Rinnai RH180 Installation Fundamentals page 31

Vent Guidelines: Exhaust
Vent Dampers:
Vent dampers must be certified in accordance with ANSI Z21.68.
Before installing any flue damper, consult the local gas authority and damper manufacturer for proper
installation.
Thermal Operated Vent Dampers: Should NOT be used with this appliance. This appliance has a
thermal efficiency greater than 80%. This higher efficiency will result in lower flue gas temperatures.
Such temperatures may be too low to activate a thermal operated vent damper. Use of a thermal
operated flue damper on this product may result in spillage of exhaust gases and ultimately carbon
monoxide poisoning.
Vent Inspection:
The entire vent system (Combustion air ducts, louvers, and exhaust vent) must be checked
periodically for signs of obstruction 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 adaptor and must never be attached to a vent smaller
than 4". Certain applications may require vent diameters greater than 4". Consult your local gas
supplier or authority to aid in the proper vent diameter selection per the requirement of the vent tables
in the current edition of the National Fuel Gas Code ANSI Z223.1/NFPA 54.
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