Baxi Solarflo User manual

© Baxi Heating UK Ltd 2008
SolarfloTM
Evacuated Tube Collector
These instructions must be used in conjunction with the
Commissioning, Maintenance & Servicing Guide
Please read these instructions before installing or commissioning.
SolarfloTM (Solar Thermal Domestic Hot Water System) should only
be installed by a competent person.
PLEASE LEAVE THESE INSTRUCTIONS WITH THE USER
FOR SAFE KEEPING.
Installation Guide

2© Baxi Heating UK Ltd 2008
Content
© Baxi Heating UK Ltd 2008.All rights reserved. No part of this publication may be reproduced or
transmitted in any form or by any means, or stored in any retrieval system of any nature (including
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Designs and Patents Act 1988.
Applications for the copyright owner’s permission to reproduce or make other use of any part of
this publication should be made, giving any details of the proposed use to the following address:
The Company Secretary, Baxi Heating UK Ltd,The Wyvern Business Park, Stanier Way, Derby DE21 6BF.
Full acknowledgement of author and source must be given.
WARNING: Any person who does any unauthorised act in relation to a copyright work may be
liable to criminal prosecution and civil claims for damages.
1.0 Introduction to Solar 3
2.0 Solar Collector Specifications 4
3.0 Pump Station Specifications 5
4.0 Solar Controller 6
5.0 Ancillary Components 7
6.0 Cylinder Specifications 8
7.0 General 10
8.0 Installation of Collector Sensor 12
9.0 Installation of Pump Station 13
10.0 Installation of Solar Controller 19
Section Page

3
© Baxi Heating UK Ltd 2008
1.0 Introduction to Solar
1.1 Description
Thank you for purchasing a high quality SolarfloTM Solar Thermal
Domestic Hot Water System.
The sun is the ultimate source of most of our renewable
energy supplies. Energy from the sun is clean and abundant.
There is a widely held opinion that the UK does not have
enough sun to make solar systems worthwhile. In fact parts of
the UK have annual solar radiation levels equal to 60% of those
experienced at the equator.
However, this energy is not received uniformly throughout the
year. Some 70% of UK annual radiation is received over the
period April to September and 25% is received in the months
of June and July.
Solar water heating technology captures energy from the sun
and transfers this to a water heater to raise the water
temperature therefore reducing the reliance on fossil fuel
energies such as gas, oil and electricity. Up to 60% of a
dwelling’s annual hot water requirement can be provided by a
solar water heating system.The balance is provided by
traditional means via a second heat exchanger connected to a
fossil fuel boiler or electrical heating by electric boiler or
immersion heater.
The SolarfloTM water heating system provides all the principal
components required for an efficient solar water heating
system.The sun’s energy is captured by a series of solar
collectors through which a special heat transfer fluid is pumped.
As the fluid passes through the collector its temperature is
raised.The heated fluid is circulated through a heat exchanger
coil in the base of the solar storage cylinder transferring the
heat gained to the stored water, gradually raising its
temperature. The cooled fluid then returns to the collector to
be heated again. Heating by the solar coil is controlled by a
solar differential temperature controller that ensures the system
will only operate when there is useful solar heating gain at the
collector. As the sun’s energy input to the collector is variable
supplementary heating by a conventional boiler or electric
immersion heater should be provided.The optional cylinders
that can be supplied with the SolarfloTM package provide a
supplementary heat exchanger coil and immersion heater as
standard.
1.2 General
Avoid the use of hacksaws if at all possible. Using the correct
pipe cutting tools will reduce the amount of debris in the
system prior to flushing.
Read in conjunction with Solar Collector Guide.
Fig. 1- Schematic
Cold Feed
Reheat
Sensor
Combi Valve
Drain Points
Flow Meter
Return
Sensor

