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more than 18 in. (450 mm) nor less than 6 in. (152
mm) above the floor level. The duct can also "goose
neck" through the roof. The duct is preferred to be
straight down 18 in. (457 mm) from the floor, but not
near piping.
4. Refer to the B149 Installation Code for additional
information
Ducted Combustion Air
Instead of drawing combustion air from the room,
combustion air may be brought directly to the unit via
ductwork. PVC, CPVC, or single-wall galvanized sealed
ducting may be used.
1. Install combustion air duct in accordance with Figure
30 (horizontal) or Figure 31 (vertical) of this manual.
2. Ventilation of the space occupied by the heater(s)
is recommended and can be provided by an
opening(s) for ventilation air at the highest practical
point communicating with the outdoors. The total
cross-sectional areas should be at least 1 in.² of free
area per 20,000 BTUH (111 mm² per kW) of total
input rating of all equipment in the room, when the
opening is communicating directly with the outdoors
or through vertical duct(s). The total cross-sectional
area should be at least 1in.² of free area per 10,000
BTUH (222 mm² per kW) of total input rating of
all equipment in the room, when the opening is
communicating with the outdoors through horizontal
duct(s). Damage to the equipment due to inadequate
ventilation of the space is not a warrantable failure.
3. In cold climates, and to mitigate potential freeze-
up, Raypak highly recommends the installation of a
motorized sealed damper to prevent the circulation of
cold air through the heater during the non-operating
hours.
Truseal™ Direct Vent Combustion Air
TruSeal is Raypak's option for meeting direct vent
requirements. The duct will attach directly to the air collar
located on the inline Air Filter Box (shipped loose), using
3-4 sheet metal screws (not supplied) equally positioned
around the circumference of the duct. The screen
assembly should be removed before attaching any air
duct. The screws and duct connection point must be sealed
with RTV (not supplied). TruSeal is generally used when
damaging contaminants are present in the mechanical
room. In addition, the flue must be of a sealed-joint design
to ensure that the complete air system and combustion
system is isolated from room air.
All ducting MUST be self-supported.
Motorized Combustion Air Dampers or
Louvers
When dampers or louvers are communicating directly
with outside combustion air, they must be interlocked with
each appliance in the equipment room, to ensure proper
operation. See field wiring connection section of this
manual for proper wiring instructions, using Fan/Damper
dry contacts and external interlock.
Water Piping
General
The heater should be located so that any water leaks will
not cause damage to the adjacent area or structures.
CAUTION: This heater requires forced water
A
circulation when the burner is operating. See Table F and
Table G for minimum and maximum flow rates. The pump
must be interlocked with the heater to prevent heater
operation without water circulation.
NOTE: Minimum pipe size for in/out connections is 2
in. NPT for 503A and 753A models and 2-1/2 in. NPT for
1003A–2003A models. Verify proper flow rates and ∆T as
instructed in this manual.
Relief Valve Piping
WARNING: Pressure relief valve discharge piping
A
must be piped near the floor and close to a drain to
eliminate the potential of severe burns. Do not pipe
to any area where freezing could occur. Refer to local
codes.
Temperature & Pressure Gauge
The temperature and pressure gauge is shipped loose for
field installation and must be installed within 12 in. (305
mm) of the boiler outlet (if possible) in an easily readable
location. Installation must comply with ASME Section IV
as well as all applicable national, state and local codes.
Hydrostatic Test
Unlike many types of heaters, this heater does not require
hydrostatic testing prior to being placed in operation.
The heat exchanger has already been factory-tested
and is rated for 160 psi operating pressure. However,
Raypak does recommend hydrostatic testing of the piping
connections to the heater and the rest of the system prior
to operation.
This is particularly true for hydronic systems using
expensive glycol-based anti-freeze. Raypak recommends
conducting the hydrostatic test before connecting gas
piping or electrical supply.
Leaks must be repaired at once to prevent damage
to the heater. NEVER use petroleum-based stop-leak
compounds.
13
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