System Piping - Crown Boiler AWR Series Installation Instructions Manual

• Failure to properly pipe boiler may result in improper operation and damage to boiler or building.
• Install boiler so that the gas ignition system components are protected from water (dripping, spraying, rain,
etc.) During appliance operation and service (circulator replacement, etc.).
• Operation of this boiler with continuous return temperatures below 120°F can cause severe heat exchanger
corrosion damage.
• Operation of this boiler in a system having significant amounts of dissolved oxygen can cause severe heat
exchanger corrosion damage.
• Do not use toxic additives, such as automotive antifreeze, in a hydronic system.
• Pipe relief valve discharge to a safe location. The safety relief valve may discharge scalding hot water.
• Do not install a valve in the safety relief valve discharge line.
• Do not move relief valve from factory specified location.
• Do not plug relief valve discharge. Blocking the safety relief valve may result in boiler explosion.
Figure 7.3 shows typical boiler system connections on a single zone system. Additional information on hydronic system
design may be found in the I=B=R Guide RHH published by the Air-Conditioning, Heating and Refrigeration Institute
(AHRI). The components in this system and their purposes are as follows:
1) Relief valve (Required) - Mount the relief valve on the left side of the boiler as shown in Figure 8.1 using the 1-1/4 x 4
nipple, 1-1/4 x 3/4 reducing elbow and 3/4 x close nipple provided. The relief valve shipped with the boiler is set to open
at 30 psi. This valve may be replaced with one having a pressure up to the "Maximum Allowable Working Pressure"
shown on the rating plate. If the valve is replaced, the replacement must have a relief capacity in excess of the DOE
heating capacity for the boiler.
Pipe the discharge of the relief valve to a location where water or steam will not create a hazard or cause property damage
if the valve opens. The end of the discharge pipe must terminate in an unthreaded pipe. If the relief valve discharge is
not piped to a drain it must terminate at least 6 inches above the floor. Do not run relief valve discharge piping through an
area that is prone to freezing. The termination of the relief valve discharge piping must be in an area where it is not likely
to become plugged by debris.
If necessary, the relief valve may be installed in the supply piping as shown in Figure 7.2. When this is done, the relief
valve must be as close to the boiler supply tapping as possible with no intervening shut-off valves.
2) Circulator (Required) - The circulator and circulator flanges are shipped loose with the boiler. The ideal location for the
circulator is in the supply piping, just downstream of the expansion tank, however installation in the return as shown in
Figure 7.3 is usually acceptable.
3) Expansion Tank (Required) - If this boiler is replacing an existing boiler with no other changes in the system, the
old expansion tank can generally be reused. If the expansion tank must be replaced, consult the expansion tank
manufacturer's literature for proper sizing.
4) Fill Valve (Required) - Either a manual or automatic fill valve may be used. The ideal location for the fill is at the
expansion tank.
5) Automatic Air Vent (Required) - At least one automatic air vent is required. Manual vents will usually be required in
other parts of the system to remove air during initial fill.
6) Low Water Cut-Off (factory supplied) This boiler is equipped with a low water cut-off (LWCO) that prevents the boiler
from firing if there is inadequate water in the boiler. This LWCO is an automatic reset type, meaning that it will allow
the boiler to restart automatically if the low water condition is corrected. This LWCO satisfies the requirements of most
installation codes used for residential installations, however some jurisdictions may require a manual reset low water cut-
off which requires a reset button to be pushed to restart the boiler.
If a manual reset LWCO is required, it must be installed in the supply piping just above the boiler in accordance with the
LWCO manufacturer's instructions (the factory supplied LWCO is left in place). No intervening valves may be installed
between an externally piped LWCO and the boiler. Wire on external manual reset LWCO to either break 120VAC power
to the boiler, or break the external limit connection shown in Section IX.
VII System Piping
Standard Piping
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WARNING
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