2.0 Solar collector specifications
4© Baxi Heating UK Ltd 2008
C
AD
B
Table of dimensions (mm)
20 tube 30 tube
A 1418 2127
B 1996 1996
C 1475 2184
D9797
Fig. 2
2.1 Technical Data
20 tube 30 tube
Gross area: 2.83m23.23m2
Net area: 2.00m23.00m2
Weight: 54.8 kg 81.4 kg
Fluid Volume: 3.8 litres 5.6 litres
Pressure: 8 bar 8 bar
Absorption: 95% 95%
Emission: 5% 5%
Stagnation temp: 286°C 286°C
Glass: 65mmØ Low-iron - transmission 0.92
Light transmittance: >90.8% ± 2%
All dimensions shown in mm
0
2468
40
80
120
160
Pressure Drop (Pa)
Flow Rate (l/min)
0
200
240
30 tubes
20 tubes
Coefficients of efficiency (20 tubes)
(determined in the sun simulator SUSI 1)
η= ηo - a1.(tm - ta)/G - a2.(tm - ta)2/G
Based on: aperture area absorber area
ηo = 0.773 0.830
a1 = 1.43 W/m2K 1.53 W/m2K
a2 = 0.0059 W/m2K 0.0063 W/m2K
Coefficients of efficiency (30 tubes)
(determined outdoor)
η= ηo - a1.(tm - ta)/G - a2.(tm - ta)2/G
Based on: aperture area absorber area
ηo = 0.779 0.832
a1 = 1.07 W/m2K 1.14 W/m2K
a2 = 0.0135 W/m2K 0.0144 W/m2K
Fig. 3

3.0 Pump station specifications
3.1 Technical Data
Dimensions
(Height/Width/Depth) 375/250/190mm
Flow and return connections
(compression fittings) 22mm
Maximum working temperature: 120°C
Maximum working pressure: 6 bar
Pressure Relief Valve setting: 6 bar
Circulating Pump: Grundfos UPS 25-60
/ Wilo ST 25/6
Circulating Pump voltage: 230/240 V ~
Power consumption Setting 1: 40W
Setting 2: 60W
Setting 3: 80W
Maximum Pump Head: 6 metres
Maximum Pump Capacity: 4.5 m3/h / 3.5 m3/h
Flow meter scale: 2 to 15 l/min
Features
Air Separator
Adjustable Control Valves
Drain Point
Temperature Gauges
Flow Gauge
5
© Baxi Heating UK Ltd 2008
Fig. 4

4.0 Solar controller
4.1 Technical Data
Housing Material 100% recyclable ABS
Dimensions
L x W x D in mm 175 x 134 x 56
weight 360 g
Ingress protection IP40 according to VDE 0470
Electrical values
Operating voltage 230/240V ~ 50 Hz
Interference grade N according to VDE 0875
Max. conductor
cross-section
240V-connections 2.5 mm2fine-strand/single-wire
Temperature sensor /
temperature range PTF6 - 25°C to 200°C
PT1000, 1,000 kΩ at 0°C
Test voltage 4 kV 1 min according to
VDE 0631
Switching voltage 230V / 240V
Capability per one
switch output 1A / 230VA for cos j = 0.7-1.0
Total capability of
all outputs 2A / 460VA maximum
Fuse protection fine-wire fuse 5 x 20mm, 2A/T
(2 amperes, slow)
Features
Menu driven operation
System monitoring
Solar gain measurement
Suitable for flat plate and evacuated tube type collectors
Auxiliary heat source control
Can be used in a number of system configurations see Fig. 27
NOTE: This controller is suitable for S plan and Y plan systems.
However, in the event of an installation having a ‘Y’ plan boiler
system that is to be controlled by the solar controller, a relay is
required (not supplied).This is available as a Baxi Spares Item,
Code No. 5122765.
6© Baxi Heating UK Ltd 2008
Fig. 5

