Baxi 2nd Fix Solar User manual

© Baxi Heating UK 2012
Please read these instructions before installing or commissioning.
This Solar Thermal Domestic Hot Water System should only be
installed by a competent person.
PLEASE LEAVE THESE INSTRUCTIONS WITH THE
USER FOR SAFE KEEPING.
2nd Fix Solar Manual

2© Baxi Heating UK 2012
Index
© Baxi Heating UK Ltd 2012. All rights reserved. No part of this publication may be reproduced or
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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, Brooks House, Coventry Road, Warwick CV34 4LL.
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.
2 Index
3 Introduction to Solar
4 Hydraulic station specifications
5 Differential temperature controller specifications
6 Ancillary components
Expansion vessel
Solar heat transfer fluid
7 Cylinder specifications
Unvented
Cistern-fed vented
9 Safety information
11 Installation of hydraulic station
Parts list
Identification of components
Pipework installation - general
Installing the hydraulic station - positioning
Installing the wall brackets and hydraulic station
Installing the safety group
Connecting the solar expansion vessel
Connecting pipework
17 Commissioning of system
Air test
Flushing and filling the pipework
19 Installation of solar controller
Appliance installation
Opening the controller
Electrical connection overview
230/240V~ connections
Solar gain measurement
Connection of temperature sensors
Control of auxiliary heat input
24 Commissioning of hydraulic station
Ensure the solar primary system is free from air
Setting the system pressure
25 Commissioning of solar controller
Main menu
Control button
Menu “info”
Menu “programming”
Menu “Manual operation”
Menu “Basic adjustment”
Overview of display and operating elements
Controller functions
General controller functions
Cylinder heating by solar primary system
Systems with two storage cylinders
Rotational speed regulation
Thermostat (heating)
Thermostat (cooling)
Tube collector
Sensor monitoring
Flow monitoring
System protection function
Frost protection
Energy productivity measurement
Operating hours meter
37 Setting the system flow rate
Checking and adjusting the flow rate
Installation of the thermal insulation
Commissioning record
41 Maintenance
Check heat transfer fluid
Maintenance of the collector
Cylinder
42 Fault Finding
Failures with error message
45 Spares
Spare parts and accessories
46 Warranty
Standard warranty terms & conditions

3
© Baxi Heating UK 2012
1.0 Introduction to Solar
1.1 Description
1.Thank you for purchasing a high quality Solar Thermal
Domestic Hot Water System.
2.The sun is the ultimate source of most of our renewable
energy supplies. Energy from the sun is clean and abundant.
3.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.
4. 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.
5. 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.
6.The 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 collector panels
through which a special heat transfer fluid is pumped. As the
fluid passes through the collector panels 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
panel 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 panel. As the sun’s energy input to the collector
panels is variable supplementary heating by a conventional boiler
or electric immersion heater should be provided.The optional
cylinders that can be supplied with the package provide a
supplementary heat exchanger coil and immersion heater as
standard.
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3
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11
12
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8
4
6
14
13
Cold Supply for Domestic Hot Water
Domestic Hot Water Outlet
Auxiliary Discharge Arrangement
Solar Collector 1
Solar Collector 2 (For East / West Array Installation)
Collector Sensor 1 (PT 1000)
Collector Sensor 2 (PT 1000)
Solar Pumping Station with Controller
Solar Pumping Station Cascade Module
Solar Expansion Vessel
Auxiliary Heat Source (Central Heating Boiler)
Flow Meter on a ‘COMMON’ Return (Accessory code 84515064)
4
5
6
7
9
2
3
1
11
12
10
8
14
13
Solar Fluid Discharge Vessel (Accessory code 720294601)
Thermostatic Blending Valve (Accessory code 720223301)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Fig. 1
Fig. 2

4© Baxi Heating UK 2012
2.0 Hydraulic station specifications
2.1 Technical data
Dimensions (Height/Width/Depth)
System Module
Pump Station 375/250/190mm
Cascade Module
Pump Station 375/190/190mm
Flow and return connections
(compression fittings) 22mm
Maximum working temperature: 160°C
Maximum working pressure: 6 bar
Pressure Relief Valve setting: 6 bar
Circulating Pump: Baxi
Circulating Pump voltage: 230/240 V ~
Power consumption Setting 1: 45W / 45W
Setting 2: 68W / 65W
Setting 3: 90W / 85W
Maximum Pump Head: 6 metres
Maximum Pump Capacity: 4.5 m3/h / 3.5 m3/h
Flow meter scale: 2 to 15 l/min
Fig. 3 System Module
Fig. 4 Cascade Module

