Dimplex SCxn175sd User manual

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Unvented hot water cylinder – SCxn…d/i, SCxn…sd/si
Installation and operating instructions

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0 Overall view
Figure 1 – Overall view of proposed installation sequence SCxn…d/i
SCxn80/130/150/175/215/255/305d
01
02
03
04
05
06
07
SCxn80/130/150/175/215/255/305i
11
08
Standard SCxn cylinder
01
02
03
04
05
07
09
10

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Figure 2 – Overall view of proposed installation sequence SCxn…sd/si
SCxn175/215/255/305sd
SCxn175/215/255/305si
18
01
02
03
04
05
07
08
09
10
11
12
13
14
15
16
17
18
01
02
03
04
05
07
12
13
14
15
16
17
06
Solar SCxn cylinder

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1 Contents
0 OVERALL VIEW 2
1 CONTENTS 4
2 BEFORE YOU START 5
GENERAL 5
COMPETENCE 5
HEALTH AND SAFETY 5
RISK ASSESSMENT 6
3 SCOPE OF DELIVERY 6
4 PRODUCT FEATURES AND DESCRIPTIONS 7
5 INSTALLATION 9
5.1 GENERAL ADVICE 9
5.2 SITING CONSIDERATIONS 10
5.3 COLD WATER SUPPLY AND DISCHARGE PIPE WORK 10
5.4 HOT WATER OUTLET 12
5.5 IMMERSION HEATER 12
5.6 INDIRECT HEATING LOOP 13
5.7 SOLAR LOOP 14
5.8 SECONDARY RETURN 15
5.10 INSTALLATION EXPANSION VESSEL 15
5.11 WIRING SCHEMATIC AUXILIARY LOOP 16
5.12 WIRING SCHEMATIC SOLAR LOOP 19
5.13 SOLAR SENSOR INSTALLATION 19
6 COMMISSIONING 21
6.1 SCXN …D/I RANGE 21
6.2 SCXN …SD/SI RANGE 21
7 OPERATION 22
7.1 WATER TEMPERATURE DIRECT ELECTRIC HEATING 22
7.2 WATER TEMPERATURE AUXILIARY HEATING 23
8 MAINTENANCE 23
9 TROUBLESHOOTING 24
10 TECHNICAL DATA 25
10.1 SCXN …D/I25
10.2 SCXN …SD/SI 26

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2 Before you start
General
Thank you for choosing a Dimplex product. We ensure you that every effort was made
at design, manufacture and delivery stages of this product to meet your expectations.
We ensure you of our best possible support throughout the product’s lifespan.
As part of ongoing product development and improvement Dimplex reserves the right to
undertake changes to the product without prior notice. Great care has been taken to
ensure this manual was correct at the time of print. Should you however discover any
issues with the information contained therein please do not hesitate to contact your
vendor.
We strongly recommend you read the whole contents of this manual before commenc-
ing the work.
Competence
Dimplex products have been designed and manufactured to the current relevant stan-
dards and under stringent quality control. It is therefore imperative that the product is
only installed by a:
- trained and
- competent
person as defined in the relevant regulations. Dimplex does not accept any liability for
damage done to persons or property resulting from undue handling and usage of this
product.
All regulations current at the time of installation are to be considered alongside the con-
tent of this manual as they form the code of best practice.
The guarantee of this product is linked to the ability of proving that the product was
installed, commissioned and maintained:
- by a competent person
- in accordance with Dimplex instructions and the current relevant regulations and leg-
islation
- the product being registered with Dimplex at the time of installation using the form in
the Dimplex On Site Guide
- records showing the date of maintenance in accordance with the maintenance sched-
ule as detailed in the On Site Guide
Health and Safety
The installation of this product is subject to the Health and Safety at Work Act. It is
your responsibility to ensure that the transport, storage, installation and operation of
the product is carried out in a safe manner.
Dimplex will not accept any liability due to damage caused to people or property result-
ing from negligence or not adhering to the relevant Health and Safety practises.

