Operating instructions

11
Part Number 550-142-784/0812
GWA Series 2 Gas-Fired Water Boilers – Boiler Manual
Near-boiler piping continued
Figure 7 Piping refrigeration systems
Water piping — refrigeration systems
Prevent chilled water from entering boiler
Installboilersothatchilledmediumispipedinparallelwiththe
heatingboiler.Useappropriatevalvestopreventchilledmedium
from entering boiler.  See Figure 7 for typical installation of
balancingvalveandcheckvalve.
 Ifsystemincludesradiantheatingcircuits,provide
piping and controls to regulate the temperature
supplying the radiant circuits. Failure to comply could
result in substantial property damage.
 UseFigure 5 or Figure 6onlyforsystemsdesigned
forreturn wateratleast 130°F.Forsystems with
low return water temperature possible, such as
converted gravity systems and radiant heating
systems, install bypass piping (see page 12) to
protect boiler against condensation. Failure to
prevent low return water temperature to the boiler
could cause corrosion of the boiler sections or
burners, resulting in severe personal injury, death
or substantial property damage.
 Install boiler so that chilled medium is piped
in parallel with heating boiler (Figure 7). Use
appropriatevalvestopreventchilledmediumfrom
enteringboiler.ConsultAHRIInstallationandPiping
Guides.
 If boiler is connected to heating coils located in
air handling units where theycan be exposed to
refrigerated air, use owcontrol valves or other
automatic means to prevent gravity circulation
during cooling cycle. Circulation of cold water
through the boiler could result in damage to the heat
exchanger,causingpossibleseverepersonalinjury,
death or substantial property damage.
Figure 5 Diaphragm- or bladder-type expansion tank:
Piping to single-zone system using
diaphragm-type or bladder-type expansion
tank. See Table 4 for piping sizes.
3 Install water piping continued
Figure 6 Closed-type expansion tank: Piping to single-
zone system using closed-type expansion
tank. See Table 4 for piping sizes.