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© Baxi Heating UK 2012
3.0 Differential temperature controller
3.1 Technical data
Housing
Material 100% recyclable ABS
Dimensions
L x W x D in mm 175 x 134 x 56
weight ca. 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 mm2 fine-strand/single-wire
Temperature sensor /
temperature range PTF6 - 25°C to 200°C
PT1000, 1,000 kΩat 0°C
Test voltage 4 kV 1 min according to
VDE 0631
Switching voltage 230V / 240V
Capability per one
switch output 1A / ca. 230VA for cos j = 0,7-1,0
Total capability of
all outputs 2A / ca. 460VA maximum
Fuse protection fine-wire fuse 5 x 20mm, 2A/T
(2 amperes, slow)
Features
Self explanatory, menu driven operation
Adjustable control values
System monitoring
Energy yield, (solar gain) measurement
Suitable for flat plate and evacuated tube type collectors
Reheat thermostat function
Can be used in a number of system configurations
Fig. 5

6© Baxi Heating UK 2012
4.0 Ancillary components
4.1 Expansion vessel
1. Membrane expansion tanks for solar primary heating
circuit. Manufactured according to the Directive PED 97/23/CE
(approved noZ-DDK-MUC-02-396876-04).
2. Butyl membrane suitable for solar primary heating fluid, DIN
4807-3 approval.
Maximum working temperature +110°C.
Maximum percentage of glycol 50%.
Connection: 3/4” BSP male parallel
3. 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.
4.2 Solar heat transfer fluid
1.The system uses a sealed system indirect solar primary circuit
which must be filled with the solar heat transfer fluid provided.
This is a Pre-mixed (40% glycol / 60% water) Solar thermal
transfer fluid, based on1,2 - propylene glycol with corrosion
inhibitors. It is Non-toxic, odourless, bio-degradable.
2. DO NOT mix the fluid with other types.
3.The use of chemical resistant gloves and suitable eye
protection is required when handling.
4. A full safety data sheet is available on request.
5.The system should be filled when there is no direct radiation
from the sun. If direct radiation occurs the collector panels
should be shaded by covering them during filling and flushing.
6. Although the solar heat transfer fluid is non corrosive and bio-
degradable appropriate precautions should be taken when
handling.
7. Wash with soap and water if the fluid comes into contact with
skin.
8. If fluid gets into eyes, immediately rinse with large quantities of
clear running water.
9.The solar heat transfer fluid must be pumped into the system.
The pump can be electric or manual but must be capable of
producing a pressure of at least 2 bar. The system should be
thoroughly flushed to remove any contaminants in the solar
primary circuit prior to filling with the heat transfer fluid
10.The fluid is supplied in 20litre container.
Weight of container full - 21kg.
11. Systems found to have low glycol concentrations will not be
covered by the warranty.
Ø300mm
392mm
3/4”
Expansion vessel
Fig. 6

7
© Baxi Heating UK 2012
5.0 Cylinder specifications
5.1 Unvented
Nominal capacities 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 (60mm thick). GWP 3.1
(Global Warming Potential).
Cylinder Duplex stainless steel.
Pressure testing To 15 bar.
Heat unit Titanium
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 85°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 85°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.
N.B. 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.
The cylinders are unvented so installation must comply with
Building Regulation G3 and / or other local regulatory
requirements.
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Unvented system - schematic diagram
Fig. 7
Note: Indirect twin coil unit shown.

8© Baxi Heating UK 2012
Vented system - schematic diagram
Fig. 8
Note: Direct unit shown.Auxiliary heating by immersion heater.
5.0 Cylinder specifications
5.2 Cistern-fed vented
Nominal capacities 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 (60mm thick). GWP 3.1
(Global Warming Potential).
Water container Duplex 2304 stainless steel. 40 metres
(4 bar) maximum working head.
Heat unit Titanium 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 85°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.
NOTE: The system is also compatible with cylinders configured
for solar DHW systems. For installation and specification details
refer to the manufacturers instructions supplied with the solar
cylinder.
Any system installed using an unvented cylinder must comply
with Building Regulations G3 and/or other Local Regulations.

