3.5.2 ApplicationsAll EX series boilers are approved with alternative venting options: either 2-pipe Direct Vent or Vent pipewith Indoor Air. With the Direct Vent case, combustion air is piped directly to the boiler’s air intake fromoutdoors (see Vent termination clearance on page 30) for air intake piping requirements. Using the indoorair alternative, air for combustion is drawn from the indoor air surrounding the boiler.Provided the maximum overall vent length limit is not exceeded, the boiler may be vented through the wall,directly through the roof, or upward using an existing -- but otherwise unused - chimney as a vent raceway.3.5.3 Exhaust vent materialWarningCondensate can cause corrosion of metal roofing components and other roofing materials.Check with the builder or roofing contractor to ensure that materials are resistant to acidiccondensate. pH levels can be as low as 3.0.Exhaust vent material – CANADAUse PVC, CPVC, Polypropylene (PPs), or Stainless Steel (SS) vent component systems approved underULC-S636 Standard for Type BH Gas Venting Systems, or stainless steel Type BH venting systems*. Thevent temperature is limited by the boiler controller with the use of a flue temperature sensor to ensure themaximum temperature of the PVC venting material is not exceeded.Exhaust vent material – USAPVC, CPVC, PPs, or SS venting materials are approved for use with these boilers in most of the USA.Check local codes to determine if any materials are prohibited. The vent temperature is limited with the useof the flue temperature sensor and software to ensure that the maximum temperature of the PVC ventingmaterial is not exceeded. PVC venting material shall be certified to Sch. 40 ASTM D1785 or D2665. CPVCmaterial shall be certified to Sch. 40/ASTM F441.Exhaust vent materialUse of cellular core PVC (ASTM F891), cellular core CPVC, or Radel® (polyphenolsulfone) in ventingsystems is prohibited.Do not use ABS or any cellular core pipe for exhaust venting.The exhaust fitting has a 6" PVC (schedule 40) connection. Use fittings to adapt to either PPs or SS ventingmaterial. Insert exhaust venting directly into the 6" female stainless steel fitting, and secure with the built-inclamp (see Figure 8 ).213.5.2 Applications