Amana AMH8 Operations Instructions download pdf (Page 28)

PRODUCT DESIGN

Check 7 - Complete the Installation.

If Checks 1 through 6 have been satisfactory, and the liner

is an acceptable size as determined by the tables in Na-

tional Fuel Gas Code NFPA 54/ANSI Z223.1 - latest edition

and in the National Standard of Canada, CAN/CGA B149.1

and CAN/CGA B149.2 - latest editions and amendments,

then the clay tile liner can probably be used as a vent for

the gas appliances. However, the installer must keep in mind

the following factors which may render the tile liner unsuit-

able for use as a vent:

• Extremely cold weather

• Long vent connectors

• Masonry chimneys with no air gap between the liner

and the bricks. (In practice, this can be difficult to

detect.)

• Exterior chimneys (The tables in National Fuel Gas

Code NFPA 54/ANSI Z223.1 - latest edition and in

the National Standard of Canada, CAN/CGA B149.1

and CAN/CGA B149.2 - latest editions and amend-

ments assume interior chimneys.)

If, in the judgment of the local gas utility, installer, and/or

local codes; one or more of the above factors is likely to

present a problem, the chimney must be relined (Fix 4).

Fix 1 - Liner Termination.

Any cap or roof assembly used with a liner must be ap-

proved by the liner manufacturer for such use. The liner

and cap/roof assembly must then terminate above the roof

in accordance with the manufacturer’s instructions.

In some cases, a shorter extension above the roof may be

possible with a liner than would be required with a masonry

chimney.

For further information on relining, see Fix 4.

Fix 2 - Change Venting Arrangements

If the masonry chimney has more than one channel, it may

be possible to vent the gas appliances into one channel and

vent the solid or liquid fuel appliance(s) into another

channel(s). Do not vent an 80% furnace inside of a metal

liner with other appliances vented outside the liner.

Alternatively, the homeowner may agree to discontinue use

of the fireplace (solid fuel appliance). If so, the tile liner

must be cleaned to remove creosote buildup. The fireplace

opening must then be permanently sealed.

If oil-fired appliance(s) are being replaced by gas-fired

appliance(s), the tile liner must first be cleaned to remove

the fuel oil residue.

If none of the above options are practical, the 80% furnace

may need to be vented vertically with B vent.

Under some conditions a 90%+ furnace could be installed

rather than an 80%. The 90% furnace can be vented hori-

zontally or vertically through PVC pipe.

Fix 3 - Rebuild the Crown.

If the chimney crown is damaged, a qualified mason must

repair it in accordance with nationally recognized building

codes or standards. One such standard which may be ref-

erenced is the Standard for Chimneys, Fireplaces, Vents,

and Solid Fuel Burning Appliances, ANSI/NFPA 211.

Fix 4 - Relining.

Relining options include B vent and flexible liners.

If the chimney has diagonal offsets, B vent probably cannot

be used.

If B vent is to be used, it must be supported adequately.

Supports (such as fire stops or thimbles) must be used to

prevent the B vent from coming into direct contact with the

tile liner or chimney walls. Direct contact would result in

higher heat loss, with an increased possibility of poor vent-

ing system performance.

It is not acceptable to vent one appliance inside the B vent

and other appliances outside. The excess space between

the B vent and the chimney walls must be covered at the top

of the chimney by a weatherproof, corrosion resistant flash-

ing.

The B vent should then be topped with a listed vent cap. The

listed vent cap will, when installed per the manufacturer’s

instructions, prevent problems due to rain, birds, or wind

effects.

A B vent installed as described in this section is considered

to be an enclosed vent system, and the sizing tables in

National Fuel Gas Code NFPA 54/ANSI Z223.1 - latest edi-

tion and in the National Standard of Canada, CAN/CGA

B149.1 and CAN/CGA B149.2 - latest editions and amend-

ments may be used.

If a flexible liner is to be used, it must be made of the proper

materials:

• For most residential applications, an aluminum liner

should be acceptable.

• If the combustion air supplied to the furnace will be

contaminated with compounds containing chlorine or

fluorine, a liner of AL29-4C stainless steel should be

used. Common sources of chlorine and fluorine com-

pounds include indoor swimming pools and chlorine

bleaches, paint strippers, adhesives, paints, var-

nishes, sealers, waxes (which are not yet dried) and

solvents used during construction and remodeling.

Various commercial and industrial processes may

also be sources of chlorine/fluorine compounds.

• Heavier gauge 300 and 400 series stainless steel lin-

ers were developed for use with oil or solid fuel appli-

ances. They are not suitable for use with gas-fired

appliances. Flexible liners specifically intended and

tested for gas applications are listed in the UL "Gas

and Oil Equipment Directory". (UL Standard 1777).

For sizing of flexible liners, see Note 22 and the tables in

the National Fuel Gas Code NFPA 54/ANSI Z223.1 - latest

edition and in the National Standard of Canada, CAN/CGA

B149.1 and CAN/CGA B149.2 - latest editions and amend-

ments.

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