OSO HOTWATER Delta Twincoil DTC 200 User manual

142225-01 - 12-2018
Manufactured by OSO Hotwater AS
Industriveien 1 - 3300 Hokksund - Norway
Tel: + 47 32 25 00 00 / Fax: + 47 32 25 00 90
E-mail: [email protected] / www.osohotwater.com
Delta Twincoil - DTC
200-250-300 l.
EN
SAFETY INFORMATION
O&M INFORMATION
INSTALLATION MANUAL
TDS - TECHNICAL DATA SHEET

2
CONTENTS
1. Safety instructions................................................. 3
1.1 General information ...................................... 3
1.2 Safety instructions for users...................... 4
1.3 Safety instructions for installers .............. 4
2. Product description............................................... 5
  2.1. Productidentication................................... 5
2.2. Intended use.................................................... 5
2.3 CE marking....................................................... 5
2.4 Technical data.................................................. 5
2.5. ErP data (TDS).................................................. 5
3. Installation instructions ...................................... 6
3.1. Products covered by these instructions 6
3.2. Included in delivery........................................ 6
3.3. Product dimensions...................................... 6
3.4. Requirements for installation location . 7
3.5. Pipe installation............................................... 8
3.6. Electrical installation.................................. 10
4. Initial commissioning......................................... 12
4.1. Filling with water.......................................... 12
4.2. Turning on the power................................ 12
4.3. Setting the mixer valve.............................. 12
4.4 Control points................................................ 12
4.5. Emptying of water....................................... 12
4.6. Handover to end-user ............................... 12
5. User Guide............................................................... 13
5.1. Settings............................................................ 13
5.2. Maintenance ................................................. 13
6. Troubleshooting ................................................... 14
  6.1. Faultsandxes............................................. 14
7. Warranty conditions........................................... 15
7.1. Warranty and registration........................ 15
7.2. Customer service........................................ 15
8. Removing the product ...................................... 15
8.1. Removal........................................................... 15
8.2. Returns scheme........................................... 15
!
This document should be kept in a suitable place where it is accessible for future reference.

3
1. SAFETY INSTRUCTIONS
1.1 General information
• Read the following safety instructions
carefully before installing, maintaining or
adjusting the water heater.
• Personal injury or material damage may
result if the product is not installed or used
in the intended manner.
• Keep this manual and other relevant docu-
ments where they are accessible for fu-
ture reference.
• The manufacturer assumes compli-
ance (by the end-user) with the safety, op-
erating and maintenance instructions sup-
pliedand(bytheinstaller)withthetting
manual and relevant standards and regu-
lationsineectatthedateofinstallation.
Symbols used in this manual:
!
WARNING Could cause serious injury or death
!
CAUTION Could cause minor or moderate injury or damage to property
DO NOT
!
DO
!
20
30
405060 70
80
90
100
11010
1200
°C
1.1.2 Aknowledgement of purchase
Thank-you for purchasing the DELTA Twin Coil VIP
unvented hot water cylinder.
DELTA Twin Coil VIP is an unvented hot water cyl-
inder for use with solar installations available in
capacities200, 250and300litres.Itsenergye-
ciencyas denedbystanding heatlosses is  the
best in its class due to the use of vacuum insulated
Panels(VIP)andwillsavethehouseholdersigni-
cant energy costs over the lifetime of the cylinder.
This manual gives detailed advice for installation
and should be read carefully prior to tting any
unvented unit. OSO DELTA Twin Coil VIP cylinders
are not suitable for gravity fed primary systems. In
known hard water regions, precautions should be
taken to prevent limescale formation in hot water
cylinders, in accordance with Building Regulation
Part L, Domestic Heating Compliance Guide.
This OSO cylinder must be installed by a compe-
tent person and be installed in compliance with the
OSO Installation and Maintenance Instructions, all
current legislation, codes of practice and regula-
tions governing the installation of unvented hot
water cylinders in force at the date of installation.
!
NOTE
Please read this manual before installation and
leave with the cylinder. The ,manual and at-
tached logbook serve as the cylinder guarantee.

4
1.3 Safety instructions for installers
!
WARNING
SafetyvalveoverowsmustNOTbesealedorplugged(safetyvalvenotincluded)
!
AnyoverowpipefromthesafetyvalveMUSTbe> 18 mm inside, clear, undamaged and
frost-free with a fall to the drain.
!
Fixedelectricttingsshouldbeusedforinstallationinnewhomesorwhenchangingan
existing electrical setup in accordance with regulations. A mains cable with plug for wall
socket can be used when replacing the product without changing the electrical setup.
!
Themainscableshouldwithstand90°C.Astrainrelievermustbetted.
!
Theproductshouldbelledwithwaterbeforethepowerisswitchedon.
!
The relevant regulations and standards, and this installation manual, must be followed.
1.2 Safety instructions for users
!
WARNING
SafetyvalveoverowsmustNOTbesealedorplugged(safetyvalvenotincluded).
The product must NOT be covered over the cover on the front.
TheproductmustNOTbemodiedorchangedfromitsoriginalstate.
Children must NOT play with the product or go near it without supervision.
!
Theproductshouldbelledwithwaterbeforethepowerisswitchedon.
!
Maintenance/settings should only be carried out by persons over 18 years of age, with suf-
cientunderstanding
!
CAUTION
The product must not be exposed to frost, over-pressure, over-voltage or chlorine treatment.
See warranty provisions.
Maintenance/settings should not be carried out by persons of diminished physical or mental capa-
city, unless they have been instructed in the correct use by someone responsible for their safety.
!
CAUTION
!
The product should be placed in a room with a drain, in accordance with the wetroom
standard/latestTEK.Alternatively,tanautomaticstopvalvewithsensorandoverow
from safety valve to drain.
Liability for consequential damage will only apply if this is followed.
!
Theproductshouldbeproperlyalignedverticallyandhorizontally,onaoororwallsuitablefor
the total weight of the product when in operation. See type plate.
!
The product must have a clearance for servicing of 40 cm in front of the cover / 10 cm over the
top connection.