9
© Baxi Heating UK 2012
6.0 Safety Information
6.1 Safety
1. In order to reduce the number of deaths 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.
2. 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.
3.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.
4. 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.
5. Collective protection measures, such as guard rails on scaffold,
should be given priority over personal protection measures,
such as safety harnesses.
6. Within the regulations’ framework, you are required to:
a) Assess the risk to help you decide how to work safely.
b) Follow the hierarchy for safe work at height (i.e. avoid,
prevent and mitigate).
c) Plan and organise your work properly, taking account of
weather conditions and the possibility of emergencies.
d) Make sure those working at height are competent.
e) Make use of appropriate work equipment.
f) Manage the risks from working on or around fragile surfaces
and from falling objects.
g) Inspect and maintain the work equipment to be used and
inspect the place where the work will be carried out
(including access and egress).
7. 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 conditionsand the experience and
competence of colleagues or contractors who may be working
at height with you.

10 © Baxi Heating UK 2012
6.0 Safety Information
6.1 Safety (cont)
Risk Assessments
8.The HSE has published a number of very useful free
publications that advise how to undertake risk assessments.
9.Two of these that you should obtain are:
Five Steps to Risk Assessment.
A Guide to Risk Assessment Requirements.
10. 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.

11
© Baxi Heating UK 2012
7.0 Installation of hydraulic station
7.1 Parts 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 temperature controller.
3. Safety group, comprising-
Pressure relief valve, pressure gauge and fill &
drain valve.
4. 22mm compression fitting nut and olive(4 off).
5. Sensor extension cable (13m) (not shown).
Ancillary component carton:
6. Solar expansion vessel complete with mounting bracket
and strap assembly.
7. Expansion vessel connecting hose.
8. Expansion vessel self sealing connection.
1
2
3
4
Fig. 9 (Diagrams not to scale)
8
7
6

12 © Baxi Heating UK 2012
7.0 Installation of hydraulic station
7.2 Identification of components
1.The main components of the hydraulic station are:
– Two isolating valves (Fig. 10, Item 1 & 2) with integral
thermometers which display the solar primary flow
and return temperatures.
– A safety group (Fig. 10, 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. 10, Item 4).
– A flow meter with fill & drain valve and shut-off valve
(Fig. 10, Item 5).
– An air separator.
2.The heat transfer fluid is circulated by the solar circulation
pump integrated in the hydraulic pump station (Fig. 10).
3.The hydraulic station has a solar differential temperature
controller (Fig. 10 Item 6) integrated into the front
insulation moulding.This is pre-wired to the solar pump.
Fig. 10
21 3
4
5
6

13
© Baxi Heating UK 2012
7.0 Installation of hydraulic station
7.3
See Fig. 11
1 Cold Supply for Domestic Hot Water
2 Domestic Hot Water Outlet
3 Auxiliary Discharge Arrangement
4 Solar Collector 1
5 Solar Collector 2 (For East / West Array Installation)
6 Collector Sensor 1 (PT 1000)
7 Collector Sensor 2 (PT 1000)
8 Solar Pumping Station with Controller
9 Solar Pumping Station Cascade Module
10 Solar Expansion Vessel
11 Auxiliary Heat Source (Central Heating Boiler)
12 Flow Meter on a ‘COMMON’ Return
(Accessory code 84515064)
13 Solar Fluid Discharge Vessel
(Accessory code 720294601)
14 Thermostatic Blending Valve
(Accessory code 720223301)
7.4 Pipework installation - general
1. In Solar Heating Systems, the collectors, the hydraulic station
and solar cylinder (Fig. 11, Item 1) must be connected with
brazed or silver soldered copper pipes, compression fittings or
the multifit accessory flexible steel tube and insulation. (See
brochure for details) N.B. Plastic pipes MUST NOT be used.
2. Connections supplied are suitable for pipe diameters of
22mm. However for short pipe runs (up to 10m flow and
return) the use of 15mm diameter pipe is acceptable.
3. All connections and joints must be resistant to temperatures
of up to 150°C and resistant to glycol.
4. If any pipe sealants are used these should be resistant to
glycol and be able to withstand temperatures of up to 150°C.
5.The difference in height between the highest point in the
pipework (collector) and the level of the hydraulic pump
station determines the static head for the system.The static
head is 0.1 bar times this height in metres.This static head is
used when setting the expansion vessel precharge pressure
and the system pressure.
6. If the static head is greater than 1.5 bar (15m) then a larger
expansion vessel may be required for larger collector arrays.
7. If the pipe runs between the solar collector and pump
station are short (<6m) then a protection vessel (Accessary
No. 5131963) should be installed between the pump station
and expansion vessel.
8. Earthing pipework
All solar primary pipework between the solar collectors,
hydraulic station and solar cylinder should be earth bonded in
accordance with current IEE wiring regulations.;
Fig. 11
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10
8
4
6
14
13
Static
Height (m)

