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TROUBLESHOOTING VENTING PROBLEMS

Flue Gas Spillage

Causes of Spillage and Corrective Action

CAST IRON STOVE AND B-VENT BURNER SYSTEM INSTALLATION

Check Gas Type

TROUBLESHOOTING

VENTING PROBLEMS

Most venting problems are caused by incorrect vent sizing, im- proper installation, or inadequate air supply. A preliminary check for a field problem might include:

Checking the vent sizing according to manufacturer’s specifica- tions, appliance input, and venting configuration

Examining the entire venting system for faults such as discon- nected joints for damaged vent sections

Making sure vent and air openings are not obstructed

If these procedures do not reveal the source of the problem, trouble- shooting may include attention to common venting problems.

Elbows

Too many elbows cause excessive restriction of flow and may result in spillage. Usually, two 90º turns can be tolerated in a properly sized venting system. More than two may cause problems and necessitate changing the system.

Negative Pressure in the Dwelling

An extremely tight house may not supply adequate combustion and venting air. Use of mechanical exhaust such as a dryer vent or range vent may worsen the problem. An air exchange system must be installed in the dwelling to correct this problem.

FLUE GAS SPILLAGE

Spillage occurs when flue gases cannot exit the vent system and back up into the dwelling. A primary symptom of appliances equipped with a Vent Safety Shutoff System (flue spill switch) is unexplained appliance shutoffs. Other symptoms of flue gas spill- age at the draft hood include condensation on walls and windows and/or noticeable odors. Spillage may also result in the release of carbon monoxide, a colorless, odorless, highly toxic gas. A simple spillage test can be conducted if spillage is suspected. See Checking Gas Connection, page 14.

CAUSES OF SPILLAGE AND CORRECTIVE ACTION

Incorrect Vent Sizing

If the vent is too small or too short, spillage may occur. If the vent is too large, excessive dilution air may cool flue gases and reduce draft, causing spillage. The vent cap size should also be checked. Check manufacturer’s instructions, appliance input rating, and appropriate sizing tables.

Venting Condition

Loose joints can affect draft and cause spillage. “Mashed” vent sections and damaged vent caps can restrict flow and cause spillage. Examine and replace as needed.

Obstructions

Small animals or birds may get into and block the vent or draft hood outlet. Dust, lint, and foreign objects may obstruct air inlets. Remove obstructions and clean openings.

Lateral Run

Lengthy horizontal or non-vertical runs cause resistance to flow and may reduce draft enough to cause spillage. The pitch of lateral runs can also be a problem; lateral runs should be pitched 1/4" rise per foot of horizontal run from the appliance to the vent.

Flue Gas Cooling

Venting exposed to extremely cold temperatures or venting of single wall construction loses heat needed to maintain draft; mas- sive masonry chimneys absorb needed heat. If the flue gases cool excessively, draft is reduced and spillage may result. Use proper materials, insulate and protect properly, reline when necessary.

Down Drafts

In certain wind conditions and in certain relationships with nearby structures and objects, high pressure conditions may affect draft negatively. Relocate the vent cap, raise its height, or use an approved high wind cap.

CAST IRON STOVE AND B-VENT BURNER SYSTEM INSTALLATION

NOTICE: This burner system is intended for use as supplemental heat. Use this burner system along with your primary heating system. Do not install this stove and burner system as your primary heat source. If you have a central heating system, you may run system’s circulating blower while using heater. This will help circulate the heat throughout the house. In the event of a power outage, you can use this burner system as your primary heat source.

CHECK GAS TYPE

Use proper gas type for the burner system unit you are installing. If you have conflicting gas types, do not install burner system. See dealer where you purchased the stove and burner system for proper burner system according to your gas type. Conversion kits are also available for these models, see Accessories on page 32.

IMPORTANT: If installing gas conversion kit, do so at this time. Be sure to follow all installation instructions included with conversion kit.

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Desa SBVBP Troubleshooting Venting Problems, Cast Iron Stove and B-VENT Burner System Installation, Flue GAS Spillage