CEN/TS 12977-5:2010

SLOVENSKI STANDARD
01-september-2010
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Thermal solar systems and components - Custom built systems - Part 5: Performance
test methods for control equipment
Thermische Solaranlagen und ihre Bauteile - Kundenspezifisch gefertigte Anlagen - Teil
5: Prüfmethoden für Regeleinrichtungen
Installations solaires thermiques et leurs composants - Installations assemblées à façon -
Partie 5 : Exigences générales
Ta slovenski standard je istoveten z: CEN/TS 12977-5:2010
ICS:
27.160 6RQþQDHQHUJLMD Solar energy engineering
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
91.140.65 Oprema za ogrevanje vode Water heating equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL SPECIFICATION
CEN/TS 12977-5
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
April 2010
ICS 27.160
English Version
Thermal solar systems and components - Custom built systems
- Part 5: Performance test methods for control equipment
Installations solaires thermiques et leurs composants - Thermische Solaranlagen und ihre Bauteile -
Installations personnalisées - Partie 5 : Méthodes d'essai Kundenspezifisch gefertigte Anlagen - Teil 5: Prüfmethoden
de performances des systèmes de régulation von Regeleinrichtungen
This Technical Specification (CEN/TS) was approved by CEN on 9 September 2008 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available
promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS)
until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 12977-5:2010: E
worldwide for CEN national Members.

Contents Page
Foreword .4
Introduction .5
1 Scope .6
2 Normative references .7
3 Terms and definitions .8
4 Symbols and abbreviations .8
5 Controller classification (including equipment classification) .9
5.1 Controller .9
5.2 Sensor .9
5.3 Actuator . 10
6 Requirements . 11
6.1 General requirements . 11
6.2 Controllers, system clocks, timers and counters . 12
6.3 Sensors . 12
6.4 Indicators . 15
6.5 Actuators . 15
6.6 Initial operation and commissioning . 16
6.7 Documentation . 16
7 Testing of Sensors. 16
7.1 Testing of temperature sensors . 17
7.2 Testing of solar irradiance sensors . 21
7.3 Testing of further sensors and measuring equipment . 25
8 Testing of system clocks, timers and counters . 25
8.1 General . 25
8.2 Test equipment . 25
8.3 Installation of system clocks, timers and counters . 26
8.4 Test procedure . 26
8.5 Data processing and evaluation . 27
9 Function testing of simple differential thermostats . 27
9.1 General . 27
9.2 Test equipment . 27
9.3 Installation of differential thermostats and/or sensors . 29
9.4 Test procedure . 29
10 Function testing of multi-function controllers . 31
10.1 General . 31
10.2 Intellectual property of the manufacturer . 31
10.3 Principle of multi-function controller testing . 32
10.4 Test facility for multi-function controller testing . 32
10.5 Preliminary steps when using a test facility provided with an input/output emulator . 34
10.6 Test procedure . 37
10.7 Data acquisition and processing . 39
11 Testing of actuators and additional control equipment . 40
11.1 General . 40
11.2 Determination of the electric power consumption of actuators and further components . 40
11.3 Measuring the electric power of pumps with varying power consumption . 40
12 Documentation . 40
12.1 General . 40
12.2 Marking . 40
12.3 Information for the installer, assembly and installation . 41
12.4 Information for the user, operation and maintenance . 41
13 Test report . 42
Annex A (informative) Testing the mains voltage dependence of control equipment . 43
A.1 General . 43
A.2 Test equipment . 43
A.3 Test procedure . 43
A.4 Data processing . 44
Bibliography . 45

Figures
Figure 1 — Elevation of an oven-arrangement to test temperature sensor accuracy, high-temperature
resistance and differential thermostat functions . 18
Figure 2 — Example of a simulation box for testing differential thermostats of solar heating systems 28
Figure 3 — Schematic of a controller test facility including an input/output emulator . 34
Figure 4 — Flow chart of preliminary steps when using a test facility provided with an input/output
emulator according to Figure 3 . 35
Tables
Table 1 — Classification of controllers for solar heating systems . 9
Table 2 — Common sensors for solar heating systems . 10
Table 3 — Most common actuators for solar heating systems . 10
Table 4 — Accuracy of system clocks, timers and counters . 12
Table 5 — Accuracy requirements of temperature sensors for solar heating systems . 13
