Thermo Pride CDX1-100N Installation And Operation Manual page 15

All installations and services must be performed by qualified service personnel.
Equipment must be installed in accordance with regulations of the National Board of Fire
Underwriters and the National Fuel Gas Code. Authorities having jurisdiction should be consulted
before installations are made.
C. REPLACING AN EXISTING FURNACE FROM A COMMON VENT
: These furnaces may not be common vented with any other appliance.
D. GENERAL REQUIREMENTS FOR VENTING CHX1/CDX1
The CHX1/CDX1 furnace venting system must be installed by a qualified service person in accordance
with local codes, the National Fuel Gas Code (NFPA 54/ANSI Z223.1 or latest edition) and these
instructions.
The following items and local code requirements must be followed:
1. The vent/air intake terminations outlined by Thermo Products in this manual must be used.
2. The entire vent/air intake system must be made of PVC Schedule 40 pipe.
NOTE: All CHX1/CDX1 furnaces recommended to be installed with outside combustion air.
3. The flue vent pipe and combustion air pipe must be at least as large as the exhaust vent/air intake
pipe specified by Thermo Products. No reduction in size is permissible. The CHX1, CDX1-75 requires
2" Schedule 40 PVC pipe. The (CHX1, CDX1)-100 and 125 require 3" Schedule 40 PVC pipe.
4. This CHX1/CDX1 furnace shall not be common vented with any other appliance including those
burning solid fuels.
5. Horizontal runs of exhaust vent pipe shall slope upward at least 1/4" per foot from the outlet of the
furnace (CHX1's) or the outlet of the drain tee (CDX1's) to the vent termination at the outside wall.
This will permit proper drainage of the condensate. Horizontal runs of inlet vent pipe shall slope
downward at least 1/4" per foot from the outlet of the last elbow or last horizontal run, before exiting
the wall, to the vent termination at the outside wall.
6. The vent pipe must be supported every 4 feet and at every joint to prevent pipe blockage caused by
condensate trapped by a sag in the vent.
7. The maximum permissible vent length of straight pipe and number of elbows permitted for the
exhaust vent and combustion air inlet is shown in Table 2. The elbows shown are in addition to the
length of straight pipe permitted. When counting elbows, all elbows used in the exhaust vent or
combustion air intake must be counted. This includes elbows used inside the furnace jacket and
termination elbows. In addition, up to three elbows may be dropped and the vent length extended five
feet for each elbow dropped.
VENT SIZE
FURNACE VENT
MODEL LENGTH
(FT.)
CHX1/CDX1-75
CHX1/CDX1-100
CHX1/CDX1-125
MAXIMUM VENT LENGTH
2 IN. PVC
EXHAUST
VENT
ELBOWS (NO.)
1, 2
35 8
NOT PERMITTED
NOT PERMITTED
TABLE 2
COMBUSTION VENT
AIR INTAKE LENGTH
ELBOWS (NO.) (FT.)
2
7
35
35
9
3 IN. PVC
EXHAUST
VENT
ELBOWS (NO.)
- -
1, 2
8
1, 2
8
COMBUSTION
AIR INTAKE
ELBOWS (NO.)
-
2
7
2
7