Armstrong World Industries 123, 243 Removal of Unit from Common Venting System, Gas Connections

SRM-HW/HWC 8/99

Service Reference Manual INSTALLATION

6-9

Removal of Unit from Common Venting

System

When an existing furnace is removed from a common venting system serving other appliances, the venting system is likely to be too large to properly vent the remaining attached appliances. The following test should be conducted with each appliance while the other appliances connected to the common venting system are not in operation.

1.Seal any unused openings in the common venting system.

2.Visually inspect the venting system for proper size and horizontal pitch and determine there is no blockage or restriction, leakage, corrosion or other deficiencies which could cause an unsafe condi- tion.

3.Insofar as is practical, close all building doors and windows between the space in which the appliances remaining connected to the common venting system are located and other spaces in the building. Turn on clothes dryers and any appliance not connected to the common venting system. Turn on 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.Following the lighting instructions, place the unit being inspected in operation. Adjust the thermostat so the appliance will operate continuously.

5.Test for spillage at the draft control relief opening after five minutes of main burner operation. Use the flame of a match or candle.

6.Follow the preceding steps for each appliance connected to the common venting system.

7.After it has been determined that each appliance remaining con- nected to the common venting system properly vents when tested as outlined above, return doors, windows, exhaust fans, fireplace dampers and any other fuel burning appliance to their previous condition of use.

8.If improper venting is observed during any of the above tests, the common venting system must be corrected. See National Fuel

Gas Code, ANSI Z223.1 (latest edition) or CAN/CGA B149.1 & .2 Canadian Installation Codes to correct improper operation of common venting system.

Gas Connections

The gas line to the unit should be adequately sized to prevent undue pressure drop and should never be smaller than the manual valve used. Consult the local utility or National Fuel Gas Code for complete details on special requirements in sizing gas piping.

The units supplied for operation with natural gas contain a gas regulator which must be operated with inlet gas pressures specified on the rating plate. If gas line pressure exceeds this figure, an additional high pressure regulator must be installed to reduce this pressure.