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CGi-4E Gas-Fired Water Boiler — Boiler Manual
22
Part Number 550-110-711/1108
4c
Piping multiple zones
Follow instructions on pages 20 and 21 to install near-
boiler or single-zone piping. (Also refer to Piping for
radiant heating systems or converted gravity sys-
tems
, below, if applicable.)
SeeFigure 18 or Figure 19 to complete installation.
Zoning with circulators (Figure 18)
(return temp over 130°F)
1. Sizeeachcirculatortoindividual circuitrequire-
ments.
2. Donotinstallcirculatoronboiler(exceptforpri-
mary/secondary piping).
3. Install isolation (balancing) valves to adjust flow to
distribute heat to all zones.
4. Install and wire a separate relay for each zone cir-
culator.
Zoning with zone valves (Figure 19)
(return temp over 130°F)
1. Install isolation (balancing) valves to adjust flow to
distribute heat to all zones.
2. Provide a separate 24-volt transformer to power the
zonevalves.Sizethetransformertohandlethetotal
rated load of all connected zone valves.
Piping for radiant heating
systems or converted gravity
systems
Converted gravity (or steam) systems
Whenever possible, use the primary/secondary piping
shown in Figures 20 or 21 on page 25. This piping de-
sign allows changing boiler flow rate without affecting
primary circuit flow rate.
If
Figures 20 or 21 cannot be used, use the boiler-bypass
piping shown in
Figure 22 or Figure 23 on page 27.
YoucanalsousethepipingshowninFigure 24 on
page 29 (system-bypass), if the reduced flow rate in
the heating system will not cause heat distribution
problems.
Failure to prevent low return water
temperature to the boiler could
cause corrosion of the boiler sec-
tions or burners, resulting in severe
personal injury, death or substantial
property damage.
Radiant heating systems
Preferably, use primary/secondary piping, as shown
in Figures 20 or 21 on page 25. Alternatively, use the
method of either Figure 22 or Figure 23 on page 27.
Do not use the piping of Figure 24 (system-bypass),
because this method does not control radiant system
supply temperature.
If radiant system tubing has no oxygen barrier, a heat
exchanger
must be used.
Radiant heating system piping should include a means of regulating the boiler return water
temperature and the system supply temperature (such as provided by an injection pumping
control).Boilerreturnwatertemperaturewillbeadequatelycontrolledusingthemethods
shown in this manual provided the system supply temperature is relatively constant.
DO NOT apply the methods in this manual if the system is equipped with an outdoor reset
control
. Instead, provide controls and piping which can regulate the boiler return water
temperatureatnolessthan130°Fregardlessofsystemsupplytemperature.Contactyour
Weil-McLain representative for suggested piping and control methods. Failure to prevent
cold return water temperature to the boiler could cause corrosion damage to the sections
or burners, resulting in possible severe personal injury, death or substantial property dam-
age.
Water piping — multiple zones