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 is practical, the Air Command 80 may need to be vented vertically with a B Vent.
Under some conditions, Furnace G*9 could be installed rather than an G*8. The G* 9 can be vented horizontally 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 referenced 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 venting 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 flashing.
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 edition and in the National Standard of Canada, CAN/CSA B149.1 and CAN/CSA B149.2 - latest editions and amendments 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 AL294C stainless steel should be used. Common sources of chlorine and fluorine compounds include indoor swimming pools and chlorine bleaches, paint strippers, adhesives, paints, varnishes, 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 liners were developed for use with oil or solid fuel appliances. 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/CSA B149.1 and CAN/CSA B149.2 - latest editions and amendments.
To install the liner, read and follow the liner manufacturer’s instructions and your local codes. Excess liner length should be pulled out of the chimney and cut off. Use caution when doing this, as the cut edges of flexible liners may be sharp. Do not spiral excess liner inside of the chimney. Support the liner as recommended by the liner manufacturer.
Some manufacturers of flexible liners offer an insulation sleeve designed to be added to the liner before it is installed in the chimney. (Poured insulation, either vermiculite or other materials, is no longer recommended.) Insulation will need to be added to the flexible liner if:
•It is required by the liner manufacturer’s instructions.
•The previous liner was properly sized and installed, and suffered from condensation damage.
•It is required by your local building codes.
Even if none of those three conditions exist which require additional liner insulation, the installer may wish to consider it if:
•The local climate is very cold.
•The chimney is very tall.
•The vent connectors used are very long or have a large number of elbows.
•Local experience indicates that flexible liners installed without insulation are likely to have condensation problems.
Insulation must be selected and installed in accordance with the liner manufacturer’s instructions.
Finally, cap the chimney and terminate the liner in accordance with the liner manufacturer’s instructions.
VIII. ELECTRICAL CONNECTIONS
WARNING
TO AVOID THE RISK OF ELECTRICAL SHOCK, WIRING TO THE UNIT MUST BE POLARIZED AND GROUNDED.
WARNING
TO AVOID INJURY, ELECTRICAL SHOCK OR DEATH, DISCONNECT ELECTRICAL POWER BEFORE SERVICING OR CHANGING ANY ELECTRICAL WIRING.
