Beckett CG4 - Manual (Page 7)

7 CG4 Burner Manual
Section: INSPECT/PREPARE INSTALLATION SITE
5. Any leakage between tiles, around clean-out doors,
or around the vent pipe should be sealed.
6. A Draft regulator is required, it shall be a double-
acting type, agency recognized for use with gas
vent systems.
7. The design and sizing of the appliance’s vent
system shall comply with the requirements of NFPA
54 Chapters 12 and 13.
8. A chimney flue shall extend at least 3 feet above
the highest point at which the chimney comes in
contact with the roof, and not less than 2 feet above
the highest roof surface or structure within 10 feet
horizontally of the chimney. Refer to Figure 4.
Some local codes and gas
utilities require the installation of
a thermal Safety switch on the double-acting draft
control, or draft hood. This is a very good practice
and provides the following protection:
The thermal safety switch senses flue gas spillage
caused by blocked flue exhaust, prolonged down-draft,
or insufficient draft. The safety is wired in series with the
burner control circuit and shuts the burner off, when the
spillage of hot flue gases is detected.
Minimum Clearence: 2 FT.
Figure 4 – Chimney Design - Above the Roof
NOTE: Correct chimney design is shown by dotted lines. Incorrect chimney design, as shown by the solid
lines, may result in down-drafts.
Insulated stainless steel chimney liners
The new designs of furnaces and boilers in conjunction
with flame retention gas burners are more efficient.
One result of increased efficiency is lower flue gas
temperatures. As flue gases rise in the chimney, they
cool and condense when they reach the dew point.
The condensation mixes with sulphur in the flue gases
creating sulfuric acid. The acid attacks the chimney
mortar, brick and clay liners causing corrosion,
deterioration and blockage of the chimney. Eventually
the blockage could prevent exhausting the flue gases.
Instead, the flue gases vent out the barometric damper
into the living space.
Therefore it is strongly recommended that an approved
insulated stainless steel chimney liner be installed. The
installing contractor is solely responsible for installation
of the proper vent system.
○ For those installations not requiring a chimney, such
as through-the-wall vented appliances, follow the
instructions given by the appliance and power venter
(if used) manufacturers.