Procom PCD18T User Manual page 6

of one perm (6x0
b) weather stripping has been added on windows that can be opened and doors
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 your home meets all of the three criteria above, you must provide additional fresh air. See "Ventilation Air From
Outdoors" (page 6).
If your home does not meet all of the three criteria above, proceed to "Determining Fresh-Air Flow For Heater Location"
(below).
DETERMINING FRESH-AIR FLOW FOR HEATER LOCATION
Determining if You Have a Confined or Unconfined Space
Use this worksheet to determine if you have a confined or unconfined space.
Space: Includes the room in which you will install heater plus any adjoining rooms with doorless passageways
or ventilation grills between the rooms.
. Determine the volume of the space
Length×Width×Height=
Example: Space size 20 ft. (length) × 16 ft.(width) × 8 ft. (ceiling height) = 2560 cu. ft. (volume of space)
If additional ventilation to adjoining room is supplied with grills or openings, add the volume of these rooms
to the total volume of the space.
. Divide the space volume by 50 cubic feet to determine the maximum Btu/Hr the space can support.
(volume of space) ÷ 50 cu. ft.= (Maximum Btu/Hr the space can support)
3. Add the Btu/Hr of all fuel burning appliances in the space.
Vent-free heater
Gas water heater*
Gas furnace
Vented gas heater
Gas heater logs
Other gas appliances* +
Total
*Do not include direct-vent gas appliances. Direct-vent draws combustion air from the outdoors and vents to the outdoors.
4. Compare the maximum Btu/Hr the space can support with the actual amount of Btu/Hr used.
Btu/Hr (maximum the space can support)
Btu/Hr (actual amount of Btu/Hr used)
Example : 5,00 Btu/Hr(maximum the space can support)
7,000 Btu/Hr(actual amount of Btu/Hr used)
The space in the above example is a confined space because the actual Btu/Hr used is more than the maximum
Btu/Hr the space can support. You must provide additional fresh air. Your options are as follows:
a) Rework worksheet, adding the space of an adjoining room. If the extra space provides an unconfined
space, remove door to adjoining room or add ventilation grills between rooms. See "Ventilation Air From
Outdoors", page 7.
b) Vent room directly to the outdoors. See "Ventilation Air From Outdoors", page 7.
c) Install a lower Btu/Hr heater, if lower Btu/Hr size makes room unconfined. If the actual Btu/Hr used is less
than the maximum Btu/Hr the space can support, the space is an unconfined space. You will need no ad-
ditional fresh air ventilation.
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/NFPA. Air for combustion
and ventilation or applicable local codes.
- 
kg per pa-sec-m ) or less with openings gasketed or sealed
cu.ft. (volume of space)
=
Btu/Hr
Btu/Hr
Btu/Hr
Btu/Hr
Example:
Btu/Hr
Gas water heater
Btu/Hr
Vent-free heater
Btu/Hr
Total
6
and
and
40,000 Btu/Hr
+ 3,500 Btu/Hr
= 7,500 Btu/Hr