Vermont Casting 2477CE manual Draft Management, Masonry Chimney

Dutchwest Non-Catalytic Convection Heater

•Inspect for and remove ash build-up behind the com- bustion package. This should be done in conjunction with annual cleaning of the chimney connector since this inspection is most conveniently done through the flue collar opening. Inspect the passages to either side of the combustion package (a mirror will be helpful) and vacuum away ash using a flexible vacu- um hose inserted into each passage. Care should be taken not to damage the white fibrous material in this rear chamber. (Fig. 30)

The Chimney Connector

TWO WEEKS:

•Inspect the chimney connector and chimney. Clean if necessary.

TWO MONTHS:

•Inspect the chimney and chimney connector. Pay particular attention to the horizontal runs of chimney

connector, and the elbows. Clean the system if nec- essary.

ANNUAL SPRING CLEANING:

•Disassemble the chimney connector and take it outdoors for inspection and cleaning. Replace weak sections of connector.

•Inspect the chimney for signs of deterioration. Re- pairs to a masonry chimney should be made by a professional mason. Replace damaged sections of prefabricated chimney. Your local Dutchwest dealer or a chimney sweep can help determine when re- placement is necessary.

•Thoroughly clean the chimney.

Inspect and

Vacuum Both

Rear Corners

ST876 Ash Build-Up

Fig. 30 Inspect and clean out ash accumulation on either side of the non-catalytic combustion system.

Draft Management

Your stove is only one part of a system that includes the chimney, the operator, the fuel, and the home. The other parts of the system will affect how well the stove works. When there is a good match between all the parts, the system works well.

Wood stove operation depends on natural (unforced) draft. Natural draft occurs when exhaust gas is hotter (and therefore lighter) than the outdoor air at the top of the chimney. The greater the temperature difference, the stronger the draft. As the hot exhaust gas rises out of the chimney, it generates suction that draws air into the stove for combustion. A slow, lazy fire when the stove’s air inlets are fully open indicates a weak draft. A brisk fire, supported only by air entering the stove through the air inlets, indicates a good draft. The inlets are passive; they regulate how much air can enter the stove, but they don’t force air into it.

The efficiency of a modern woodburning appliance, (in which the amount of air available for combustion is regulated), depends on the chimney to keep exhaust gases warm all the way outdoors. The characteristics

of your chimney - whether it is steel or masonry, interior or exterior, matched or mismatched to the stove outlet,

-determine how quickly it will warm up and how well it will sustain the optimum temperatures necessary to maintain strong draft and efficient combustion. Here fol- lows a description of various flue system characteristics and the related effects on stove performance.

Masonry Chimney

Although masonry is the traditional material used for chimney construction, it can have distinct performance disadvantages when used to vent a controlled-combus- tion woodstove. Masonry forms an effective ‘heat sink’

-that is, it absorbs and holds heat for long periods of time.

The large mass, however, may take a long time to become hot enough to sustain a strong draft. The larger the chimney (in total mass), the longer it will take to warm up. Cold masonry will actually cool exhaust gases enough to diminish draft strength. This problem is worse if the chimney is located outside the home or

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