14 © Baxi Heating UK 2012
7.0 Installation of hydraulic station
7.4 Pipework installation - general (cont)
9.Venting the pipework
The hydraulic station the component 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 should be fitted with an additional air vent valve to relieve
any trapped air which may cause air locking in the system.The
automatic air vent and isolating valve used must be compatible
with solar primary systems, i.e. be resistant to glycol and
temperatures up to 180ºC.
10. Insulating the pipework
External pipework should be insulated with high temperature
resistant materials and be protected against UV degradation.
The insulation must be peck-proof and rodent-proof. Internal
pipework, especially through unheated spaces such as a loft
space, should also be insulated with high temperature resistant
materials. Mark the outside of any insulation to identify the flow
and return pipes.The collectors are supplied with 2x2m pre
insulated flexible stainless steel tubes. Additional lengths (30m)
of stainless steel flexible tubes and high temperature insulation
can be supplied.
Fig. 12
2
3
1
11
12
10
8
4
6
14
13
See Section 7.3 for Key

15
© Baxi Heating UK 2012
7.0 Installation of hydraulic station
7.5 Installing the hydraulic station - positioning
1. It is usual to install the hydraulic station and solar differential
temperature 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 (See also comments regarding system static
head given in Section 7.4).
2.The solar differential controller should also be accessible for
system operational monitoring. If not in close proximity to the
solar cylinder it will be necessary to extend the solar cylinder
temperature sensor cable, refer to section 9.6 for details of how
to do this.
3.It is recommended that the upper mounting bracket
of the hydraulic station is positioned approx. 1600 to 1700mm
above the floor level for ease of access and operation of the
controls, see Fig. 13.
4. 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.
7.6 Installing the wall brackets and hydraulic station
1. Remove the front insulation moulding (Fig 14. Item 1) by
pulling forward whilst holding the solar differential controller
moulding (Fig 14. Item 2) in place, carefully remove the solar
differential controller mounting by pulling forward and
disconnect the pump cable connector (Fig 14. Item 3).
2. Place the hydraulic assembly on the wall at the desired
location and mark the fixing positions through the holes in the
mounting brackets.
3. Remove the hydraulic assembly from the mounting brackets
(Fig 14. Item 4) and remove rear insulation moulding (Fig 14.
Item 5).
4. Drill and plug the mounting positions and screw the mounting
brackets into position.
5. Push the rear insulation moulding over the wall brackets and
refit the hydraulic assembly (Fig 14. Item 6) to the mounting clips
on the wall brackets.
1
2
3
4
4
5
6
Fig. 13
Fig. 14