7
© Baxi Heating UK Ltd 2008
5.0 Ancillary components
5.1 Expansion Vessel
Membrane expansion tanks for solar primary heating circuit.
Manufactured according to the Directive PED 97/23/CE
(approved noZ-DDK-MUC-02-396876-04).
Factory set charge pressure 2.5 bar.
Butyl membrane suitable for solar primary heating fluid, DIN
4807-3 approval.
Maximum working temperature +110°C.
Maximum percentage of glycol 40% (Pre-mixed).
Connection: 3/4” BSP male parallel
Expansion vessel supplied with wall mounting bracket and self
sealing vessel connection that will allow removal of the vessel for
maintenance without losing solar heat transfer fluid.
Under the following circumstances, a protection vessel should be
used in the Return Leg of the solar loop from the pump station.
The following distances should be observed:
20 tube collectors should have a Protection Vessel fitted if the
expansion vessel is less than 8 metres away from its nearest
collector.This should be sited at a suitable point between the
expansion vessel and nearest collector.
30 tube collectors should have a Protection Vessel fitted if the
expansion vessel is less than 12 metres away from its nearest
collector.This should be sited at a suitable point between the
expansion vessel and nearest collector.
Instances where a protection vessel should be included
20 tube system 30 tube system
Pipe Diameter Distance to nearest collector
15mm <8m <12m
22mm <4m <6m
The size of the protection vessel should be at least the combined
volume of the following:
Total Collector volume + total pipe work volume from collector
to protection vessel.
For positioning on protection vessel (Fig. 7).
5.2 Solar Heat Transfer Fluid
Pre-mixed (40% glycol / 60% water) Solar thermal transfer fluid.
Based on1,2 - propylene glycol with corrosion inhibitors.
DO NOT dilute or mix with water.
Non-toxic, odourless, bio-degradable.
The use of chemical resistant gloves and suitable eye
protection is required when handling.
A full safety data sheet is available on request.
Supplied in 20litre container.Weight of container full - 21kg.
5.3 Thermostatic Blending Valve
Can be set to control the hot water delivered to the user outlets
to a safe working temperature enabling the solar cylinder to store
water at a higher temperature.
Connections: 22mm compression
Max working pressure (static): 14 bar
Max working pressure (dynamic): 5 bar
Min working pressure (dynamic): 0.2 bar
Max inlet pressure ratio: 2:1
Min flow required for stable control: 5 l/min
For pressure drop diagram and dimensions see Figs. 8 & 9
NOTE: For optimum operation the cold connection must be
taken from a balanced cold water feed. For details of balanced
cold water feed please refer to the cylinder manufacturer’s
instructions.
Ø300mm
392mm
3/4”
Expansion vessel
Fig. 6
Flow l/s
Pressure Loss kPa
0.2 0.3 0.4 0.5 0.7 1.0 1.4 2
30
40
50
70
100
120
140
160
180
200
22mm
28mm
60mm
81mm
92mm
22mm
22mm Hot
Mix
Cold
Fig. 9
Fig. 8
Fig. 7

6.0 Cylinder specifications
6.1 Unvented
SolarfloTM is designed to work with the Heatrae Sadia Megaflo
Solar Unvented.
Nominal capacities 190, 210, 250 and 300 litre.
Rating Immersion heater(s) 1 x 3 kW (indirect models),
2 x 3kW (direct models) @ 240V~.
Outer casing White plastic coated corrosion proofed steel.
Thermal insulation CFC/HCFC-free (ODP zero) flame-
retardant expanded polyurethane (50mm thick). GWP 3.1
(Global Warming Potential).
Water container Duplex 2304 (Grade 1.4362 EN 10088)
stainless steel.
Pressure tested To 15 bar.
Heat unit Long-life Superloy 825 alloy sheathed element/s,
incorporated into an easily removable heater plate, should
replacement be necessary. Rated 3.0kW @ 240V~.
Primary coil (for Auxiliary boiler heating) 22mm diameter
stainless steel. Coil in coil design for improved performance
Solar coil 25mm diameter stainless steel. Coil in coil design
and large surface area for improved performance.
Thermostat
Direct models: Element thermostat adjustable from 10°C to
70°C.
Indirect models: Factory-fitted cylinder thermostat adjustable
to 70°C.
Solar: Factory fitted control pocket suitable for insertion of
solar controller temperature probe.
Factory fitted safety features:
Direct models: Manually re-settable cut-out on heating
element operates at 80° ±3°C.
Indirect models: High limit thermal cut-out operates at 85°C.
Wired in series with two-port motorised valve (supplied) to
provide primary over temperature protection when using
auxiliary (boiler) coil.
All models: Temperature and Pressure Relief Valve,
factory set to operate at 10 bar and 90°C.
High limit thermal cut-out operating at 80°C ±3°C at solar
coil position. Wired in series with the solar differential
temperature controller to provide over temperature
protection if overheating occurs from solar collector panels.
NOTE: This must be used in an unvented installation to
comply with the requirements of Building Regulation G3.
Anode Not required.
For full technical and performance specification see
cylinder installation instructions.
8© Baxi Heating UK Ltd 2008
Unvented system - schematic diagram
Fig. 10
Note: Indirect twin coil unit shown.
NOTE: For optimum operation the cold connection must be taken from a
balanced cold water feed.
Balanced
Cold Feed
Reheat
Sensor
Combi Valve
Drain Points
Flow Meter
Solar coil
controls housing
Location of solar sensor pockets
Warning: Isolate mains supply before accessing controls housings
remove screw for access
Auxiliary coil
controls housing
View with immersion
control stat fitted. Pull
to remove for access
to sensor pocket
View with immersion
control stat removed.
Insert sensor here
Reassemble in
reverse order
Solar cylinder sensor position
remove screw
for access
Fig. 11

