User Guide

RH180 Manual 17
Venng Requirements
Vent Dampers
Vent dampers must be cered in accordance with ANSI Z21.68
Before installing any ue damper, consult the local gas authority and damper manufacturer for proper
installaon.
Vent Inspecon
The enre vent system (Combuson air ducts, louvers etc., and exhaust vent) must be checked periodically for
signs of obstrucon or damage. If damaged components are observed they must be repaired or replaced
immediately.
Vent Size
This water heater is equipped with a 4” vent adapter and must never be aached to a vent smaller than 4”.
Certain applicaons may require vent diameters greater than 4” Consult your local gas supplier or authority to
aid in the proper vent diameter selecon per the requirements of the vent tables in the current edion of the
Naonal Fuel Gas Code ANSI Z223.1/NFPA 54.
Vent Connectors
Vent Connectors are relavely short runs of vent connecng the appliance to the chimney or vercal vent run.
Following is a list of appropriate vent connector material for use between the water heater and the chimney:
 Type B (B-Vent) Double wall, U.L. listed vent pipe
 Type B (B-Vent) Single wall, U.L. listed vent pipe
Note the following when installing a vent connector from the appliance to the chimney or vercal vent:
Length: A vent connector shall be as short as praccal and the appliance located as close as praccal to the
chimney or vent. The maximum horizontal length of the vent connector cannot exceed 75% of the
height of the chimney or vent. Unnecessary bends should be avoided as to not create excessive
resistance to ow of vent gases.
Prohibited locaons: Vent Connectors cannot pass through any ceiling, oor, rewall, or re paron.
CHIMNEY
OR
LISTED VENT
MIN. ¼ inch rise
per foot
Vent Connector
Single wall vent connectors: A single wall vent
connector must not pass through any interior
walls, oors or ceilings. A single wall vent
connector must not be installed in acs, crawl
spaces or any other conned space or inaccessible
locaon. Maintain a minimum of 6” from
combusbles when using single walled vent
connectors.
Double Walled, B-Vent: It is acceptable to pass
through walls or parons with double walled, B-
Vent.
Slope: Vent connectors must pitch ¼ inch per foot
(21mm per meter) upward.
WARNING
Thermal Operated Vent Dampers: Should NOT be used with this appliance. This appliance has a thermal ecien-
cy greater than 80%. This higher eciency will result in lower ue gas temperatures. Such temperatures may be
too low to acvate a thermal operated vent damper. Use of a thermal operated ue damper on this product may
result in spillage of exhaust gases and ulmately carbon monoxide poisoning.