Horizontal Venting; Vertical Venting; Unvented Operation Tube Termination; Length Requirements - Roberts Gorden Combat CM-80 Installation, Operation & Service Manual

If exhaust fans are used to supply ventilation air, an
interlock switch must be used to prevent the heater
from coming on when the fans are off. This may be
done using a pressure switch.

8.3 Horizontal Venting

In noncombustible walls only, vent terminal
(P/N 02537801-1P) may be used.
For 4" (10 cm) vents in either combustible or
noncombustible walls, use Tjernlund VH1-4 (P/N
90502100) or equivalent, insulated vent terminal.
Follow the manufacturer's instructions for proper
installation.
For 6" (15 cm) common vents in either combustible or
noncombustible walls, use Tjernlund VH1-6 (P/N
90502101) or equivalent, insulated vent terminal.
Follow the manufacturer's instructions for proper
installation.

8.4 Vertical Venting

For 4" (10 cm), an approved vent cap
(P/N 90502300) must be used.
For 6" (15 cm) common vent, an approved vent cap
(P/N 90502302) must be used.
For common vertical venting of more than two heaters,
See Page 35, Section 8.10.
A vent shall not extend less than 2' (.6m) above the
highest point where it passes through a flat roof of a
building.

8.5 Unvented Operation Tube Termination

Turndown type vent terminal with a screen must be

8.7 Horizontal Ventilation 4" (10 cm) Pipe

Vent Adapter
4" (10 cm)
Single Wall Pipe
Description
Vent Terminal (Comb. Wall)
Vent Terminal
Combustible or
Non-Combustible Wall
4" (10 cm) Single Wall Pipe
Vent Terminal
Part Number
90502100
02537801-XX
installed at the exhaust end of the tube. Vent terminal
design shall not incorporate backdraft flap.

FIGURE 20: Tube Termination

8.6 Length Requirements

The maximum vent length allowed is 45' (13.7 m). The
maximum outside air supply duct length allowed is 45'
(13.7 m).
The total vent length, plus outside air duct length and
any extensions to minimum heat exchanger lengths,
cannot exceed 65' (19.8 m).
Vent length should be limited to less than 20' (6 m).
If using extended heater lengths or vent lengths
greater than 20' (6 m), condensation will form in the
vent pipe. Insulation and additional sealing measures
(high temperature silicone at all seams) are required.
Optional heat exchanger beyond minimum lengths are
considered as vent length for length determination.
Subtract 15' (4.6 m) of maximum allowed vent or duct
length per vent elbow if more than two are used.
SIDE VIEW
Non-Combustible Wall Only
Vent Adapter
SECTION 8: V
ENTING
18" (46 cm)
Min.
Vent Terminal
33 of 73