Table 6 — Requirements of high-temperature resistance of temperature sensors . 13
Table 7 — Climate test conditions for solar irradiance sensors capability to resist to high irradiance . 14
Table 8 — Climate test conditions for solar irradiance sensors capability to resist to high surrounding
temperatures . 14
Table 9 — Accuracy requirements for solar irradiance sensors . 14
Table 10 — Total maximum electrical power of the pump(s) . 15
Table 11 — Temperatures to be used for the accuracy test . 20
Table 12 — Minimum climate test conditions for exposure and for external shock test . 23
Table 13 — Irradiance levels to test the accuracy of solar irradiance sensors . 24
Table 14 — Examples of control algorithms with the corresponding test sequences for multi-function
controllers . 38
Foreword
This document (CEN/TS 12977-5:2010) has been prepared by Technical Committee CEN/TC 312 “Thermal
solar systems and components”, the secretariat of which is held by ELOT.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Croatia, Cyprus,
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland and the United Kingdom.
Introduction
One purpose of this document is to define how to check that a controller is behaving as it is intended when in
combination with associated equipment (e.g. sensors, pumps and other actuators). In addition, function testing
of differential thermostats and so-called "multi-function" controllers are described in order to determine switch
on and switch off temperature differentials as well as control algorithms where dependent on temperature
differences, temperature levels or operating conditions of the system. For all functions and operations it
should be tested and documented, whether the controller and control equipment comply with the
manufacturer's guidance.
In addition, the capability for all sensors to resist extreme operating conditions and to determine any
significant drift in accuracy caused by this should be tested. The energy consumption of the controller and the
associated control equipment should be documented, e.g. actuators.
Performance predictions for the associated system that the control equipment belongs to are considered. For
the determination of the component parameters according to the CTSS method, as specified in
CEN/TS 12977-2, a detailed investigation of all relevant algorithms, features and parameters controlling the
system is relevant.
NOTE The most widely used control equipment for solar heating systems is described in CEN/TS 12977-5. For
control equipment not widely used in solar heating systems or auxiliary heaters, if part of the system, accompanying
standards should be applied.
In respect of potential adverse effects human health or life (e.g. drinking water quality) caused by the products
covered by CEN TS 12977-5 it should be noted that:
 this document provides no information as to whether the product may be used without restriction in any of
the Member States of the EU or EFTA;
 while awaiting the adoption of verifiable European criteria, existing national regulations concerning the
use and/or the characteristics of this product remain in force.
1 Scope
This Technical Specification specifies performance test methods for control equipment. Furthermore this
document contains requirements on accuracy, durability and reliability of control equipment.
The tests described in this document are limited to components delivered with or for the system by the final
supplier. For the purposes of this document controller and control equipment for solar heating systems and
auxiliary heaters, if part of the system, are restricted to:
a) controllers as:
1) system clocks, timers and counters;
2) differential thermostats;
3) multi-function controllers;
b) sensors as:
1) temperature sensors;
2) irradiance sensors (for short wave radiation);
3) pressure sensors;
4) level sensors;
5) flow meters; or
6) heat meters;
c) actuators as:
1) pumps;
2) solenoid and motor valves; or
3) relays.
Furthermore combinations of controllers, sensors and actuators listed above.
An additional objective of the procedures described in this document is to verify control algorithms and,
together with the accuracy of sensors, to determine control parameters. In addition to verifying the functioning
of a controller, its equipment and actuators, the determined parameters may be used for numerical system
simulations.
Typically electrical anodes are not part of the control equipment and are not controlled by the control
equipment. However, because they are electrical appliances, electrical anodes are included in this document.
