HTP EL-399NVWH - Manual (Page 37)

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LP- 346 REV. 3.20.14
K. UNBALANCED FLUE / VERTICAL VENT
Figure 17 – Unbalanced Flue/Vertical Vent - NOTE: Drawing is meant to demonstrate system venting ONLY.
All vent pipes must be glued, properly supported, and the exhaust must be pitched a minimum of ¼” per foot back to the heater to allow
drainage of condensate. When placing support brackets on vent piping, the first bracket must be within 1 foot of the heater and the
balance at 4 foot intervals on the vent pipe. Heater venting must be readily accessible for visual inspection for the first three feet from
the heater.
An unbalanced vent system can be installed ONLY when the exhaust is in a vertical position.
L. VENTING THROUGH AN EXISTING SYSTEM
This heater may be vented through an existing unused vent system. The inner diameter of the existing vent system is utilized for the
combustion air source. Two methods have been approved for such venting: Concentric Venting Through an Existing System and
Venting as a Chase.
Do not install the heater into a common existing vent with any other appliance. This will cause flue gas spillage or heater malfunction,
resulting in substantial property damage, severe personal injury, or death.
Contractors must check state and local codes before installing through an existing vent opening. State and local codes always take
precedence over manufacturer’s instructions. Failure to check state and local codes before installing through an existing opening could
result in property damage and add significantly to installation costs.