Boiler piping in heating/cooling application
The boiler, when used in connection with a refrigeration
system, must be installed so the chilled medium is piped in
parallel to the boiler with appropriate valves to prevent the
chilled medium from entering the boiler (Fig. 5a).
The boiler piping system of a hot water heating boiler
connected to heating coils located in air handling units where
they may be exposed to refrigerated air circulation must be
equipped with flow control valves or other automatic means to
prevent gravity circulation of the boiler water during the cooling
cycle.
Check installation instructions of chiller manufacturer carefully
for additional requirements.
Cooling season starts: Close valve V1 and open valve V2.
Heating season starts: Close valve V2 and open valve V1.
A metal tag should be attached to these valves as to purpose.
Low water cut-off
If the ECD boiler is installed above radiation level then a low
water cut-off device must be installed. See Fig. 5b for location
of low water cut-off device. Note: Flow direction must be as
shown in Fig. 5b. Low water cut-off is field supplied. Follow
instructions provided with low water cut-off.
When required by the authority having jurisdiction, the
installation must conform to the Standard for Controls and
Safety Devices for Automatically Fired Boilers, ANSI/ASME
CSD-1, latest edition.
Bypass piping (see Fig. 5a and Fig. 5b)
In some cases it is necessary to install a bypass. If you find the
bypass is not needed, then simply close the bypass valve.
Install a bypass in order to prevent flue gas condensation from
occurring in the heat exchanger casting and vent system when
installing the boiler in a large water volume system (i.e.
converted gravity system with tube type cast iron radiators).
A bypass is not a substitute for a mixing valve driven by an
indoor/outdoor control for proper weather responsive control of
an underfloor heating system.
1.
Install full size bypass as shown below.
2.
Use valve in bypass and valve in supply line to balance
flow so that boiler water temperature quickly reaches
140°F or higher. Use globe valve or ball valve.
3.
Bypass line should be minimum 12˝ long.
4.
Bypass will lower flow rate through boiler to allow higher
average water temperature rise. Water flow will bypass
boiler depending on setting of bypass valve.
5.
If the bypass is not needed, simply close the bypass
valve.
6.
The water flow direction must be as shown. Water flows in
at bottom and out at top.
Initial system fill
Treatment for boiler feed water should be considered in areas
of known problems, such as high mineral content and hardness.
In areas where freezing might occur, an antifreeze may be
added to the system water to protect the system. Please adhere
to the specifications given by the antifreeze manufacturer. Do
not use silicate based automotive antifreeze solutions.
Install a strainer on return pipe when necessary.
Wait for fill water to warm up to room temperature (70°F)
before firing boiler. Firing boiler with cold water will stress the
casting and could cause failure.
Please observe that an antifreeze/water mixture may require a
backflow preventer within the automatic water feed and
influence components such as diaphragm expansion tanks,
radiation and pumps selection. A 40% antifreeze content will
give freeze-up protection to approximately -10°F (-23.3°C). Do
not use antifreeze other than specific brands made for hot
water heating systems. System also may contain components
which might be negatively affected by antifreeze. Check total
system frequently when filled with antifreeze.
A field supplied pressure reducing valve (or “fill” valve) is
10
Fig. 5b
Low water cut-off location
Low water
cut-off
2˝ min.
Fig. 5a
Boiler piping in a heating/cooling application
Heating/
Cooling unit
Heating/
Cooling unit
Water
chiller
Heating/
Cooling unit
V
FC AFV V
V2
FC V
V1
V
FC
CP
required to reduce the incoming water pressure to between 12
and 15 psig.