This document is valid for control equipment of solar heating systems for the purpose of hot water preparation
and/or space heating. If the solar system is connected to or part of a conventional heating system, the validity
is extended to the entire system. In combination with the standards EN 12976-1, EN 12976-2 as well as
CEN/TS 12977-1, CEN/TS 12977-2, EN 12977-3 and CEN/TS 12977-4 this document is valid for:
d) factory made solar heating systems;
e) small custom built solar heating systems;
f) large custom built solar heating systems; and
g) auxiliary heater equipment used in connection with d), e) and f).
NOTE Factory Made and Custom Built solar heating systems.
EN 12976-1, EN 12976-2 as well as CEN/TS 12977-1, CEN/TS 12977-2, EN 12977-3, and CEN/TS 12977-4 distinguish
two categories of solar heating systems:
 Factory Made solar heating systems; and
 Custom Built solar heating systems.
As defined in CEN/TS 12977-1, the classification of a system as factory made or custom built is a choice of the final
supplier.
Custom Built solar heating systems are subdivided into two categories:
 Small Custom Built systems offered by a company are described in a so-called assortment file, in which all
components and possible system configurations, marketed by the company, are specified;
 Large Custom Built systems are uniquely designed for a specific situation.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN 809, Pumps and pump units for liquids — Common safety requirements
EN 982, Safety of machinery — Safety requirements for fluid power systems and their components —
Hydraulics
EN 1151-1, Pumps — Rotodynamic pumps — Circulation pumps having a rated power input not exceeding
200 W for heating installations and domestic hot water installations — Part 1: Non-automatic circulation
pumps, requirements, testing, marking
EN 12975-2, Thermal solar systems and components — Solar collectors — Part 2: Test methods
EN 12976-1:2006, Thermal solar systems and components — Factory made systems — Part 1: General
requirements
CEN/TS 12977-1:2010, Thermal solar systems and components — Custom built systems — Part 1: General
requirements for solar water heaters and combisystems
EN 60255 (all parts), Electrical relays
EN 60335-1, Household and similar electrical appliances — Safety — Part 1: General requirements
(IEC 60335-1:2001, modified)
EN 60335-2-21, Household and similar electrical appliances — Safety — Part 2-21: Particular requirements
for storage water heaters (IEC 60335-2-21:2002, modified)
EN 60730 (all parts), Automatic electrical controls for household and similar use
EN ISO 9488:1999, Solar energy — Vocabulary (ISO 9488:1999)
IEC 60038, IEC standard voltages
IEC 62305-3, Protection against lightning — Part 3: Physical damage to structures and life hazard
ISO 9060, Solar energy — Specification and classification of instruments for measuring hemispherical solar
and direct solar radiation
ISO 15218, Pneumatic fluid power — 3/2 solenoid valves — Mounting interface surfaces
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 12976-1:2006,
CEN/TS 12977-1:2010, EN ISO 9488:1999 and the following apply.
3.1
controller
device to control a solar heating system, sometimes in connection/combination with auxiliary heater(s)
NOTE For classification see Table 1.
3.2
sensor
device to measure physical (or chemical) qualities/properties
NOTE 1 With respect to solar heating systems, temperature, irradiance, flow/circulation, pressure and level sensors
are most common.
NOTE 2 For classification see Table 2.
3.3
actuator
component and device designed to perform actions to operate a solar heating system or auxiliary heating
system according to signals from the control equipment
NOTE For classification see Table 3.
3.4
reference device/measurement
device or measurement which control equipment under test or measured quantities are referred or compared
to
3.5
control equipment assortment
complete list of components (controller, sensors, actuators), which a company offers to control a solar heating
system, including auxiliary heater control equipment, if the auxiliary heater is part of the solar heating system
4 Symbols and abbreviations
G hemispherical solar irradiance in the plane of the radiation sensor, in watts per square metre;
reference temperature, in degrees Celsius;
ϑ
ref
surrounding air temperature, in degrees Celsius;
ϑ
amb
maximum (allowed) temperature of a temperature sensor, in degrees Celsius;
ϑ
max
ϑ temperature of the storage tank for heated water, in degrees Celsius;
tank
start temperature, e.g. of pump in solar collector circuit, in degrees Celsius;
ϑ
start
stop temperature, e.g. of pump in solar collector circuit, in degrees Celsius;
ϑ
stop
hysteresis, difference between ON- and OFF-temperature difference for switching an actuator,
∆ϑ
hyst
in kelvins;
v surrounding air speed, in metres per second;
air
t time, in seconds.
