System Piping - Dunkirk PWXL Installation, Operation & Maintenance Manual

For Use With Cooling Units
The boiler, when used in connection with a refrigeration
1.
system, must be installed so the chilled medium is
piped in parallel with the boiler with appropriate valves
to prevent the chilled medium from entering the boiler.
(Figure 6).
The boiler piping system of a hot water boiler connected
2.
to heating coils located in air handling units where they
may be exposed to refrigerated air circulation must be
equipped with fl ow control valves or other automatic
means to prevent gravity circulation of the boiler water
during the cooling cycle.
Low Design Water Temperature Systems (Below
140º)
If the boiler is to be used in a heating system where
1.
water temperatures below 140ºF are desired (e.g.
radiant fl oor heating) a 3-way or 4-way mixing valve
or suitable alternative is required to prevent low
temperature return water from entering the boiler.
Follow the mixing valve manufacturer's installation
instructions.
The minimum design return water temperature to the
2.
boiler to prevent condensation in the boiler and venting
is 120ºF. The minimum high limit setting is 140º F.
Figure 5 -Typical Hot Water Piping
Cool Water Inlet
Safety Relief Valve

SYSTEM PIPING

Circulator
Air Vent
Supply Main
Expansion Tank
Gauge
Sensor Wire
Return Line
Figure 6 - Chilled Water Piping
Valves A & B - Open For Heating; Closed For Cooling
Valves C & D -Closed For Heating; Open For Cooling
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