Operating instructions

PROCEDURE 4—MINIMUM VENT PIPE CLEARANCE
Wood and other combustible materials must not be closer than 6 in. from any surface of single-wall metal vent pipe. Listed Type-B vent pipe or
other listed venting systems shall be installed in accordance with their listing.
PROCEDURE 5—REMOVING EXISTING BOILER FROM COMMON VENTING SYSTEM
When an existing boiler is removed from a common venting system, common venting system is likely to be too large for proper venting of
appliances remaining connected to it.
At time of removal of an existing boiler, the following items shall be followed with each appliance remaining connected to common venting system
placed in operation, while other appliances remaining connected to common venting system are not in operation.
1. Seal any unused openings in common venting system.
2. Visually inspect venting system for proper size and horizontal pitch and determine there is no blockage or restriction, leakage, corrosion,
and other deficiencies which could cause an unsafe condition.
3. Insofar as is practical, close all building doors and windows and all doors between space in which appliances remaining connected to
common venting system are located and other spaces of building. Turn on clothes dryers and any appliances not connected to common
venting system. Turn on any exhaust fans, such as range hoods and bathroom exhausts, so they will operate at maximum speed. Do not
operate a summer exhaust fan. Close fireplace dampers.
4. Place in operation appliance being inspected. Follow lighting instructions. Adjust thermostat so appliance will operate continuously.
5. Test for spillage at draft hood relief opening after 5 minutes of main burner operation. Use flame of a match or candle, or smoke from a
cigarette, cigar, or pipe.
6. After it has been determined that each appliance remaining connected to common venting system properly vents when tested as outlined
above, return doors, windows, exhaust fans, fireplace dampers, and any other gas-burning appliance to their previous conditions of use.
7. Any improper operation of common venting system should be corrected so installation conforms with the NFGC ANSI Z223.1-2002. When
resizing any portion of common venting system, common venting system should be resized to approach minimum size as determined using
the appropriate tables in Part 11 of the NFGC in the United States or Appendix B of the NSCNGPIC in Canada.
Table 4—Typical Chimney Sizes
BOILER INPUT
(BTUH)
FLUE AREA IN INCHES
Height (HT)*
10-15 ft 15-25 ft 25 ft up
Up to 100,000 6X6 6X5 5X5
Up to 155,000 6X7 6X6 6X5
Up to 230,000 7X8 7X7 6X7
Up to 350,000 9X9 8X9 8X8
* HT = top of thimble to top of flue. (See Fig. 4.)
For boiler input, refer to Fig. 1.
For information only — not meant to imply minimum sizes.
Fig. 4—Typical Masonry Chimney Requirements
A95144
3
/4 HT MAXIMUM
MUST SLOPE UP
AT LEAST
1
/4 IN.
PER FT OF
HORIZONTAL RUN
2-FT MIN
HT
3-FT MIN
ROOF RIDGE
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