5 Controller classification (including equipment classification)
5.1 Controller
Control device designed to control a solar heating system, sometimes in connection/combination with auxiliary
heaters are classified according Table 1.
Table 1 — Classification of controllers for solar heating systems
Controller
C1 System clock, Timer and Counter
Controlling the operation of one or more actuators by means of real or relative time. Timers and
counters might be connected with different kinds of sensors influencing their behaviour by superposition
of the commands. Beside time intervals counter might count and sum up events or quantities.
C2 Differential thermostat
Control of one or more actuators by means of a temperature difference between two temperature
sensors. In most cases a hysteresis between switching ON and OFF is present. Differential controllers
are sometimes used with other signals, e.g. solar irradiation, pressure or level sensors.
C3 Multi-function controller
Controller designed to control one or more actuators based on measured quantities delivered by
different kinds of sensors, real time or relative time and/or control concepts including specific control
algorithms.
With regard to this document multi-function controllers are used to control and operate a solar heating
system, and may also control a combination of hot water preparation, space heating, heat distribution or
any kind of back-up heating. Multi-function controllers may use more than one differential algorithm in
one unit or at least one operation is caused by more than a simple differential algorithm.
If a device operates its output(s) depending on more than one (temperature) difference or not simply in
an ON/OFF mode, then a controller incorporating such differential algorithm (thermostat) should be
treated as a multi-function controller. If this is not the case the unit shall be treated as a differential
thermostat.
5.2 Sensor
Typical sensors used for controllers listed in Table 1 are summarized in Table 2.
Table 2 — Common sensors for solar heating systems
Sensor
S1 Temperature sensor
Sensing of temperatures of different parts in the system. In connection with the electronic layout of a
controller or accessory measuring device determination of temperatures, e.g. in degrees Celsius.
S2 Irradiance sensor
Instrument measuring the hemispherical solar irradiance in the plane of the radiation sensor within a
spectral range of approx. 0,3 µm to 3 µm. To control a (solar) heating system irradiance sensors and
accessory control equipment might have special designs to meet the specific requirements to solar
energy utilization. With respect to this document both, irradiance sensors with thermoelectric sensor and
irradiance sensors based on the photoelectrical effect are included. Supplementary photocells or other
devices used to measure the solar irradiance are treated equate to solar irradiance sensor.
S3 Flow/circulation sensors
Sensing of the flow/circulation of a fluid. In connection with the electronic layout of a controller or
accessory measuring device determination of the volume and/or mass flow.
S4 Pressure sensor
Sensing of absolute or relative pressure. In connection with the electronic layout of a controller or
accessory measuring device determination of absolute pressure or pressure differences.
S5 Level sensor
Sensing of the level of a fluid within a vessel or a store.
NOTE 1 The controller or accessory-measuring devices shall enable the conversion of sensor signals to values
suitable to serve as control criterion for functioning and supervising of the system.
NOTE 2 Values serving as control criterion should be displayed by a control device or, at least, a read back of data
should be possible.
NOTE 3 If other physical quantities or conditions than listed under S1, S2, S3, S4 or S5 are measured, the use of
those sensors and the data processing might be in a similar manner to S1, S2, S3, S4 or S5.

5.3 Actuator
Table 3 gives a selection of the most common actuators that can be found in solar heating systems.
Table 3 — Most common actuators for solar heating systems
Actuator
A1 Pump
Device to circulate a heat transfer medium and/or water in a forced-circulation system, e.g. a collector
circuit, a circuit for space heating/cooling and/or hot water preparation.
A2 Solenoid and motor valve
Electric driven device to start and/or to stop flow/circulation as well as to join, divide and/or to divert
flow streams.