9
© Baxi Heating UK Ltd 2008
Vented system - schematic diagram
6.0 Cylinder specifications
6.2 Cistern-fed Vented
SolarfloTM is designed to work with the Heatrae Sadia Megaflo
Solar Unvented and Megalife Solar Vented cylinders.
Nominal capacities 190, 210, 250 and 300 litre.
Rating Immersion heater(s) 1 x 3 kW (indirect models),
2 x 3kW (direct models) @ 240V~.
Outer casing White plastic coated corrosion proofed steel.
Thermal insulation CFC/HCFC-free (ODP zero) flame-
retardant expanded polyurethane (50mm thick). GWP 3.1
(Global Warming Potential).
Water container Duplex 2304 (Grade 1.4362 EN 10088)
stainless steel. 40 metres (4 bar) maximum working head.
Heat unit Tin plated long-life Superloy 825 alloy sheathed
element/s, incorporated into an easily
removable heater plate, should replacement be necessary.
Rated 3.0kW @ 240V~.
Primary coil (for auxiliary boiler heating) 22mm
diameter stainless steel. Coil in coil design for improved
performance.
Solar coil 25mm diameter stainless steel. Coil in coil design
and large surface area for improved performance.
Thermostat
Direct models: Element thermostat adjustable from 10°C to
70°C.
Indirect models: Factory-fitted cylinder thermostat from 10°C
to 70°C.
Solar: Factory fitted control pocket suitable for
insertion of solar controller temperature probe.
Safety features Thermostats with manually resettable thermal
cut-out.
High limit thermal cut-out operating at 80°C ±3°C at solar
coil position. Wired in series with the solar differential
temperature controller to provide over temperature
protection if overheating occurs from solar collector panels.
Anode Not required.
For full technical and performance specification see
cylinder installation instructions.
Detailed installation and commissioning instructions are
supplied with the cylinders.
Fig. 12
Note: Direct unit shown.Auxiliary heating by immersion heater.
NOTE: For optimum operation the cold connection must be taken from a
balanced cold water feed.
2m Min Head
Blending Valve
Shower

7.0 General
7.1 Safety Information
In order to reduce the number of fatalities and major accidents
attributable to work at height, the Health and Safety Executive
has introduced comprehensive regulations and guidance that
should be followed by all businesses working at height.
We consider in the following paragraphs some of the main
features of the regulations and guidance.This is, however, only a
limited summary and it is recommended that all businesses
planning on undertaking solar water heating installations obtain
a copy of the regulations and guidance issued by the Health
and Safety Executive and carefully consider the contents.
The regulations and guidance state that you are required to
carry out a risk assessment for all work conducted at
height and to put in place arrangements for:
• Eliminating or minimising risks from work at height.
• Safe systems of work for organising and performing work
at height.
• Safe systems for selecting suitable work equipment.
• Safe systems for protecting people from the consequences
of work at height.
The regulations and guidance highlight a hierarchy for safe
work at height:
•Avoid the risk by not working at height if practicable.
•Prevent falls, where it is not reasonably practicable to
avoid work at height; you are required to take suitable and
sufficient steps to prevent the risk of a fall including
selecting the most suitable work equipment
(in accordance with the regulations).
•Mitigate the consequences of a fall; where the risk of a
person or object falling still remains, take suitable and
sufficient measures to minimise the distance and
consequences of any fall.
Collective protection measures, such as guard rails on scaffold,
should be given priority over personal protection measures,
such as safety harnesses.
Within the regulations’ framework, you are required to:
1) Assess the risk to help you decide how to work safely.
2) Follow the hierarchy for safe work at height (i.e. avoid,
prevent and mitigate).
3) Plan and organise your work properly, taking account of
weather conditions and the possibility of emergencies.
4) Make sure those working at height are competent.
5) Make use of appropriate work equipment.
6) Manage the risks from working on or around fragile surfaces
and from falling objects.
7) Inspect and maintain the work equipment to be used and
inspect the place where the work will be carried out
(including access and egress).
When preparing to install a solar water heating system, it is
required that you perform a risk assessment in relation
to work at height and plan how you will organise your work,
taking into account the site, the weather conditions
and the experience and competence of colleagues or
contractors who may be working at height with you.
10 © Baxi Heating UK Ltd 2008

