Form I-VR (10-14), P/N 205202 R14, Page 29
Single wall outer dual vent pipe
Single wall inner dual vent pipe
FIGURE 28B -
Horizontal Dual Vent
Terminal Arrangement
FIGURE 28A -
Vertical Dual
Vent Terminal
Arrangement
Dual Vent Terminal Arrangements with Option CC5
Model VR/GVR heaters are approved for operation without an outdoor vent.
Before installing a tubular infrared heater in the unvented mode, extreme care
should be exercised in examining the building atmosphere and structure.
Where an unvented infrared heater is used, natural or mechanical means
shall be provided to supply and exhaust at least 4 cfm for natural gas and
5 cfm for propane gas, per hour input of installed heaters.
Exhaust openings for removing flue products shall be above the level of the
heater.
When mechanical means is provided to supply and exhaust, a positive inter
-
lock must be provided by the installer so that the heater cannot operate unless
the supply and exhaust system is operating.
•
Do not
operate in the unvented mode when dust or dirt are present.
•
Do not
operate in the unvented mode in a building where contaminants
are in the air that will produce a toxic gas when burned or exposed to high
temperatures.
NOTE:
If either of the above situations exist, it is recommended that a vented
system with an optional combustion air inlet be installed.
6.4.3 Unvented
Installation
Single-wall outer dual vent pipe
Single-wall inner dual vent pipe
FIGURE 29 - Install
“Inverted” Terminal
Cap on an Unvented
Heater