Raypak RAYTHERM 133-4001 - Manual (Page 13)

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Fig. 13: Drafthood Installation—Models 514–824
Models 962-1826
Locate and assemble as shown in Fig. 14. Secure with
screws supplied in envelope in carton.
Models 2100-4001
These models have built-in drafthoods. For proper
operation, the drafthood outlet must be connected to
the venting system.
Vent Piping
Vent piping the same size or larger than the drafthood
outlet is recommended, however, when the total vent
height is at least 10 ft. (drafthood relief opening to vent
terminal), the vent pipe size may be reduced as spec-
ified in Chapter 10 of the latest edition of the National
Fuel Gas Code, ANSI Z223.1.
As much as possible, avoid long horizontal runs of
vent pipe and too many elbows. If installation requires
horizontal non-vertical runs, the vent pipe must have a
minimum of 1/4 inch per foot rise and should be sup-
ported at not more than 5 ft. intervals. Plumbers tape,
criss-crossed, will serve to space both horizontal and
vertical piping.
Gas vents supported only by the flashing and extend-
ing above the roof more than 5 ft. should be securely
guyed or braced to withstand snow and wind loads.
We recommend the use of insulated vent pipe spacers
through the roof and walls.
For protection against rain or blockage by snow, the
vent pipe must terminate with a vent cap which com-
plies with the local codes or, in the absence of such
codes, to the latest edition of the National Fuel Gas
Code, ANSI Z223.1.
The discharge opening must be a minimum of 2 ft. ver-
tically from the roof surface and at least 2 ft. higher
than any part of the building within 10 ft.
Vent stack shall be at least 5 ft. in vertical height above
the drafthood outlet. The vent cap location shall have
a minimum clearance of 4 feet horizontally from, and
in no case above or below, unless a 4-foot horizontal
distance is maintained, from electric meters, gas
meters regulators and relief equipment.
The weight of the vent stack or chimney must not rest
on boiler drafthood. Support must be provided in com-
pliance with applicable codes. The boiler top and
drafthood must be readily removable for maintenance
and inspection. Vent pipe should be adequately sup-
ported to maintain proper clearances from combustible
construction.
Fig. 14: Drafthood Installation—Models 962–1826
WARNING: Indoor boilers require a drafthood
that must be connected to a vent pipe and properly
vented to the outside. Failure to follow this
procedure can cause fire or fatal carbon monoxide
poisoning.