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LP- 428 REV. 9.2.14
When installing a condensate pump, select one approved for use with condensing boilers and furnaces. The pump should have an
overflow switch to prevent property damage from condensate spillage.
The condensate line must remain unobstructed, allowing free flow of condensate. If condensate freezes in the line, or if line is
obstructed in any other manner, condensate can exit from boiler tee, resulting in potential water damage to property.
F. EXHAUST VENT AND INTAKE PIPE SIZING
MAX. TOTAL EQUIVALENT
VENT LENGTH
(INTAKE AND EXHAUST)
INPUT DE-
RATE PER 25’
OF VENT
Table 7 – Exhaust Vent and Intake Pipe Sizing
1. The equivalent length of friction loss in elbows, tees, and other fittings are listed in Table 8.
FRICTION LOSS EQUIVALENT FOR STAINLESS OR PLASTIC PIPING AND FITTINGS
Table 8 – Friction Loss in Equivalent Feet - *Friction loss for long radius elbow is 1’ less.
2. For example: If the exhaust vent has two short 90
o
elbows and 10 feet of PVC pipe we will calculate: Exhaust Vent Equivalent Length
= (2x3) + 10 = 16 feet.
Further, if the intake pipe has two short 90
o
elbows, one 45
o
elbow, and 10 feet
of PVC pipe, the following calculation applies: Intake Pipe Equivalent Length =
(2x3) + 1 + 10 = 17 feet.
3. The exhaust vent and intake pipe are intended to penetrate the same wall or
roof of the building.
4. The minimum total equivalent length is 16 feet.
G. EXHAUST VENT AND INTAKE PIPE INSTALLATION
All joints of positive pressure vent systems must be sealed completely to prevent leakage of flue products into living space.
1. Use only solid PVC or CPVC pipe, or a Polypropylene vent system, approved for use with Category IV boilers.
FOAM CORE PIPING IS NOT APPROVED FOR EXHAUST APPLICATIONS. Foam core piping may be used on air inlet piping only.
2. Remove all burrs and debris from joints and fittings.
3. When using PVC or CPVC pipe, all joints must be properly cleaned, primed, and cemented. Use only cement and primer approved
for use with the pipe material. Cement must conform to ASTM D2564 for PVC and ASTM F493 for CPVC pipe. NOTE: DO NOT
CEMENT POLYPROPYLENE PIPE.
4. Ensure the vent is located where it will not be exposed to prevailing winds.
5. In all roof venting applications, exhaust discharge must point away from the pitch of the roof.
6. To prevent water leakage, install adequate roof flashing where the pipe enters the roof.