292278-UIM-A-0108
14
Unitary Products Group
ACCESSORY CONNECTIONS
The furnace control will allow power-switching control of various acces-
sories. Refer to Figure 10, for connection details.
ELECTRONIC AIR CLEANER CONNECTION
Two 1/4” (6.4 mm) spade terminals (EAC and NEUTRAL) for electronic
air cleaner connections are located on the control board. The terminals
provide 115 VAC (1.0 amp maximum) during circulating blower opera-
tion.
HUMIDIFIER CONNECTION
Two 1/4” (6.4 mm) spade terminals (HUM and NEUTRAL) for humidifier
connections are located on the control board. The terminals provide 115
VAC (1.0 amp maximum) during heating system operation.
TWINNING
These furnaces are not to be twinned. If more than one furnace is
needed in an application, each furnace must have its own complete
duct system and its own wall thermostat.
SECTION VII: COMBUSTION AIR AND
VENT SYSTEM
COMBUSTION AIR AND VENT SAFETY
This Category IV, dual certified direct vent furnace is designed for resi-
dential application. It may be installed without modification to the con-
densate system in a basement, garage, equipment room, alcove, attic
or any other indoor location provided the space temperature is 32 °F
(0°C) or higher and where all required clearance to combustibles and
other restrictions are met. The combustion air and the venting system
must be installed in accordance with Section 5.3, Air for Combustion
and Ventilation, of the National Fuel Gas Code Z223.1/NFPA 54 (latest
edition), or Sections 7.2, 7.3 or 7.4 of CSA B149.1, National Gas and
Propane Codes (latest edition) or applicable provisions of the local
building code and these instructions.
IMPORTANT:
The “VENT SYSTEM” must be installed as specified in
these instructions for Residential and Non HUD Modular Homes. The
sealed combustion air / vent system is the only configuration that can
be installed in a Non HUD Modular Home.
COMBUSTION AIR/VENT PIPE SIZING
The size of pipe required will be determined by the furnace model, the
total length of pipe required and the number of elbows required.
Table 6 lists the maximum equivalent length of pipe allowed for each
model of furnace. The equivalent length of elbows is shown in Table 7.
The equivalent length of the vent system is the total length of straight
pipe PLUS the equivalent length of all of the elbows.
The following rules must also be followed:
1.
Long radius (sweep) elbows are recommended. Standard elbows
may be used, but since they have a longer equivalent length, they
will reduce the total length of pipe that will be allowed. Short radius
(plumbing vent) elbows are not allowed. The standard dimensions
of the acceptable elbows are shown below.
2.
The maximum equivalent length listed in Table 6 is for the vent pip-
ing and the air intake piping separately. For example, if the table
allows 65 equivalent feet for a particular model, then the vent can
have 65 equivalent feet of pipe, AND the combustion air intake can
have another 65 equivalent feet of pipe.
3.
Three vent terminal elbows (two for the vent and one for the com-
bustion air intake) are already accounted for and need not be
included in the equivalent length calculation.
4.
All combustion air and vent pipe must conform to American
National Standards Institute (ANSI) and American Society for Test-
ing and Materials (ASTM) standards D1785 (Schedule 40 PVC),
D2665 (PVC-DWV), F891 (PVC-DWV Cellular Core), D2261
(ABS-DWV) or F628 (Schedule 40 ABS). Pipe cement and primer
must conform to ASTM Standard D2546 (PVC) or D2235 (ABS). If
ABS pipe is to be used, any joint where ABS pipe is joined to PVC
pipe must be glued with cement that is approved for use with
BOTH materials. Metallic materials must not be used for venting or
air intake.
5.
If a flexible connector is used in the vent system, it must be made
of a material that is resistant to acidic exposure and to at least
225° F temperature. Flexible connectors are also allowed in the
combustion air pipe.
6.
All models are supplied with 2" vent connections. When the pipe
must be increased to 3" diameter, the transition from 2" to 3" must
be done as close to the furnace as possible. For upflow models,
the transition from 2" to 3" should be done immediately above the
furnace. For downflow or horizontal models, the transition from 2"
to 3" pipe should be done immediately after the drain tee or drain
elbow.
7.
In Canada, vents shall be certified to ULC S636, Standard for Type
BH Gas Venting Systems. IPEX System 636 PVC is certified to
this standard.
8.
In Canada, the first three feet (900 mm) of the vent must be readily
accessible for inspection.
FIGURE 10:
Accessory Connections
This furnace may not be common vented with any other appliance,
since it requires separate, properly sized air intake and vent lines.
The furnace shall not be connected to any type of B, BW or L vent
or vent connector, and not connected to any portion of a factory-
built or masonry chimney
The furnace shall not be connected to a chimney flue serving a sep-
arate appliance designed to burn solid fuel.
HUMIDIFIER
TERMINALS
EAC
TERMINALS
DELAY
COOL
ADJUST
HUMIDISTAT
CONNECTED
YES NO
AIR
RECIRC
ERROR
TEST
CFM
115 VOLT
HUMIDIFIER
115 VOLT
EAC
BLK
WHT
BLK
WHT
HOT NEU
HOT NEU
When combustion air pipe is installed above a suspended ceiling or
when it passes through a warm and humid space, the pipe must be
insulated with 1/2” Armaflex or other heat resistant type insulation.
Vent piping must be insulated with 1/2” insulation if it will be sub-
jected to freezing temperatures such as routing through unheated
areas or through an unused chimney.
TABLE 6:
Maximum Equivalent Pipe Length
Model Input
BTUH (kW)
Pipe Size
Inches (cm)
Maximum Equivalent
length feet (m)
60,000 (17.6)
2
(5.1)
65
(19.8)
60,000 (17.6)
3
(7.6)
90
(27.4)
80,000 (23.4)
2
(5.1)
65
(19.8)
80,000 (23.4)
3
(7.6)
90
(27.4)
100,000 (29.3)
2
(5.1)
30
(9.2)
100,000 (29.3)
3
(7.6)
85
(25.9)
120,000 (29.3)
3
(7.6)
60
(18.3)
