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Keep the clearances.
INDOOR INSTALLATION
1.
Follow all local codes, or in the absence of
local codes, follow the most recent edition
of the National Fuel Gas Code: ANSI
Z223.1/NFPA 54 in the USA or CAN/CSA
B149.1 Natural Gas, Propane Installation
Code in Canada.
2.
When installed indoors, the water heater
shall be located in an area to maintain the
following minimum clearances around the
unit:
Combustion Air Supply
The water heater location must provide enough air for proper combustion and ventilation of the
surrounding area. See the latest edition of ANSI Standard Z223.1 or any applicable local codes.
In general, these requirements specify that if the unit is installed in a confined space, there must
be a permanent air supply opening.
Minimum recommended air supply opening size for water heater:
Water heater size
When drawing make-up air from
outside the building
When drawing make-up air from inside
the building (from other rooms within)
MAX
380,000 BTU/h
25.3 Sq. IN
380 Sq. IN
When combustion air is supplied
from outside the building, an
opening communicating directly
with the outside should have a
minimum free area of one
square inch per 15,000 BTUH
input of the total input rating of
water heater in the enclosed
area.
When combustion air is supplied from
inside the building, an opening
communicating with the rest of the
dwelling should have a minimum free
area of one square inch per 1,000
BTUH input of the total input rating of
water heater in the enclosed area.
This opening should never be less
than 199 sq. in.
Combustible Air Supplied by Mechanical fan or Make up air device
The water heater is equipped with a combustible air sensor that will shut off the unit when
inadequate combustible air supply to unit is detected.
•
If a mechanical fan or make up air device is used to supply air to the water heater or
utility room, the installer should make sure it does not create drafts which could cause
nuisance shutdowns.
•
If a blower is necessary to provide adequate combustion air to the water heater, the
blower and water heater must be set up so that the water heater cannot fire unless the
blower is operating. Possible methods include the use of the water heater internal fan
control port or the use of external flow sensors/transmitters and relays.
Top 12”
Side 2”
Side 2”
Front 4”
(24” Recommended
for Maintenance)
Bottom 12”
Back 0.5”
