VOKERA ETV-10 Release note

THESE INSTRUCTIONS
TO BE RETAINED
BY USER
Installation
& Servicing
Instructions
Vokèra is a licensed member of the Benchmark scheme
which aims to improve the standards of installation and
commissioning of domestic hot water systems in the UK.
ETV-10

ETV-102
MODEL CODE
ETV-1025 20026323
ETV-1025 conf. x5 20031295
ETV-1035 20031297
ETV-1035 conf. x5 20031298
Solar collectors conform to EN 12975 standard
and to Solar Keymark certification standard.
CONFORMITY
RANGE

ETV-10 3
GENERAL
General safety information and precautions page 4
Description of the solar collector “ 5
Identification “ 5
Design “ 6
Technical specifications “ 7
Accessories “ 8
Collectors connection “ 8
Water circuit “ 9
Location of probes “ 10
FOR THE INSTALLER
Unpacking the collector page 11
Dimensions and weight “ 12
Handling the collector “ 13
Installation “ 13
Filling the circuit “ 15
Controls “ 16
TECHNICAL ASSISTANCE CENTRE
Maintenance page 17
The following symbols are used in some parts of this
booklet:
b CAUTION = actions that require special care
and suitable preparation
aPROHIBITED = actions that absolutely must
NOT be carried out
This booklet, code 20026421 - Rev. 2 (11/10), contains
20 pages.
CONTENTS

ETV-104
GENERAL SAFETY INFORMATION AND PRECAUTIONS
b As soon as you open the packaging, check imme-
diately that the contents are all present and unda-
maged. Contact the reseller from whom you purcha-
sed the solar collector if you notice any problems.
b This solar collector must be used only for the proper
purpose for which it is designed and made.
The manufacturer declines all responsibility, con-
tractual or other, for damage to property or injury to
persons or animals caused by improper installation,
adjustment, maintenance or use.
b The solar collector must be serviced every six months.
b Work near uncovered and live electrical wires, with
which it is possible to come into contact, is only
permitted under the following conditions:
- wires must be free from voltage for the entire
duration of the work
- parts remaining live must be covered or accidental
contact prevented
- the following minimum safety distances must be
respected:
1 m for voltages of up to 1000 Volts
3 m for voltages from 1000 to 11000 Volts
4 m for voltages from 11000 to 22000 Volts
5 m for voltages from 22000 to 38000 Volts
over 5 m if the voltage is not known.
Contact with open, live electrical wires may lead to
electrocution and may even be fatal.
b Always wear safety goggles when drilling. Always
wear safety shoes, cut-proof protective gloves and
a safety helmet when performing installation work.
b Before beginning installation work on roofs, install
the necessary fall prevention and fall arrest devices
and ensure that all applicable safety standards are
applied.
Use only tools and materials that conform to the
safety standards that are applicable in the place of
work.
b Only wear overalls that have a safety harness (with a
suitable safety or fall-arrest belt, ropes or slings, fall
dampers or dissipaters). In the absence of adequa-
te fall prevention and security devices, failure to use
a proper safety harness may lead to falls from great
heights with serious or even fatal consequences.
b The use of ladders leaned against walls can lead to
serious falls if the ladder slips, slides of falls.
When using ladders, always ensure that they are
stable, and that suitable ladder stops are present.
If possible secure the ladder with hooks. Make sure
that there are no live electrical wires near the ladder.
b Especially when installing the solar collector as part
of a domestic hot water system, follow the orienta-
tion and angle of the roof to ensure that the collector
blends in with the architecture of the building.
b This instruction manual is an integral part of the solar
collector. It must be kept safe and must ALWAYS
accompany the solar collector, even if it is sold to
another owner or transferred to another user or to
another installation. If you lose this manual, order a
replacement immediately from your local Technical
Assistance Centre.

