Page 16
NOTE - Assembly  should  be  completed  within  20 
seconds  after  last  application  of  cement.  Hammer 
blows should not be used when inserting pipe.
8 -   After assembly, wipe excess cement from pipe at 
a bead around its entire perimeter. Any gaps may 
      
solvent.
9 -  Handle joints carefully until completely set.
Venting Practices
Figure 20 
1 -   In areas where piping penetrates joists or interior 
walls, hole must be large enough to allow clearance 
on all sides of pipe through center of hole using a 
hanger.
2 -   When furnace is installed in a residence where unit 
is shut down for an extended period of time, such 
as a vacation home, make provisions for draining 
condensate collection trap and lines.
Removal of the Furnace from Common Vent
In the event that an existing furnace is removed from a 
venting system commonly run with separate gas applianc-
es, the venting system is likely to be too large to properly 
vent the remaining attached appliances.
* See  Piping and Fittings Specifications table
Piping Suspension Guidelines
NOTE 
- Isolate piping at the point where it exits the outside wall o
roof in order to prevent transmission of vibration to the structure.
SCHEDULE 40
PVC - 5'
all other pipe*  - 3'
Wall
edistuoedisni
24” maximum
3/4” minimum
Wall Thickness Guidelines
Conduct the following test while each appliance is oper-
ating and the other appliances (which are not operating) 
remain connected to the common venting system. If the 
venting system has been installed improperly, you must 
correct the system as indicated in the general venting re-
quirements section.
 WARNING
CARBON MONOXIDE POISONING HAZARD
Failure to follow the steps outlined below for each 
appliance connected to the venting system being placed 
into operation could result in carbon monoxide poisoning 
or death.
The following steps shall be followed for each appliance 
connected to the venting system being placed into 
operation, while all other appliances connected to the 
venting system are not in operation:
1 -   Seal any unused openings in the common venting 
system.
2 -   Inspect the venting system for proper size and 
horizontal pitch. Determine that there is no blockage, 
which could cause an unsafe condition.
3 -   Close all building doors and windows and all 
doors between the space in which the appliances 
remaining connected to the common venting system 
are located and other spaces of the building. Turn on 
clothes dryers and any appliances not connected to 
the common venting system. Turn on any exhaust 
fans, such as range hoods and bathroom exhausts, 
so they will operate at maximum speed. Do not 
      
dampers.
4 -   Follow the lighting instructions. Turn on the appliance 
that is being inspected. Adjust the thermostat so 
that the appliance operates continuously.
5 -   After the main burner has operated for 5 minutes, 
  
6 -   After determining that each appliance connected 
to the common venting system is venting properly, 
(step 3 return all doors, widows, exhaust fans, 
     
appliances to their previous mode of operation.
7 -   If a venting problem is found during any of the 
preceding tests, the common venting system must 
Resize the common venting system to the minimum 
vent pipe size determined by using the appropriate ta-
bles in Appendix G. (These are in the current standards