11At the time of removal of an existing boiler, the follow-ing steps shall be followed with each applianceremaining connected to the common venting systemplaced in operation, while the other appliances remain-ing connected to the common venting system are notin operation.1. Seal any unused openings in the common ventingsystem.2. Visually inspect the venting system for proper sizeand horizontal pitch and make sure there is noblockage or restriction, leakage, corrosion andother deficiencies which could cause an unsafecondition.3. Insofar as is practical, close all building doors andwindows and all doors between the space in whichthe appliances remaining connected to the com-mon venting system are located and other spacesof the building. Turn on clothes dryers and anyappliance not connected to the common ventingsystem. Turn on any exhaust fans, such as rangehoods and bathroom exhausts, so they will oper-ate at maximum speed. Do not operate a summerexhaust fan. Close fireplace dampers.4. Place in operation the appliance being inspected.Follow the lighting instructions. Adjust thermostatso appliance will operate continuously.5. Test for spillage at the drafthood relief openingafter 5 minutes of main burner operation. Use theflame of a match or candle, or smoke from a ciga-rette, cigar or pipe to visually check spillage.6. After it has been determined that each applianceremaining connected to the common venting sys-tem properly vents when tested as outlined above,return doors, windows, exhaust fans, fireplacedampers and any other gas burning appliance totheir previous conditions of use.7. Any improper operation of the common ventingsystem should be corrected so that the installationconforms with the latest edition of the NationalFuel Gas Code, ANSI Z223.1. When resizing anyportion of the common venting system, the com-mon venting system should be resized toapproach the minimum size as determined usingthe appropriate tables in Chapter 10 and inAppendix G of the National Fuel Gas Code, ANSIZ 223.1 and CSA - B149.Vent Damper InstallationLocationThe vent damper supplied with each boiler must belocated in the vent so that it serves only the appliancefor which it is intended.If improperly installed, a hazardous condition, such asan explosion or carbon monoxide poisoning, couldresult. Make certain that it is mounted in an accessiblelocation at least 6 in. (152.4 mm) from any combustiblematerial or the heat exchanger and that the positionindicator is in a visible location.The vent damper must be installed at the appliancedrafthood, and without modification of the drafthood.To connect the vent damper wiring to the boiler wiring,connect the damper circuit plug to the boiler circuitplug.Fig. 7: Vent Damper LocationWARNING: Carefully read and follow theinstallation instructions furnished with the ventdamper package. Failure to follow these instructionscan cause asphyxiation, explosion or fire.