HTP PHR199-55C - Manual (Page 36)

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LP- 325 REV. 3.21.14
FRICTION LOSS EQUIVALENT IN PIPING AND FITTINGS
FITTINGS OR PIPING
EQUIVALENT FEET
2” 3” 4”
90 DEGREE ELBOW* 5’ 5’ 3’
45 DEGREE ELBOW 3’ 3’ 1’
COUPLING 0’ 0’ 0’
AIR INLET TEE 0’ 0’ 0’
STRAIGHT PIPE 1’ 1’ 1’
CONCENTRIC VENT KIT 3’ 3’ N/A
V500 2” VENT KIT 1’ N/A N/A
V1000 3” VENT KIT N/A 1’ 1’
V2000 4” VENT KIT N/A 1’ 1’
Table 7 - *Friction loss for long radius elbow is 1 foot less. NOTE: Consult Polypropylene venting instructions for friction loss
and pressure drop equivalents.
For example: If the exhaust vent has two 90° elbows and 10 feet of PVC pipe we will calculate:
Exhaust Vent Equivalent Length = (2x5) + 10 = 20 feet.
Further, if the intake pipe has two 90° elbows, one 45° elbow and 10 feet of PVC pipe, the following calculation applies:
Intake Pipe Equivalent Length = (2x5) + 3 + 10 = 23 feet.
Finally, if a concentric vent kit is used we find:
Total Equivalent Length = 20 + 23 + 3 = 46 feet.
The total equivalent length is 46 feet which is well below the maximum of 85 feet.
b. Effort should be made to keep a minimum difference in equivalent length between the exhaust vent and intake pipe.
3. The minimum total equivalent length is 16 equivalent feet.
Failure to provide a minimum total vent length of 16 equivalent feet could result in property damage and improper product operation.
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 appliances.
FOAM CORE PIPING IS NOT APPROVED FOR EXHAUST VENT 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 appliance 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.