Giacomini R478 Guide

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Thermo-elecTric acTuaTors
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r478, r478m
Main characteristics
• R478 thermo-electric actuators are equipped with a 2-conductors wire to
connect them to ambient thermostats or control units.
• R478M thermo-electric actuators are equipped with a 4-conductors wire for
a stroke-end micro switch to control circulators or zone valves (brown: phase -
blue: neutral- black and grey: micro switch).
• The R478VX121 and R478VX021 versions include a varistor for installation
in areas where the network voltage is subject to sudden changes that may
damage the electronic components.
Thermo-electric actuators normally open in heating and cooling radiant
panel systems are especially useful as they are not electrically fed for most of
the time, thus oering great energy saving levels.
Position mechanic indicator
R478 and R478M thermo-electric actuators include a position mechanical
indicator (A) on the top which enables to visually identify the current position
of the actuator and the valve it serves.
The actuator closes the valve when electrically powered.
The position indicator (A) lowers when the valve is closed.
The position indicator is particularly useful during testing to perform
operation verications without activating the system or disassembling the
actuator.
A
Position indicator lifted =
thermo-electric actuator and
valve it serves open
A
Position indicator lowered =
thermo-electric actuator and
valve it serves closed
Description
Thermo-electric actuators installed on distribution manifolds, radiator
thermostatizable valves or fan coil units enable to adequately control the
ambient temperature by combining energy saving to high levels of comfort.
The R478 and R478M thermo-electric actuators feature absolute operational
quietness, a long life as they have no mechanical parts subject to wear and tear
and a proper slowed-down closing system to prevent water hammer eects.
The activation mechanism includes wax bulbs controlled by low-
consumption electrical PTCs.
Versions and product codes
Series Product code Voltage Characteristics
R478
R478X121 230 V
2-conductors wire
R478X122 24 V
R478VX121 230 V 2-conductors wire with varistor
R478M
R478MX021 230 V 4-conductors wire,
with stroke-end micro switch
R478MX022 24 V
R478VX021 230 V 4-conductors wire,
with stroke-end micro switch and varistor
Technical data
• Complies with B.T. directive provision and ENEC 03 certicate
• Status without voltage: normally closed (N.C.)
• Rapid connection for Giacomini standard valves and/or manifolds
• Position mechanic indicator
• Linear movement
• Valve useful lift: 2.4 mm
• Pollution class: II
• Nominal pulse voltage: 4 kV
• Protection class: IP40
• Protection against direct contacts through double insulation (Class II)
• Power wire: H05 VV-F; useful length 1,5 m
• Closing time at room temperature: ~ 6 mins.
• Room temperature of use: -5÷50 °C
• Storage room temperature: -20÷65 °C
• PBT self-extinguishing case material V0-UL94
• Normally closed microswitch with open valve (only for versions with stroke-
end micro switch)
R478 R478M
This appliance should not be operated
by children younger than 8 years, people
with reduced physical, sensory or mental
capacities, or inexperienced people who are
not familiar with the product, unless they
are given close supervision or instructions
on how to use it safety and are made aware
by a responsible person of the dangers its
use might entail.
Children must not play with the appliance.
It is the user’s responsibility to clean and
mantain the appliance. Children should
never clean or mantain it unless they are
given supervision.

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Warning.
• The actuator case cannot be disassembled and should never be
opened.
• Tampering immediately voids the warranty.
• The power wire is not replaceable; if the cable is damaged, replace
the actuator.
• Electrical connections must be carried out by qualied personnel
and voltage-free after carefully verifying the voltage which must
comply with the one specied.
• Connection of power wires to the x distribution network must be
performed in a safe manner as provided for by the Technical Rules in
force in the Country of use.
• Giacomini S.p.A. will not be held responsible for damages suered
by individuals or objects for misuse of the product.
Dimensions
CD
A
B
A [mm] B [mm] C [mm] D [mm]
68 65 51 37
Electrical data
Installation
R478 and R478M thermo-electric actuators may be installed on
thermostatizable valves and/or manifolds with Giacomini standard ttings,
using the special toothed ring provided with the actuators.
They can be installed horizontally or vertically, but not upside down with the
indicator pointing downwards.
To install the actuators on valves and/or manifolds, follow the steps below:
C
1Install the toothed ring
(C) on the Giacomini standard
connection valve and/or manifold
pushing down.
Connect the thermo-electric
actuator to the ring.
15°
2Turn the thermo-electric
actuator by 15° clockwise till you
hear a locking click (to remove
the actuator, turn by 15° in
anticlockwise direction).
3Electrically connect the
actuator according to the
electrical diagrams.

