Camus Hydronics ADVANTUS AVH 1000, Installation, Operation And Service Manual

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2.1.1 CATEGORY II AND CATEGORY IV VENTING
A Category II venting system operates with a negative pressure in the vent.
A Category IV venting system operates with positive pressure generated by the internal combustion air fan which operates the combustion
process and also exhausts the flue products from the building.

The Category II flues from multiple appliances can be combined into a common vent. This special venting system must be
engineered by venting manufacturer and to be approved by local authority.

The Category IV flues from multiple appliances CAN NOT be combined into a common vent.

The Category IV flue must be a dedicated stack.

The Category IV flue appliance must have all vent joints and seams sealed gas tight.

The flue products in the vent system will be cooled below their dew point and will form condensate in the flue. Flue construction
must be of AL29-4C, 316L Stainless, S636 CPVC, S636 PPE.

The flue from a Category II and IV vent system must have a condensate drain with provisions to properly collect, neutralize and
dispose of any condensate that may occur.
2.1.2 VENTING GUIDELINES FOR CATEGORY II AND/OR IV VENTING

This installed length of the positive pressure flue from the appliance to the point of termination, outside of the building, must not
exceed a maximum of 100 equivalent feet (30.5 m) in length. Depending on diameter and centerline radius subtract from 7 to
19 feet per 90° elbow using published data. Subtract half this value for each 45° elbow.

The flue may terminate either vertically at the roof top or horizontally on a SIDEWALL. See the information about the specific
vent termination location for recommended location and clearances.

For direct vent applications, the maximum wall thickness must be between 0.5” – 12” (1.2 cm to 30 cm).
2.1.3 APPROVED VENTING MATERIALS
Exhaust Vent for Use for Advantus Category II or IV
Installations
1. Manufactured prefabricated UL/ULC listed vent of AL29-4C or equivalent, Single or Double wall.
2. 316L Stainless Steel is
Limited to use in applications where there is no possibility of contaminants in the air such as refrigerants,
chlorine etc.
3.
“BH” type
4. CPVC Schedule 40 or 80 approved to ULC S636
5. CPVC Schedule 40 approved to comply with ANSI/ASTM F441. (US Jurisdictions ONLY when permitted)
6. Polypropylene appr
oved to comply with ULC S636 up to 12” diameter.
NOTE
1) Use of cellular core PVC (ASTM F891), cellular core CPVC or Radel® (polyphenosulfone) in venting systems is prohibited.
2) Covering non-metallic vent pipe and fittings with thermal insulation is prohibited.
Table 4: Maximum Flue Temperatures for Various Vent Materials
Vent Material Maximum Flue Temperature (°F)
CPVC 194
Polypropylene 230
AL29-4C 300+, Limited only by rating of seals
316L Stainless Steel 300+, Limited only by rating of seals
Stack temperature is generally 10-25°F above boiler inlet temperature when operating at steady state at full fire.
Vent Material Selection
When selecting vent material, take into consideration that appliances installed near a corrosive or potentially corrosive air supply must be
isolated from it or they will suffer damage to the appliance and the venting system.
The corrosion resistance of AL29-4C is typically higher than that of 316L. Always choose the venting system which best satisfies the
requirements of the application.
This recommendation does not supersede local codes or the provision of the B149 in Canada or the National Fuel Gas Code in
the United States.