Munchkin VWH High Efficiency Hot Water Supply Boiler - Manual (Page 15)

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The connection of air inlet and exhaust vent at the heater must remain 3” for 199VWH and 4” for
399VWH and each vent must extend from the heater a minimum of 15 equivalent feet before transi-
tioning to a 4” vent for the 199VWH and 6” vent for the 399VWH. The overall extended maximum
length of pipe on the inlet and exhaust combined, must not exceed 125 equivalent feet. Listed below
are the 3”, 4” and 6” size equivalent table.
Example: Installation requires the following material for both the inlet and exhaust piping when
extending the vent run for the Munchkin 199VWH.
3" Vented Appliance
2 Pcs. – 3" 90 degree elbow (2 x 5 = 10 Equivalent Feet) = 10 Equivalent Feet
20' of 3" Plastic PVC Pipe (20 x 1 = 20 Equivalent Feet) = 20 Equivalent Feet
Total of 3" Equivalent Piping with Fittings = 30 Equivalent Feet
Requirements for 4" Venting
6 Pcs. – 4" 90 degree elbows (6 x 3 = 18 Equivalent Feet) = 18 Equivalent Feet
4 Pcs. – 4" 45 degree elbows (4 x 1 = 4 Equivalent Feet) = 4 Equivalent Feet
40' of 4" Plastic PVC Pipe (40 x 1 = 40 Equivalent Feet) = 40 Equivalent Feet
Total of 4" Equivalent Piping with Fittings = 62 Equivalent Feet
Total Friction Loss in Equivalent Feet for both 3" and 4" (30 + 62 = 92
Equivalent Feet) = 92 Equivalent Feet
D. HEATER REMOVAL FROM A COMMON VENT SYSTEM
At the time of removal of an existing heater, the following steps shall be followed with each appli-
ance remaining connected to the common venting system placed in operation, while the other appli-
ances remaining connected to common venting system are not operating.
1. Seal any unused openings in the common venting system.
2. Visually inspect the venting system for proper size and horizontal pitch to determine if there
is blockage, leakage, corrosion or other deficiencies that could cause an unsafe condition.
DANGER
The Munchkin is not intended to be common vented with any other
existing appliance!
VENTING
Friction Loss Equivalent in Piping and Fittings
Fittings or Piping Equivalent Feet
90 degree elbow = 5
45 degree elbow = 3
Coupling = 0
air inlet tee = 0
Plastic Pipe = 1
concentric vent kit = 3
vent kit = 0
WARNING
Transitioning into a larger diameter pipe should be done in the Vertical position to
avoid condensation blockage. If done in the horizontal position check to make sure
condensation blockage will not occur.