User Guide

RH180 Manual 13
Combuson Air Requirements
This water heater requires adequate combuson air for venlaon and diluon of ue gases. Failure to provide
adequate combuson air can result in unit failure, re, explosion, serious bodily injury or death. Use the
following methods to ensure adequate combuson air is available for correct and safe operaon of this water
heater.
Important: Combuson air must be free of corrosive chemicals. Do not provide combuson air from corrosive
environments. Appliance failure due to corrosive air is not covered by warranty.
Combuson air must be free of acid forming chemical such as sulfur, uorine and chlorine. These chemicals have
been found to cause rapid damage and decay and can become toxic when used as combuson air in gas
appliances. Such chemicals can be found in, but not limited to bleach, ammonia, cat lier, aerosol sprays,
cleaning solvents, varnish, paint and air fresheners. Do not store these products or similar products in the
vicinity of this water heater.
Unconned Space:
An unconned space is dened in Naonal Fuel Gas Code, ANSI Z223.1/NFPA 54 as “a space whose volume is not
less than 50 cubic feet per 1000 Btu/hr (4.8 m3 per kW per hour) of the aggregate input rang of all appliances
installed in that space. Rooms communicang directly with the space in which the appliances are installed,
through openings not furnished with doors, are considered a part of the unconned space.” If the “unconned
space” containing the appliance(s) is in a building with ght construcon, addional outside air may be required
for proper operaon. Outside air openings should be sized the same as for a conned space.
Unconned Space Unconned Space
91,300 BTU Water Heater and a
100,000 BTU Furnace
(7.6m)
(7.6m)
(10.6m)