Thermal Solutions EVO-500 Installation, Operating And Service Instructions page 11

p. Locate vent terminal above combustion air intake
terminal (if used) and no closer than one (1) foot
horizontally.
q. Vertical venting requires flashing and a storm collar to
prevent moisture from entering the structure.
r. Vertical vent termination must be at least two (2)
feet plus the expected snow accumulation above roof
penetration height.
s. This boiler's venting may be Category IV (positive
vent pressure, flue condensing) or Category II (non-
positive vent pressure, flue condensing), with regards to
National Fuel Gas Code/NFPA 54 ANSI Z223.1.
2. Positive Pressure Venting Requirements
a. Vent pipe system must be fully sealed.
WARNING
Do not use vent dampers or barometric dampers
with positive pressure vent systems.
b. Direct vent applications: For direct vent (ducted
combustion air) installations, the maximum vent length
is 50 equivalent feet. The vent length is equal to the
total length of straight pipe plus the equivalent length of
vent fittings.
Non-direct vent applications: For non-direct vent
c.
installations (those without ducted combustion air),
design the vent system so that the pressure measured at
the outlet of the boiler is between 0"w.c. and 0.3"w.c. at
high fire.
d. For sidewall venting, slope pipe toward vent
termination, if possible.
e. See Figures 2, 3 and 4 for examples of positive pressure
venting arrangements.
3. Negative Pressure (Conventional) Venting
Requirements
This section outlines requirements for conventional
venting installations, where a negative pressure at
the boiler flue outlet is achieved by means of natural
convection through a vertical length of vent pipe or
lined chimney.
a. Refer to Figure 5 for an example of a typical
conventional venting arrangement.
b. A lined chimney or vertical length of vent pipe may be
used. Chimney lining must be acceptable for use with
condensing flue gas.
c. The minimum chimney/vertical vent height is 15 feet.
d. Install a condensate drain to collect any condensate that
may form in the lined chimney/vertical vent.
e. Install a double acting barometric damper with integral
flue spillage interlock.
f. The chimney/vertical vent and flue connector must be
sized and configured to provide a minimum - 0.04 inch
w.c. pressure (draft) at the boiler flue outlet.
g. The chimney must be protected from down drafts, rain
and debris by using a chimney cap or star.
4. General Guidelines
a. This boiler has been certified with AL29-4C® venting.
Select a vent material that is approved for use with
condensing flue gasses.
b. Install vent system before installing air intake, water,
gas or electrical connections.
c. For instances where the vent system manufacturer's
instructions do not make a specification, refer to the
below points.
i. Make sure pipe and fittings are clean by swabbing
with alcohol. Use Dow Corning 736 or 732 RTV,
Polybar #500 RTV or Sil-bond 4500 or 6500 to seal
vent pipe.
ii. Refer to the appropriate drawings in this section
of this manual to determine common acceptable
configurations of venting system.
5. IMPORTANT
The Commonwealth of Massachusetts requires
compliance with regulation 248 CMR 4.00 and 5.00
for installation of side-wall vented gas appliances as
follows:
a. For all side wall horizontally vented gas fueled
equipment installed in every dwelling, building or
structure used in whole or in part for residential
purposes, including those owned or operated by the
Commonwealth and where the side wall exhaust
vent termination is less than seven (7) feet above
finished grade in the area of the venting, including
but not limited to decks and porches, the following
requirements shall be satisfied:
1. INSTALLATION OF CARBON MONOXIDE
DETECTORS. At the time of installation of the side
wall horizontal vented gas fueled equipment, the
installing plumber or gasfitter shall observe that
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