Procom SSU320RHL-B Owner'S Operation And Installation Manual Download Page 6

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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 additional fresh air ventilation.

3. Add the Btu/Hr of all fuel burning appliances in the space.

     Vent-free heater                                                     Btu/Hr
     Gas water heater*                                                    Btu/Hr
     Gas furnace                                                             Btu/Hr
     Vented gas heater                                                   Btu/Hr
     Gas heater logs                                                       Btu/Hr
     Other gas appliances* +                                          Btu/Hr
  Total                     =                                       Btu/Hr

        *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

: 51,200 Btu/Hr(maximum the space can support)

                           56,000 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 Inside Building

B. Vent room directly to the outdoors. See

Ventilation Air From Outdoors

C. Install a lower Btu/Hr heater, if lower Btu/Hr size makes room unconfined.

Figure 2 -Ventilation Air from Inside Building

Example:
Gas  water  heater          30,000        Btu/Hr
Vent-free  heater    +      26,000        Btu/Hr
Total                         =     56,000        Btu/Hr

NOTE:

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.

This fresh air would come from an adjoining unconfined
space. When ventilating to an adjoining unconfined space,
you must provide two permanent openings: one within
12" of the ceiling and one within 12" of the floor on the
wall connecting the two spaces (see options 1 and 2,
Figure 2). You can also remove door into adjoining room
(see option 3, Figure 2). Follow the

National Fuel Gas

Code. NFPA 54/ANSI Z223.1, Section 5.3, Air for Com-
bustion and Ventilation

for required size of ventilation grills

or ducts.

Ventilation Air From lnside Building

Ventilation Air From Outdoors

Provide extra fresh air by using ventilation grills or ducts.
You must provide two permanent openings: one within
12" of the ceiling and one within 12" of the floor. Connect
these items directly to the outdoors or spaces open to
the outdoors. These spaces include attics and crawl
spaces. Follow the

National Fuel Gas Code, NFPA 54/

ANSI Z223.1, Section 5.3, Air for Combustion and Ven-
tilation

for required size of ventilation grills or ducts.

IMPORTANT:

Do not provide openings for inlet or outlet

air into attic if attic has a thermostat-controlled power
vent. Heated air entering the attic will activate the power
vent.
Rework worksheet, adding the space of the adjoining
unconfined space. The combined spaces must have
enough fresh air to supply all appliances in both spaces.

Figure 3 -Ventilation Air from Outdoors