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Risk assessment
The compilation of a risk assessment is strongly recommended before installing the
product. The following areas require particular consideration in addition to the informa-
tion required by the Health and Safety at Work Act.
- scalding: where appropriate or required by law a thermostatic mixing valve is to be
fitted to the hot water outlet of the cylinder
- explosion: the unit is fully equipped with all relevant safety equipment to comply with
current regulations. The correct design and function has been verified by independent
third party testing. The correct application thereof is the responsibility of the compe-
tent installer.
- water borne organisms (i.e. Legionella): if applicable a risk assessment should be
carried out following the recommendations outlined in the Approved Code of Practise
L8.
- the user preference must be considered when commissioning the system, in particular
when adjusting the solar and auxiliary system temperature and timer settings.
3 Scope of delivery
Please check the contents and condition of your delivery before signing the delivery
documentation. Contact your supplier immediately for any missing or damaged compo-
nents. Claims for missing or damaged parts after signing for the delivery will not be
accepted.
SCxn
175/215/255/305
SCxn
80/150/175/215/255/305
d i sd si
Unvented stainless steel
cylinder including:
- cold water inlet
- hot water outlet
- ½” sensor pockets
- ½” secondary return
- auxiliary heating coil
- solar coil
- twin thermostat
- 3kW immersion
- T&P Valve
x1
x1
-
-
-
-
-
x1(SCxn80)/x2
x1
x1
x1
-
-
x1
-
x1
x1
x1
x1
x1
x2
x1
-
x1
x1
x2
x1
x1
x1
x2
x1
x1
x1
x2
x1
x1

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Figure 3 – Scope of delivery
4 Product features and descriptions
The Dimplex®unvented stainless steel cylinder range incorporates many features to
ensure the highest level of comfort in providing hot water while minimising energy re-
quirements and environmental impact during manufacturing, operation and disposal.
The range covers storage volumes from 80 litres to 305 litres in various designs from
direct electric heated units, indirect units to a range of units allowing the use of renew-
able energy sources such as solar thermal.
A complete list of features provided by the whole range of cylinders is given in Figure 4.
Expansion vessel:
18 l: 175 l, 215 l
24 l: 255 l, 305 l
-
-
-
-
x1
x1
Expansion vessel
fixing kit
- - x1
x1
Inlet control
group
2ba
r
6bar
2ba
r
6bar
3ba
r
6bar
3ba
r
6bar
Tundish
15mm – 22mm
x1
x1 x1 x1
Two port motor-
ised valve 22mm
-
x1 - x1
Instructions x1
x1 x1 x1
Benchmark card x1
x1 x1 x1
SCxn…d SCxn…i
SCxn…sd SCxn…si
Pres. red.
Pres. rel.

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Feature
SCxn
d
i
si
sd
80
-
305
80 130 150 175 215 255 305
175
-
305
175
-
305
Materials
- inner cylinde
r
- outer cylinder
- inlet/outlet
- coils
- insulation
Duplex stainless steel
Dove grey leather grain coated steel
Stainless steel
Corrugated stainless steel
60mm PU foam (GWP=1, ODP=0)
Maximum operating conditions
- potable water temperature
- heating water temperature
- operating pressure
70°C
95°C
6bar
Cold water supply
- minimum dynamic pressure
- maximum pressure
- minimum flow rate
1.5bar
25bar
15 l/min
Connections
- cold water inlet
- hot water outlet
- secondary return
- coil flow and return
- sensor pocket
22mm stainless steel
22mm stainless steel
½”F BSP
22mm stainless steel
½”F BSP
Coil specification
- surface area [m²]
- rating [kW]
-
-
0.3
7
0.5
14
0.75
17
0.75/1.1
17/-
Immersion heater 1/
2 1 1 2
Thermostatic control
- direct input
- indirect input
- integral immersion heater thermostat and cut out
- external twin thermostat and cut out
Safety components
- pressure reducing valve and
strainer
- expansion relief valve
- temperature and pressure relief
valve
- factory pressure test
2bar
6bar
7bar / 90°C
10bar
3bar
6bar
7bar /
90°C
10bar
Other features Water inlet diffuser – prevents cold and hot water from mix-
ing
Water outlet sloped – improves stratification during draw off
and reduces heat loss
Light weight – easy handling
No anode – reduced service requirements
Approvals KIWA
BBA
Guarantee
- inner cylinder
- immersion heaters
- other components
25 years
2 years – excluding the effects of lime scale
5 years – excluding expansion vessel membrane pressure
Figure 4 – Product features

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5 Installation
5.1 General advice
Please read the following section carefully before commencing installation. If in any
doubt, please call the appropriate help desk. Disregarding the instructions given in this
manual in its entirety and any relevant regulations, standards and codes of practice will
void the guarantee of this product.
Please note: the following instructions are structured in such a way that individual steps
are described. Not all steps will apply to all products. Figure 5 shows which steps apply
to which cylinder types.
Figure 5 – Chapter reference
Handling – depending on the size of the unit and access to its installation location con-
sideration must be given to the handling of the unit. Please note that handling, installa-
tion and use of this product is subject to the Health and Safety at Work Act.
If the unit is not installed immediately, it should remain in its protective packaging with
all pipe protectors/end caps applied to prevent damage and dirt deposit inside the cyl-
inder and the coils.
Pipe work – the pipe runs should be executed as short as possible, unused pipe work
should be removed and all remaining pipe work should be lagged in accordance with
regulatory requirements to prevent heat loss and the formation of condensation.
Taps and fittings – all taps and fittings incorporated in the unvented system should
have a rated operating pressure of 6 bar or above.

