18
Venting Specification
GU100 is factory configured as a sealed combustion unit with dedicated intake and exhaust connections.
When installed as a Direct Vent appliance, all combustion air is drawn directly from outside of the home.
Direct Vent configuration is suitable for indoor only.
Recommended for facilities with difficulty accessing combustion air.
When installed outdoors, outdoor venting cap should be used.
Can be installed indoors, if combustion air supply is sufficient.
Is not sealed combustion if intake is not used to bring air directly from outside.
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Direct Vent
Power Vent
To configure the unit for power vent, insert a 6" section
of 3" pvc and terminate the intake with a 90° elbow. Be
sure to insert the included mesh screen into the intake
hole before the PVC pipe.
● Reduce the maximum allowable length for each elbow used as follows:
- 45 degree elbow : Deduct 3 feet
- 90 degree elbow : Deduct 5 feet
How To Configure Unit For Power-Vent
Maximum Allowable Vent and Combustion Air Piping Length
2 inch Piping
3 inch Piping
Feet
Max # of 90° elbows
Feet
Max # of 90° elbows
35
3
100
6
Insufficient air supply used with Power Vent appliance may cause the building to experience negative pressure
inside. Negative pressure is not allowable by most building codes and can cause back drafting of cold air from
outside through the unit potentially freezing the heat exchanger.
WARNING
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For installation in altitude over 4,000 feet, Do Not connect the venting system with 2” piping.
WARNING
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Mesh Screen
6"
3" Elbow
3" PVC Tube
To use 2" piping for your vent run, you must first use
3" PVC for the first 6" run off the water heater before
reduce down to a 2" PVC Pipe. Do not expand back to
3" pipe after reduced to 2" pipe.
How To Configure Unit With 2 Inch Pipe
3"x2" Reducer
2" PVC Tube
6"
● The intake vent length can be of equal length or less; there is no balancing requirement between intake and exhaust.
● Some termination is considered as a type of elbow, correct deduction should be applied. Such as, a turn down 90˚ or
an open T termination is considered 1x90˚ elbow and a candycane termination is considered as 2x90˚ elbow.
● Allow minimum length of 6" vent run vertically off the water heater is required before using any elbow.
