HTP EFT-399 - Manual (Page 40)

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LP-387 REV. 6.10.14
b. For example: If the 3” exhaust vent has two short 90 o elbows and
10 feet of PVC pipe we will calculate: Exhaust Vent Equivalent Length
= (2x5) + 10 = 20 feet.
Further, if the 3” 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 = (2x5) + 3 + 10 = 23 feet.
The Exhaust Vent Equivalent Length + the Intake Pipe Equivalent
Length equal the Total Equivalent Length. In this example, the Total
Equivalent Length is 43 feet.
c. The minimum Total Equivalent Length is 15 feet.
F. 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, AL29-4C Stainless Steel, 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.
7. Do not locate vent over public walkways, driveways, or parking lots. Condensate could drip and freeze, resulting in a slip hazard or
damage to vehicles and machinery.
8. Due to potential moisture build-up, sidewall venting may not be the preferred venting option. To save time and cost, carefully
consider venting installation and location.
9. Horizontal lengths of exhaust vent must slope back towards the boiler not less than ¼" per foot to allow condensate to drain from the
vent pipe.
10. The exhaust vent must terminate where vapors cannot make accidental contact with people or pets, or damage shrubs or plants.
11. In vacant chimney applications, install and seal a rain cap over existing chimney openings.
12. All piping must be fully supported. Use pipe hangers at a minimum of 4 foot intervals to prevent sagging of the pipe where
condensate may form.
13. Do not use the boiler to support any piping.
14. A screened straight coupling is provided with the boiler for use as an outside exhaust termination.
15. A screened inlet air tee is provided with the boiler to be used as an outside intake termination.
The following information on Table 12 lists optional exhaust/intake terminations available from HTP:
DESCRIPTION STOCK CODE
3” PVC CONCENTRIC VENT TERMINATION KIT KGAVT0601CVT
3” POLYPRO VENT KIT 8400P-001
3” STAINLESS STEEL TERMINATION KIT V1000
4” STAINLESS STEEL TERMINATION KIT V2000
Table 12
Figure 18