A3 Relay / Contactor
Device to connect and/or to switch electrical loads and/or actuators, e.g. when using a low level signal
(voltage and/or current) of a controller to start and stop a high voltage/power pump.

6 Requirements
6.1 General requirements
6.1.1 Durability - Reliability
Any part of the control equipment has to be suitable for the application it is applied to and has to be suitable
for all conditions it might come in contact with. Any part of the control equipment mounted outdoors shall be
resistant to UV radiation and ozone. For indoor and outdoor mounted control equipment harmful impact and
mechanical damage, e.g. caused by birds or rodents and other operating conditions shall be prevented (see
EN 60730 (all parts)). If any maintenance or replacement of the control equipment is required in order to
maintain the system working, this shall be clearly stated in the documents for the user. The durability to
withstand all operating conditions which might occur during operation, and depending on the mounting
location, is mandatory. All equipment, particularly parts installed outside, have to be protected against
corrosion and mechanical impact at least over the prescribed lifetime or maintenance interval specified by the
manufacturer or final supplier.
6.1.2 Electrical safety
The control equipment shall fulfil general safety requirements.
See EN 60335-1, EN 60335-2-21, EN 60730 (all parts).
6.1.3 Freeze damage protection
If the control equipment includes algorithms and/or devices for freeze damage protection, e.g. preventing heat
transfer medium in the collector circuit to freeze, those algorithms and/or devices shall be reliable.
6.1.4 Scald protection
If the control equipment includes algorithms and/or devices for scald protection, the algorithms and/or control
equipment shall be reliable. The default value of the temperature for domestic hot water delivered to the user
shall at maximum be 60 °C.
If the temperature of the domestic hot water delivered to the user might exceed 60 °C, an external, automatic
cold water mixing devices or any other device to limit the temperature to at maximum 60 °C shall be installed.
6.1.5 High temperature protection for materials and components
If the control equipment includes algorithms and/or devices to avoid overheating of materials and/or
components, e.g. stopping the collector loop pump(s) and possibly draining down the heat transfer medium
from the collector, these algorithms and/or control equipment shall be reliable.
If an upper temperature limit for materials and/or components specified by the manufacturer or final supplier is
reached, the control equipment should stop the circulation pump(s) of the collector loop. With regard to
restarting the circulation pump(s) the control strategies should be designed in a way to prevent damage to the
system, the components and materials.
If the control equipment includes algorithms and/or devices for limitation of the flow temperature, e.g. to a floor
heating circuit, these algorithms and/or control equipment shall be reliable.
6.1.6 Lightning
The control equipment shall meet the requirements given in IEC 62305-3. The manufacturer or the final
supplier shall specify particular features for lightning protection within the control equipment.
6.2 Controllers, system clocks, timers and counters
6.2.1 General
All kinds of controllers, system clocks, timers and counters this document refer to shall be reliable and
resistant to all impact that might occur under normal operation at least over the prescribed lifetime or
maintenance interval specified by the manufacturer or final supplier.
6.2.2 Accuracy requirements for controllers
In combination with all other control equipment controllers, system clocks, timers and counters shall behave
as specified and intended by the manufacturer. The accuracy of controllers, e.g. signal processing and
activating of actuators, shall enable the operation of all systems layouts the controller is designed for in
accordance to the specifications of the manufacturer. Regarding all functions and operations controllers,
system clocks, timers and counters shall comply with the manufacturer's guidance.
6.2.3 Accuracy requirements for system clocks, timers and counters
The accuracy requirements of system clocks, timers and counters in charge of controlling a solar heating
system are listed in Table 4.
Table 4 — Accuracy of system clocks, timers and counters
Clock / timer / counter Tolerance
Real time clock
± 1,0 min per 30 days
Timer
± 1,0 min per 30 days operation time
Counter
± 1,0 %
In case of solar heating systems installed in regions with a shift between summer and wintertime,
adjustments – if necessary – have to be specified by the final supplier.
6.3 Sensors
6.3.1 Temperature sensors
6.3.1.1 General
For all temperature sensors the location and installation shall ensure a reliable thermal contact with the part of
which the temperature shall be measured. Surrounding conditions, when not relevant, shall not influence the
measurement. With exception of ambient temperature sensors, temperature sensors shall be
protected/insulated against external influences.
