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Example 2
A direct-vent 60,000 BTUH furnace installed at 2100 ft. (640M). Venting system includes FOR EACH PIPE:
100 feet (30 M) of vent pipe, 95 feet (29 M) of combustion air inlet pipe, (3) 90º long-radius elbows, and a polypropylene concentric vent kit.
Also includes 20 feet (6.1 M) of flexible polypropylene vent pipe, included within the 100 feet (30 M) of vent pipe.
VERIFY FROM POLYPROPYLENE VENT MANUFACTURER'S INSTRUCTIONS for the multiplier correction for flexible vent pipe.
Can this application use 60mm o.d. (2") polypropylene vent piping? If not, what size piping can be used?
Measure the required linear length of RIGID air inlet and vent pipe; insert
the longest of the two here: 100 ft. Of rigid pipe --- 20 ft. Of flexible pipe
Add equiv length of (3) 90º long-radius elbows
(use the highest number of elbows for either the
vent or inlet pipe)
Add equiv length of 45º long-radius elbows
(use the highest number of elbows for either the
vent or inlet pipe)
Add equiv length of factory concentric vent term
Add correction for flexible vent pipe, if any
* VERIFY FROM VENT MANUFACTURER'S INSTRUCTIONS; For example only, assume 1 meter of flexible 60mm (2") or 80mm (3")
polypropylene pipe equals 2.0 meters (6.5 ft.) of PVC/ABS pipe.
Total Equivalent Vent Length (TEVL)
Maximum Equivalent Vent Length (MEVL)
Is TEVL less than MEVL?
Maximum Equivalent Vent Length (MEVL)
Is TEVL less than MEVL?
START- - UP, ADJUSTMENT, AND SAFETY
CHECK
NOTICE
Important Installation and Start- -up Procedures
Failure to follow this procedure may result in a nuisance
smoke or odor complaint.
The manifold pressure, gas rate by meter clocking,
temperature rise and operation must be checked after
installation.
Minor smoke and odor may be present
temporarily after start- -up from the manufacturing process.
Some occupants are more sensitive to this minor smoke and
odor. It is recommended that doors and windows be open
during the first heat cycle.
General
1. Furnace must have a 115-v power supply properly connect-
ed and grounded.
NOTE: Proper polarity must be maintained for 115-v wiring.
Control status indicator light flashes rapidly and furnace does not
operate if polarity is incorrect or if the furnace is not grounded.
2. Thermostat wire connections at terminals R, W/W1, G, and
Y/Y2 must be made at 24-v terminal block on furnace con-
trol.
3. Natural gas service pressure must not exceed 0.5 psig (14-
in. w.c., 350 Pa), but must be no less than 0.16 psig (4.5-in.
w.c., 1125 Pa).
4. Blower door must be in place to complete 115-v electrical
circuit and supply power to furnace components.
Before operating furnace, check flame rollout manual reset switch
for continuity. If necessary, press button to reset switch.
EAC-1 terminal is energized whenever blower operates. HUM
terminal is only energized when the blower is energized in heating.
=
(24 M)
5 ft.
3
x
=
(1.5 M)
(4.6 M)
0
x
=
(0 M)
3.3 ft
9
x
=
(0.9 M)
(9 M)
20 ft.
2*
x
=
(6.1 M)
(12.2 M)
165 ft.
(50 M)
(29 M)
185 ft.
(57 M)
UNIT OPERATION HAZARD
Failure to follow this caution may result in intermittent unit
operation or performance dissatisfaction.
These furnaces are equipped with a manual reset limit
switch in burner assembly. This switch opens and shuts off
power to the gas valve if an overheat condition (flame
rollout) occurs in the burner assembly/enclosure. Correct
inadequate combustion- -air supply, improper gas pressure
setting, improper burner or gas orifice positioning, or
improper venting condition before resetting switch. DO
NOT jumper this switch.
Setup Switches
There are two sets of setup switches on the furnace control board.
These switches configure the furnace for correct application
requirement. They also select the airflow settings for Air
Conditioning and Continuous Fan airflows.
The Setup Switch locations are shown and described on Fig.
The setup switches are also shown on the unit wiring label.
Setup Switches (SW1)
The furnace control has 8 setup switches that may be set to meet
the application requirements. Refer to the Adjustments section for
setup switch configurations. To set these setup switches for the
appropriate requirement:
1. Remove blower door.
2. Locate setup switches on furnace control.
3. Configure the setup switches as necessary for the
application.
4. Replace blower door.
56
80 ft.
Use length of the longer of the vent
or air inlet piping system
15 ft.
Example from polypropylene vent
0 ft.
manufacturer's instructions, Verify from vent
manufacturer's instructions.
30 ft.
40 ft.
Add all of the above lines
95 ft.
Table
For 2" pipe from
Therefore, 60mm (2") pipe may NOT be
NO
used; try 80mm (3")
Table
For 3" pipe from
YES
Therefore, 80mm (3") pipe MAY be used
CAUTION
!
13
13
60.
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