ETV-10 5
CODICE:
20025360
DESCRIZIONE: CTE25V
S/N:
COLLETTORE SOLARE SOTTOVUOTO
DIMENSIONI: 1600X1730X145 mm
SUPERFICIE LORDA: 2,77 m
2
TEMP. DI STAGNAZIONE: 236°C
SUPERFICIE DI APERTURA: 2,40 m
2
CONTENUTO LIQUIDO: 2,05 l
SUPERFICIE ASSORBITORE: 2,69 m
2
MAX CONCENTRAZIONE GLICOLE: 50 %
PESO A VUOTO: 52 kg LIQUIDO TERMOVETTORE:
ACQUA+GLICOLE PROPILENICO
COLLEGAMENTO IN SERIE FINO 20022981_E1 AD UN MASSIMO DI 6 COLLETTORI
MAX PRESSIONE ESERCIZIO: 10 bar
FABBRICATO IN ITALIA
da Riello S.p.A.
CEN 025
EN 12975
Certif. XXXX
Anno di produzione
10xxxxxx
The solar collectors are identified by two plates:
b If these plates or any other means of clearly identifying the product are defaced, removed or lost, proper installa-
tion and servicing may be rendered difficult.
- Data plate
This lists the technical specifications and performance of the product.
- Serial number plate
This bears the collector’s code number, model and serial number.
Code
Year of production
Serial Number
Description Made in Italy
by Riello S.p.A.
Evacuated
solar collector
Dimensions
Gross area
Aperture area
Absorber area
Empty weight
Max. operating pressure
Stagnation temperature
Liquid content
Max glycol concentration
Heat transfer fluid:
water+propylene glycol
Up to max 6 collectors can be connected
DESCRIPTION OF THE SOLAR COLLECTOR
IDENTIFICATION
Serial number
Model
Code
ETV-10 collectors are made up of 14 or 20 double slee-
ve evacuated glass tubes, each of which contains a "U"
shaped copper pipe. These copper pipes are connected
in parallel and filled with heat transfer fluid that descends
and rises to absorb the heat generated by solar radiation,
direct and reflected by a mirror known as a compound
parabolic concentrator. There is a vacuum inside the
double sleeved glass tubes. This provides effective ther-
mal insulation (on the same principle as a vacuum flask)
and permits the collectors to generate heat from the sun
even in bad weather and in the winter. The outside of the
internal pipes is finished in a selective absorbent coating.
The main characteristics of the ETV-10 collector are as
follows:
- Evacuated tube technology for high temperatures and
high efficiency even in bad weather.
- Circular absorbers and CPC mirrors for maximum
absorption even in oblique light.
- Long working life, with no metal parts passing through
the glass tubes to cause loss of vacuum.
- Constant absorption over time, thanks to a selective
coating that is well protected inside the vacuum envi-
ronment.
- Easy replacement of glass tubes without having to
empty the solar heating circuit.
- Elegant design.

ETV-106
Aluminium absorber
Insulation
Top pipe
Bottom pipe
Collector
return
Collector
outlet
Collector
probe socket
Glass
Vacuum
Absorbent
coating
Support frame
Direction of flow
Reflective
mirror
Collector
foot
Evacuated
tube Seal
Top
cover
plat
DESIGN

