Empire Comfort Systems SR-30-3 Manuel D’Utilisation

16942-3-0506

Page 6

WATER VAPOR: A BY-PRODUCT OF UNVENTED ROOM HEATERS

Water vapor is a by-product of gas combustion. An unvented room

heater produces approximately one (1) ounce (30ml) of water for

every 1,000 BTU's (.3KW's) of gas input per hour.
Unvented room heaters must be used as supplemental heat (a

room) rather than a primary heat source (an entire house). In most

supplemental heat applications, the water vapor does not create a

problem. In most applications, the water vapor enhances the low

humidity atmosphere experienced during cold weather.

The following steps will help insure that water vapor does not

become a problem.

1. Be sure the heater is sized properly for the application, including

ample combustion air and circulation air.

2. If high humidity is experienced, a dehumidiﬁer may be used to

help lower the water vapor content of the air.

3. Do not use an unvented room heater as the primary heat source

(an entire house).

PROVISIONS FOR ADEQUATE COMBUSTION & VENTILATION AIR

Provisions for Adequate Combustion and Ventilation Air

This heater shall not be installed in a conﬁned space or unusually

tight construction unless provisions are provided for adequate

combustion and ventilation air.
The National Fuel Gas Code, ANSI Z223.1 deﬁnes a conﬁned space

as a space whose volume is less than 50 cubic feet per 1,000 Btu per

hour (4.8m

per kw) of the aggregate input rating of all appliances

installed in that space and an unconﬁned space as a space whose

volume is not less than 50 cubic feet per 1,000 Btu per hour (4.8m

per kw) of the aggregate input rating of all appliances installed in

that space. Rooms communicating directly with the space in which

the appliances are installed, through openings not furnished with

doors, are considered a part of the unconﬁned space.
The following example is for determining the volume of a typical

area in which the SR-18 may be located and for determining if

this area ﬁts the deﬁnition of an unconﬁned space.
The maximum input of the SR-18 is 18,000 Btu per hour. Based

on the 50 cubic feet per 1,000 Btu per hour formula, the minimum

area that is an unconﬁned space for installation of the SR-18 is

900 cubic feet, 50 cubic feet x 18 = 900 cubic feet. To determine

the cubic feet of the area in which the SR-18 is to be installed,

measure the length, width and height of the area. Example: The

area measures 13 feet in length, 9 feet in width and 8 feet in

height, the area is 936 cubic feet. The SR-18 can be installed in

this unconﬁned space with no requirement to provide additional

combustion and ventilation air.

Warning: If the area in which the heater may be operated is smaller

than that deﬁned as an unconﬁned space or if the building is of

unusually tight construction, provide adequate combustion and

ventilation air by one of the methods described in the National Fuel

Gas Code, ANSI Z223.1, Section 5.3 or applicable local codes.
Unusually Tight Construction

The air that leaks around doors and windows may provide enough

fresh air for combustion and ventilation. However, in buildings of

unusually tight construction, you must provide additional fresh

air.

Unusually tight construction is deﬁned as construction where:

a. Walls and ceilings exposed to the outside atmosphere have

a continuous water vapor retarder with a rating of one perm

or less with openings gasketed or sealed, and

b. Weatherstripping has been added on openable windows and

doors, and

c. Caulking or sealants are applied to areas such as joints

around window and door frames, between sole plates and

ﬂoors, between wall-ceiling joints, between wall panels, at

penetrations for plumbing, electrical, and gas lines, and at

other openings.

If the heater is installed in a building of unusually tight construction,

adequate air for combustion, ventilation and dilution of ﬂue gases

shall be provided in accordance with ANSI Z223.1/NFPA54.