Backflow Preventer - Vesta VRC-100 Installation Manual

Essential Elements in a Space Heating System
Low Water Cut Off(LWCO) Device
Internal LWCO
The VESTA DS VRC boiler already has a type of low water cut off
(LWCO) device that senses the pressure inside of the product. The
minimum operating pressure of this device is 7.1psig.
Refer to the local code to see if LWCO is necessary for the system. In
addition, check if the LWCO attached inside meets such code.
External LWCO
Install LWCO if it is required by local code.
The following figure shows an example of general LWCO
installation.
Space heating
return
LWCO installed outside should be installed at least 6 inches
(150mm) or more away from the end of the heat exchanger.

Backflow Preventer

When filling the device with water, install a backflow preventer if it is
required by local code.
Expansion Tank
The expansion tank should be installed in the system pipes in order
to prevent excessive pressure in the heating pipes.
When installing the expansion tank, follow the guidelines below.
•
If the air separator is located on the suction side of the system
circulator, connect the air separator to the expansion tank.
• VESTA DS VRC boiler has a connection (water fill connection) for
additional water. Therefore, in most cases, an additional water
fill connection is not necessary.
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Installation Manual
External LWCO
Space heating
supply
•
If an additional water fill connection is necessary for special
use, install the water fill connection at the same location as the
expansion tank's connection to the system.
•
When replacing the expansion tank, refer to the literature of the
expansion tank manufacturer for selecting the proper size.
• When installing the diaphragm expansion tank, always install
an automatic air vent at the top of the air separator in order to
remove residual air in the system.
Isolation Valves and Unions
•
This boiler system requires a full port ball valve. If a full port ball
valve is not used, water may flow at a limited flow rate through
the boiler.
•
It is recommended to use unions for the serviceability of the
device.
Pressure Relief Valve
This boiler comes with an ASME-approved pressure relief valve to
install space heating. To complete the installation of the boiler, you
must install an approved 3/4", maximum 30 PSI (for space heating).
Improper installation of the pressure relief valve may result
in property damage, personal injury, or death. Follow all
instructions and guidelines wllen installing the pressure relief
Warning
valve. Only a licensed professional should install the valve.
Install the pressure relief valve as close to the boiler as possible.
No other valve should be installed between the pressure relief
Caution valve and boiler.
Space heating return Space heating supply
Pressure rilief valve