ETV-10 7
1
0,8
0,6
0,4
0,2
00 0,02 0,04 0,06 0,08 0,1
Tm[m2K/W]
*
bMinimum recommended slope is 15° (to ensure efficient self-cleaning and minimise snow pressure).
Installation in locations liable to frequent snow and hail is not recommended.
Do not install outlet pipe probes that could limit flow, because this could cause overheating.
b These specifications are purely indicative. The entire structure must be inspected by an expert in static loading in
compliance with applicable standards.
Diameter of connection pipes for a specific flow rate of 30 lt/m2h
Total surface area (m2)2 - 4 6 - 12 14 - 20
Diameter of copper pipe (mm) 10 - 12 14 18
Diameter of steel pipe (inch) 3/8" - 1/2" 1/2" 3/4"
Efficiency curve referred to exposed area
Tested according to EN 12975, referred to a
flow rate of 0.0196 Kg/(s*m2) and irradiation
G = 1000 W/m2.
Tm = (Coll._inlet _temp. + Coll._outlet_temp.)/2
T*m = (Tm - ambient_temp)/G
Optical
efficiency
(ηο)
Thermal dispersion factor
a1
W/(m2K)
a2
W/(m2K2)
0,676 1,15 0,004
TECHNICAL SPECIFICATIONS
DESCRIPTION ETV-1025 ETV-1035
Total area 2,77 3,91 m2
Exposed area 2,40 3,43 m2
Effective absorption area 2,69 3,84 m2
Connections threaded on Ø 18 pipes mm
Empty weight 52 74 kg
Liquid content 2,05 2,9 l
Recommended flow rate per m2of panel 30 l/(m2h)
Absorption (α) > 94 %
Emissions (ε)<7%
Maximum permitted pressure 10 bar
Stagnation temperature 236 °C
Maximum number of collectors connectable in
series 6n°
WIND AND SNOW LOADS ON COLLECTORS
Installation
height above
ground
Wind speed
Mass in kg to secure collector
against lifting by wind
Load on roof from wind, snow, and
collector weight
At angle of 45° At angle of 20° At angle of 45° At angle of 20°
ETV-1025
0 - 8 m
8 - 20 m
20 - 100 m
100 km/h
130 km/h
150 km/h
80 kg
130 kg
180 kg
40 kg
70 kg
100 kg
320 kg
470 kg
624 kg
345 kg
430 kg
525 kg
ETV-1035
0 - 8 m
8 - 20 m
20 - 100 m
100 km/h
130 km/h
150 km/h
150 kg
240 kg
340 kg
80 kg
130 kg
180 kg
500 kg
740 kg
980 kg
540 kg
680 kg
820 kg

ETV-108
The following accessories are available, to be ordered separately.
ACCESSORY CODE
Glycol anti-freeze 4383118
Connections kit for copper pipes 20027281
Connections kit for flexible hoses 20027289
Support rail kit for 1 x 2.5 m2collector 20026236
Support rail kit for 2 x 2.5 m2collectors 20026240
Support rail kit for 1 x 3.5 m2collector 20026238
0° installation kit 4383543
45° installation kit 20024357
Connecting piece kit 4383545
The diagram below illustrates the connections between solar collectors in lines.
The fittings are available as accessories to be ordered separately.
The collectors in a line are connected so that the heat transfer fluid goes through them in series.
It is also possible to connect more then one line of solar collectors both in series (max 6 collectors in series) or in paral-
lel. Anyway the circuit must be hydraulically balanced (see the following schemes as an example).
If more than 4 solar collectors are installed in a row, fit an expansion joint of the sort designed for solar collectors at the
central join.
collector
temperature sensor
to heat
exchange circuit
from heat
exchange circuit
union
olive
olive
ring nut
ring nut
union
olive
olive
ring nut
union
olive
olive ring nut
stub pipe
stub pipe stub pipe
T T
Two lines in series Two lines in parallel
ACCESSORIES
COLLECTORS CONNECTION

ETV-10 9
Pressure drop (mbar)
Flow rate (l/h)
700
800
900
600
500
400
300
200
100
0
0 1000 2000 3000
ETV-1025
ETV-1035
4000 5000 6000
The diagram below illustrates the water connections between solar collectors and a storage cylinder.
3
11
RM
°C
M
4
4
4
9
8
11
17
10
13
14
2
6
12
Gruppo idraulico
5
7
15
16
Pressure drop in solar collectors
1 - Solar collector
2 - Storage cylinder
3 - Collector probe
4 - Disconnect valves
5 - Non-return valve
6 - Temperature gauge
7 - Vent valve
8 - Safety valve
9 - Pressure gauge
10 - Drain
11 - Expansion vessel
12 - Pump
13 - Flow regulator
14 - Flow meter
15 - Vent cock
16 - Manual bleed valve (accessory)
17 - Heat transfer fluid recovery
M - Collector outlet
R - Collector return
b Connect no more than 6 collectors in series.
b We recommend the use of stainless steel pipes spe-
cially made for solar collectors for the outlet, return
and probe pipes. The probe cable should be of the
shielded type.
b Do not use plastic or multistrate pipes. Operating
temperature can exceed 180°C.
b Pipe lagging must be able to resist high temperatu-
res (180°C).
Water system
WATER CIRCUIT

