Combustion Research Omega II, Installation, Operating, Maintenance And Parts Manual

Omega II

®

 Installation, Operation & Maintenance 

Combustion Research Corporation 

Page 21 

GENERAL NOTES 

WARNING 

IMPROPER INSTALLATION CAN CAUSE 
DEATH, SEVERE INJURY AND/OR 
PROPERTY DAMAGE. 

Improper venting and insufficient ventilation may result 
in health problems, carbon monoxide poisoning and 
death. Vent enclosed spaces and buildings according 
to national, state, provincial and local codes.

Heater vent must be installed in accordance with the 
National Fuel Gas Code, ANSI Z223.1 (current standard) 
(NFPA No. 54). Partial information pertaining to this 
specification is provided in this section with regard to size 
and configuration for various venting arrangements. 
Consult the ANSI Z223.1 (current standard) and any 
applicable local codes for complete information. 

1.  Make sure that the venting method selected is in 

compliance with any local codes. 

2.  Heater exhaust end will receive a 4 inch diameter 

(single wall galvanized, aluminized or stainless steel) 
flue pipe.  

3.  Heater may be vented to the outdoors vertically or 

horizontally. The vent piping shall be adequately 
supported to prevent sagging. 

4.  Where the vent pipe passes through areas where the 

ambient temperature is likely to induce condensation of 
the flue gases the vent pipe shall be insulated. 

5.  If the heater is to be vented horizontally: 

a. Vent must terminate at least 3 feet (0.9m) above any 
Forced air inlet located within 10 feet (3.1m). 

b. Vent shall terminate at least 4 feet (1.2m) below, 4 
feet (1.2m) horizontally from, 1 foot (30cm) above any 
door, window or gravity air inlet into any building. 

c. The bottom of the vent terminal shall be located at 
least 12" inches (30cm) above grade. 

6.  Vent opening must be beyond any combustible 

overhang. 

7.  Any portion of the flue pipe that passes through 

combustible material of the building must have a 
minimum 1" clearance and be dual insulated or use an 
approved thimble (refer to ANSI Z223.1 current 
standard) 

WALL THIMBLES

Combustion Research Corp. PN 1810.WT.400 
Hart & Cooley Metalvent PN 4RWT 

8.  Maximum flue length may be twenty feet (20') for all 

models.  

9.  If condensation within the flue becomes a problem, the 

flue should be shortened or insulated. 

VENTING EQUIPMENT 

VERTICAL VENTING

1.  A four inch O.D. flue pipe is recommended.  Maximum 

flue length may be twenty feet (20'). Do not use more 
than two (2) 90° elbows. Insulate as required to prevent 
condensation. 

2.  Use “B” vent for any roof penetration.  Any vent pipe 

that passes through an attic or enclosed space must 
also be “B” vent. 

3.  A minimum 1" clearance around vent is required to pass 

through combustible materials (check local codes).   

4.  All Joints in the flue should be sealed. Use General 

Electric RTV 106 or Permatex Form-A-Gasket Red High 
Temperature Silicone Adhesive Sealant or equivalent. 

5. 

Use Combustion Research Corp. P/N 1810.VT.400 
(Metalbestos 4RV-RT) or P/N 1811.VT.400 (Simpson 
Dura Vent 4GVVTH) vent caps.

HORIZONTAL VENTING

1.  For single burner horizontal venting use: 

Combustion Research Corporation  P/N 1811.VT.400 
(Simpson Dura Vent 4GVVTH).  

2.  A 4 inch O.D. flue pipe (single wall galvanized, 

aluminized or stainless steel) is recommended.  
Maximum flue length may be twenty feet (20'). Do not 
use more than two (2) 90° elbows. Insulate as required 
to prevent condensation. 

3.  Use “B” vent for any combustible wall penetration. 

4.  For multiple unit venting use: 

Combustion Research Corporation PN 1811.VT.600 
(Simpson Dura Vent 6GVVTH) for side wall or roof 
penetrations. 
A 6 inch O.D. flue pipe (single wall galvanized, 
aluminized or stainless steel) is recommended.  
Maximum flue length may be twenty feet (20'). Do not 
use more than two (2) 90° elbows. Insulate as required 
to prevent condensation. 

5.  Any portion of the flue pipe that passes through 

combustible material of the building must use “B” vent 
and have a minimum 1" clearance and use an approved 
thimble (refer to ANSI Z223.1 current standard).  

NOTE:

 Use ONLY the PN 1811.VT.400 or 1811.VT.600 

for horizontal side wall applications.  The vent cap shall 
extend at least 18" from the wall. 

6.  All Joints in the flue should be sealed.  Use General 

Electric RTV 106 or Permatex Form-A-Gasket Red High 
Temperature Silicone Adhesive Sealant or equivalent. 

7.  Make sure that horizontal vents will not be obstructed by 

snow build up.  It is recommended that a minimum two-
foot clearance be maintained around the vent. 

8.  Because exhaust gases may cause degradation of 

building materials, the horizontal vent cap must be 
installed a distance from the exterior wall surface of at 
least 6 inches - See page 21. 

9.  The vent piping shall rise not less than 1/4" per foot 

from the start of the vent system to the vent terminal.

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