16 © Baxi Heating UK 2012
7.0 Installation of hydraulic station
7.7 Installing the safety group
1. Connect the safety group (Fig 15 Item 1) to the connection
on the hydraulic station return isolating valve assembly (Fig 15
Item 3). Ensure that the pre-fitted gasket is securely in place on
the safety group prior to connection.
7.8 Connecting the solar expansion vessel
1. Mount the solar expansion vessel (Fig 16 Item 1) adjacent to
the hydraulic station (Fig 16 Item 2) so that the vessel can be
connected to the vessel connection of the safety group (Fig 16
Item 3) using the flexible pipe (Fig 16 Item 4) supplied. (Note:
Solar expansion vessel, mounting bracket, self sealing connection
and flexible pipe are supplied in the Ancillary Components kit).
2.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. 16 Item 5).
3. DO NOT replace the solar expansion vessel with either a
potable water expansion vessel or boiler sealed system vessel.
4.The charge pressure of the solar expansion vessel must be
adjusted (when the fluid circuit is empty or de-pressurised) to a
pressure equal to the static head + 0.4 bar, or a minimum of 1.2
bar. (NOTE: the static head is the height difference between the
highest point in the pipework (collector) and the hydraulic
station in metres x 0.1 bar.The charge pressure should not
normally exceed 1.9 bar - see also Section 7.4.
7.9 Connecting pipework
1. Connect the flow and return pipes to the pump station via
compression fittings (Fig 17 Item 1). Fittings are for 22mm o/dia
pipe. Support the hydraulic assembly when tightening
connections.
2. Installing a drain valve
It is recommended to install a device for draining the solar
heating system (tee piece with drain valve, Fig. 18) into the flow
and return at the lowest point in the solar heating system.The
drain and its rubber seal must be suitable for solar applications.
3. Connecting the solar cylinder
For detailed installation instructions refer to the
installation instructions supplied with the solar cylinder.
1
2
3
4
5
1
2
3
3
2
4
1
Flow
from
panel
Return
to
panel
Flow
to
cylinder
Return
from
cylinder
To a suitable container
(e.g. Solar fluid discharge vessel
Accessory No. 720294601)
Flow to cylinder
Return from cylinder
Return to hydraulic station
Fig. 15
Fig. 17
Fig. 18
Fig. 16

17
© Baxi Heating UK 2012
8.0 Commissioning of system
8.1 Air Test
1. An air test may be used on the pipework to detect any gross
leakage prior to flushing and filling with solar heat transfer fluid.
Pressurise the system to a maximum of 1 bar to check for leaks.
2. Ensure that the solar expansion vessel pre-charge pressure
has been set prior to flushing and filling.
8.2 Flushing and Filling the pipework
1. Before the system is commissioned the pipework must be
flushed to remove any contaminants. This must be done using
the solar heat transfer fluid as it will be impossible to fully
drain all parts of the system.
2. Connect the flushing pipes to the fill & drain valve on the
safety group (Fig. 19 Item 1) and to the fill & drain valve on the
flow meter (Fig. 19 Item 2).
3. Open the fill & drain valves.
4.Turn the slot of the adjusting screw (Fig. 19 Item 3) in the
return so the slot is vertical to open the non-return valve.
5.Turn the left hand isolating valve with integral thermometer in
the flow (Fig. 19 Item 4) in the direction indicated by the arrow
(to a 45° position) to open the non-return valve.
6. Ensure that the right hand isolating valve with integral
thermometer in the return (Fig. 19 Item 5) is open indicated by
the dot on the thermometer bezel being at the top.
7.Turn the slot of the flow meter adjusting screw (Fig. 19 Item
6) in the return vertically to open the flow limiter (Fig. 19 Item
7).
8. Flush the solar primary pump by pumping the fluid into the
system via the fill and drain valve on the safety group (Fig. 19
Item 1).
9. Close right hand isolating valve (dot on thermometer bezel at
9 o’clock position). Flush solar primary pipework and collector
via the fill and drain valve on the safety group. If reusing flushed
fluid ensure this is filtered before re-introducing into the
system. (see Fig. 20). Use a suitable container of a large enough
volume to collect the fluid.
10. When satisfied that all pipework and component parts have
been thoroughly flushed, the system can be filled.
45
3
6
7
Fig. 19
Fig. 20
Fig. 21
Solar fluid
Filling pump
Filter
1
2
1
3
2
45°
Read at top
of float

18 © Baxi Heating UK 2012
8.3 Flushing and Filling the pipework (cont)
11. Pour an amount of the solar heat transfer fluid into the filling
pump.
12. Close the fill and drain valve - safety group (Fig. 19 Item 1) and
the fill and drain valve - flow meter (Fig. 19 Item 2) and pressurise
the pump slightly prior to filling the system. If an electric pump is
being used follow the instructions with the pump.
13. Fully open the fill and drain valve on the safety group (Fig 19,
item 1) and pump fluid into the system. Whilst pumping, open the
flow meter drain valve (Fig 19, item 2) slightly to allow the air to
vent out of the system.
14. When the pump is down to approximately 1 litre isolate the
fill and drain valves.Vent the filling pump and refill with solar heat
transfer fluid.
15. Re-pressurise the filling pump and repeat steps 3 and 4 above
until fluid is seen discharging from the drain valve on the flow
meter. (Fig 19, item 2). Close the drain valve.
16. Continue filling at the fill and drain valve on the safety group
(Fig 19, item 1) until the system pressure reaches 2 bar.
17. At this point the circulation pump should be vented. If the
system pressure drops, repressurise using the procedure above.
18. After venting the pump and checking that the system pressure
is 2 bar, close the fill and drain valve on the safety group (Fig. 19
Item 1), and check the system for leaks.
19.Turn the left hand isolating valve (Fig 19, item 4) back 45°
clockwise until the dot on the bezel is back at 12 o’clock.
20.Turn the right hand isolating valve (Fig. 19 Item 5) back 90°
clockwise until the dot on the bezel is back at 12:00 O’clock.
21.Turn the slot of the adjusting screw (Fig. 19 Item 3) back to
the horizontal position.
8.0 Commissioning of system

