User Guide

14
TABLE 7.1: VENT/ AIR INTAKE FITTING EQUIVALENT LENGTH
CPVC/PVC FITTING EQUIVALENT LENGTH (ft)
2” 90 ELBOW (“SANITARY BEND”) 2.6
3” 90 ELBOW (“SANITARY BEND”) 4.0
2” 90 ELBOW (“SHORT BEND” ) 6.0
3” 90 ELBOW (“SHORT BEND”) 10.0
2” 45 ELBOW 1.5
3” 45 ELBOW 2.0
2” COUPLING 0.0
3” COUPLING 0.0
FIGURE 7.2: CPVC AND PVC ELBOWS
4. Minimum Vent and Air Intake Lengths - Observe the minimum vent lengths shown in Tables 7.5, 7.11 and 7.15.
5. Clearances to Combustibles - Maintain the following clearances from the vent system to combustible construction:
• Vent - 1/4” (also observe clearances through both combustible and non-combustible walls - see 9 below)
• Air Intake - 0”
• Concentric Portion of Concentric Terminals - 0”
6. Pitch of Horizontal Vent Piping - Pitch all horizontal CPVC/PVC vent piping 1/4” per foot so that any condensate which
forms in the piping will run towards the boiler.
LeschaudièresdecatégoriesI,IIetIVdoiventprésenterdestronçonshorizontauxdontlapentemontanteestd’aumoins
5/8poparpied(52mm/m)entrelachaudièreetl’évent.
7. Supporting Pipe - Vertical and horizontal sections of pipe must be properly supported. Maximum support spacing is 4 feet.
Les instructions d´installation du système d´évacuation doivent préciser que les sections horizontales doivent être
supportéespourprévenirleéchissement.Lesméthodesetlesintervallesdesupportdoiventêtrespéciés.Les
instructions divent aussi indiquer les renseignements suivants:
• les chaudières de catégories II et IV doivent être installées de façon à empêcher l´accumulation de condensat: et
• si nécessaire, les chaudières de catégories II et IV doivent être pourvues de dispositifs d´évacuation du condensat.
8. Allowing for Thermal Expansion -
 • Designtheventsystemtoallow3/8”ofthermalexpansionforevery10ftofCPVC/PVCpipe.Theboilerwillalways
act as an anchor to one end of the vent system. If at all possible, select and install hangers and wall thimbles so that
the vent system can expand towards the terminal. When a straight run of pipe exceeds 20ft and must be restrained at
both ends, an offset or expansion loop must be provided (Figures 7.3a, 7.3b). When a straight horizontal run of pipe
exceeds 20ft and is restrained at one end with an elbow at the other, avoid putting a hanger or guide less than “Y”
  inchesfromtheelbowintheadjoiningstraightsection(Figure7.3c).Thermalexpansionttingsarenotpermitted.