Central Boiler Classic CL 4030 Owner's Manual page 44

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CLASSIC OUTDOOR FURNACE • OWNER'S MANUAL
4. Excessive draft - If a very tall extension is added to the chimney, the increased
draw through the draft may cause excessive wood consumption. Decreasing the
draft opening may increase efficiency and reduce wood consumption.
5. Supply and return line heat loss - If not using ThermoPEX, supply and return
lines buried in a wet, low-lying area may cause a large heat loss that will greatly
increase wood consumption.
6. High heat demand - Concrete slabs (with radiant heat) that are poorly insulated
or are exposed to water or cold outside temperatures will require increased wood
consumption (see Hydronic Installations section). Bringing a cold concrete slab
up to temperature the first time will take a considerable amount of time and
wood; once warm, wood consumption will be reduced if the concrete slab and
building are insulated properly. The following will also have a high heat demand:
poorly insulated buildings, buildings with large amounts of glass windows/doors,
buildings with overhead doors, greenhouses, uninsulated crawl spaces, outdoor
air infiltration and air leaking through foundation.