19
© Baxi Heating UK 2012
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
Solar Coil
over-temp
cut-out
9.0 Installation of solar controller
9.1 Appliance installation
1. Always disconnect from the mains before opening the
controller cover. The solar differential temperature controller
is designed to be mounted on the front of the hydraulic
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.
9.2 Opening the controller
1. Always disconnect from the mains before opening the
controller cover.
2. No tools are required to open the controller.The front of
the controller is secured by two latches which engage with the
controller backplate.
3. It can be opened by gently pulling the lower side edges
outwards and then hinging the front upwards.
126mm
118mm
84mm
Fig. 22
The collector panel temperature sensor should be installed in
the sensor pocket at the collector array flow connector as
part of the first fix process. Ensure that the cable from this
sensor can be identified for connection to the pump station
wiring centre. Use the 13m extension cable supplied if
required.

© Baxi Heating UK 2012
20
F U S E
Fuse rating T 2A L 250V
A1 L
A2
A3
PEPE
PE
PE NN
NN M1 M2 M3 M4 M5 M6 M7
T2 T6T5 T7
T1 T3 T4
Mains 230/240V connections Low Voltage (SELV) connections
240 Volts
Terminal
Reference
Description
L 240V Supply Live
N 240V Supply Neutral
A1 Switched Output to Solar Pump
N Solar Pump Neutral
A2 Switched Output - Live 2 (For East West Array or Dual Tanks)
N Switched Output 2 Neutral
A3 Switched Output - Live 3 (For Auxiliary Heat Control)
N Switched Output 3 Neutral
PE Earth Connection
T1 & M1 Temperature Sensor Collector 1 (Tc1)
T2 & M2 Temperature Sensor Storage Tank 1 (Ts1)
T3 & M3 Temperature Sensor Collector 2/Storage Tank 2 (Tc2 / Ts2)
T4 & M4 Temperature Sensor Collector Return (Tret)
T5 & M5 Temperature Sensor for 2nd temperature differential controller (Tth)
T6 & M6 Frost Protection or 2nd temperature differential controller
Flow Meter (Optional)
T7 & M7
9.0 Installation of solar controller
9.3 Electrical connection overview
1. 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.
2.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 extra
low voltage connections (temperature sensors and flow
transmitters). The terminals on the left side of the
terminal block are for 230/240 V~ connections.
General connection guidelines.
3. 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.
4. Cables are inserted in the controller through knockouts
provided in the controller backplate.
5. Flexible cables must be secured against straining by
suitable strain relief bushes or devices.
6.The controller must be earthed.
9.4 230/240V~ connections
1. For 230V connections you must follow the following points:
2.The mains supply to the controller should be via a suitable
double pole isolating switch with a contact separation of at
least 3mm in both poles. Additionally 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 cylinder overheating (see Fig. 24).
3. Controllers are intended for the operation in 230/240V~
/50Hz mains. Any motorised valves connected must be suitable
for this voltage.
4. All earth wires must be connected to terminals marked with
PE. Any bare wire earth conductors must be sleeved with
green/yellow sleeving.
5.The neutral terminals (N) are electrically connected and are
not switched.
6. All switch outputs (A1, A2 and A3) are 230/240V~ closers. If
potential-free contacts are needed, appropriate accessories are
required.
Fig. 23
230V/240V~
Mains supply
L
N
E
Solar
differential
controller
Hydraulic Station
Double pole
isolating switch
Solar coil
over-temp
cut-out
Fig. 24