Thermo Pride CDX1-100N Installation And Operation Manual page 24

All installations and services must be performed by qualified service personnel.
NOTICE: The exhaust vent piping must slope upward at least 1/4" per foot from the furnace to outdoor
vent terminal. The inlet vent piping must slope downward at least 1/4" per foot from the beginning of the
last horizontal run of pipe to the outdoor vent terminal. The PVC pipe must be supported directly over the
vent tee assembly (CDX1) or (CHX1), every four feet thereafter and at every joint. After making sure the
slope and length of the piping are correct, glue the furnace tee and vent terminal connections in place.
3. CONNECTING THE COMBUSTION AIR INLET
a. Install a 2" PVC elbow with sleeve and coupling (CHX1/CDX1-75 series) or 3" PVC elbow with sleeve
(CHX1/CDX1-100, 125 series) on the inlet of the burner box. Using a tape measure, measure the
length of 2" or 3" PVC pipe needed to clear the casing. Be sure to allow sufficient length for insertion
to the elbow at the burner box and the elbow or coupling on the end. Cut the 2" or 3" PVC to the
measured length.
b. After preparation of the PVC pipe, secure the coupling or sleeve in place using a black-coated #8x3/4
sheet metal screw through the PVC into the metal collar of the burner box.
Note: The PVC connection to the metal burner box collar does not require silicone sealant or PVC
cement. Attach the PVC elbow to the sleeve and then to the coupling where required, using
silicone type sealant (see figure 12).
c. Install the precut 2" or 3" PVC pipe into the elbow at the burner box and to the elbow or coupler just
outside the furnace using silicone type sealant. To make these seals, run a bead of silicone type
sealant around the PVC pipe 3/8" from either end, insert into the appropriate couplings and elbows
and rotate 1/4" turn. This will allow for easy disconnection in case the burner assembly must be
removed at a later date (see figure 12).
Note: When applying silicone sealant, ensure that no excess sealant is pushed into the vent
opening. This may cause flow restriction within the vent.
NOTICE: The air intake pipe must be supported every 4 feet. After making sure the length of the piping is
correct, glue all connections in place except the length of pipe between the combustion air fitting on the
burner box and the first fitting.
If the combustion air piping is installed in a warm humid place, such as a laundry room or above a
suspended ceiling, it must be insulated with a 1.0" foil faced insulation or its equivalent.
If the vent piping is run through an unconditioned space, it must be insulated with a1.0" foil faced
insulation or its equivalent.
DO NOT! SILICONE OR SEAL
THIS CONNECTION IN
ANYWAY. MUST BE LOOSE
FIT WITH LEAKAGE BETWEEN
PVC AND METAL COLLAR.
Figure 12
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