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Venting, Sidewall venting - negative draft – Lochinvar 45 User Manual

Page 16

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Installation & Service Manual

16

Masonry Chimney Installation

A masonry chimney must be properly sized for the
installation of a gas fired appliance. Venting of an appliance
into a cold or oversized masonry chimney can result in
op

er

a

tion

al and safety problems. Exterior masonry

chim neys, with one or more sides exposed to cold out door
tem per a tures, are more likely to have venting problems. The
temperature of the flue gases from an appliance may not be
able to suf fi cient ly heat the ma son ry structure of the chim ney
to generate proper draft. This will result in condensing of flue
gases, damage the masonry flue/tile, insufficient draft and
possible spill age of flue gases into an occupied living space.
Care ful ly in spect all chimney systems before installation. If
there is any doubt about the sizing or condition of a masonry
chimney, it must be relined with a prop

er

ly sized and

approved chimney liner system.

Inspection of a Masonry Chimney

A masonry chimney must be carefully inspected to determine
its suitability for the venting of flue gas es. A clay tile lined
chimney must be structurally sound, straight and free of
misaligned tile, gaps between liner sections, missing sections
of liner or any signs of con den sate drainage at the breaching
or clean out. If there is any doubt about the condition of a
masonry chimney, it must be relined. An unlined masonry
chimney must not be used to vent flue gases from this appliance.
An unlined chimney must be relined with an approved
chimney liner system when a new appliance is be ing attached to
it. Metallic liner systems (Type “B” double wall or flexible or
rigid metallic liners) are recommended. Consult with local
code officials to determine code requirements or the
advisability of using or relining a masonry chimney.

Sidewall Venting - Negative Draft

Figure 2-6_Unit with Fan Assisted Venting

The in duced draft fan MUST also be equipped with a prov ing
switch, properly interlocked into the ap pli ance’s con trol circuit
to prove fan operation before the main burn ers are allowed to
fire. A vertical or sidewall vent termination for an induced draft
fan MUST be in stalled per the recommendations of the fan
manufacturer and provide proper clearances from any
combustion or ventilation openings, win dows, doors or other
open ings into the building. All induced draft fan in stal la tions
must comply with local code requirements.

Fan Assisted Venting

A Power Venter Kit is available on Models 45,000 - 135,000
Btu/hr only (see Table 2B).

TABLE - 2B

VENT MATERIALS

Kit

Number

Input

Btu/hr

Material

KIT3103

45,000

PVC Rated (CPVC Optional)

75,000

PVC Rated (CPVC Optional)

KIT3104

90,000

CPVC Rated

135,000

CPVC Rated

Minimum Vent Length = 12 Equivalent Feet*

(ALL UNITS)

Maximum Vent Length = 25 Equivalent Feet*

(ALL UNITS)

* Equivalent Feet: 90° Elbow = 5 Feet

45° Elbow = 3 Feet

2

Venting

This appliance is NOT approved for sidewall venting with
the negative draft venting system as shipped from the
factory. An induced draft fan MUST be used if the
installation requires that the flue gases be vented out a
sidewall unless a power venter is used, see Fan Assisted
Venting
. A properly sized and in stalled induced draft fan
may also be used to vent the flue gases ver ti cal ly if required
by jobsite re stric tions. The induced draft fan must be listed
by a nationally recognized test agency, be properly sized and
installed per the rec om men da tions of the in duced draft fan
manufacturer and meet local code requirements. Use care to
ensure that the me chan i cal ly supplied draft does not exceed
the range of a negative 0.02 to 0.05 inches water column to
ensure proper operation. If draft exceeds the spec i fied range,
the fan must be adjusted or the installation of a baro met ric
damper in the flue may be required to prop er ly control draft.
An induced draft fan MUST be interlocked into the
appliance’s control circuit to start when the appliance calls
for heat.

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