7.0 General
11
© Baxi Heating UK Ltd 2008
7.2 Risk Assessments
The HSE has published a number of very useful free
publications that advise how to undertake risk assessments.
Two of these that you should obtain are:
Five Steps to Risk Assessment.
A Guide to Risk Assessment Requirements.
The five steps outlined in the HSE leaflet are:
Step 1: Look for the hazards
This will mean looking at the site and identifying significant
hazards.These could be features such as a steep roof, a fragile
surface where the collectors may be mounted, uneven ground
or obstructions where access to the roof might be required.
Step 2: Decide who may be harmed and how
This might mean considering the particular risks that young
workers or trainees might face and thinking about the
residents of the household or visitors who could be hurt by
your activities.
Step 3: Evaluate the risks and decide which precautions should
be made You should consider how likely it is that each hazard
will cause harm, decide which precautions you might take and
then assess, after you have taken those precautions, whether
the remaining risk will be high, medium or low. Where you
identify remaining risks, you should consider which further
action you could take to control the risks so that harm is
unlikely.
Step 4: Record your findings
If you have fewer than five employees you do not need to
write anything down, though it is useful to keep a written
record of what you have done. If you employ five or more
people you must record the significant findings of your
assessment.You must also tell your employees about your
findings.You need to be able to show that a proper check was
made, that you considered who might be affected, that you
dealt with all the obvious significant hazards, that the
precautions you propose are reasonable and that the
remaining risk is low.
Step 5: Review your assessment if necessary
Each solar water heating installation may bring its own
challenges and present its own particular hazards.You should
therefore be careful not to rely on a “standard” risk assessment
for installing a solar water heating system in a house, but
review the particular hazards for each new situation.The issue
of work equipment must be considered, but at the preparation
stage you should consider where scaffold or other access
equipment might be positioned and look out for any obvious
obstacles to this, such as a conservatory or porch.
In addition to the risks associated with work at height, you
should also consider the risks associated with lifting and
carrying solar collectors, using electric drills and using blow
lamps or blow torches for soldering.This is not an exclusive list
and so you should consider all aspects of the proposed
installation to assess whether there are additional risks that
need to be taken into account.

12 © Baxi Heating UK Ltd 2008
8.1 Installation
The Solar Collector temperature sensor should be installed in
the sensor pocket securely.The sensor with the black silicone
sheathing must be used in the solar collector pocket.
All materials used for installing temperature sensors (sensor
element, conducting compound, cables, sealing and insulating
materials) must be suitably temperature resistant (up to
200°C).
Solar Collector sensor may be extended (using the 13m
extension cable supplied) as described in section 10.7.
The sensor may be extended up to 50m but 0.75mm
screened flex must be used, see page 22 section 10.7.
8.0 Installation of collector sensor
Fig. 13

13
© Baxi Heating UK Ltd 2008
9.0 Installation of pump station
9.1 Components List
Before commencing the installation check all listed
components are contained in the following cartons.
Hydraulic Station carton:
1. Hydraulic pump station with insulation incorporating
wall mounting bracket.
2. Solar differential controller.
3. Safety group, comprising-
Pressure relief valve, pressure gauge and fill &
drain valve.
4. 22mm compression fitting (4 off).
5. Re Heat sensor (auxiliary heat source).
6. Solar Gain Module comprising-
Flowmeter and return temperature sensor.
7. Sensor extension cable (13m) (not shown)
see Fig 24.
Ancillary component cartons:
8 Solar expansion vessel complete with mounting
bracket assembly.
9. Expansion vessel connecting flexible pipe.
10. Expansion vessel self sealing connection.
11. Thermostatic Blending valve.
12. 2m insulated flexible steel hoses for connection
to collectors
13. 30m coil with insulation and fittings (not shown)
1
2
3
4
Fig. 14 (Diagrams not to scale)
10
9
11
6
5
8
12