5
2.4ErPproductche-TechnicalDataSheet
Trade mark M T
item No. Model/identier ErP Rating
Standing heat
loss W
Capacity
L
OSO Hotwater AS 10211600 DTC 200 - 2.8kW @ 230V/3.0kW @ 240V+HX 0.7+0.7m² B49 192
OSO Hotwater AS 10211700 DTC 250 - 2.8kW @ 230V/3.0kW @ 240V+HX 0.7+0.7m² B54 242
OSO Hotwater AS 10211800 DTC 300 - 2.8kW @ 230V/3.0kW @ 240V+HX 0.7+0.7m² B58 284
Directive: 2010/30/EU Regulation: EU 812/2013 Directive: 2009/125/EC Regulation: EU 814/2013
Heat loss tested acc. to standard: EN 12897
2.PRODUCTDESCRIPTION
2.1Productidentication
Identicationdetailsforyourproductcanbefound
on the type plate xed to the product. The type
plate contains details of the product in accordance
with EN 12897:2016 and EN 60335-2-21, as well as
other useful data. See Declaration of Conformity at
www.osohotwater.com for more information.
OSO products are designed and manufactured in
accordance with:
• Pressure vessel standard EN 12897:2016
• Safety standard EN 60335-2-21
• Welding standard EN ISO 3834-2
OSOHotwaterASiscertiedfor
• Quality ISO 9001
• Environment ISO 14001
• Work environment OHSAS 18001
2.2 Intended use
Delta Twincoil is designed to supply homes with
hot running water. The product is intended for use
with two alternative energy sources.
2.3 CE marking
The CE mark shows that the product complies
with the relevant Directives. See Declaration of
Conformity at www.osohotwater.com for more
information.
The product complies with Directives for:
• Low voltage LVD 2014/35/EU
• Electromagnetic compatibility EMC 2014/30/EU
• Pressurised equipment PED 2014/68/EU
Any safety valve(s) used should be CE-marked
and comply with the PED 2014/68/EU.
This OSO product is approved to building and
water regulations by KIWA waterlec LTD.
Tel: [phone]
Email: wat[email protected]

6
!
CAUTION
Pipe stubs, valves etc. should not be used to lift
the product as this could cause malfunctions.
3. INSTALLATION INSTRUCTIONS
3.1 Products covered by these instructions
800 0306 Delta Twincoil - DTC 200
800 0308 Delta Twincoil - DTC 300
3.1.1 Health and safety regulations
Handling Operations Regulations 1992 denes
manual handling as: “any transporting or support-
ing of a load (including the lifting, putting down,
pushing, pulling, carrying or moving thereof) by
hand or bodily force” The Regulations set no spe-
cicrequirementssuchasweightlimits.However
common sense still has to be used based on an
ergonomic approach for each individual.
The DELTA Twin Coil VIP should be transported
and stored in a vertical position.
3.3.2 Delivery
The product should be transported carefully as
shown, with packaging. Use the handles in the
box.
3.3.3 Siting the DELTA Twin Coil VIP
There are few restrictions on the siting of the
OSO DELTA Twin Coil VIP, however it should not
be sited anywhere open to frost attack. The unit
shouldbeplacedonastableatsurfacecapable
of withstanding the weight of the cylinder when
full (see data plate) and access must be allowed
for maintenance purposes. Provision should
also be allowed for the routing of the discharge
pipe away from the cylinder to an outside point
according to building regulation G3.
3.4 Requirements for installation, location and
positioning
!
CAUTION
!
The product should be placed in a room with a drain, in accordance with the wetroom
standard/latestTEK.Alternatively,tanautomaticstopvalvewithsensorandoverow
from safety valve to drain.
!
The product should be placed in a dry and permanently frost-free position.
!
Theproductshouldbeplacedonaoororwallsuitableforthetotalweightoftheproduct
when in operation. See type plate.
!
The product must have a clearance for servicing of 40 cm in front of the cover / 10 cm over the
top connection.
!
The product should be easily accessible in the home for servicing and maintenance.
Min.
40 cm
Min. 10 cm

