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VISystemPiping
StandardPiping
Figure 17 shows typical boiler system connections on a single zone system. Additional information
on hydronic system design may be found in Installation of Residential Hydronic Systems (Pub. #200)
published by the Hydronics Institute in Berkely Heights NJ. The components in this system and their
purposes are as follows:
1) Relief valve (Required) – The relief valve is factory mounted and must not be moved. The relief
valve shipped with the boiler is set to open at 30 psi. This valve may be replaced with one
having a setting of up to the MAWP shown on the boiler 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 oor. 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.
2) Circulator (Required) – Although the circulator is shipped on the boiler return, it can be installed on
the boiler supply. If the circulator is moved to the supply it should be positioned just downstream of
the expansion tank as shown in Figure 17.
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.
CAUTION
• Operation of this boiler with continuous return temperatures below 120f can
cause severe heat exchanger corrosion damage
• Operation of this boiler in an system having signicant amounts of dissolved
oxygen can cause severe heat exchanger corrosion damage
• Do not use toxic additives, such as automotive antifreeze, in a hydronic system
DANGER
• PIPE RELIEF VALVE DISCHARGE TO A SAFE LOCATION
• DO NOT INSTALL A VALVE IN THE RELIEF VALVE DISCHARGE LINE
• RELIEF VALVE MUST BE INSTALLED IN BOILER AT LOCATION
SHOWN IN FIGURE 17.
• DO NOT PLUG RELIEF VALVE DISCHARGE