ETV-1010
3
11
°C
M
4
4
4
9
8
11
10
13
14
2
6
12
Gruppo idraulico
REGOLATORE
SOLARE
17
7
5
15
16
18
19
RM
The temperature sensor must be installed in a socket as near as possible to the collector outlet. Make sure that the sen-
sor makes good contact with the socket. Materials (sensor, cables, seals and insulation) used to install the temperature
sensor must be able to withstand high temperatures (up to 300°C).
1 - Solar collector
2 - Storage cylinder
3 - Collector probe
4 - Disconnect valves
5 - Non-return valve
6 - Temperature gauge
7 - Vent valve
8 - Safety valve
9 - Pressure gauge
10 - Drain
11 - Expansion vessel
12 - Pump
13 - Flow regulator
14 - Flow meter
15 - Vent cock
16 - Manual bleed valve (accessory)
17 - Storage cylinder bottom probe
18 - Storage cylinder top probe
19 - Heat transfer fluid recovery
M-Collector outlet
R- Collector return
Water system
SOLAR
REGULATOR
LOCATION OF PROBES

ETV-10 11
The solar collectors are packed in various ways depen-
ding on the number of units supplied.
A - Individually packaged collectors
Pallet contents:
- collector
- Documentation envelope containing:
- certificate of warranty and label with bar code.
B - Packages of 5 collectors
Pallet contents:
- 5 collectors
- Documentation envelope containing:
- certificate of warranty and label with bar code.
b Keep the front of the packaging and use it to shade
the glass tubes before the system is started up.
If the solar collectors are not going to be put into
operation immediately, and there is any risk of their
being exposed to rain, do not use the packaging to
shade them as it is not water-proof.
b The instruction manual is an integral part of the solar
connector. Once located, read it thoroughly and
keep it safe.
UNPACKING THE COLLECTOR

ETV-1012
DIMENSIONS AND WEIGHT
1600 145
68
1552
110x14
110x20
65
1730
1700
2260 145
68
2212
1730
1700
65
ETV-1025
ETV-1035
ETV-1025 ETV-1035
Net weight 52 74 kg

ETV-10 13
Assembly
The solar collector must be fitted by specialist personnel.
Use only the assembly material supplied with the solar
collector. The supporting framework and all masonry or
brickwork fixing points must be checked by a person
expert in static loading, and must be suitable for the
nature of the installation site.
Static load
The solar collector must only be installed on roofs or
frames that are strong enough to support its weight. The
strength of the roof or frame must be verified on site by a
person expert in static loading before the solar collector
is installed. During this process, it is important to verify
the suitability of the supporting frame to hold the screw
fasteners that fix the solar collector in place. An expert in
static loading must verify that the entire frame complies
with relevant standards, especially in areas liable to snow
and areas exposed to high winds. Conditions (gusts of
wind, formation of wind vortices, etc.) at the point where
the solar collector is to be installed must be carefully
considered since these can increase the loads on the
supporting structure.
GENERAL INSTRUCTIONS
A
A
A
A
Once you have removed the outer packaging, proceed
as follows to unpack and handle the solar collector:
- Remove the PVC wrapping to free the solar collector
from the pallet
- Tilt the solar collector slightly and grip it at the four
points shown (A) to lift it.
- Use a hoist or other suitable lifting equipment to hoist
the solar collector on to the roof.
b Never lift the collector by its threaded water fit-
tings.
b Wear suitable personal protective equipment and
use suitable safety devices.
a Do not dispose of the packaging material into
the environment where it can become a potential
hazard. Dispose of the packaging material in com-
pliance with applicable legislation.
Lightning protection
The metal piping of the solar heating circuit must be
connected to the main potential compensation bar by a
(yellow-green) copper wire (H07 V-U or R) of at least 16
mm2. If a lightning conductor system is already installed,
the solar collectors may be connected to the existing
system. Alternatively, the solar collector piping may be
connected to ground via a ground wire sunk into the
earth. Ground wires must be sunk outside the house. The
ground wire must be connected to the potential compen-
sation bar through a wire of the same diameter.
Connections
Solar collectors must be connected in series using the
threaded unions provided.
If flexible pipes are not used to connect the solar col-
lectors, the piping must be fitted with expansion joints
(U-type expansion joints, flexible hoses) to absorb ther-
mal expansion. Provided adequate expansion joints are
used, up to 6 solar collectors may be connected in series.
Make sure that the unions are located correctly when
tightening them. When tightening a union with a pipe
wrench or spanner, always hold the opposite union stea-
dy with a second tool to avoid twisting the pipe to which
the union is attached.
HANDLING THE COLLECTOR
INSTALLATION