7
3.5 Component check list
Components supplied with the unit in a separate
accessorykitforsitetting:
• Multibloc valve, includes pressure reduc-
ing valve, line strainer, balanced cold water
take o,(for shower or bidet only) check
and expansion valve.
• Tundish
• 3/4’’ x 22mm Elbow / Drain Cock
• Motorized valve
• Expansion vessel.
3.5.1 Components factory tted
• Immersion heater(s)
• Thermostats / thermal cut-out
• Temperature and pressure relief valve.
3.5.2 Documentation supplied
• Installation manual & log book
3.6 Supply requirements
An uninterrupted 22mm cold water mains sup-
ply is recommended, a minimum standing pres-
sure of 2.5 bar and a ow rate of 20 litres per
minute with a 1 bar dynamic pressure is recom-
mended. The cylinder will operate at lower pres-
suresandowrateshowevertheperformance
will be compromised. The OSO unvented unit
is designed for use with supply pressure up to
10 bar. For pressures over 10 bar an additional
pressure reducing valve must be tted in the
supply pipe to the unit.
3.6.1 Expansion vessels
The vessel accommodates expanded water
when the cylinder is heated and prevents the
cylinder reaching its maximum working pres-
sure.
3.6.2 Compatible ttings and components
All thermostatically controlled boilers are com-
patible with indirect OSO cylinders.
3.6.3 Non-compatible products.
Solid fuel boilers, wood burning stoves and oth-
er non-thermostatically controlled heat sources
must not be used with unvented cylinders.

8
3.7 General layout
Ref no. Key Part No.
1Flow 3/4” BSP Solar
2Return 3/4” BSP solar
3Flow 3/4” BSP Solar
4Return 3/4” BSP solar
5Pressure Reducing Valve Multibloc
3/4” (adjustable) includes Item 4 355030
6Expansion relief valve (6 bar) PREL355030
7Temperature and Pressure Relief
Valve 550853
8Tundish 219005
9Immersion Heater 71242
10 Immersion heater control thermo-
stat 80314
11 Digital Dual Thermostat 80345
12 Cold feed tube (not supplied, see
pt. 3.7.2 Cold feed tube)
13 Hot Water Outlet 3/4” BSP
14 Elbow/Drain Cock 250445
15 Discharge Pipe (not supplied)
Ref no. Key Part No.
16 Motorizedvalve(notfactorytted) 92000
17 Expansion vessel AX18, AX24
18 Secondary Return
Vessel
size Length of tube (ø28) mm Expansion vessel pre charge / size
200 980 3 bar / 18 litre
250 1200 3 bar / 24 litre
300 1450 3 bar / 24 litre
3.7.2 Cold feed tube
3.7.1 Reference chart

9
3.8 Pipe installation
The product is designed to be permanently
connected to the mains water supply.
Approved pipes of the correct size should be
used for installation. The relevant standards and
regulations must be followed.
3.8.1 Incoming water pressure
Theeciencyoftheproductdependsonthein-
coming cold water pressure. The water pressure
should be min. 2 bar and max. 6 bar throughout
the day. Excessive water pressure can be adjust-
ed by installing a pressure reduction valve.
3.8.2 Connecting pipes
Pipes of suitable size and quality should be run to
theconnectionsontheproductandxedwitha
suitable sealant.
A safety valve of the approved type (see page 3)
should be tted in the heating circuit (not sup-
plied). The safety valve should not be plugged or
blocked.Anyoverowpipefromthesafetyvalve
must be clear, undamaged and frost-free with a
fall to the drain.
3.9 Positioning the unit
Thewaterheatershouldbettedlevelonahard
surfacewithsucientloadstrengthtotakethe
full weight of the cylinder (see technical data ta-
ble page 12). There are no limitations regarding
thettingdistancefromwallsetc.,butitisstrong-
ly recommended to ensure easy access to all
pipettingsetc.TheTemperatureandPressure
relief valve and immersion heater are positioned
at 90° apart. The DELTA Twin Coil VIP cylinder
must be positioned to ensure that the tundish is
visible and there is easy access to the thermostat
and to remove the immersion heater if required.
3.9.1 Protection from frost
If the water heater is in danger of being exposed
to frost while not operating under electric power,
the unit must be drained to avoid damage. Make
suretheelectricpoweristurnedobeforedrain-
ing, otherwise the heating elements can be dam-
aged and the warranty is void. Draining instruc-
tions, see “Draining ” on page 5.
3.9.2 Cold water supply
1. To obtain the best performance from your
OSO unvented system it is advisable to feed
the unit with an uninterrupted supply.
2. Beforeconnectingtothemultibloc,ushthe
coldsupplypipeworkofalluxanddebris.
3. Locate the water heater in a suitable posi-
tion to facilitate the installation of the cold
water supply, discharge ttings and pipe-
work. Also take into account access to the
immersion heater.
4. Fit the combined male elbow drain cock to
cold supply point (14), so that the compres-
sionttingisvertical.
5. Fit the length of copper tube 22 mm speci-
ed in Table 1 tothe cold feedelbow (see
pt. 4 above).
6. Fit the Multibloc (5) to the top of the copper
tube (see pt. 5 above).
7. Connect 15 mm copper tube from the ex-
pansion relief valve (4) and also from the
T&P valve (5) and join together in a Tee as
shown on page 8.
8. Fit the tundish (8) to the bottom connection
of this tee.
9. Connect the cold supply to the multibloc (5).
10. Fit the expansion vessel to the wall close to
the water heater using the enclosed mount-
ing bracket. Connect the expansion vessel
to the multibloc, as shown on page 8.
3.9.3 Hot water supply
Connect the hot water supply pipe to the outlet
(13). Ensure connection is water tight.
3.9.4 Balanced cold water supply (optional)
If no balanced cold supply is required, tighten
the supplied blanking cap. If a balanced mains
pressure cold water supply is required to a
shower or bidet (over rim type only, ascending
spray type requires type AA,AB or AD air gap),
remove blanking cap and connect to the shower
or bidet cold supply on the multibloc valve (5).
(Major shower manufacturers advise tting a
mini expansion vessel in the balanced cold sup-
ply pipework to accommodate thermal expan-
sion and prevent tightening of shower controls)
Using the balanced cold connection to feed bath
tapscanreducetheowavailabletotheunvent-
ed cylinder.
3.9.5 Secondary return (optional)
Connect secondary return if required to tting
(18) page 8, see technical data table on page ??

