Keston Solar Thermal System Instruction
WD435/0/2006 DRAFT2 Keston Solar Thermal
SOLAR THERMAL
SYSTEMS
User, Installation and Servicing
Instructions
These instructions must be left with the
user
Keston Boilers Ltd
34 West Common Road
Hayes, Bromley, Kent BR2 7BX
Tel. +44 (0)20 8462 0262 Fax. +44 (0)20 8462 4459
email : info@keston.co.uk web : www.keston.co.uk
WD435/0/2006 DRAFT2 Keston Solar Thermal
CONTENTS
Section Description
0 LIST OF CONTENTS
1 GENERAL INSTRUCTION
2 INSTALLATION
3 COMMISSIONING
4 HANDING OVER TO THE USER
5 ROUTINE SERVICING
6 FAULT FINDING
7 PARTS LIST
Page : i
T
1 Collector
R
1 Pump Cable
Flowmeter
SRV
AAV
TMV
CW
HW
DTC
Manometer
Thermometers
Collector
WD
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Chapter 1 :
General
Instruction
Keston
Solar
Thermal
1.
The Keston Solar Thermal System is a state-of-the-art solar system. It features high
performance collectors with highly advanced features. The collector has been awarded the
Solar Keymark, the EUs quality mark for solar collectors. The collectors are mounted on a
fast-to-fit frame and, for the Solar Packs and Solar Duet, a solar pump station is also
supplied to ease the internal component location. The Keston Solar Controller ensures
efficient use of the available solar energy at any given time and features several extra
functions such as modulating pump speed which further improve system efficiency
Keston Solar System
General Instruction and Schematic Layout
Recommended
Solar
Hydraulic and Control Circuit Layout
Sensor Cable
230 V Live
Exp
ansion
Vessel
Pump
Station
T
2 Sensor Cable
Boiler
Coil
Solar
Coil
Installation & Servicing Instructions
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1
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Chapter 1 :
General
Instruction
Keston
Solar
Thermal
1.1
Performance Requirements
The Keston Solar System uses a similar hydraulic circuit to a standard system boiler.
However, there are several important differences between these two circuits. A solar circuit
has to manage both freezing and steam conditions in the solar collector.
The freezing is managed by using a suitable solar-grade glycol antifreeze within the circuit
mixed to a suitable ratio for the climatic conditions.
The steam conditions can occur during stagnation . The Differential Temperature Controller
(DTC) has an setting for the maximum temperature of stored (secondary) water in the cylinder (st. limit). During the summer months, when the building is unoccupied for several days,
this store limit can be exceeded and the DTC will switch the solar primary pump off. With no
flow through the collector, the collector temperature can exceed 200 °C on sunny days and
steam will be generated in the collector. This steam can travel up to 2 m down both the flow
and return pipes. In this condition, when the pump is eventually switched on again, the
steam will travel down the flow line and typically condense when it reaches the hot water
store. In this way the return line can contain water at up to 3 bar and 140 °C. The system
has to be installed to manage these conditions.
1.2
Keston Solar Pack Contents
In your Solar Pack, Keston has provided you with the following:
Solar-grade glycol antifreeze (which is designed to evaporate and condense)
A solar pump station where all the components are designed to withstand these
temperatures and pressures.
Solar-grade Auto Air Vent (AAV) with manual isolator
DTC with silicon high temperature collector sensor and intermediate temperature
cylinder sensor
A 2 or 3 collector system
Pitched roof mounting kit OR
Flat roof mounting frame
(depending on pack type)
Before starting any work you should check that you have all the above items. A full break
down of each parts list is provided in each relevant section of this manual.
1.3
Parts Not Included in the Solar Pack
You will have to provide all pipework, fittings and insulation. The following specifications are
required for items provided by the installer:
Pipework.
This should be 15 mm copper or flexible stainless on both flow and return.
Plastic pipework is not suitable for the temperature extremes possible in solar
circuits
. Pipe clips must withstand the temperatures mentioned above. It is suggested to
use gutter type external brackets over the insulation.
Fittings.
Brass olive compression fittings must be used within 2 metres of the flow and
return pipework from the collector. Lead free soldered fittings or brass olive compression
fittings can be used on the rest of the solar primary circuit. Unleaded solder is not designed
for solar circuits. Alternatively, high performance crimped fittings or similar performance
Installation & Servicing Instructions
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Chapter 1 :
General
Instruction
Keston
Solar
Thermal
fittings can be used. Any drain valves etc. must be capable of handling the temperatures and
pressures indicated above.
Insulation.
This should be High Temperature Armaflex or similar grade insulation or
above. Class O Armaflex is not UV-resistant or designed for the temperatures realised in the
solar primary circuit. Polyethylene insulation will melt on a solar primary circuit. All external
items such as cable clips to hold the collector sensor must be UV-resistant.
Flexible stainless steel hose is available in pre-insultated form using suitable high
temperature UV-resistant insulation and a suitable two-core cable for the solar collector
sensor. This hose is specifically designed for solar applications. Contact Keston Technical
Support for further detail.
