Calculating Equivalent Feet (Pv); Vent Installation; Condensate (Exhaust) - A.O. Smith 100 Series Installation And Operating Manual

CALCULATING EQUIVALENT FEET (PV)

Water Heater Heater Input
Model (Btu/Hr)
40 gal. 50,000
50 gal. 65,000
40 gal. 50,000
50 gal. 65,000
40 gal. 50,000
50 gal. 65,000
Notes:
1. All vent pipe material must be schedule 40.
2. Snorkel termination elbows' equivalent lengths must be deducted from total vent length.
3. Concentric vent terminations are not available for PV installations.
4. Use long radius elbows where possible. Minimum distance between 90º elbows should be 6" (150 mm) wherever possible.
5. Venting systems may use a maximum of five (5) 90° elbows.
6. Use proper screen termination.
7. The check valve must not be installed on the heater in a Power Vent (PV) configuration.

VENT INSTALLATION

1. Carefully inspect the entire venting system for any signs of
cracks or fractures, particularly at joints between elbows and
other fittings and straight runs of vent pipe.
2. Check system for signs of sagging or other stresses in joints
as a result of misalignment of any components in the system.
If any of these conditions are found, they must be corrected
in accordance with the venting instructions elsewhere in this
manual before completing installation and putting the water
heater into service.
3. The vent piping shall be connected to the condensate trap with
a rubber coupling and secured with gear clamps. The coupling
and clamps are provided with the heater.

CONDENSATE (EXHAUST)

This appliance is a condensing unit and will have condensate
build up throughout the exhaust venting system. The vent pipe
should be sloped upwards 21 mm per metre away from the water
heater. Adequate means for draining back to the condensate trap
and disposing of the condensate must be made by the installer.
Condensation in the venting system is dependent upon installation
conditions including, but not limited to:
• ambient temperature and humidity of installation location,
• ambient temperature and humidity of venting space,
• vent discharge and slope,
• product usage.
Note: Do not use the condensation trap as a support point. It not
designed to carry the load or stresses of the venting system.
Vent piping must be supported adequately and not put any
weight on the condensation trap.
Connect a suitable condensate drain to the port on the condensate
trap using a 1/2" FNPT connector. The condensate line must be
horizontal or inclined towards the drain. Ensure the drain line
terminates at a drain as condensate will flow from the end. Ensure
that any discharge will exit the condensate drain line no more
than 150 mm (6") above a suitable building drain, or external to
the building.
Table 16. Calculating Equivalent Feet (PV)
Pressure Switch
Settings (in. w.c.)
Vent Size (Inside
Diam.) Intake
-1.88
2"
-1.88
-1.88
3"
-1.88
-1.88
4"
-1.88
Max. Equivalent Vent
Exhaust
1.8
60 ft. (18.3 m) + termi-
nation
1.8
1.8
150 ft. (45.7 m) +
termination
1.8
1.8
180 ft. (54.8 m) +
termination
1.8
Note: In cold climates it is recommended the condensate drain be
terminated at a suitable drain inside the building.
DRAIN LINE TO
TERMINATE NO
MORE THAN
150mm (6")
ABOVE DRAIN
Figure 34. Condensate Drain Configuration
Caution must be used to ensure that drain is free and clear of
debris and will not allow backflow through the condensate drain
line. If the condensate does not drain properly it will build up in the
exhaust (vent) elbow. This will restrict the flow of flue gases and
cause the Blocked Exhaust pressure switch to open its contacts.
The control system monitors all pressure switches, if the Blocked
Exhaust Switch contacts are open the control system will lock
out and disable heating operation. The "Blocked Exhaust" Fault
message will be displayed on the control system's LCD.
Note: If the "Blocked Exhaust" Fault message is ever displayed
on the control system LCD, check the condensate drain first
and ensure it is not blocked.
DO NOT remove, modify or alter the factory installed exhaust/
condensate elbow for any reason. See Figure 34. The water heater's
vent pipe is under a slight positive pressure while unit is in operation.
The water trap inside of the exhaust/condensate elbow prevents
flue gases from escaping into the installed space.
28
Min. Equivalent Vent
Length Length
7 ft. (2.1 m) + termina-
tion
10 ft. (3.0 m) + termina-
tion
15 ft. (4.6 m) + termina-
tion
CONDENSATE
DRAIN LINE
CONNECTION
BUILDING
DRAIN
CONDENSATE
DRAIN LINE -
FIELD SUPPLIED