10
3.10.1 Fitting instructions
3.9.6 Discharge pipe
!
CAUTION
!
The product should be placed in a room with a drain, in accordance with the wetroom
standard/latestTEK.Alternatively,tanautomaticstopvalvewithsensorandoverow
from safety valve to drain.
!
Theproductshouldbeproperlyalignedverticallyandhorizontally,onaoororwallsuitablefor
the total weight of the product when in operation. See type plate.
!
The product must have a clearance for servicing of 40 cm in front of the cover / 10 cm over the
top connection.
!
WARNING
!
Theproductshouldbelledwithwaterbeforethepowerisswitchedon.
!
Anyoverowpipefromsafetyvalvesmustbeofasuitablesize,clear,undamagedandfrost-
free with a fall to the drain.
Connect the tundish outlet to the discharge pipe.
Install the Tundish in a vertical position within
a maximum of 600 mm from the Temperature
and Pressure Relief Valve drain connection and
away from electrical components. Ensure the
expansion relief pipework discharges through
the tundish. Tundish pipework must be 22 mm
with a minimum vertical length of 300 mm below
tundish. Maximum permitted length of 22 mm
pipework is 9 m. Each bend or elbow is equiva-
lent to 0.8 m of pipework. All pipework must
have continuous fall and discharge in a safe, vis-
ible position. If any doubt, refer to Building Regu-
lation G3. Discharge pipe must be dedicated to
the cylinder and must not be used for any other
purpose.
3.10 Flow and Returns and Motorized valve
The boiler primary ow and return connections
should be made connections 3 & 4. The motor-
ized valve can be connected to either the primary
oworreturnpipe.Theprimaryowandreturnt-
tings are 3/4’’ BSP female. The valve has 22mm x
copperconnections.Thedirectionofprimaryow
in the upper coil is bottom to top. The maximum
operatingtemperatureoftheprimaryowwould
typically be 82°C.
For electrical connection of the motorized valve
and immersion heater, please read Electrical
Installation Instructions. (Page ??).
TheSolarowandreturnconnectionsshouldbe
made to the lower connections 1 & 2. Tempera-
ture control from the Solar circuit is achieved us-
ing a dierential solar controller. This controller
must be wired in series through the thermal cut-
out on the OSO thermostat. If Solar Collectors
are to be installed at a later date then connect the
boiler primaries to the lower coil. If boiler prima-
ries are connected to lower coil then the thermo-
stat must be removed , and the grey wire uncoiled
from inside thermostat. The thermostat must then
be replaced inserting both wires into sensor pock-
et, resetting temperature to 60°C. The direction of
solarprimaryowinthesolarcoilistoptobottom.
The solar circuit must be installed with a solar hy-
draulic station which must incorporate a pump and
non-return valves in both ow and return within
the solar circuit. This system will prevent thermal
siphoning when the pump is not active
.
Temperature sensors for the cylinder provided
withthedierentialcontrollershouldbeinserted
into the pockets provided.
There is no maximum primary temperature from the
solar system and primary temperatures in excess
of 100°C are not unusual. All components on the
solar circuit must be suitable for these higher
temperatures. Should the solar circuit be installed
incorrectly, then all approvals and guarantees of the
cylinder are invalid.