14 © Baxi Heating UK Ltd 2008
9.0 Installation of pump station
9.2 Identification of Components (Fig. 15)
The main components of the pump station are:
– Two isolating valves (Fig. 15, Item 1 & 2) with integral
thermometers which display the solar primary flow
and return temperatures.
– A safety group (Fig. 15, Item 3, supplied unconnected),
which protects the solar primary circuit.The pressure
relief valve and pressure gauge are integrated in the
safety group.
– A non-return valve in both feed and return prevents
the possibility of gravity circulation in the solar
primary circuit.
– A solar circulation pump (Fig. 15, Item 4).
– A flow gauge and regulator with fill & drain valve and
shut-off valve (Fig. 15, Item 5).
– An air separator.
The heat transfer fluid is circulated by the solar circulation
pump integrated in the hydraulic pump station (Fig. 15).
In most instances the 20 litre container of Tyfocor LS will be
sufficient quantity of transfer fluid to fill 30 metres of pipework
when connected to a 30 tube collector.
The pump station has a solar controller (Fig. 15 Item 6)
integrated into the front insulation moulding.This is pre-wired
to the solar pump.
Fig. 15
21 3
4
5
6

15
© Baxi Heating UK Ltd 2008
9.0 Installation of pump station
9.3
See Fig. 16
1 Solar cylinder
2 Collector temperature sensor lead
3 Solar primary return (to collector)
4 Solar collector
5 Solar primary flow (from collector)
6 Solar primary return (from cylinder)
7 Solar primary flow (to cylinder)
8 Solar differential temperature controller
9 Cylinder temperature sensor lead
9.4 Pipework installation - general
The collectors, the pump station and the solar cylinder (Fig. 16)
must be connected with the stainless steel pipework supplied.
For additional lengths over 15 metres use copper pipe with
compression fittings.
NOTE: Plastic pipes MUST NOT be used.
Connections supplied are suitable for pipe diameters up to
22mm. However for short pipe runs (up to 10m flow and
return) the use of 15mm diameter pipe is acceptable.
In solar heating systems, use only pipes and fittings made from
copper, brass, bronze brass or stainless steel. Compression
fittings only must be used.
All connections and joints must be resistant to temperatures
quoted and resistant to glycol.
The height difference between the highest point in the
pipework (collector) and the pump station may be a maximum
of 15m (this is called the ‘static height’). If the static height is
greater than 15m a larger expansion vessel may be required.
If any pipe sealants are used these should be resistant to glycol
and able to withstand temperatures of up to 200°C.
Earthing pipework
All solar primary pipework between the solar collectors,
hydraulic station and solar cylinder must be earth bonded to
avoid electrical potential differences.This work must be carried
out by a qualified electrician.
Fit earthing clamps to the solar primary flow and return pipes
and connect the earth clamps to the earthing system of the
property using an earth bonding cable of min. 6mm2diameter.
9
8
7
6
5
4
3
1
Fig. 16
2

9.0 Installation of pump station
9.4 Pipework installation - general (cont)
Venting the pipework
The SolarfloTM hydraulic station includes an air
collector/separator and bleed point so an automatic air vent is
not necessary. Any section of solar pipework that falls and rises
again may require an additional air vent valve to relieve any
trapped air which may cause air locking in the system.The air
vent must be compatible with solar primary systems, i.e. be
resistant to glycol and temperatures up to 200ºC.
Insulating the pipework
External pipework should be insulated with high temperature
resistant materials and be protected against UV degradation.
Internal pipework, especially through unheated spaces such as
a loft space, should also be insulated with high temperature
resistant materials. The SolarfloTM is supplied with 2x2m pre
insulated flexible stainless steel tubes and with additional
lengths (30m) of stainless steel flexible tubes and high
temperature insulation.
16 © Baxi Heating UK Ltd 2008
Fig. 17