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Product code Absorbed power Voltage Max. peak current
(*)
Current absorbed
after 12 mins. (*) Resistance (*) Power wire section Microswitch Varistor
R478X121 3,5 W 230 V 50 Hz ≤ 1,0 A ≤ 0,015 A 1200 Ω +46 % -35 % 2 x 0,75 mm2- -
R478X122 3 W 24 V 50 Hz ≤ 0,22 A ≤ 0,125 A 147 Ω ± 25 % 2 x 0,75 mm2- -
R478VX121 3,5 W 230 V 50 Hz ≤ 1,0 A ≤ 0,015 A 1200 Ω +46 % -35 % 2 x 0,75mm2- S10K250
R478MX021 3,5 W 230 V 50 Hz ≤ 1,0 A ≤ 0,015 A 1200 Ω +46 % -35 % 4 x 0,75 mm25 A 125 Vac
3 A 250 Vac -
R478MX022 3 W 24 V 50 Hz ≤ 0,22 A ≤ 0,125 A 147 Ω ± 25 % 4 x 0,75 mm25 A 125 Vac
3 A 250 Vac -
R478VX021 3,5 W 230 V 50 Hz ≤ 1,0 A ≤ 0,015 A 1200 Ω +46 % -35 % 4 x 0,75mm25 A 125 Vac
3 A 250 Vac S10K250
(*) Values read at room temperature
Electrical connections
Avvertenza.
On the supply circuit, a fuse or a protection device external to the device, has to be installed to intervene in case of fault/short circuit conditions.
R478 thermo-electric actuators provide for various connection options able to satisfy a wide range of installation needs. The most frequent cases require simple
direct connections to ambient thermostats or interposition of relays to control the circulators or zone valves.
L1
N1
N1
N2
L2
R1
R478X121
R478VX121
R478X122
230 Vac
24 Vac
3W
3,5W
Termostati ambiente / Room thermostats
NC C NO NC C NO NC C NO
R478M thermo-electric actuators equipped with a stroke-end microswitch enable to easily activate circulators or zone valves. They are generally connected to
ambient thermostats taking into consideration that the R478M is open when there is no voltage (while the microswitch is electrically closed in such status). To
control signicant power loads, we recommend installing a relay to prevent overloading of the actuator microswitches.
L2
L1
N1
N3
L3
N2 R1
R1
Termostati ambiente / Room thermostats R478MX021
R478VX021
230 Vac
MAX 5A 125Vac
MAX 3A 250Vac
MAX 3A 250Vac
3,5W
R478MX022
24 Vac
MAX 5A 125Vac
3W
NC C NO NC C NO NC C NO
Product specications
R478
Thermo-electric actuator normally open for thermostatizable valves and manifolds. 2-conductors wire, length 1,5 m. Protection class IP40. Rapid connection. Position
mechanic indicator. Room temperature range -5÷50 °C. Available with 230 V, 24 V power. Complies with Directive B.T. and provided with ENEC 03 certication.
R478M
Thermo-electric actuator normally open for thermostatizable valves and manifolds. 4-conductors wire with stroke-end microswitch, length 1,5 m. Protection
class IP40. Rapid connection. Position mechanic indicator. Room temperature range -5÷50 °C. Available with 230 V, 24 V power with or without varistor.
Complies with Directive B.T. and provided with ENEC 03 certication.

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0814EN November 2016
Thermo-elecTric acTuaTors
Thermo-elecTric acTuaTors Normally opeN
r478, r478m
Additional information
For additional information please check the website www.giacomini.com or contact the technical service: '[phone]+39 0322 923255 *consulenza.prodotti@giacomini.
com This pamphlet is merely for information purposes. Giacomini S.p.A. retains the right to make modications for technical or commercial reasons, without prior notice, to the items described
in this pamphlet. The information described in this technical pamphlet does not exempt the user from following carefully the existing regulations and norms on good workmanship. Giacomini
S.p.A. Via per Alzo, 39 - 28017 San Maurizio d’Opaglio (NO) Italy