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5.2 Siting considerations
When choosing a suitable location for the cylinder the following aspects should be con-
sidered:
- structural integrity
- access for installation, operation, maintenance and replacement
- routing of discharge pipe work
- access to water mains supply, hot and cold water distribution pipe work
- access to suitable electricity supply
- location in relation to remaining system components such as auxiliary and solar heat-
ing system
- frost protection
The Dimplex SCxn cylinder range is designed to be floor standing, vertically mounted,
indoors and in a frost free environment. The cylinder may be located on any flat and
level surface, provided it is sufficiently robust to support the weight of the cylinder
when full of water (see chapter 10).
The position and orientation of the cylinder should be such that easy access is provided
for servicing the controls and replacing the immersion heater should the need arise.
Ensure that no pipe work hinders any work to be carried out on the various cylinder
components.
Particular care must be taken when placing the cylinder in a garage or outbuilding. All
exposed pipe work must be correctly insulated to avoid frost damage. If required the
occurrence of frost has to be avoided by means of heating the space in which the cylin-
der is located.
5.3 Cold water supply and discharge pipe work
The required operating conditions of the Dimplex SCxn cylinder range are summarised
in Figure 4. The following instructions have to be followed when installing the cold water
mains supply to the cylinder.
1 The cold water supply to the cylinder must come directly from the cold water mains
after the mains stop valve to the property.
2 The inlet group supplied with the cylinder contains a line strainer, pressure reducing
valve, pressure relief valve, check valves, balanced cold water supply port and a
connection point for the expansion vessel (required for SCxn solar only).
3 The cold water inlet pipe work should have at least an inside diameter of 19mm and
meeting the requirements of the water regulations for the supply of wholesome wa-
ter.
4 The discharge pipe work from the expansion relief valve must be installed constantly
falling to an open point of discharge. It is recommended to combine it with the dis-
charge of the temperature and pressure relief valve as illustrated in Figure 6.
When completing the installation of the discharge pipe work ensure the valve itself is
secured by tightening the screw on the side of the assembly. Loosening the screw
allows the best possible orientation of the valve.

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5 It is recommended to install a drain valve in the lowest point of the cold water feed
to the cylinder. This allows the cylinder to be drained in a controlled manner should
this become necessary.
Note: Between the inlet group and the cold water inlet on the cylinder NO isolating
device should be fitted as by doing so important safety devices could be isolated!
6 The temperature and pressure relief valve must be discharged into the tundish. The
sizing of the discharge pipe work is regulated through building regulation G3. An ex-
tract is shown in Figure 6.
01
02
03
04
05
Discharge pipe constantly
falling to safe discharge
location.
max. 500mm
06
min. 300mm

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Figure 6 – Cold water supply and discharge pipe work installation
5.4 Hot water outlet
The hot water pipe work is to be directly connected to the how water outlet connections
of the cylinder as indicated in Figures 1 and 2.
Should a thermostatic mixing valve be required the valve is to be installed following the
manufacturers instructions. When fitting the thermostatic mixing valve ensure that
none of the safety relevant devices of the unit can be isolated (see 5.3).
It is recommended to insulate the hot water pipe work from the cylinder to the outlets
to reduce the energy requirements for providing hot water.
5.5 Immersion heater
The immersion heater has to be connected in accordance with IEE Wiring Regulations
and the installer carrying out the work has to be suitably qualified. It must be con-
nected through a double pole isolating switch or suitable controller which must have a
contact separation of at least 3mm in all poles. The wiring diagram for the immersion
heater is shown in Figure 7. For further details please see instructions provided with
immersion heater.
The immersion heater incorporates an independent non-self resetting over temperature
cut-out. Should the over temperature cut-out operate, the rest pin will be pushed up-
wards, and become level or slightly proud of the cover at the position marked “Safety”.
Use a suitable sized implement to reset the pin by pushing it hard into its original posi-
tion.
Figure 7 – Wiring diagram immersion heater

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Note: The cylinder must be filled with water before switching on the immersion
heater. Failure to do so will damage the element and void any guarantee on the
product.
5.6 Indirect heating loop
The indirect heating source can be connected to the cylinder in various ways as de-
scribed by the chosen control system supplier. The wiring and installation principles for
two typical integration methods are detailed in chapter 5.11.
Figure 8 – indirect heating loop installation
To conform with building regulations it is imperative that the motorised two port valve
is installed in the indirect heating loop and connected into the control circuit as required.
08
SCxn…i
SCxn…si
09
11
10
08
09
11
10

