OWNER’S MANUAL
VENTING INSTALLATION
Continued
HIGH ALTITUDE
INSTALLATION
Your Sun Valley
When installing this fireplace at an eleva- tion above 2000 feet (in the USA), you may need to decrease the input rating by chang- ing the existing burner orifice to a smaller size. Reduce input 4% for each 1000 feet above sea level. Check with your local gas company for proper orifice size identifica- tion and proper orifice for your location.
When installing this fireplace at an eleva- tion above 4500 feet (in Canada), check with local authorities.
For assistance with any high altitude installa- tion contact DESA International’s Technical Service Department at
TROUBLESHOOTING VENTING PROBLEMS
Most venting problems are caused by incor- rect vent sizing, improper installation, or inadequate air supply. A preliminary check for a field problem might include:
•Using a draft meter to determine if venting system draft meets manufacturer’s specifications
•Checking the vent sizing according to manufacturer’s specifications, appliance input, and venting configuration
•Examining the entire venting system for faults such as disconnected 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, troubleshooting may include attention to common venting problems.
FLUE GAS SPILLAGE
Spillage occurs when flue gases cannot exit the vent system and back up into the dwell- ing. A primary symptom of appliances equipped with a Vent Safety Shutoff System (flue spill switch) is unexplained appliance shutoffs. Other symptoms of flue gas spillage 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 con- ducted if spillage is suspected. See Checking Gas Connection, pages 13 and 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 in- put rating, and appropriate sizing tables.
Venting Condition
Loose joints can affect draft and cause spill- age. “Mashed” vent sections and damaged vent caps can restrict flow and cause spill- age. 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. Re- move obstructions and clean openings.
Lateral Run
Lengthy horizontal or
Elbows
Too many elbows cause excessive restric- tion 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 Cooling
Venting exposed to extremely cold tem- peratures or venting of single wall construc- tion loses heat needed to maintain draft; massive masonry chimneys absorb needed heat. If the flue gases cool excessively, draft is reduced and spillage may result. Use proper materials, insulate and protect prop- erly, 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.
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