ETV-1014
bAll pipes in the water circuit must be insulated in
conformity to relevant standards. Lagging and insu-
lation must be protected against damage by the
weather and birds and animals.
Angle of collectors / General
Solar collectors are designed to be installed at angles of
between 15° (minimum) and 75° (maximum).
Make sure that the bleed and vent valves of the collectors
remain open while the collectors are being installed.
Take care to protect all fittings, connections, bleed and
vent valves against dirt and dust etc..
In installations which serve primarily to produce domestic
hot water in the summer, install the collectors facing from
east to west at an angle of between 20 and 60°. The ideal
orientation is southwards, at an angle equal to the latitude
of the location minus 10°.
If the system sustains the greatest thermal load in the
winter (as in systems that combine domestic hot water
production with central heating), install the collectors
facing south (or south-east or south-west) at an angle
greater than 35°. The ideal orientation is southwards, at
an angle equal to the latitude of the location plus 10°.
Flushing and filling
For safety reasons, the solar collector must be covered,
using the packaging it came in, for at least two hours
before it can be filled.
In areas liable to frost, fill the collector with an anti-freeze
heat transfer fluid.
b DO NOT ADD WATER TO THE GLYCOL PREMIX.
The glycol premix supplied for use with solar col-
lectors comes ready to use. It provides anti-freeze
protection down to -28°C. IT MUST NOT BE MIXED
WITH WATER.
b Take care if you flush the system out, because water
trapped inside the circuit before filling with glycol
premix may freeze.
Bleeding
Bleed the circuit:
-
On startup (after initial filling) (see the figure on page 16).
- Whenever necessary, as in the event of system malfun-
ctioning.
Make quite sure that all air has been bled out of the
system.
b Risk of burns from hot fluid inside the collectors!
b Only open the vent valve if the temperature of the
fluid in the circuit is below 60°C.
Make sure that the collectors are not hot before you
start bleeding the circuit. Always cover the solar
collectors before bleeding the circuit. Always per-
form bleeding in the morning.
Checking the heat transfer liquid
Check the anti-freeze effect and the pH level of the heat
transfer liquid every 2 years.
- Use an instrument like a refractometer or densime-
ter to check the anti-freeze effect (which must have a
nominal protection value of approx. -28°C). If density is
other than 1.030 kg/dm3, replace the mix, or add anti-
freeze as required.
- Use litmus paper to check the pH (nominal value 9 to
10.5). If the measured value is below 7, change the
mix.
bAt the end of its useful life, dispose of the product in
compliance with applicable legislation.

ETV-10 15
Perform the following steps before starting up the system.
1 - FLUSHING AND SEAL TESTING THE SYSTEM
If copper piping has been used and joints have been hot brazed, flush out the system to remove any brazing residues.
Seal test the system after you have flushed it out.
b Fill the solar collector with anti-freeze heat transfer liquid immediately after flushing it out, because flushing water
may remain trapped in the circuit (with a consequent risk of freezing).
b The glycol premix supplied is specially formulated
for solar collector applications and is efficient throu-
ghout the -28 to +170°C temperature range.
The mix is also non-toxic, biodegradable and bio-
compatible.
b Do NOT part fill the circuit with glycol then top up
with water.
b Temperatures in excess of 200°C can cause the gly-
col mix to break down. This is easily visible because
the liquid becomes darker.
°C
M
A
RM
7
Manual bleed
valve (accessory)
Anti-freeze mix
Heat exchanger
of solar storage
cylinder
Solar collectors
Heat
transfer fluid
filling pump
Water control system
2 - FILLING
1 - Open the non-return valve (A).
2 - Open the air vent at the highest point in the system
(see figure alongside) and keep it open throughout
the filling operation.
3 - Open the vent valve (7).
4 - Pump the heat transfer fluid around the circuit with an
external filling pump until all air bubbles have been
eliminated. Close the manual bleed valve.
5 - Temporarily raise the pressure in the system to 4 bar.
6 - Start up the system for about 20 minutes.
7 - Bleed the system again from step 2 until all the air has
been removed.
8 - Set the pressure in the system to 3 bar.
9 - Close the non-return valve (A) and any open vent
valves to prevent the heat transfer fluid from evapora-
ting.
b Do not fill the system in bright, sunny conditions or if
the collectors are hot. Cover the solar collector with
the packaging it came in for at least two hours befo-
re filling it.
b Make sure that you have bled all the air out of the
system, using the water control system vent too.
Heat transfer fluid filling pump (accessory). A manual
bleed valve is not required if this pump is used.
Anti-freeze Temperature Density
Glycol premix 20°C
1,032÷1,035 kg/dm3
FILLING THE CIRCUIT

