Section 10: Outside Air Supply; Pressurized; Non-Pressurized - Roberts Gorden Corayvac CRV-B Series Installation, Operation & Service Manual

CRV-S I , O
ERIES NSTALLATION PERATION AND

SECTION 10: OUTSIDE AIR SUPPLY

CAUTION
Product Damage Hazard
Do not use heater in area containing
corrosive chemicals.
Refer to appropriate Material Safety Data
Sheets (MSDS).
Failure to follow these instructions can result
in product damage.
The CRV-Series system is approved for use with an
outside air system. Halogenated hydrocarbons or
other corrosive chemicals in the air can be drawn into
the equipment and seriously damage the system
components. Avoid the use of such chemical
compounds near the air inlet to the heaters.
IMPORTANT: If the building has a slight negative
pressure or corrosive contaminants are present in the
air, an outside combustion air supply to the heater is
required.
All joints and seams in the air supply system must be
airtight. Attach the filter housing to the burner
assembly using the wing nut provided.
Note: Outside air terminal must not be more than 1'
(31 cm) above the vent termination while maintaining
a minimum distance of 3' (93 cm) for both vertical
and horizontal venting.

10.1 Pressurized

See Page 49, Figure 34 for a typical layout of a
pressurized air supply system.
For pressurized outside air supplies, the outside air
blower motor has a pressure switch that must be
used. Wire this switch in series with the pump
pressure switch. When using an outside air blower
with a CORAYVAC ® Heating Control or CORAYVAC
Modulating Heating Control or relay transformer, a
separate load relay package is required. Wire the
control for the relay in parallel with the pump. The
outside air blower must have a separate 20 A, 120 V
power supply. See Page 47 , Figure 31 for outside air
blower internal wiring requirements. The outside air
blower has an adjustable internal damper that should
be wide open. On smaller systems (about 3 burners)
this damper might need to be closed up to half way if
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ERVICE ANUAL
the pressure switch does not make.

10.2 Non-Pressurized

For a non-pressurized outside air supply, a 4" (O.D.)
single wall pipe duct may be attached to the burner
and end vent. For length and duct sizing
requirements, see duct design rules in Figure 30. To
prevent condensation, insulate the outside air duct.
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