11
RECOMMENDATION
-Allowclearancetotheoor.Screwthefeetoutaminimumof15mmfromthebottomoftheprod-
uct.
-Mains cable for wall socket (1) should be hidden under one of the channels in the bottom of the
product.
-Ifthenon-returnvalveistight,areductionvalveandexpansionvesselshouldbetted(to
stop dripping from the safety valve).
-If the maximum water pressure exceeds 6 bar in a 24-hour period, a reduction valve and expansion
vesselshouldbetted.
-
For installation in a rooms which does not conform to the wetroom standard, a watertight
driptraywithoverowpipe> 18mm.insidediametershouldbettedundertheproduct,in
addition to an automatic stop cock with sensor. This will prevent possible material damage.
3.10.2 Fitting recommendation
1
3.11 Commissioning
1. Check all connections for tightness.
2. Open hot water tap furthest away from the
OSO water heater. Open the mains stop
cock to ll the water heater. When water
owsevenlyfromtap,allowtorunforafew
minutes to ush through any dirt, swarf or
residue, then close the tap. Open succes-
sive hot taps to purge any remaining air.
3. Check all water connections for leaks and
rectify if necessary
4. Manually operate Expansion relief valve
6 (see  page 8) to ensure free water ow
through discharge pipe by turning knob
counter-clockwise. To close continue to turn
counter-clockwise until the valve shuts.
5. Manually operate Temperature and Pres-
sure Relief Valve 7 (see page 8) to ensure
free water ow through discharge pipe
(Turn knob counter-clockwise).
6. Switch electrical power on.
3.12Draining
Switch o the electrical power (Important to
avoid damage to element).
IsolateboilerfromOSOunit.Turnothecoldwa-
ter supply valve. Open hot water tap. Open drain
14 (see page 8) at base of cylinder.The unit will
drain.
Draining process may be speeded up by open-
ing the temperature and pressure relief valve. An
internal ø18 mm hose can be applied to lead the
water to a gully, sink or similar.
3.13Systemushing
This will not be necessary under nor-
mal circumstances as the line strainer will
prevent ingress of foreign materials, however
if ushing is required, run at least 50 litres of
water from the cylinder at the highest possible
ow rate. Close the taps and follow draining
procedure (above).

12
3.14PipingDiagrams
3.14.1 S-plan piping diagram
3.14.2 Y-plan piping diagram
Pump
flow
2-port valve
(supplied)
Automatic
bypass
Radiators/
UFH
Heat
source
Pump
flow
2-port valve
(supplied)
Mid pos. valve
(not supplied)
Radiators/
UFH
Boiler
Automatic
bypass

13
4.2.2 Torque settings
!
WARNING
Constant voltage present at terminals L and N.
Before any electrical work is done, the power
supply must be disconnected and secured
against activation while the work is in progress.
Component Torque
5/4” heating element 60 Nm (+/- 5)
Thermostat screws (A and B) 2 Nm (+/- 0.1)
Earth screw on the element head 2 Nm (+/- 0.1)
A) Blue wire (R) – Neutral – connected to point
‘A’ on the thermostat.
B) Brown wire (S) – Live – connected to point ‘B’
on the thermostat.
C) Yellow wire with green stripe – Earth –
connected to the terminal for the heating
element (hexagonal brass)
4. ELECTRICAL INSTALLATION
4.1 Electrical components
Component Note
Work thermostat 5-70°C adjustable
Heating element 1-phase 230 V
All wiring must conform to current IEE regulations
Anyxedelectricttingsmustbeinstalledbyan
authorised electrician. The relevant standards and
regulations must be followed.
4.2 Electrical connections in the junction box
4.2.1 Wiring diagram
N L
!
WARNING
The thermostat must never be dismantled/
opened. This will compromize its function
and cause risk of overheating. Warranty will
cease.
IP21

14
4.3 Immersion heater thermostat
The immersion heater is designed as an auxiliary
heater as an emergency back-up. Power to immer-
sion heaters should not be switched on until the
unitislledwithwater.
Allunitsarettedwithone3kWimmersionheater
which is located behind the electrical box. Alter-
native thermostats should not be used, regula-
tions require immersion heaters on unvented
cylinders to be connected with a thermal cut-out.
Follow the wiring instructions shown connecting
the live, neutral and earth as indicated. The unit
must be permanently connected to the electrical
supply through a double-pole linked switch with a
minimum break capacity of 13 amps.
Each immersion heater has a working thermostat
adjustable between 18°C - 70°C (+/- 5°C). A safety
cut-out is also incorporated within the thermostat
and will operate at 87°C (± 7°C). Should this hap-
pen, check reasons for thermal cut-out button be-
ing released and when satised press the reset
button.
The immersion wiring should be run through a
channel from base of cylinder to the immersion
housing . The cable should be secured using the
supplied clamps in the bottom opening of the
channel.
4.4 Indirect heating system
4.4.1 Motorized valve
To comply with regulations governing the instal-
lation of indirect unvented cylinders, a motorized
valvemustbettedintheprimarypipework.Your
OSO unit has been supplied with a two port mo-
torized valve, which will act as a positive energy
cut-out should the safety cut-out operate. The
motorized valve will also control the temperature
of the domestic stored water via the cylinder ther-
mostat, which is located in the electrical box. The
unit can be installed on an “S” or “Y” plan system.
Please follow the wiring instructions carefully.
4.4.2 Digital Dual Cylinder Thermostat
The Digital Dual Thermostat has real safety and
energy saving benets and provides accurate
temperature control. It also features a clear and
informative LCD display. Leave the cylinder ther-
mostat set at 60°C in line with current govern-
ment guidelines. Lowering the temperature will
substantially reduce the amount of usable hot
water available on a daily basis and could result
in bacterial growth unless the legionella facility
is activated. THIS FUNCTION IS DEACTIVATED
AS STANDARD. To activate turn the unit OFF
and back ON again by holding down the black
Holiday button until the display is blank (OFF),
and again until the display is on to turn ON.).
The legionella mode gives a weekly automatic
one hour “boost” to above 60°C which kills any
legionella bacteria, This function is adjustable al-
lowing the duration of the legionella override to be
adjusted from 1 to 7 days or completely disabled
to operate as a conventional Dual Cylinder Ther-
mostat.
The LCD display shows the current water tem-
peratureandtheuserdenedwatertemperature,
while the red LED indicates that the unit is calling
for heat. The sensitive electronic sensors operate
at a far greater accuracy than conventional ther-
mostats. The dial makes it easy to set the required
controller temperature (between 25°C and 65°C)
.The second (limit) safety thermostat is pre-set
to 80°C with a concealed manual reset, to com-
ply with building regulations. Should the safety
cut out be brought into operation, the motorized
valvewilloperateandclosedowntheprimaryow
to the cylinder. To reset the safety cut-out and
the motorized valve the reset button must be
pressed in.
Also see S-Plan and Y Plan Wiring page 15-16.
This product requires a fused permanent Live
and Neutral supply.

