Roberts Gorden 100, 75, 125 service manual Maximum Vent Lengths, Vent Material, Vent and Roof Detail

UHD LOW PROFILE DUCT FURNACE INSTALLATION OPERATION AND SERVICE MANUAL

7.7.1 Maximum Vent Lengths

Model UHD[X][S] 75, 100, 125	Number of Elbows
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

7.8 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 12, Section 7.3.

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 B-1 vent material may be used at the roof or wall penetration instead of a thimble. Ensure vent manufacturer's clearance from vent material is maintained. Seal annular space of the type B-1 vent as well as all joints in the remaining vent.

7.9Replacing 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 system.

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 gas-burning appliances to their previous conditions of use.

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 gas-fired equipment or your local gas supplier. If the venting must be resized, use appropriate tables in (US) Appendix G of NFPA 54/ANSI Z223.1 - latest revision, National Fuel Gas Code (US) or Standard CSA B149.1 Natural Gas and Propane Installation Code (Canada) to determine minimum size. All vent corrections must be in accordance with the appropriate local codes and 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).

Figure 8: Vent and Roof Detail

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