11
IMPORTANT TO NOTE
1. Breaching runs must be as short as possible.
2. No more than six modules may be served by one
breaching run to assure adequate draft (unless otherwise
specified on factory-approved specially-designed venting
systems).
3. Observe breaching construction requirements.
4. Observe proper chimney requirements.
5. Flues from other gas-burning appliances must not be
connected into heating plant breaching; otherwise, inad-
equate draft may result.
6. Natural draft equipment (heating plants without
mechanical draft components) must not be connected into
any portion of a mechanical draft or power vent system
operating under positive pressure, including the chimney.
7. If shop drawings with approved breaching and chimney
sizes are not available, you can use the sizing guidelines
recommended in Appendix A at the rear of this manual.
MULTI-TEMP HEATING PLANT VENTING SYSTEM
:
Consists of draft regulators (factory-supplied), vent con-
nectors, breaching and chimney or vent pipe (see Figure
4.1). Draft regulators are installed between the modules’s
flue outlet and vent connector. Breaching is the horizon-
tal manifold for connecting each module’s vent connector
to the chimney. Venting system components must be
installed in accordance with requirements of the local
authority having jurisdiction.
BREACHING CONSTRUCTION REQUIREMENTS:
Round breaching is preferred to maximize flue gas flow.
Rectangular breaching is the only acceptable alternative;
the larger dimension of the rectangle must be in the
vertical.
Breaching should be constructed of sheet metal
with smooth interior surfaces. Figure 4.2 provides mini-
mum sheet metal gauges (adhere to local requirements
for sheet metal thickness). All joints must be tight to pre-
vent leakage, by sufficient joint overlap, rolled joints or
welding.
CHIMNEY REQUIREMENTS:
Lined masonry chimneys
or Type B metal vent systems, constructed in accordance
with national codes, are suitable. Chimney construction
materials must be compatible with the fuel being used.
Chimney condition is of paramount importance for a safe
and efficient installation. For existing chimneys, all instal-
lations must include a chimney inspection by a qualified
individual or agency. Particular attention should be paid
on oil-to-gas conversions. Soot may have accumulated in
the chimney and/or degraded the chimney liner. Most util-
ities require the installation of a new liner, safety spill
switches or other chimney upgrades. Check with the local
utility for the required safety precautions.
MECHANICAL DRAFT REQUIREMENTS:
When pro-
per venting of the Multi-Temp heating plant cannot be
accomplished by natural means, mechanical draft induc-
ers or power venters may be used, properly sized and
properly installed, following the recommendations of their
manufacturers. A fan prove switch must be used in the
control system and wired such that the heating plant will
not fire (prevent flow of gas) until inducer or power venter
fan operation is proved.
VENT
CONNECTORS
DRAFT
REGULATORS
BREECHING
POWER GAS HEATING PLANT
C
H
I
M
NE
Y
FIGURE 4.1
MINIMUM SHEET METAL GAUGE
FOR ROUND AND RECTANGULAR BREECHING
DIAMETER
IN INCHES
6 TO 10
10 TO 12
SHEET
METAL
GAUGE
24
22
20
16
14 TO 16
OVER 16
GREATER
DIMENSION
IN INCHES
10 TO 13
14 TO 18
19 TO 20
OVER 20
ROUND
RECTANGULAR
FIGURE 4.2
STEP 1: PLANNING AHEAD
SECTION 4: VENTING THE HEATING PLANT
DANGER: A chimney which does not meet modern
safety standards will result in a fire or deadly carbon
monoxide poising of the building residents.
