Roberts Gorden UHD[X][S][R] 150 User Manual

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The entire vent should be insulated with foil faced 
fiberglass insulation (1/2" thick, 1-1/2# density 
minimum).

6.8 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 9, Section 
6.3.
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.

6.9 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 

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).

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