Instructions / Assembly
®
System 1738 Installation Methods4
(a)  Installation and location of terminations must be 
in accordance with the latest edition of appliance 
manufacturer’s installation instructions, local 
building code requirements and NFPA 54 / ANSI 
Z223.1 National Fuel Gas Code.
(b)  Intake and vent pipes may be routed either 
horizontally through an outside wall (see Figure 1) or 
vertically though the roof (see Figure 2).
(c)  Except for: 1) appliances certified to ANSI Z21.10.3 
/ CSA 4.3 (Gas-fired Water Heaters, Volume III, 
Storage water heaters with input ratings above 
75,000 Btu per hour, circulating and instantaneous) 
and 2) appliances certified to ANSI Z21.13 / CSA 
4.9 (Gas-fired low pressure steam and hot water 
boilers) insulating in unconditioned space is 
required for all vent piping. Insulation should also 
be considered for inlet piping near the outside 
wall to prevent pipe condensation (See Figure 2). 
Insulation must have an R value sufficient to prevent 
freezing of condensate. Consult with the insulation 
manufacturer for compatibility of insulation with 
System 1738 pipe and fittings.
8" MINIMUM
12" MAXIMUM
Insulation in 
unconditioned 
space
Reducer coupling
Insulation
Outside Wall
2" 90º Elbow
Top View
Typical Wall Termination
6" MAX
separation
Vent
Intake
8" MIN.
Separation
Typical Roof Termination
3" MAX separation
Insulation in 
unconditioned 
space
Reducer Coupling
Approved Penetration
and Flashing as per
Building Code
Unconditioned
Attic Space
12" Above avg. 
snow accumulation
Provide support for
intake and vent lines
Install condensate drain 
as per appliance
manufacturer’s
recommendations
Vent Intake
Figure 2 
Typical Roof Snorkel Termination
(d)  THE FOLLOWING RECOMMENDATIONS ARE NOT TO 
SUPERSEDE LOCAL BUILDING CODE REQUIREMENTS.
  Clothes Dryer Clearances for Side wall Terminations:
  Domestic Type Clothes Dryers (Type 1): 
A moisture-exhaust duct from a domestic type 
clothes dryer shall not terminate within 3 feet in any 
direction of any System 1738 pressure regulator vent 
termination or fresh air intake.
  Commercial Type Clothes Dryers (Type 2): 
A dryer shall be connected to a metal moisture-
exhaust duct that terminates outdoors and shall not 
be less than 3 feet from any System 1738 pressure 
regulator vent terminations and not less than 10 feet 
from a fresh-air intake.
Termination Requirements
Figure 1  
Top View: Typical Wall Snorkel Termination