15
Thethermostathasuserdenedsettingswhere
the duration of the legionella Override/Boost can
be adjusted from 1 to 7 days or completely disa-
bled to operate as a conventional dual cylinder
thermostat.
1. To disable/adjust the legionella boost turn
the unit o by pressing and holding down
the HOLIDAY button until an audible click is
heardandtheredLEDturnsoandthedigi-
tal display goes blank.
2. Release the button and after approx. 10 sec-
onds press and hold the HOLIDAY button
again. After 5 seconds an audible click is
heard, the red LED will light up and the digi-
tal display will come back on, keep the HOLI-
DAY button pressed for a further 5 seconds
untilthedigitaldisplayashes.
3. Release the button and use the HOLIDAY
button to choose between disabling the
override/Boost (OF in display) or setting de-
lay between boost/override from 1 - 7 days
(1-7 in display)
4. Once selected release the button and the
unit will return to the user set position within
5 seconds
4.6 Holiday mode
Holiday mode is set using the black button locat-
ed under the display. Press and hold the holiday
switch (1) for a minimum of 10 seconds until you
hear an audible click, and this switches the digital
DualCylinderThermostatocompletelysothere
is no water heating and no weekly “boost” heat-
ing.WheninHolidaymode,thedisplayiso.This
feature should only be used when the property
is vacant for extended periods and there is no
requirement for water heating or for the weekly
“boost”.
Pressing and holding the holiday switch (1)
again for a minimum of 10 seconds until you
5
4
3
2
1
49°
1
20
30
405060 70
80
90
100
11010
1200
°C
5
4
3
2
1
49°
5
4
3
2
1
49°
hear an audible click will restart the Electron-
ic Dual Cylinder Thermostat, the display will
show the cylinder temperature and the weekly
“boost “ will immediately start, and recur every 7 days
at the same time depending on the user set position.
4.7 Lower (solar) coil
Heat sources to unvented hot water cylinders
must be controlled by a thermal cut-out as well as
a thermostat. The OSO Solarcyl is supplied with
solar sensor pockets . The solar controller (not
supplied) and solar sensor point should be wired
through the OSO thermal cut-out.
4.8 Solar control
ADierentialSolarControllerisrequiredtoachieve
Solar thermal control and Solar water heating.
Pleasenotethatthedirectionofowinthesolar
coil is reversed compared to the boiler coil. If the
cylinder is not being used for solar use, connect
theboilertothelowercoilwiththeprimaryowin
a bottom to top direction.
If using a 6-wire 28mm or 1” BSP V4043H on ei-
ther circuit the white wire is not needed and must
be made electrically safe.
4.8.1 Solar controller pipe tting and wiring
4.5 Adjusting the 1 hour boost
1
1
2
2
3
1
23
L N E
N L C NC NO
L
N
E
Solar
controller
wiring
Solar
th.stat
Dierential
solar controller

16
!
WARNING
OSO Hotwater (UK) Limited can not be held responsible
if alternative wiring plans are used.
Important: Before resetting the safety cut-out or altering
the thermostat setting isolate electrical supply to the
unit before removal of the lid. Ensure the lid to the elec-
trical box is replaced before power is switched back on.
4.9S-planwiring
OSODELTATwinCoilVIPcylinderscanbettedwith
all types of boilers. Standard boilers operate using
room and cylinder thermostats. Please follow upper
diagram: ‘Wiring for Standard Boiler’.
4.9.1 Thermistor controlled boilers
Many popular boilers now use a thermistor principle.
A thermistor temperature sensor is supplied with the
boiler to attach to the cylinder. Temperature infor-
mation is relayed back to the boiler control system.
A Pocket is provided (see below to secure the sensor
on the DELTA Twin Coil VIP cylinder. The probe is run
through a channel from base of cylinder to the immer-
sion housing and housed there in a pocket. The ther-
mistor cable should be secured using the supplied
clamps in the bottom opening of the channel. The
supplied motorisedvalvemust beusedin accordance
with Building Regulation G3. This is wired from the
supplied cylinder thermostat, wired as high limit stat.
Please follow lower diagram: ‘Wiring for Thermistor
Controlled Boiler’.
1 2
E
231
T6360B
B1BrG O
G/Y
3 5 7
34NL
C NONC LN
ENL ENL
ST6400
Boiler Pump
321 32 32
2 2 31
V4043H
Zone Valve (DHW)
(supplied)
OSO cylinder thermostat
(supplied)
Isolated Mains
Supply From
Fused Spur
L N E
Zone Valve (Htg)
(not supplied)
Room
thermostat
6
B1BrG O
G/Y
2
2
31
1
V4043H
4 8 109
HTG
ON
HW
ON
1 2
E
231
T6360B
B1BrG O
G/Y
3 5 7
34NL
C NONC LN
ENL ENL
ST6400
Boiler Pump
321 32 32
2 2 31
V4043H
Zone Valve (DHW)
(supplied)
OSO cylinder thermostat
(supplied) - Wired as
high limit thermostat
Isolated Mains
Supply From
Fused Spur
L N E
Zone Valve (Htg)
(not supplied)
Room
thermostat
6
B1BrG O
G/Y
22
31 1
V4043H
4 8 109
HTG
ON
HW
ON
Thermistor wire
Connected to
boiler control
system
Thermistor
Wiring diagram
for Standard
Boiler
Wiring diagram
for Thermistor
controlled Boiler
Please contact
boiler manufact-
urer for boiler
specicwiring.

