Direct Vent Installations — Gv Without Other Gas Appliances; Special Considerations — Direct Exhaust Or Direct Vent; Exhaust Fans And Air Movers; Motorized Air Dampers - Weil-McLain Gold GV Manual

• Installation • Start-Up • Parts • Maintenance
Direct vent installations —
GV without other gas appliances
Direct-vented GV boilers installed with no other
appliances in the same space may need openings for
ventilation air as described below.
• If direct-vented GV boilers are installed in a space
whose volume is at least 10 ft
ventilation openings are required
• If direct-vented GV boilers are installed in a space
whose volume is less than 10 ft
two ventilation air openings into the space
may be necessary — one near the floor and the
other near the ceiling as shown in the illustration
below. Each opening must have a free area no less
than 1 square inch per 1,000 Btuh input of GV
boiler(s) in the space.
• If direct-vented GV boilers are installed in a space
with clearances less than the recommended minimum
service clearances shown on page 10,
openings into the space are required
within 6 inches of the top of the space and one within
6 inches of the bottom of the space. See illustration
below. Each opening must have a free area no less
than 1 square inch per 1,000 Btuh input of GV
boiler(s) in the space.
If ventilation air openings are not
installed as directed above and the
room does not have adequate
ventilation, the higher temperature
in the space may result in reduced
component life.
Part number 550-141-856/0703
Special considerations —
direct exhaust or direct vent
Tight construction
ANSI Z223.1 defines unusually tight construction
where:
a. Walls and ceilings exposed to the outside
3
/1,000 Btuh input,
no
.
3
/1,000 Btuh input,
b. Weatherstripping has been added on openable
c. Caulking or sealants are applied to areas such as
For buildings with such construction, provide air
openings into the building from outside, sized per the
two ventilation
appropriate case in Figure 3 if appliances are to use
— one
inside air for combustion and ventilation.

Exhaust fans and air movers

The appliance space must never be under a negative
pressure, even if the appliance(s) are installed as direct
vent. Always provide air openings sized not only to
the dimensions required for the firing rate of all
appliances, but also to handle the air movement rate of
the exhaust fans or air movers using air from the
building or space.

Motorized air dampers

If the air openings are fitted with motorized dampers,
electrically interlock the damper to:
•
•
To accomplish this interlock, wire an isolated contact
(proving the damper open) in series with the
thermostat input to the boiler. The boiler will not start
if this contact is open, and will shut down should it
open during operation.
atmosphere have a continuous water vapor retarder
with a rating of 1 perm or less with openings
gasketed, and . . .
windows and doors, and . . .
joints around windows and door frames, between
sole plates and floors, between wall-ceiling joints,
between wall panels, at penetrations for plumbing,
electrical, and gas lines, and in other openings.
Prevent the boiler from firing if the damper is not
fully open.
Shut the boiler down should the damper close
during boiler operation.
15