ETV-1016
On completion of the installation, perform the checks listed in the table below.
DESCRIPTION OK
Collector circuit
Cold pressure 3 bar
Collector circuit seal test
Safety valve check
Anti-freeze checked to - ____ °C
pH of heat transfer fluid = ____
Collector circuit bled
Flow rate of 30l/h per m2checked
Non-return valve functioning
DESCRIPTION OK
Solar collectors
Visual check of collectors
Collectors cleaned if necessary
Visual check of collector fixing points
Visual check of roof impermeability
Visual check of insulation/lagging
CHECKS

ETV-10 17
The collector must be cleaned and all parts (reflector, glass tubes, etc.) inspected every six months.
REPLACING EVACUATED TUBES
The evacuated tubes are fully functional when delivered. Nevertheless, if problems occur, they can be replaced quickly
and easily.
Defective tubes are easy to recognise because their undersides turn white and their surfaces become extremely
hot.
Proceed as follows to remove an evacuated tube. Wear
gloves and take all the necessary precautions.
- Smear the top of the tube (1) near the seal ring with a
lubricant paste
- Unscrew and remove the plug (2) from the foot of the
tube
- Pull the tube (3) downwards, twisting it gently to release
it from the top seal
- Remove the tube from the bottom of the collector
If you do not have sufficient room to remove the tube
downwards, proceed as follows.
- Remove the tube from the collector foot as instructed
above
- Pull the tube down about 20 cm
- Hold the tube in a glove, lift it gently and swivel it to
the left or right. This bends the copper pipes inside the
glass tube. Take care not to damage them, however
- Pull the tube out diagonally across the collector to
remove it.
Reverse the above steps to fit the new tube.
b Remove any pieces of broken glass without dama-
ging the surface of the mirror. Also remove any resi-
dues that might have formed around the copper
pipes.
b Make sure that the silicon seal ring is still correctly
seated.silicone.
1
3
2
A
MAINTENANCE

ETV-1018
REPLACING THE CPC REFLECTOR
Our CPC reflectors are manufactured and delivered under the best possible conditions.
Nevertheless, if a fault (e.g. a large dent) is found, they can be replaced quickly and easily.
Proceed as follows, taking all the necessary precautions,
to remove a damaged reflector:
- Unscrew and remove the plug (1) from the foot of the
collector.
- Remove the bracket (2) into which the plug was scre-
wed by bending back the clips (3).
- Remove the reflector (4) without moving its glass tube.
14
2
3
4

Registered address:
Vokèra Ltd
Borderlake House
Unit 7 Riverside Industrial Estate
London Colney
Herts AL2 1HG
[email protected]
www.vokera.co.uk
www.vokera.ie
Sales, General Enquires
T0844 391 099
F0844 391 0998
Vokèra Ireland
West Court, Callan
Co Kilkenny
T056 7755057
F056 7755060
Vokèra Limited reserve the right to change
specification without prior notice
Consumers statutory rights are not affected.
A Riello Group Company.
Company Reg No: 1047779
Cod. 20026421 - Rev. 2 (11/10)