na­tional Fuel Gas Code (ANSI-Z223.1, NFPA-54).
The current revision of the National Fuel Gas
Code is available from:

American National Standards Institute, Inc.
1430 Broadway

New York, New York 10018
Canada installations shall comply with CAN/
CGA-B149 installation codes, local plumbing or
waste water codes and other applicable codes.
Additional helpful publications are:

• NFPA-90A - Installation of Air Conditioning
and Ventilating Systems.

• NFPA-90B - Warm Air Heating and Air
Conditioning Systems.

These publications are available from:

National Fire Protection Association, Inc.
Batterymarch Park
Quincy, Massachusetts 02269

!

WARNING:

This furnace is not approved for in­stallation in mobile homes. Installa­tion in a mobile home could cause
fire, property damage, and/or personal
injury.

Model

Number

G6R(C,D)040C 40,000 14 1/4 12 3 /4 5 1/8 11 3/ 4 133
G6R(C,D)060C 60,000 14 1/4 12 3 /4 5 1/8 11 3/ 4 140
G6R(C,D)080C 80,000 19 3/4 18 1 /4 7 7/8 17 1/ 4 172
G6R(C,D)100C 100,0 00 19 3/4 1 8 1/ 4 7 7/8 17 1/ 4 180
G6R(C, D)12 0C 120,000 22 1/2 21 9 1/4 20 204

G6RL040C 40,000 14 1/ 4 1 2 3 /4 4 5/8 12 3/ 4 135
G6RL060C 60,000 14 1/ 4 1 2 3 /4 4 5/8 12 3/ 4 135
G6RL080C 80,000 19 3/ 4 1 8 1 /4 10 18 1/4 174
G6RL100C 100,000 19 3/4 1 8 1 /4 10 18 1/4 185

Furnace

Btuh

Table 3. Furnace Dimensions and Shipping Weights

AB

Dimensions (inches)

CD

Shipping

Weight

lbs

CLEARANCES TO COMBUSTIBLE MATERIALS

This furnace is Designed Certified by AGA/CGA Laboratories for the minimum clearances to
combustible material listed in Table 4. See the furnace name plate, located inside the furnace
cabinet, for specific model number and clearance information.

MINIM UM CL EARANCES TO COMBUS TI BLE MATERI AL

Furn ace Cabi net Mi n imu m Cl earan ces (In ch es)

Input Width

(Btuh) (Inches) Side Vent Back Top Front

40, 000 14 1/ 4 0 0 0 1 1*
60, 000 14 1/ 4 0 0 0 1 1*

80, 000 14 1/ 4 0 0 0 1 1*
100,000 19 3/ 4 0 0 0 1 1*
120,000 22 1/ 2 0 0 0 1 1*

* 24 inches is the minimum clearance for servicing.
36 inches is the recommended clearance for service.

Table 4. Minimum Clearances to Combustible Materials

8

Location

The furnace must be installed on a level surface,
and as close to the center of the air distribution
system as possible. See Table 3 for overall
dimensions to determine the required clear­ances in hallways, doorways, stairs, etc. to allow
the furnace to be moved to the installation point.
The furnace must be installed so that all electri­cal components are protected from water.
Minimum clearances to combustible materials
are listed in Table 4. Access for positioning and
servicing must be considered when locating the
unit. 24 inches is the minimum required clear­ance for servicing the unit. 30 inches is the
minimum required clearance for positioning the
unit. 36 inches is the recommended clearance
from the front of the unit. Please note that a
panel or door can be located such that the
minimum clearance on the rating plate is satis­fied, but that panel or door must be removable
and allow the appropriate clearance for your
installation.

This furnace is certified for use on wood flooring.
The furnace must be installed on a solid surface
and must be level front to back and side to side.
This furnace must not be installed directly on
carpeting, tile, or any combustible material other
than wood flooring.

DOWNFLOW WARNING
(G6RL Models):

The design of the downflow furnace is certified
for natural or propane gas and for installation on
non-combustible flooring. A special combus­tible floor sub-base is required when installing
on a combustible floor. Failure to install the sub­base may result in fire, property damage and
personal injury. The special downflow sub-bases
are factory supplied accessories, part numbers
902677 and 902974. When the furnace is in­stalled on a factory or site-built cased air condi­tioning coil, the sub-base is not necessary.
However, the plenum attached to the coil casing
must be installed such that its surfaces are at
least 1" from combustible construction.
A gas-fired furnace installed in a residential
garage must be installed so that the bottom of
the furnace is located a minimum of 15" from the
floor. The furnace must be located or protected
to avoid physical damage by vehicles.

HORIZONTAL INSTALLATIONS

The G6RC model furnaces are approved for
horizontal installation. Installation Kit #903568
is required for horizontal applications. Follow
the installation instructions in the kit for proper
conversion. NOTE: The G6RD and G6RL mod­els are NOT approved for horizontal installation.

SUPPLY AIR PLENUM INSTALLATION

A. Installation on a concrete slab - G6RL

1. Construct a hole in the floor per the
dimensions in Figure 3.

2. Place the plenum and the furnace as
shown in Figure 4.

B. Installation on a combustible floor - G6RL

1. Cut and frame the hole in the floor per
the dimensions in Figure 5.

2. Place the sub-base for combustible floors
over the hole with its duct collar extended
downward. Attach the supply air plenum to
the base in a manner which will ensure 1"
clearance to the flooring or other combustible
material. Place furnace on the combustible
base as shown in Figure 6.