6.3.1.2 Accuracy requirements
The accuracy requirements of temperature sensors in charge of controlling a solar heating system are listed in
Table 5.
Table 5 — Accuracy requirements of temperature sensors for solar heating systems
Temperature range Tolerance
– 20 °C to 70 °C
± 1,0 K
More than 70 °C to 100 °C
± 1,5 K
More than 100 °C to 150 °C
± 1,5 % of temperature value
More than 150 °C to max. operating temperature (to be specified by final
± 2,0 % of temperature value
supplier)
6.3.1.3 High-temperature resistance
The requirements to the capability of sensors to resist to extreme operating conditions depend on the location
where the sensor is mounted. The minimum requirements are listed in Table 6.
Table 6 — Requirements of high-temperature resistance of temperature sensors
For all kinds of temperature sensors installed within a solar heating system or auxiliary heater,
if the auxiliary heater is part of a solar heating system
Maximum temperature declared by the manufacturer or final supplier
Minimum required temperature
plus 10 K
Time of exposure At least 6 h
6.3.1.4 Reduction of temperature sensor accuracy caused by extreme operating conditions
All kinds of temperature sensors installed within a solar heating system or auxiliary heater, if the auxiliary
heater is part of a solar heating system, shall withstand extreme operating conditions as specified in Table 6
without reduction of the accuracy by more than 1 K. In addition the accuracy requirements as specified in
Table 5 shall be kept.
6.3.2 Irradiance sensors
6.3.2.1 General
For control purposes the solar irradiance sensor shall at least be sensitive to wavelength in the range of
approximately 0,4 µm to 0,8 µm.
6.3.2.2 High irradiance resistance
The irradiance sensors shall resist to any extreme solar irradiance that might occur during operation within the
prescribed lifetime or maintenance interval, specified by the manufacturer or final supplier. The requirements
to capability of an irradiance sensor to resist to extreme irradiance conditions are listed in Table 7.
Table 7 — Climate test conditions for solar irradiance sensors capability to resist to high irradiance
Climate parameter Value
Hemispherical solar irradiance in the plane of the irradiance sensor, G > 1 000 W/m²
Surrounding air temperature while testing irradiance sensor's resistance against high
20 °C to 40 °C
irradiance, t
a
Surrounding air speed, v
< 1 m/s
air
Time the solar irradiance sensor should be exposed to the test conditions, t > 1 h

6.3.2.3 High temperature resistance
The conditions to test high temperature resistance of an irradiance sensor are given in Table 8.
The conditions to test solar irradiance sensors capability to resist to high surrounding temperatures are listed
in Table 8.
Table 8 — Climate test conditions for solar irradiance sensors capability to resist to high surrounding
temperatures
Climate parameter Value
Hemispherical solar irradiance in the plane of the irradiance sensor, G > 900 W/m²
Surrounding air temperature for testing sensor's resistance against high
> 30 °C
temperatures, t
a
Surrounding air speed, v
< 1 m/s
air
Time the solar irradiance sensor should be exposed to the test conditions, t > 12 h

6.3.2.4 Accuracy requirements
The accuracy requirements of a solar irradiance sensor in charge of controlling a solar heating system are:
Table 9 — Accuracy requirements for solar irradiance sensors
Range of measurement Tolerance
100 W/m² to 300 W/m² ± 15,0 % of the specified solar irradiance
More than 300 W/m² to 900 W/m² ± 10,0 % of the specified solar irradiance
More than 900 W/m² ± 15,0 % of the specified solar irradiance

6.3.2.5 Reduction of solar irradiance sensor accuracy caused by extreme operating conditions
The irradiance sensor shall withstand extreme operating conditions as specified in Tables 7 and 8 without
reduction of the accuracy out of the range given in Table 9. The sensor, gasket(s), cable(s) and all related
mounting equipment shall not show decomposition or significant discolouring.
