Instructions / Assembly
®
System 1738 Installation Methods 11
Expansion and Contraction
To accommodate expansion/contraction movement 
and stresses that may occur, IPEX suggests the following 
guidelines during installation:
1.  Leave adequate clearance between any System 
1738 elbows and walls or the underside of floor 
boards or joists.
2.  Use loose fitting clamps and hangers to allow free 
pipe movement if required. 
3.  For critical areas such as near the appliance outlet, 
two 45
o
 elbows may be used in lieu of one 90
o
elbows for more structural flexibility. 
Temp. 
change
 Length of Run (ft)
PVC
(°F) 10 20 30 40 50
10 0.04 0.07 0.11 0.14 0.18
20 0.07 0.14 0.22 0.29 0.36
30 0.11 0.22 0.32 0.43 0.54
40 0.14 0.29 0.43 0.58 0.72
50 0.18 0.36 0.54 0.72 0.90
60 0.22 0.43 0.65 0.86 1.08
70 0.25 0.50 0.76 1.01 1.26
80 0.29 0.58 0.86 1.15 1.44
90 0.32 0.65 0.97 1.30 1.62
100 0.36 0.72 1.08 1.44 1.80
TABLE 2 – PVC Linear Expansion (DL) in inches
Firestops
Should System 1738 pass through a fire rated floor or 
wall, the penetration shall be firestopped with a device 
or system that provides a rating equivalent to the hour 
rating of the floor or wall.
Appliance Testing
Should the appliance not be equipped with an access 
port for flue gas testing, IPEX recommends the use of 
a System 1738 Access Tee during installation to allow 
access for flue gas testing. The Access Tee has a 1/2” 
female thread outlet with a removable 1/2” male thread 
plug. Each time the plug is assembled into place, it shall 
have two wraps of PTFE (Teflon
®
) tape applied to the 
bare male threads. The Access Tee shall be installed as 
close to the appliance as possible. DO NOT drill holes in 
piping. 
Vent Connection to the Appliance
Please refer to the appliance manual for instructions 
to connect System 1738 to the appliance exhaust and 
intake collar. DO NOT use screws to join System 1738 to 
the appliance.