3. When the furnace is installed on a factory
or site-built cased air conditioning coil,
the sub-base is not necessary. However,
the plenum attached to the coil casing
must be installed such that its surfaces
are at least 1" from combustible material.

18.75"

19.25"

Hole in

Floor

G6RL 080/100 G6RL 040/060

Figure 3. Opening for Concrete Slab

13.25"

19.25"

Hole in

Floor

9

Concrete

Furnace

Floor

Sheet

Metal

Plenum

Figure 4. Furnace on a Concrete Slab

18.75"

or 13.25"*

16.75"

or 11.25"*

* Smaller
dimensions for
G6RL 040/060

9.25"

2.0"

28.38"

18.75"

19.63"

Hole in

Floor

G6RL 080/100 G6RL 040/060

Figure 5. Opening in Wood Floor

Downflow

Sub-base

Furnace

13.25"

19.63"

Hole in

Floor

Wood

Floor

Sheet

Metal

Plenum

Figure 6. Furnace on a Wood Floor

CIRCULATING AIR SUPPLY

Plenums and air ducts must be installed in
accordance with the Standard for the Installa­tion of Air Conditioning and Ventilating Systems
(NFPA No. 90A) or the Standard for the Installa­tion of Warm Air Heating and Air Conditioning
Systems (NFPA No. 90B).

1.50"

1.58"

1 inch thick fiberglass 3 lb density

19.75"

or 14.25"*

Figure 7. Downflow Sub-Base Dimensions

If outside air is utilized as return air to the furnace
for ventilation or to improve indoor air quality, the
system must be designed so that the return air to
the furnace is not less than 50°F (10°C) during
heating operation. If a combination of indoor and
outdoor air is used, the ducts and damper system
must be designed so that the return air supply to
the furnace is equal to the return air supply under
normal, indoor return air applications.

When a cooling system is installed which uses
the furnace blower to provide airflow over the
indoor coil, the coil must be installed down­stream (on the outlet side) or in parallel with the
furnace.

If a cooling system is installed in parallel with the
furnace, a damper must be installed to prevent
chilled air from entering the furnace and con­densing on the heat exchanger. If a manually
operated damper is installed, it must be de­signed so that operation of the furnace is pre­vented when the damper is in the cooling posi­tion and operation of the cooling system is
prevented when the damper is in the heating
position.

19.63"

3"

10

!

WARNING:

Products of combustion must not be
allowed to enter the return air ductwork
or the circulating air supply. Failure to
prevent products of combustion from
being circulated into the living space
can create potentially hazardous con­ditions including carbon monoxide
poisoning that could result in per­sonal injury or death.

All return ductwork must be ad­equately sealed, all joints must be
taped, and the ductwork must be
secured to the furnace with sheet metal
screws. When return air is provided
through the bottom of the furnace, the
joint between the furnace and the re­turn air plenum must be sealed.

The floor or platform on which the
furnace is mounted must provide
sound physical support of the furnace
with no gaps, cracks, or sagging be­tween the furnace and the floor or
platform.

Return air and circulating air ductwork
must not be connected to any other
heat producing device such as a fire­place insert, stove, etc.

An important consideration in selecting one or
two pipe installation is the quality of the combus­tion air. Indoor air is sometimes contaminated
with various household chemicals which can
cause severe corrosion in the furnace combus­tion system. Some common sources of these
chemicals are detergents, bleaches, aerosol
sprays, and cleaning solvents. Unless indoor air
is known to be free of these materials, two pipe
installation is recommended.

Provisions must be made for adequate supply of
air for combustion and ventilation. For United
States installations, the adequacy of air provi­sions can be determined by consulting the cur­rent version of the National Fuel Gas Code
(ANSI Z223.1/NPFA-54). For Canadian installa­tions, requirements are specified in the National
Standard of Canada (CAN/CGA B149.1 & .2).
Consult local codes for special requirements.

NOTE: If the furnace is operated without ad­equate air for combustion and ventilation, it may
not perform properly. Furnace components may
be strained by high temperature and could fail
prematurely.

!

WARNING:

Furnace installation using methods
other than those described in the fol­lowing sections must comply with the
National Fuel Gas Code and all appli­cable local codes to provide sufficient
combustion air for the furnace.

Return Air

The return air ductwork may be connected to
any or all of the following: left side return, right
side return, or bottom return. Tables 1 and 2
show the airflow data for each furnace model.

Where maximum airflow is 1800 CFM or
more two openings must be used.

VENTING AND COMBUSTION AIR
REQUIREMENTS

NORDYNE condensing furnaces may be in­stalled with outdoor combustion air piped di­rectly to the furnace, or without such special
piping. Codes refer to the former as "direct vent"
or "two pipe" installation. Installation with air
taken from around the furnace is sometimes
referred to as "one pipe" installation - i.e. only
the vent (exhaust) pipe is provided.

G6RC/G6RD

Protective Screen

G6RL

Figure 8. Protective Screen for One Pipe

Installations

11