Weil-McLain EG 5 Series Manual page 15

EG PEG
&
SERIES
Connect piping – water boilers – EG only
When using 3-wire zone valves, install an isolation
relay. Connect the zone valve end switch wires to
the isolation relay coil. Connect the isolation relay
contact across the boiler T-T terminals. Failure
to comply can result in damage to boiler com-
ponents or cause unreliable operation, resulting
in severe property damage.
Recommended piping – forced hot water boilers
with closed type expansion tanks
Recommended piping – forced hot water boilers
with diaphragm type expansion tanks
Part Number 550-142-782/1112
5 EGH 5
SERIES
-
GAS FIRED BOILERS
Use Figure 13 or Figure 14 only for systems designed
for return water at least 130 °F. For systems with
.
low return water temperature possible, such as con-
verted gravity systems and radiant heating systems,
install bypass piping (see page 16) to protect boiler
against condensation. Failure to prevent low return
water temperature to the boiler could cause corro-
sion of the boiler sections or burners, resulting in
severe personal injury, death or substantial property
damage.
If system includes radiant heating circuits, provide
piping and controls to regulate the temperature sup-
plying the radiant circuits. Failure to comply could
result in substantial property damage.
Water piping — refrigeration systems
Prevent chilled water from entering boiler
Install boiler so that chilled medium is piped in par-
allel with the heating boiler. Use appropriate valves
to prevent chilled medium from entering boiler. See
Figure 15 for typical installation of balancing valve
and check valve.
Install boiler so that chilled medium is piped in
parallel with heating boiler (Figure 15). Use ap-
propriate 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 flow control valves or other au-
tomatic 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.
Recommended piping – refrigeration systems
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BOILER MANUAL
(continued)
15