2G. Securing Special Gas Vent, 3A. Gas Piping

Page 8	LAARS HEATING SYSTEMS

Figure 10. Special Gas Vent Connection.

Figure 11. Non-Concentric Combustion Air Source.

(6.5 sq. cm) per 1,000 BTU/hr (293W) boiler input, but not be less than 100 square inches (645.2 sq. cm). These openings shall freely connect with areas having adequate infiltration from outside.

3.When all air is provided from outdoors, the confined space shall be provided with one opening within 12" of the ceiling. This opening shall connect directly, or by ducts, with outdoors or spaces (crawl or attic) that freely connect with the outdoors, and shall have a minimum free area of:

a.1 sq. in. per 3000 BTU/hr (7 cm2/kw) of the total input rating of all equipment located in the enclosure, and

b.Not less than the sum of the areas of all vent connectors in the confined space.

2F. Connecting Special Gas Vent to the Appliance

Part number 2400-372 is used with a vent terminal (p/n 2400-277) to secure the 3 inch special

gas vent to the flue outlet of the appliance. Heat-Fab pipe or fittings (p/n 2400-350 or 2400-352) or the male end of Z-Vent pipe (Z-Vent # 02 SVEPXX030) may be installed over the flue outlet of the Appliance (see Figure 10).

2G. Securing Special Gas Vent

Attach p/n 2400-277 with sheet metal screws to the 5" collar on the appliance with a short piece of 5" pipe or to the end of the 5" combustion air duct.

Attach p/n 2400-372 bracket and tighten clamp. Form the tabs on the bracket onto the special gas vent pipe and secure the tabs with the 3" clamp. After the clamp has been tightened, fold the end of the tabs down over the clamp (see Figure 10).

DO NOT use screws in any portion of the 3" special gas vent.

When providing combustion air from another location, the connection of the 5" duct to the appliance must be secured with sheet metal screws.

Each 5" joint in the 5" duct must be secured with sheet metal screws.

In this type of installation, p/n 2400-372 must be used to secure the special gas vent at the point where it exits the duct. The combustion air supply should be protected from debris entering the duct with an appliance vent terminal, p/n 2400-277, as shown in Figure 8 or with a large mesh screen.

Follow the special gas vent manufacturer's instructions for cleaning and sealing all parts before assembling.

Apply ¼" bead of silicone sealer (GE108 or Novagard 400) to the 3" flue outlet of the appliance approximately 1" from the end.

Slide 3" inner vent pipe or 1-880 adapter, when using outer 3" telescoping section, over the appliance flue outlet and push down to stop (do not force pipe beyond stop).

Apply another bead of silicone around this joint and smooth out.

Apply ¼" bead of silicone to subsequent 3" joints. An alternate, nonconcentric combustion air

source may be installed (as shown in Figure 11), provided that the minimum 4" diameter combustion air duct does not exceed 15' (4.6m). Termination should include an air screen and be located in a qualified air space (see Section 2E) or outside.

SECTION 3.

3A. Gas Piping

The appliance requires an inlet gas pressure of at least 4" w.c. (1.0kPa) and no greater than 13" WC (3.2kPa). Check with your local gas utility or supplier for availability of this pressure range.

Refer to Table 3 to size the supply piping to minimize pressure drop between meter or regulator and unit.

LAARS HEATING SYSTEMS