17
© Baxi Heating UK Ltd 2008
9.0 Installation of pump station
9.5 Installing the pump station - positioning
It is usual to install the hydraulic station and solar controller
near to the solar cylinder. However this does not have to be
the case, the hydraulic station can be installed anywhere
convenient on the solar primary pipework although adequate
access will be necessary for commissioning and maintenance.
The solar controller should be accessible for system
operational monitoring. Also if an auxiliary heating source is to
be controlled by the solar controller, consideration must be
given to the accessibility of the controls to allow the user to
make adjustments to the settings. If not in close
proximity to the solar cylinder it will be necessary to extend
the solar cylinder temperature sensor cable, refer to section
10.7 for details of how to do this. It is recommended that the
upper mounting bracket of the hydraulic station is positioned
for ease of access and operation of the controls, see Fig. 18.
When choosing the site for the hydraulic station provision of a
discharge pipe from the safety group and the location of the
solar expansion vessel must be considered.
9.6 Installing the wall brackets and pump station
Remove the front insulation moulding (Fig 19. Item 1) by
pulling forward whilst holding the solar controller moulding (Fig
19. Item 2) in place. Carefully remove the solar controller
mounting by pulling forward and disconnect the pump cable
connector (Fig 19. Item 3). Place the pump assembly on the
wall at the desired location and mark the fixing positions
through the holes in the mounting brackets. Remove the
hydraulic assembly from the mounting brackets (Fig 19. Item 4)
and remove rear insulation moulding (Fig 19. Item 5). Drill and
plug the mounting positions and secure the mounting brackets
into position using the fixings provided.These fixings may not
be suitable for all wall materials. Push the rear insulation
moulding over the wall brackets and refit the hydraulic
assembly (Fig 19. Item 6) to the mounting clips on the wall
brackets.
1
2
3
4
4
5
6
Fig. 18
Fig. 19
Wall Mounting Brackets

9.0 Installation of pump station
9.7 Installing the safety group
Connect the safety group (Fig 20 Item 1) with the washer
(Fig 20 Item 2) enclosed to the connection on the hydraulic
station return isolating valve assembly (Fig 20 Item 3).
9.8 Connecting the solar expansion vessel
Mount the solar expansion vessel (Fig 21 Item 1) adjacent to
the hydraulic station (Fig 21 Item 2) so that the vessel can be
connected to the vessel connection of the safety group (Fig 21
Item 3) using the flexible pipe (Fig 21 Item 4) supplied.
(NOTE: Solar expansion vessel, mounting bracket, self sealing
connection and flexible pipe are supplied in the Ancillary
Components kit).The vessel must be mounted as shown
(connection to top) and securely supported using the wall
bracket supplied.The self sealing vessel connection should be
screwed onto the vessel connection before connecting the
flexible pipe (Fig. 21 Item 5).
DO NOT replace the solar expansion vessel with either a
potable water expansion vessel or boiler sealed system vessel.
Solar expansion vessel has a pre-set pressure of 2.5 bar and
must be adjusted to suit your installation.
The charge pressure at the solar expansion vessel should be
adjusted such that when not under load the charge pressure is
0.7 bar above the static system head (the height of the top of
the collector panels above the hydraulic station). A one metre
head represents 0.1 bar. However, the charge pressure should
be at least 1.5 bar.
The maximum static system head is 15m (1.5 bar).
9.9 Connecting pipework
Connect the flow and return pipes to the collectors and to the
cylinder via compression fittings (Fig 22 Item 1). Fittings are for
22mm o/dia pipe. Support the pump assembly when tightening
connections.
Run a pipe (Fig 22 Item 2) from the exit opening in the
pressure relief valve (Fig 18 Item 3) to a suitable container
(Fig 22 Item 4) and secure it. Ensure the pipe enters the
container to a level which will allow a safe discharge of fluid in
the event of the pressure relief valve opening. Ensure the
catchment container can be removed after the pipe has been
secured. After commissioning, add the pressure relief catchment
vessel warning label to the container. Align the arrows on the
label with any remaining fluid in the container.
Installing a drain valve
Install a device for draining the solar heating system
(tee piece with drain valve, Fig. 23) into the flow and return at
the lowest point in the solar heating system. Drain valve must
be suitable for glycol, 180° C and 6 bar.
Connecting the solar cylinder
For detailed installation instructions refer to the installation
instructions supplied with the solar cylinder.
18 © Baxi Heating UK Ltd 2008
1
2
3
4
5
1
2
3
3
2
4
1
Flow
from
panel
Return
to
panel
Flow
to
cylinder
Return
from
cylinder
Flow to cylinder
Return from cylinder
Return to hydraulic station
Fig. 20
Fig. 22
Fig. 23
Fig. 21
Commissioning Label

