Thermo Pride Gas/Propane Furnace Concentric Vent (CMA) - Manual (Page 6)

ALL INSTALLATIONS AND SERVICE MUST BE PERFORMED BY QUALIFIED SERVICE PERSONNEL.
INSTALLING CONCENTRIC VENT THRU THE ROOF USING 3” FLASHING PLATES.
1. Required kit: AOPS7473
2. Type installation: Thru the roof.
3. If a roof jack is in place it will need to be removed.
4. Install one of the 3” flashing plates on the roof covering the existing opening of the
previous roof jack or if no roof jack was in place previously, a 3 ½” to 4” diameter hole
will need cut in roof. Then place flashing plate over hole. Plate should be secured with
some type of roofing fasteners and an appropriate type of roof caulk or sealant to
ensure no leakage after installation.
5. Determine vertical height dimension (DIM-D) of ceiling surface to rain cap, see FIG-8. If
this dimension is less than 16-9/16” skip to step 7. If dimension is greater than 16-9/16”
the 3” and 2” PVC pipes in the concentric vent assembly will need to be replaced with
longer pipes to ensure proper installation.
6. To extend the concentric vent assembly, the two pipes supplied in the kit will need to be
replaced with single piece (no coupling connections allowed) same diameter solid core,
field supplied SDR-26 PVC (ASTM D2241) pipe. See FIG-1, FIG-6 & FIG-7 for
calculating new pipe cut lengths.
UNIT OPERATION HAZARD.
Failure to follow this caution may result in intermittent unit operation.
Do not use field supplied couplings to extend the pipes. Airflow restriction will occur and the
furnace pressure switch may cause intermittent operation.
7. Drop 3” pipe (FIG-6) thru hole leaving the required length of pipe above roofline for
snow level clearance. Seal with RTV sealant where pipe and flashing meet and clamp
tightly with factory supplied clamp, see FIG-8.
8. Affix rain cap to 2” pipe with either PVC cement of a field supplied stainless steel screw,
see FIG-7.
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