Drolet Heat Commander Installation And Operating Instructions Manual page 18

Proper installation
o Maximum unsupported horizontal length: 3 feet (1 m);
o Galvanized flue pipes must not be used because the coatings vaporize at high
temperatures and release dangerous gases;
o Flue pipes must be at least 24 gauge in thickness;
o The chimney connector must be in good condition;
o Flue pipe joints should overlap 1 1/4". (30 mm);
o Straight up installations need to have either a connector where one end has no
fastener or a telescopic/adjustable length;
o Removal of the assembly for cleaning should not require that the furnace be
moved;
o The male ends of the sections must be oriented towards the appliance so that
falling dust and condensation stay inside the pipe;
o A straight flue pipe assembly offers the least restriction to gas flow and results in
stronger draft. Straight assemblies also need less maintenance as there are is
less restrictions from corners to collect creosote;
o The use of 45° elbows is strongly recommended;
o Elbow added resistance is equivalent to : a 90° elbow = 5' (152 cm), a 45° elbow
= 2.5' (76 cm);
o Never use more than two 90° elbows.
CAUSES
RESTRICTION
improper installation