Desa VM42P installation manual Venting Installation, Installing Transition Pipe and Starter Collar

PRE-INSTALLATION PREPARATION Continued

INSTALLING TRANSITION PIPE AND STARTER COLLAR

The transition pipe and starter collar shown in Figure 9 are supplied with the fireplace, unattached and ready for installation. Remove the starter collar and set aside. Slide the transition pipe over the vent collar and attach with a minimum of three screws. Replace the starter collar over the transition pipe and attach using four screws located on the leg stands (five used on the model M42). To install B-vent piping, slide the first piece of B-vent over the transition pipe and attach with either a mini- mum of two screws or other means approved by the vent manufacturer.

B-Vent Piping

Starter Collar

Transition Pipe

Vent Collar

Figure 9 - Installing Transition Pipe and

Starter Collar

VENTING INSTALLATION

A B-type venting system must be connected to the appliance for venting to the outside of the building.

The following section is provided as a guide to a standard B-type vent installation.

Standing codes requirements concerning B-type vent installations may vary within your state, province or local codes jurisdiction. Therefore, it is recommended that you check with your local building codes for specific requirements or in absence of local codes, follow Section 7.0 of the current National Fuel Gas Code ANSI Z223.1/NFPA 54 and in Canada with CAN/CGA B149 for Category I systems using double wall B-1 vent pipe.

This gas appliance must be vented to the outdoors only and may not be terminated into an attic space or into a chimney flue servicing a solid-fuel burn- ing appliance.

This appliance may be vented through a manufac- tured chimney system or a masonry chimney using a B-vent adapter or a chimney liner system if all are listed, inspected and approved by local codes and/or building authorities.

The examples shown in Figure 10, page 10 are typical of most B-vent installations and codes practices.

Example 1: Shows the minimum allowable sys- tem height and lateral offset for a 60° degree or greater inclination. Code specifies that offsets at 60° degrees or greater are considered horizontal and must follow the 75% percent rule for lateral to total vertical system height. Codes also allows only one offset in the total system when at 60° degrees or greater. The total vertical height in this example represents the minimum height of 8 feet and therefore the allowable lateral is 6 feet when the 75% percent rule applies. If the lateral length must exceed 75% then the system must be sized in accordance with the Category I venting tables.

Example 2: Shows a multiple offset each at 45° degrees of inclination. Multiple offsets are permit- ted if they do not exceed 45° degrees of inclination. The total lengths of the two offsets are not required to meet the 75% percent allowable rule.

Example 3: Shows a single offset at 45° degrees of inclination and therefore the lateral length at 10 feet of offset does not have to meet the 75% percent rule.

In each case the offsets must be supported and firestops must be positioned wherever the vent must pass through a sub-floor, ceiling joist or an attic overhang. The vent pipe must terminate vertically into a listed type vent cap and extend a sufficient height through an approved roof flash- ing, roof jack or a roof thimble. At all points the listed clearances must be maintained.

Vent terminations must be located in accordance with height and proximity rules of NFPA No. 54 or CAN/CGA B149. These rules apply to vents at 12 in. diameter or less and require a minimum height in accordance with the roof pitch and a minimum of 8 ft. distance from a vertical wall or obstruction (see Figure 11, page 10).

If venting horizontally through a side wall be- comes necessary, a listed thimble approved for use with B-type vent must be used. Check with your local codes before venting through a side wall.

Some codes areas allow the use of existing B-type vent systems if the system is at or above the recom- mended diameter of the flue; in this case 6".

The flue connection must be made using listed

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