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The port connections for the indirect heating flow and return are identified in Figure 1
for the SCxn…irange and in Figure 2 for the SCxn…si range.
Should the flow connection be the highest point in the indirect heating loop an adequate
device for de-aeration has to be installed. Equally, should the return connection be the
lowest point in the indirect heating loop, a suitable drain device should be installed in
the lowest point.
When installing the motorised two port valve ensure the direction of flow is adhered to
as marked on the body of the device. Connecting the control loop ensure the correct
thermostat on the cylinder is chosen for the respective loop.
The fittings used to connect to the cylinder must be suitable for stainless steel. Not all
push fit fittings can be used – please check with your supplier. Should compression fit-
tings be used ensure that the connection is not being over-tightened, always countering
the force with a second spanner.
5.7 Solar loop
The solar loop has to be completely installed:
- in metal pipe work
- insulated with high temperature insulation
- connected with compression fittings only (or other means which are suitable for solar)
Figure 9 – Solar loop installation
13
SCxn…sd/ SCxn…si
12
14

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The wiring schematic for the solar loop is detailed in chapter 5.12. Please note: the so-
lar loop does not require a motorised two port valve as long as:
- the Dimplex SOLPU1/2 pump unit is being used (non return valves in flow and return)
- the cylinder is located lower than the solar panels
- all other connection requirements in this manual are being adhered to
To conform with building regulations it is imperative that the solar circulation pump is
installed in the solar loop through the twin thermostat and not directly from the solar
control unit.
The port connections for the solar flow and return connections are identified in Figure 2
for the SCxn…sd and the SCxn…si range.
Should the flow connection be the highest point in the solar loop an adequate device for
de-aeration has to be installed should the system not be commissioned using a flush a
fill pump. Equally, should the return connection be the lowest point in the solar loop, a
suitable drain device should be installed in the lowest point.
5.8 Secondary return
A ½” boss is provided on the SCxn…sd/si cylinder range to connect a secondary return
loop to avoid:
- stagnant water in long pipe runs
- long waiting times at draw off point for hot water
- undue water wastage
To minimise the energy consumption of the secondary return circuit and to ensure reli-
able operation it is important to consider:
- the control of the circulation pump to be time and temperature controlled
- the secondary return circuit pipe work to be insulated
- the secondary return pump to be of suitable material
The location of the secondary return connection on the cylinder is highlighted in Figure
2.
5.10 Installation expansion vessel
Optional for standard SCxn d/i cylinders, mandatory for solar SCxn d/I cylinders.
The expansion vessel can be connected directly to the cold water inlet group utilising
the flexible hose supplied with the vessel. It is important not to install any isolating de-
vices between the vessel and the cold water inlet group.
Further it is recommended to mount the vessel higher than the cylinder to avoid having
to drain the cylinder when maintaining and replacing the expansion vessel. The connec-
tion of the expansion vessel to the inlet group is shown in Figure 10.

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Figure 10 – Installation expansion vessel
(optional for standard SCxn d/i cylinders, mandatory for solar SCxn d/I cylinders)
It is important to check the pre-charge pressure of the expansion vessel mem-
brane before filling the cylinder. The pre-charge should be >2bar.
5.11 Wiring schematic auxiliary loop
The auxiliary heating system can be interfaced with the Dimplex SCxn cylinder in vari-
ous. Two common examples are given in Figures 11 and 12.
Before adapting one of the proposed systems ensure the system is compatible
with the remaining control equipment installed in the system.

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Figure 11 – Auxiliary loop integration 2x motorised two port valve

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Figure 12 - Auxiliary loop integration 1x motorised two port valve and mid-position valve

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5.12 Wiring schematic solar loop
The integration of the Dimplex solar SCxn cylinder is shown in Figures 11 and 12. The
wiring schematic for the solar loop is shown in Figure 13.
Figure 13 – Solar loop integration
5.13 Solar sensor installation
The Dimplex solar SCxn range cylinders allow for the installation of two sensors. The
lower sensor is required to control the solar circulation pump. The upper sensor is for
information only to indicate the actual available hot water temperature.
Two ½” sensor pockets are supplied with the pump unit. The sensor pockets are to be
used to install the sensors in the cylinders.
The location of the sensor bosses is indicated in Figure 14, also showing the methodol-
ogy of installing the sensor into the sensor pocket. A suitable sealant is to be used such
as Loctite 577.

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Figure 14 – Solar sensor boss positions and sensor installation
01
02
03