17
FUTERA II INSTALLATION AND OPERATION INSTRUCTIONS
Low Water Cutoff
If a boiler is installed above any radiation elements it must
be fi tted with a low water cutoff device.
Refer to the wiring diagram supplied with the boiler/water
heater for proper wiring connections.
Expansion Tank & Air Separator
An expansion tank or other means to control thermal
expansion must be installed in the heating system. An
expansion tank must be installed close to the boiler on the
suction side of the pump. An air scoop and automatic air
vent must also be installed to eliminate air trapped in the
system.
Primary/Secondary Piping
Boilers connected to heating systems using zone valves,
zone pumps, or systems that have excessive fl ow rates or
return water temperatures less than 125˚F, 52˚C must be
isolated from these systems to protect the boiler.
Variable Water Flows
Figure 13 shows a typical primary/secondary piping
system. A dedicated pump is used to maintain a constant
water fl ow through the boiler. This secondary pump is sized
to overcome the head loss of the boiler and secondary
piping system while supplying the fl ow rate required to
maintain the desired temperature rise across the boiler.
The primary pump is sized to provide the required fl ow to
the heating system. The secondary piping connections to
the primary system piping must not be more than 12 in,
305 mm apart to ensure zero pressure drop in the primary
system, see Figure 13.
Low Return Water Temperatures
To prevent the problems associated with condensation of
the products of combustion due to low return water
temperatures a primary/secondary piping system with a
bypass and bypass valve must be installed, see Figure 14.
The bypass and bypass valve must be sized the same as
the secondary piping. A balancing valve must also be
installed in the supply side of the secondary piping
downstream of the bypass. The balancing valve should be
adjusted to divert some of the heated discharge water into
the return water until the required inlet water temperature
is achieved. The primary and secondary pumps should be
sized to provide the required fl ow through each system. The
secondary piping connections to the primary system piping
must not be more than 12 in, 305 mm apart to ensure zero
pressure drop in the primary system, see Figure 14.
Multiple Boiler Systems
Systems using multiple boilers can also be installed using
a primary/secondary manifold system, Figure 15.
Piping For Use With Cooling Units
The boiler, when used in connection with a refrigeration
system, must be installed so the chilled medium is piped
in parallel with the boiler. Appropriate valves must be used
to prevent the chilled water from entering the boiler.
When a boiler is connected to a heating coil that may be
exposed to refrigerated air from an air handling device, the
piping system must be equipped with fl ow-control valves
or some other automatic means of preventing gravity
circulation of the boiler water during the cooling cycle.
