Goodman Mfg AMV8 instruction manual Vii. Exterior Masonry Chimneys Category I Furnaces Only

VII. EXTERIOR MASONRY CHIMNEYS -

CATEGORY I FURNACES ONLY

An exterior masonry chimney is defined as a “Masonry chimney exposed to the outdoors on one or more sides below the roof line.” The ability to use a clay lined masonry chimney depends on a parameter not associated with interior chimneys. This variable is the geographic location of the installation. Researchers have discovered that the winter design temperatures have a direct impact on the suitability of this type of venting. In most situations, the existing masonry chimneys will require a properly sized metallic liner.

WARNING

POSSIBILITY OF PROPERTY DAM AGE, P ERSO NAL INJURY OR DEATH

DAM AGING CONDE NSATION CAN OCCUR INSIDE M ASO NRY CHIM NEYS W HEN A SINGLE FAN AS SIS TED CATEGO RY I APPLIANCE (80% AFUE FURNACE) IS VENTED WITHOUT ADEQUATE DILUTION AIR . DO NO T CONNECT AN 80% FURNACE TO A MAS ONRY CHIM NEY UNLES S THE FURNACE IS COM M ON VENTED W ITH A DRAFT HOOD EQ UIPPED APPLIANCE O R THE CHIM NEY IS LINED W ITH A M ETAL LINER OR TYPE B M E TAL VENT . ALL INS TALLATIONS USING M ASO NRY CHIM NEY S MUS T BE SIZED IN ACCORDANCE WITH THE APPROPRIATE VENTING TABLES . IF AN 80% FURNACE IS COM M ON VENTE D W ITH A DRAFT HOOD EQUIPPED APPLIANCE, THE POTENTIAL FO R CONDENSATIO N DAM AG E MAY STILL EXIS T W ITH EXTREM ELY COLD CONDITIO NS, LONG VENT CONNECTO RS, EXTERIOR CHIM NEYS, O R ANY CO M BINATION OF THESE CONDITIONS. THE RISK OF CONDENS ATION DAM AG E IS BEST AVO IDED BY USING THE M ASONRY CHIM NEY AS A PATHWAY FOR PRO PERLY SIZED M ETAL LINER O R TYPE B

M ETAL VENT.

This inspection is based upon a draft topical report, “Masonry Chimney Inspection and Relining”, issued by the Gas Research Institute. While not yet finalized, we believe this report represents the best information on this subject which is currently available.

Proper Chimney	No	Line, terminate with
Termination?		listed vent cap
(Check 1)		(Fix 1)
Yes
Chimney channel		Change venting
free of solid and	No
liquid fuel		arrangements
appliances?		(Fix 2)
(Check 2)
Yes
Crown in good		Rebuild crown
	No	(Fix 3)
condition
		and/or Reline
(Check 3)
		(Fix 4)
Yes

Crown	Wash
		Roof Line
Clay Tile Size Generally	Clay Tile Size: 8" x 8" x12"
12" x 12" (24" Length)
	(Each x 24" Length)
		Attic Floor
	1/2" to 1" Air Space
	Second Floor
Throat
Damper
		First Floor
		Water Heater
Breech	F.A.F. Vent	Vent Connector
	Connector
	Fan Assisted	Natural Draft
Clean Out	Forced Air	Water Heater
	Furnace

Basement Floor

Figure 8 - Typical Multiple Flue Clay Tile Chimney

CHECKLIST SUMMARY

This checklist serves as a summary of the items to be checked before venting an 80+ furnace into a masonry chimney. In addition, we recommend that a qualified serviceman use this checklist to perform a yearly inspection of the furnace venting system.

This checklist is only a summary. For detailed information on each of the procedures mentioned, see the paragraph referenced with each item.

IO-247A

Cleanout free of		Reline
debris?	No
		(Fix 4)
(Check 4)
Yes
Liner in good		Reline
condition?	No
		(Fix 4)
(Check 5)
Yes
Dilution air		Reline
available?	No
		(Fix 4)
(Check 6)
Yes
Complete the
installation.
(Check 7)

CHECK 1 - PROPER CHIMNEY TERMINATION.

A masonry chimney used as a vent for gas fired equipment must extend at least three feet above the highest point where it passes through the roof. It must extend at least two feet higher than any portion of a building within a horizontal distance of 10 feet. In addition, the chimney must terminate at least 3 feet above any forced air inlet located within 10 feet. The chimney must extend at least five feet above the highest connected equipment draft hood outlet or flue collar.

If the chimney does not meet these termination requirements, but all other requirements in the checklist can be met, it may be possible for a mason to extend the chimney. If this will not be practical, see Fix 1.

11 12/04