1.4
Collector Sizing and Location
Typically, approximately one square metre of solar collector should be supplied for each
house occupant. Each Keston Solar Collector panel has an external area of 1.85 sq. m.
Therefore, the Keston 2 collector array is ideal for a 3 to 4 person household and the Keston
3 collector array for a 5 to 6 person household. The collector array should be located
anywhere between South-West and South-East at a pitch of 10° to 50°. Anywhere within this
bandwidth will be within 10% of the ideal South facing 30° pitch. For an East-West roof,
either an East-West application can be installed with a collector on each pitch or additional
collector(s) can be fitted on either the East-West roof. For example, a 3 collector array on an
East facing roof would be ideal for 4 to 5 occupants where there is a 20 % loss in performance as compared to the ideal South facing 30° pitch. There should be no significant overshading of buildings, trees or other obstructions. Even obstructions to the north of the
collector can block a significant proportion of the diffuse solar radiation. Significant
overshading can be compensated by over-sizing the solar system.
1.5
Planning Permission
Planning permission for the Keston Solar System is generally only required if you are in a
conservation area or you are installing a solar system on a listed building. Solar water
heating has permitted development status. Some local councils are objecting to this ruling
and insisting that Solar requires planning permission but this is only the case if your building
is listed or you are in a conservation area. If in doubt, contact your local council planning
office.
1.6
Warranty
As you would expect, the Keston Solar Thermal system is supplied with a comprehensive
warranty cover of 5 years for the solar collector and 1 year for all other components. The
warranties are provided on a parts only basis and are conditional upon provision of the
relevant registration.
Installation & Servicing Instructions
Page :
3
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Chapter 2 :
Installation
Keston
Solar
Thermal
2.1
Installation of the Collector and external components
The Keston solar collector is made to an advanced specification. The collector is ultrasonic
welded and made with a vacuum deposited titanium selective surface. For pitched roof
installations, the collector comes with a roof mounting frame which consists of:
4 mounting plates (6 mounting plates for 3
collector systems)
2 roof S -brackets with top mounting bar and fixing nuts and bolts (3 roof S
-brack
ets for 3 collector systems)
4 L
-brackets for each collector
-
Installation & Servicing Instructions
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16 coach screws (24 coach screws for 3 collector systems)
2 Collector Inter-connectors (4 collector inter-connectors for
3 collector systems)
Collector flow cross fitting with integral sensor pocket and
top outlet (used for connection of the solar AA
tion valve, if roof mounted)
Temperature sensor dry pocket
Chapter 2 :
Installation
V and isola
-
Keston
Solar
Thermal
8 nuts, bolts and spring washers
4 aluminium strips (6 aluminium strips for 3 collector systems)
It is the installers responsibility to make sure the roof is water tight and secure.
Solar Thermal System is designed for operation in standard UK geographic applications. For
high wind exposure applications, it is the installer s responsibility to make sure the collectors
are suitably fixed to the roof. It is also the installer s responsibility to maintain the necessary
Health and Safety standards. Keston recommend the use of either scaffolding and/or custom
made solar installation access equipment for the safe lifting and installation of the solar
collectors. If in doubt, please use a competent roofer to install the collectors
The National Federation of Roofing Contractors (NFRC) offers a solar panel roof mounting
service via its network of approved members. The NFRC can be contacted on 020 7436
0387 or via www.nfrc.co.uk
The mounting plate and roof bracket are designed for use with concrete flat or profiled
pantiles. For rosemary clay tiles or slate, the top and bottom mounting bar can be fixed with
the 4 aluminium strips. Slates can be drilled with tile drills and rosemary tiles with a diamond
drill. Any holes in the roof (which ideally should be completely avoided) should be sealed
with an external grade low modulus silicon sealant or proprietary O rings. The aluminium
strips can be bent to the shape of the tile to suit any profile. The aluminium strips must be
coach screwed to either the rafters or noggins firmly located between the rafters. For
rosemary tiles, Keston suggests using two coach screws to fix one end of the aluminium
strip to the rafter and the feeding the strip out between two tiles and screwing the mounting
bar to the exposed end of the strip.
The Keston
.
Installation & Servicing Instructions
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Profile of Aluminium
Strip
Chapter 2 :
Installation
Suggested side profile
shape of aluminium
strip for a rosemary tile
roof
Keston
Solar
Thermal
Mounting
Bar
Location of
coach screws
Another method for Rosemary tiles is to use the roof S -brackets as provided and then
weathering the roof S -brackets into the roof with code 4 lead.
For slates, the tiles will need to be
drilled. The internal rafters can be
located by feeding an aluminium strip
out from the loft between the felt
sarking layers and then abutting the
aluminium strip against the roofing
rafter. The external exposed end of the
aluminium will indicate the location of
the internal rafter. Alternatively, use
noggins between the rafters to firmly
locate the aluminium strips.
Installation & Servicing Instructions
Sugges
ted
side profile
aluminium strip
Location of
Coach Screws
Profile of
Aluminium Strip
shape of
for a slate roof
Location of
Coach Screws
Mounting Bar
Felt Sarking
Slate Roof
Wooden Battens
Page :
6
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