17
!
WARNING
OSO Hotwater (UK) Limited can not be held responsible
if alternative wiring plans are used.
Important: Before resetting the safety cut-out or altering
the thermostat setting isolate electrical supply to the
unit before removal of the lid. Ensure the lid to the elec-
trical box is replaced before power is switched back on.
4.10Y-planwiring
OSODELTATwinCoilVIPcylinderscanbettedwith
all types of boilers. Standard boilers operate using
room and cylinder thermostats. Please follow upper
diagram: ‘Wiring for Standard Boiler’.
4.10.1 Thermistor controlled boilers
Many popular boilers now use a thermistor principle.
A thermistor temperature sensor is supplied with the
boiler to attach to the cylinder. Temperature infor-
mation is relayed back to the boiler control system.
A Pocket is provided (see below to secure the sen-
sor on the DELTA Twin Coil VIP cylinder. The probe
is run through a channel from base of cylinder
to the immersion housing and housed there in a
pocket. The thermistor cable should be secured us-
ing the supplied clamps in the bottom opening of
the channel. The supplied motorised valve must be
used in accordance with Building Regulation G3.
This is wired from the supplied cylinder thermostat,
wired as high limit stat Please follow lower diagram:
‘Wiring for Thermistor Controlled Boiler’.
1 2
E
231
T6360B
B1OG Br
G/Y
3
3 14NL ENL ENLST6400
Boiler Pump
321 32 32
2 2 31
V4043H
Room
thermostat
Zone Valve (DHW)
(supplied)
Isolated Mains
Supply From
Fused Spur
L N E
Mid Position Valve
(not supplied)
6
WB1 G/Y Gr O
23
V4073A1039
104 5 987
C NONC LN
OSO cylinder thermostat
(supplied)
HTG
ON
HW
ON
HW
OFF
1 2
E
231
T6360B
B1OG Br
G/Y
3
3 14NL ENL ENLST6400
Boiler Pump
321 32 32
2 2 31
V4043H
Room
thermostat
Zone Valve (DHW)
(supplied)
Isolated Mains
Supply From
Fused Spur
L N E
Mid Position Valve
(not supplied)
6
WB1 G/Y Gr O
23
V4073A1039
104 5 987
C NONC LN
OSO cylinder thermostat
(supplied)
HTG
ON
HW
ON
HW
OFF
Thermistor wire
Connected to
boiler control
system
Thermistor
Wiring diagram
for
Standard Boiler
Wiring diagram
for Thermistor
controlled Boiler
Please contact
boiler manufact-
urer for boiler
specicwiring.

18
4.12Handovertoend-user
THE INSTALLER MUST:
Brief the end-user on safety and maintenance
instructions.
Brief the end-user on settings and emptying the
product.
Hand this installation manual over to the end-
user.
Enter contact details on the type plate on the
product.
RECOMMENDATION
-Mains cable (1) for wall socket/wall box should be hidden under one of the channels in the bottom
of the product, as shown.
-Forproductswith≤2kWcapacity,a> 10A fuse / > 1.5# wire should be used*.
Forproductswith≤3kWcapacity,a> 15A fuse / > 2.5# wire should be used (230V).
4.11.1 Fitting instructions
4.11.2 Fitting recommendation
!
WARNING
!
Theproductshouldbelledwithwaterbeforethepowerisswitchedon.
!
Fixedelectricttingsshouldbeusedforinstallationinnewhomesorwhenchanginganexist-
ing electrical setup in accordance with regulations.
!
Themainscableshouldwithstand90°C.Astrainrelievermustbetted(supplied).
!
CAUTION
!
The product must have a clearance for servicing of 40 cm in front of the cover / 10 cm
over the top connection.
!
If the mains cable is damaged, it must be replaced with cable of a quality that meets the
requirementsoftheinstallation.Thecablemustbereplacedbyaqualiedelectrician.
1
4.11 Cylinder thermostat as high limit th.stat only
Coil the grey temperature probe wire (1) inside
the thermostat box and insert black probe (2)
into thermostat pocket of cylinder (3). Turn dial
(4) on the front of thermostat to position 5.
Cables are run through cable channel from cyl-
inder base (5).
P
a
t
e
n
t
e
d
T
1
1
5
1
6
A
2
5
0
V
A
B
Safety
1
5
2
3
4
Type: TSR
COTHERM
1
4
2
5
3

