Instruction manual

Part number 550-142-056/0411
GWC gas-fired water boiler — Boiler Manual
32
Venting & air — general (cont.)
Figure 39 GWC venting and air piping — OPTIONS and PIPING LIMITS
Vent length affects boiler input — the boiler automatically derates to compensate for pressure loss through the vent.
See the derate values given in Figure 105, page 99. The longer the vent, the more the input is reduced.
GWC Model
Maximum vent and air pipe lengths
(Minimum length for all applications is 2 feet)
(All applications include allowance for the termination fittings)
DIRECT VENT
(combustion air piped to boiler from outside)
DIRECT EXHAUST
(combustion air from inside)
SIDEWALL
termination
VERTICAL
termination
SIDEWALL
termination
VERTICAL
termination
3” PVC
Separate pipes
3” PVC
Concentric
[Note 1]
3” PVC
Separate pipes
3” PVC
Concentric
[Note 1]
3” PVC
Coupling
or Elbow
3” PVC
Coupling
See page 37 See page 39 See page 41 See page 43 See page 49 See page 51
Max.
Length
(feet)
Max.
Length
(feet)
Max.
Length
(feet)
Max.
Length
(feet)
Max.
Length
(feet)
Max.
Length
(feet)
-070
100 100 100 100 100 100
-105
100 100 100 100 100 100
-140
100 100 100 100 100 100
-175
100 100 100 100 100 100
Equivalent feet for elbows — deduct from maximum equivalent length of piping (does not apply to termination fittings)
• 7 feet per for each 3-inch 90° long-radius or 45° elbow
• 16 feet for each 3-inch short-radius elbow
Note 1:
Use only PVC pipe DO NOT use CPVC or ABS with concentric termination kits.
IPEX 3” PVC concentric vent kits can be used with standard PVC pipe, fittings and cement (ANSI/ASTM D1785) except where ULC
S636 compliance is required. For ULC S636 compliance, all pipe, fittings and cement must be IPEX System 636. When using IPEX
kits, use only IPEX product code 196006 for 3” venting.
Contact Williamson-Thermoflo for ordering information and availability of Williamson-Thermoflo venting kits.