Outside Air Supply - Roberts Gorden CoRayVac CRV-B-2 Installation, Operation & Service Manual

! ! ! ! ! SECTION 10: OUTSIDE AIR SUPPLY
The CORAYVAC® 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 contaminants are present
in the air, an outside combustion air
supply to the heaters is strongly
recommended.
All joints and seams in the air supply system must be
airtight. The filter housing attaches to the burner
assembly by using the wing nut provided.
FIGURE 18 – Duct Sizing
Outside Air System Design Requirements:
Blower Performance (90707500):
112 Flow Units
One outside air blower is required per each EP-100
or EP-200 series pump and two outside air blowers
may be required for each EP-300 series pump.
Outside air blowers cannot be shared between two
separate CORAYVAC
Duct Design Rules:
- System should be designed so that the blower
is positioned closest to the highest flow
requirements (end vents).
- When a duct is carrying more than 40 flow
units, it must be at least 6" (150 mm) diameter.
Pressurized Systems
- 6" diameter duct must not exceed 120' (36 m)
total per system.
- 4" diameter duct must not exceed 120' (36 m)
per radiant branch.
Non Pressurized
- 6" diameter duct must not exceed 90' (27 m)
maximum 100 flow units
- 4" diameter duct must not exceed 90' (27 m)
- Elbows are equivilant to 10' (3 m) of duct length.
® systems.
Pressurized
See Page 39, Figure 21, for a typical layout of a
pressurized air supply system.
For pressurized outside air supplies, the outside air
blower motor has a pressure switch interlock that must
be used. Wire this switch in series with the pump
pressure switch. When using an outside air blower either
with a ROBERTS GORDON
panel 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 20A, 120V power supply.
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 below in Figure 18. To prevent
condensation, insulate the outside air duct.
S 10: O A S
ECTION UTSIDE IR UPPLY
® BZC or System Control
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