19
!
WARNING
Constant voltage present in the junction box. Be-
fore any electrical work is done, the power sup-
ply must be disconnected and secured against
activation while the work is in progress.
5.1 Settings
5.1.1 Thermostat setting
The thermostat on the product is adjustable from
5-70°C. The thermostat should not be set lower
than 65°C to prevent bacteria growth. To adjust
the temperature:
A) Disconnect the power supply.
B) Remove the electric junction box cover (1) with
a screwdriver.
C) Adjust the temperature on the thermostat ad-
justment dial (3).
D) The thermostat is adjustable from 5-70°C. Turn-
ing the dial (3) all the way to + gives the high-
est temperature (70°C). The temperature can
be reduced as desired by turning the dial (3)
towards (-).
Fit the junction box cover (1) before connecting
the power supply.
5.1.2 Resetting the safety thermostat
The safety thermostat on the product cuts out
when there is a risk of overheating. This is reset
by removing the cover (1) and pressing the ‘Safety’
button (4). If the thermostat cuts out repeatedly,
contact the installer.
5.1.4 Adjusting the feet
The product is equipped with three factory-
ttedfeet(2),adjustablefrom0-40mm.Screw
the feet out a minimum of 15 mm from the bot-
tom of the product. Adjust the feet individually
untiltheproductisstandingrmandstraight
vertically and horizontally.
5.USERGUIDE
R S
-
+
P
a
t
e
n
t
e
d
T
1
1
5
1
6
A
2
5
0
V
A
B
Safety
Type: TSR
COTHERM
-
+
P
a
t
e
n
t
e
d
T
1
1
5
1
6
A
2
5
0
V
A
B
Safety
Type: TSR
COTHERM
L N
3
4
20
30
405060 70
80
90
100
11010
1200
°C
1
2
!
WARNING
The thermostat must never be dismantled/
opened. This will compromize its function
and cause risk of overheating. Warranty will
cease.

20
Maintenance must be carried out by a competent
person.
6.1SafetyCut-out
The safety cut-out operates if:
1. Wiring is incorrect.
2. The immersion heater thermostat or cylinder
thermostat fails.
3. Thermostat is set too high.
4. Remember before resetting the safety cut-
out or altering the thermostat setting, isolate
electrical supply to the unit prior to removal of
the electrical box lid.
5. Reduce thermostat setting and press the re-
set button. After adjustments are completed,
ensure the lid to the electrical box is replaced.
6. If still out of operation, contact installer.
6.2 Intermittent or slow discharge from tundish
1. Turn o the electrical supply to the immer-
sion heaters.
2. Turnocoldwatersupplyvalve.
3. Open a hot tap.
4. Turn the knob on the Temperature and Pres-
sure Relief Valve (5) to the left and hold in this
position for thirty seconds.
5. Attach a foot pump with a schraeder (car
type) valve to the expansion vessel.
6. Pump up to 3 bar
7. Open cold water supply valve.
8. When water ows through open tap, close
tap
9. Turn on electrical supply to the immersion
heaters.
6.3 Continuous very hot water discharge from
tundish
This indicates a malfunction of a thermal cut-out,
operating thermostat or the combined tempera-
tureandpressurereliefvalve.Turnotheelectri-
cal supply to the immersion heater and also isolate
an indirect unit from the boiler. Contact the install-
er or competent engineer.
6.4 Expansion vessel maintenance
The expansion vessels do not require annual
maintenance and should not be tampered with
unless an intermittent or slow discharge from the
tundish occurs when water is being heated. In
this situation, maintenance must be carried out
by competent person and the precharge pressure
6.SAFETYANDSERVICING
must be restored to the original value. An annual
visual inspection is recommended. Important: To
check the precharge the expansion vessel must
be completely empty of water. If the precharge
pressure is dierent from the value shown on
the label it must be restored to the original value.
Do not remove expansion vessel without depres-
surising the cylinder and draining 10 litres of water
from the drain valve at the base of the cylinder.
6.5 Guarantee
Cylinder should be serviced annually and the
log book should be updated in order to validate
guarantee. The log book and service records act
as guarantee document. For terms of guarantee
please see the log book on page ??
6.6 Servicing Procedure:
7.6.1 Expansion relief valve
Ensure that expansion relief valve works by manu-
ally opening to discharge water to tundish.
6.6.2 Pressure reducing valve
Isolate the cold water supply and open a ground
oor cold tap. Unscrew the pressure reducing
cartridge.Cleantheltermeshandthecartridge
under running water. Replace cartridge ensuring
that strainer is correctly located and reassemble
the unit.
6.6.3 Expansion relief cartridge
Isolate the cold supply and open a ground oor
cold tap. unscrew blue expansion relief headwork
from valve body. Clean valve seat face and seating
- do not scratch or damage either seat face or seat-
ing.Retinreverseorder.Donotovertighten.
6.6.4 Temperature and Pressure relief valve
Ensure that Temperature & Pressure Relief valve
works by manually opening to discharge water to
tundish.
6.6.5 Internal inspection
The immersion heater can be removed to provide
visual inspection access to the cylinder.