How to Guide
5
Installation Instructions and Owner’s Manual
Unvented Liquid Propane Fired Room Heater
space such as, Vent–free heater, Gas water heater, Gas 
furnace, Vented gas heater, Gas fireplace logs, and Other 
gas appliances*
*Do not include direct-vent gas appliances. Direct-vent 
draws combustion air from the outdoors and vents to 
the outdoors.
Example:
Gas water heater  40,000 Btu/hr
Vent Free Heater +  20,000 Btu/hr
Total    =60,000 Btu/hr
4.  Compare the maximum Btu/hr the space can support 
with the actual amount of Btu/hr used.
Example: 51,800 Btu/hr (maximum Btu/hr the   
  space can support)
  60,000 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, and the space of an adjoining room. 
If the extra space provides an unconfined space, remove 
door to adjoining room or add ventilation grills between 
the rooms. See Ventilation From Inside Building (Fig. 2)
B.  Vent room directly to the outdoors. See Ventilation From 
Outdoors (Fig. 3). 
C. Install a lower Btu/hr heater if lower Btu/hr size makes 
room unconfined. 
If 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.
VENTILATION AIR
Ventilation from Inside Building
This fresh air would come from an adjoining unconfined 
space. When ventilation 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 & 2 of figure 2). 
You can also remove door into adjoining room (see option3, 
fig 2). Follow the National Fuel Gas Code NFPA 54/ ANSI 
Z223.1, Section 5.3, Air for Combustion and Ventilation for 
required size of ventilation grills or ducts.
WARNING: Rework worksheet, adding the space of 
the adjoining unconfined space. The combined space 
must have enough fresh air to supply all appliance in 
both spaces. 
Ventilation from Outdoors
If necessary provide extra fresh air by using ventilation grills 
or ducts. Connect these items directly to the outdoors or 
spaces open to the outdoors. These include attics* and 
crawl spaces. Follow the National Fuel Gas Code NFPA 
54/ ANSI Z223.1, Section 5.3, Air for Combustion and 
Ventilation for required size of ventilation grills or ducts.
Ventilation 
Gills into 
Adjoining 
Room - 
Option 1
Ventilation Gills into Ad-
joining Room - Option 2
(30.5 cm) 12”
12” (30.5 cm)
Or remove 
door into 
Adjoining 
Room - 
Option 3
Figure 2
INLET 
AIR
OUTLET 
AIR
VENTILATION CRAWL SPACE
TO CRAWL 
SPACE
TO ATTIC
VENTILATION AIR
VENTILATED 
ATTIC
OUTLET AIR
Figure 3.
*IMPORTANT: Do not provide openings for inlet or 
outlet into attic. If attic has a thermostat-controlled power 
vent, heated air entering the attic will activate the power 
vent.
IMPORTANT: Vent-free heaters add moisture to the 
air. Although this is beneficial, installing heater in rooms 
without enough ventilation air may cause mildew to form 
from too much moisture. See Fresh Air for Combustion 
and Ventilation, pages 4 through 5. 
INSTALLATION
WARNING: Any change to this heater or its controls 
can be dangerous.
NOTICE: This heater is intended for the use as 
supplemental heat. Use this heater along with your 
primary heating system. Do not install this heater as your 
primary heat source. If you have a central heating system, 
you may run system’s circulating blower while using heater. 
This will help circulate the heat throughout the house. In 
the event of a power outage, you can use this heater as 
your primary heat source for the duration of the outage. 
WARNING: A qualified service person must install 
heater. Follow all local codes. 










