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Part number 550-142-054/0411
GV90+ gas-fired water boiler — Boiler Manual
48
Vent and air piping and boiler connections
DIRECT EXHAUST & DIRECT VENT
Follow termination instructions
1. Read and follow all instructions for the termination
type used before proceeding with this page.
Installing vent and air piping
1. Work from the boiler to vent or air termination. Do
not exceed the lengths given in the previous pages
for either the air or vent piping.
a. Provide stainless pipe to PVC adapters obtained
from the stainless pipe manufacturer for con-
nections at the boiler and at terminations, when
required.
2. See Figure 59 for attaching vent (and air) pipes at
the boiler.
3. Cut pipe to required lengths.
4. Deburr inside and outside of pipe ends.
5. Chamfer outside of each pipe end to ensure even
cement distribution when joining.
6. Clean all pipe ends and fittings. Dry thoroughly.
7. Dry assemble entire vent or air piping to ensure
proper fit before assembling any joint.
8. For each joint:
a. Handle fittings and pipes carefully to prevent
contamination of surfaces.
b. Apply primer liberally to both joint surfaces —
pipe end and fitting socket.
c. While primer is still damp, lightly apply ap-
proved cement to both surfaces in a uniform
coating.
d. Apply a second coat to both surfaces. Avoid
using too much cement on sockets to prevent
cement buildup inside.
e. With cement still wet, insert pipe into fit-
ting, twisting ¼ turn. Make sure pipe is fully
inserted.
f. Wipe excess cement from joint. Check joint to
be sure a smooth bead of cement shows around
the entire joint.
9. Maintain minimum clearance of C\zn inch between
vent pipe and any combustible wall or material.
10. Seal wall or floor penetration openings following
local code requirements.
DIRECT EXHAUST ONLY
DIRECT EXHAUST installations — air
inlet opening protection
: Obtain a bird
screen (sized for air inlet fitting) from
Weil-McLain. Insert the bird screen into
the air inlet fitting to prevent foreign
objects from entering the opening.
Figure 59 Boiler vent and air connections
AL294C vent pipe — If using AL294C stainless vent pipe,
you must install an AL29-4C stainless vent starter at the
boiler vent connection (and at the termination if using
the Weil-McLain plate or the concentric termination).
Use only the starter made by the vent pipe manufacturer.
See Replacement parts section for available AL29-4C
stainless vent starters.
1. PVC/ABS pipe — Clean and deburr inside and outside of other
both ends of air and vent pipes. Chamfer boiler end of vent pipe
for ease of insertion.
The vent pipe end must be smooth and chamfered to
prevent possible damage to sealing gasket in vent pipe
adapter.
2. Inspect vent adapter and air inlet fitting (above) — verify no ob-
structions or foreign objects inside.
3. Vent pipe
• Loosen vent adapter clamp screw.
• Measure 3½ inches from boiler end of vent pipe and make a
mark with felt-tip pen.
• Apply small amount of silicon grease to boiler end of vent pipe
to ease insertion.
• Insert vent pipe into adapter to depth of felt tip pen mark.
• Secure vent pipe by tightening the adapter clamp securely. Do
not overtighten. The seal is accomplished with the internal
gasket. The clamp is only to hold the pipe in place.
Do not apply excessive force or bend the vent adapter
or vent pipe when inserting. The adapter or seal could
be damaged.
4. Air pipe
• Clean the outer surface of the boiler end of the air pipe.
• Apply silicon sealant (Dow Corning 732
TM
or equivalent) to
the outside end of the air pipe and to the inside of the air inlet
fitting.
• Insert the air pipe into the air inlet fitting and give a 1/4 turn
to ensure coverage. Support until the sealant has dried.