6.3.3 Other sensors
All other sensors, such as pressure sensors, level sensors, flow meters, etc., shall have accuracy as specified
by the manufacturer or final supplier. All relevant operating conditions the sensors are claimed to withstand
shall be included in the documentation.
6.4 Indicators
Indicators, such as pressure gauges, temperature gauges, level indicators, voltage indicators of anodes and
flow/circulation indicators or heat meters, etc., shall have the accuracy as specified by the manufacturer or
final supplier. Pressure gauges shall show the permissible operating range of overpressure in the system or at
least the filling pressure of the system. Voltage indicators of anodes shall indicate whether the voltage created
by the anode is sufficient to protect the store. In the case of an electrical anode it shall be indicated whether
this device is functioning correctly. Flow/circulation indicators shall show the nominal value of the
flow/circulation specified by the manufacturer or final supplier. A possibility to adjust the flow/circulation is
recommended. All relevant operating conditions the indicators are claimed to withstand shall be included in
the documentation.
If indicators are connected to the power supply, then in the case of power failure the indicators shall be
connected to the power supply in a way that the greatest possible safety is guaranteed
If possible, the connection to the power supply should be made in a way that the power consumption is as low
as achievable.
6.5 Actuators
6.5.1 Circulation pumps
See EN 809 and EN 1151-1.
If the collector circuit is provided with one or more circulation pump(s), e.g. when an external collector loop
heat exchanger is used, the total parasitic electrical power of the pump(s) should not exceed the values given
in Table 10.
Table 10 — Total maximum electrical power of the pump(s)
System Total maximum electrical power of the pump(s)
Small systems 50 W or 2 % of the peak power delivered by the collector array, whichever higher
Large systems 1 % of the peak power delivered by the collector array

NOTE If not specified in the documentation, the peak power of a collector array shall be calculated by multiplying the
aperture area of the whole collector array with 700 W/m² of aperture area.
In the case of pumps operated with variable power (e.g. pulse width modulation) or short term alternating
operation, the requirements stated in Table 10 applies to the average power.
The maximum pump power stated above excludes the power of pumps in drain-back systems that are only
needed to refill the system after draining back (down) of the heat carrier fluid.
Other heat transfer loops within the system should be designed by comparing the parasitic power of their
pump(s) to the highest heat power transmitted. The values in Table 10 shall not be exceeded.
6.5.2 Solenoid and motor valves
See EN 982 and ISO 15218.
Valves should be installed in a way that the power consumption is as low as possible. For this the most
common mode of operating has to be taken into account.
6.5.3 Relays
See EN 60255 (all parts).
Relays should be installed in a way that the power consumption is as low as possible. For this the most
common mode of operating has to be taken into account.
6.6 Initial operation and commissioning
Default parameters within multi-function controllers and control equipment shall enable the initial operation of
the system as intended by the manufacturer or final supplier. A reset to default values in the control equipment
shall be possible. In the case of adjustable parameters, all necessary adjustments required to maintain correct
working of the system shall be clearly described in the documents and retained in non-volatile memory.
Depending on the control equipment different documents for the installer and for the user might be provided.
6.7 Documentation
The documentation of the control equipment shall be complete and clearly arranged. The documentation shall
include all instructions necessary for assembly, installation, operation and maintenance. The instructions shall
enable correct installation and operation.
The documentation shall at least include:
a) all relevant system configurations including related hydraulic, control schemes and specifications to
enable the user to understand the operating modes of the system;
b) description of the control strategies and the control system(s) including the location of the control
equipment (e.g. sensors, actuators), if relevant for different system designs. All control equipment should
be included in the hydraulic scheme(s) of the system;
c) a list of all components to be included into the respective system configurations, with full reference to
dimension and type. The identification of the listed components shall be clear and unambiguous;
d) if relevant, list of combination and dimension options within different system configurations;
e) a guideline to adjust all parameters and settings. It is recommended to include a table in which all
adjusted parameters and their actual settings are entered by the user;
f) maintenance instruction for the control equipment, including start-up and shut-down of the system;
g) instructions for function and performance testing;
h) intended action(s) in the case of most common failures.
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