G-9
A-070336_EN • B_0821
P
roduct
d
escrIPtIon
Nesta 120 - 160 - 200 - 250
General Description
This floor-standing series of Nesta boilers consists of
compact, low-emission condensing appliances with a
pre-mix burner and a stainless steel heat exchanger.
The housing of the boiler is made of aluminium.
The fully radial burner ensures a high modulation ratio,
combustion stability and very low NOx emissions.
The stainless steel heat exchanger offers a high water
capacity and a large heat exchange surface to opti-
mise energy and heating efficiency.
This series is designed for heating systems and can
be used for indirect Domestic Hot Water production
(provided that the system contains an optional exter-
nal tank).
The appliances are built for natural gas (G20) but can
be converted by a qualified professional to operate
with either G25 natural gas or G31 liquefied petroleum
gas (propane), according to the procedure provided
with the boiler. Gas conversion must comply with ap-
plicable local regulations and standards.
Nesta boilers are able to control 3 heating circuits with
mixing functions, through 3 optional extension mod-
ules . Each extension module requires a power supply
and a bus connection. Refer to
“Optional Modules”
on page I-66
for more information.
These appliances
are not
provided with a built-in cir-
culating pump. Therefore, the hydraulic system must
be equipped with at least one pump for standard sys-
tem flow operation.
The Nesta boilers can be connected in a cascade
configuration, which means that the boilers are con-
nected to the same water circuit and electronic con-
troller, with one boiler operating as the master, and the
others as “slaves”). Refer to
“Boilers in a Cascade
System” on page I-67
for more information on cas-
cade system possibilities.
Frost Protection
The Nesta boilers have a built-in an ti-frost protec-
tion. The pump and the burner are started as re-
quired when the return water temperature drops
below 5°C (as measured by the boiler internal sen-
sor installed on the return circuit). The pump and/
or burner will turn off when the re turn temperature
reaches the required setpoint. The anti-frost pro-
tection function only protects the boiler, not the en-
tire system.
Safety Devices
The Nesta boilers are equipped with a series of
sensors and switches that provide safety for your
appliance and heating system, such as:
î
Water circuit temperature sensors (supply, re-
turn, system, etc.)
î
Burner plate temperature limit switch
î
Gas pressure switch
î
Air pressure switch
î
Flue pressure switch
î
Water pressure sensor
î
Flue temperature sensor
î
Condensate level switch
î
Alarm contacts
The Nesta boilers
are not
provided with the follow-
ing mandatory safety equipment that the installer
must place in the system:
î
Expansion tank, suitable for the system size,
î
Safety group, composed of a safety valve (pres-
sure rating adapted to the system), an automatic
air relief valve and a manometer,
î
Air relief valve(s), at the high point(s) of the sys-
tem.
Optional equipment
Some optional equipment can be used with the
Nesta boilers. Please contact your AIC Europe rep-
resentative for more information and a list of availa-
ble equipment.
To lengthen the life of your boiler and heating sys-
tem, in addition to the recommended water char-
acteristics described in
“Water Quality Require-
ments to Prevent Scaling and Corrosion in a
Heating System” on page I-33,
the following
equipment can be installed in the heating circuit:
î
Water filter
î
Dirt separator
î
Low loss header
î
Plate heat exchanger
î
Air separator
See
“Requirements for the Hydraulic Connec-
tions” on page I-32
for more information on this
equipment.