SECTION 7: VENTING
Maximum Vent Lengths Table
Model UHA[X][S] | # of Elbows | |
150 - 400 | ||
| ||
40 ft (12.2 m) | 1 | |
35 ft (10.7 m) | 2 | |
30 ft (9.1 m) | 3 | |
25 ft (7.6 m) | 4 | |
20 ft (6.1 m) | 5 |
7.7 Vent Material
Vent material may be single wall 26 ga. (minimum) galvanized steel or equal thickness stainless steel. Completely seal all joints, refer to Page 11, Section 7.2.
If penetrating a combustible wall or roof, a listed thimble with 2" (5 cm) clearance must be used. Where local codes permit, a single section of type
7.8 Replacing an Existing Heater in a Venting System
When replacing an existing heater in a venting system, the venting system may not be properly sized to vent the new heater. The following steps must be followed with each appliance connected to the venting system placed in operation, while any other appliances connected to the venting system are not in operation.
1.Seal any unused openings in the venting sys- tem.
2.Inspect the venting system for proper size and horizontal pitch, as required by the NFPA 54/ ANSI Z223.1 - latest revision, National Fuel Gas Code (US) or Standard CSA B149.1 Natural Gas and Propane Installation Code (Canada) and these instructions. Determine that there is no blockage or restriction, leakage, corrosion and other deficiencies which could cause an unsafe condition.
3.Close all building doors and windows and all doors between the space in which the appliance(s) connected to the venting system are located and other spaces of the building. Turn on clothes dryers and any exhaust fans, such as range hoods and bathroom exhausts so that they shall operate at maximum speed. Do not operate a summer exhaust fan. Close fireplace dampers.
4.Follow the lighting instructions. Place the appliance being inspected in operation. Adjust
thermostat so that the appliance will operate continuously.
5.For any appliance having a draft hood, test for draft hood appliance spillage at the draft hood relief opening after five minutes of main burner operation. Use the flame of a match or candle.
6.After it has been determined that each appliance connected to the venting system properly vents when tested as outlined above, return doors, windows, exhaust fans, fireplace dampers and any other
7.If improper venting is observed during any of the above tests, the venting system must be corrected by a contractor qualified in the installation and service of
Propane Installation Code (Canada).
Figure 6: Vent and Roof Detail
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