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912SD: Installation, Start-up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
48
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?
START-UP, ADJUSTMENT, AND SAFETY
CHECK
General
1. Furnace must have a 115-v power supply properly connected 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, G, and Y must be
made at 24-v terminal block on furnace control.
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 the furnace components.
Before operating furnace, check flame rollout manual reset switch for
continuity. If necessary, press button to reset switch.
EAC-1 (115vac) terminal is energized whenever blower operates. HUM
(24vac)terminal is only energized when the gas valve is energized in
heating.
Prime Condensate Trap with Water
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
=
80 ft.
(24 M)
Use length of the longer of the vent
or air inlet piping system
Add equiv length of (3) 90º long-radius elbows (use the
highest number of elbows for either the vent or inlet pipe)
3
x
5 ft.
(1.5 M) =
15 ft.
(4.6 M)
Example from polypropylene vent
manufacturer’s instructions, Verify from vent
manufacturer’s instructions.
Add equiv length of 45º long-radius elbows
(use the highest number of elbows for either the vent or
inlet pipe)
0
x
=
0 ft.
(0 M)
Add equiv length of factory concentric vent term
9
x
3.3 ft
(0.9 M) =
30 ft.
(9 M)
Add correction for flexible vent pipe, if any
2*
x
20 ft.
(6.1 M) =
40 ft.
(12.2 M)
*
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)
165 ft.
(50 M)
Add all of the above lines
Maximum Equivalent Vent Length (MEVL)
95 ft.
(29 M)
For 2” pipe from
Is TEVL less than MEVL?
NO
Therefore, 60mm (2”) pipe may NOT be
used; try 80mm (3”)
Maximum Equivalent Vent Length (MEVL)
185 ft.
(57 M)
For 3” pipe from
Is TEVL less than MEVL?
YES
Therefore, 80mm (3”) pipe MAY be used
NOTICE
!
IMPORTANT INSTALLATION AND STRAT-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.
CAUTION
!
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 is 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.
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow these warnings could result in personal injury or
death.
Failure to use a properly configured trap or NOT water-priming trap
before operating furnace may allow positive pressure vent gases to
enter the structure through drain tube. Vent gases contain carbon
monoxide which is tasteless and odorless.