19
© Baxi Heating UK Ltd 2008
Pump
pre-wired
(mounted on
hydraulic station)
230V/240V~
Mains supply
L
N
E
Cylinder
sensor
Solar
differential
controller
Hydraulic Station Solar panel
sensor
Terminal block
for extending
collector sensor
Double pole
isolating switch
10.0 Installation of solar controller
10.1 Appliance installation
Always disconnect from the mains before opening the
controller cover.
The solar controller is designed to be mounted on the front of
the pump station. Alternatively it can be removed from the
insulation and be wall mounted (see panel below). In the case
of wall mounting the pump cable may need to be lengthened.
Alternative mounting option
In the case of wall installation proceed in the
following way:
Drill installation holes according to the dimensions
shown below. Screw in two upper screws up to 6 mm
distance. Open the appliance as described in section 10.2
and hang it onto two screws. Now two lower screws can be
mounted.Tighten all screws. Do not overtighten to avoid
damage to the controller backplate.
10.2 Opening the controller
No tools are required to open the controller.The front of the
controller is secured by two latches which engage with the
controller backplate. It can be opened by gently pulling the
lower side edges outwards and then hinged open.
10.3 Electrical connection overview
Always disconnect from the mains before opening the
controller cover.The electrical installation must conform to all
current Wiring Regulations and be carried out by a competent
electrician.
The connection of all electrical cables is to the terminal block
located on the backplate of the controller.The terminals on
the right side of the terminal block are for safety extra low
voltage connections (SELV) (temperature sensors and flow
transmitters).The terminals on the left side of the terminal
block are for 230/240 V~ connections.
126mm
118mm
84mm
Fig. 24

PE
L
N
N
A1
N
A2
N
A3
WMM
T1
T2
T3
T4
T5
T6
mains 230/240 V area low voltage area (SELV)
10.0 Installation of solar controller
20 © Baxi Heating UK Ltd 2008
PE Earthed connection
L Mains supply live conductor
N Mains supply neutral conductor
A1 Switch output to solar pump
N Neutral wire to solar pump
A2 Switch output 2 to second
system pump if used (east/west)
N Neutral wire switch output 2
A3 Switch output 3 to auxiliary
heating control
N Neutral wire switch output 3
For switch functions A2 and A3
see Fig. 27
Fig. 25
230V/240V~
Mains supply
L
N
E
Solar
differential
controller
Hydraulic Station
Fused Double pole
isolating switch
Solar coil
over-temp
cut-out
Fig. 26
10.4 General connection guidelines.
In the case of all connecting wires the outer sheath should be
stripped back to 80mm.The individual conductor sleeving
should be stripped approx. 10mm.
Flexible cables are inserted in the controller through
knockouts provided in the controller backplate.
Flexible cables must be secured against straining by suitable
strain relief bushes or devices.
Protect flexible cables from damage by hot pipework.
The controller must be earthed.
10.5 230/240V~ connections
For 230V connections you must follow the following points:
The mains supply to the controller should be via a suitable
fused double pole isolating switch with a contact separation of
at least 3mm in both poles. Additionally for unvented solar
cylinders the controller should be wired via the solar coil over
temperature cutout such that power is interrupted to the
controller and hydraulic station in the event of the unvented
cylinder overheating (see Fig. 26).
Controllers are intended for the operation in 230/240V~
/50Hz mains. Any motorised valves connected must be
suitable for this voltage.
All earth wires must be connected to terminals marked with
PE. Any bare wire earth conductors must be sleeved with
green/yellow sleeving.
The neutral terminals (N) are electrically connected and are
not switched.
All switch outputs (A1, A2 and A3) are 230/240V~ 1 Amp
max load outputs. If voltage free contacts are required, this
must be done via a relay (see Fig. 28 Block Wiring Scheme C
or E) order accessory Code No. 5122765.
NOTE: The Solar Differential Controller’s internal 1A switch
outputs are not suitable for Y plan systems.
NOTE: This controller is suitable for S plan and Y plan
systems. However, in the event of an installation having a ‘Y’
plan boiler system that is to be controlled by the solar
controller, a relay is required (not supplied).This is available as
a Baxi Spares Item, Code No. 5122765.
WMM Flow meter
T1 Temp.- sensor collector 1
T2 Temp.- storage tank 1
T3 Temp.- sensor collector
2/storage tank 2
T4 Temp.- sensor collector
return
T5 Temp.- sensor thermostat
or for 2nd temperature
differential controller
T6 Temp.- frost protection or
for 2nd temperature
differential controller
Fuse Rating:T 2A L 250V