OSO HOTWATER Maxi Standard MS 300 User manual

Maxi Standard - MS
300-400 l.
EN
SAFETY INFORMATION
O&M INFORMATION
INSTALLATION MANUAL
TDS - TECHNICAL DATA SHEET
11002341-146189-05 - 06-2023
Manufactured by OSO Hotwater AS
Industriveien 1 - 3300 Hokksund - Norway
Tel: [phone] / E-mail: [email protected]
www.osohotwater.com

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 identification...................................... 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 Installation of center support foot............ 8
3.6 Pipe installation................................................... 8
3.7 Electrical installation....................................... 10
4. Initial commissioning ............................................. 12
4.1 Filling with water .............................................. 12
4.2 Turning on the power ................................... 12
4.3 Control points.................................................... 12
4.4 Emptying of water........................................... 12
4.5 Handover to end-user................................... 12
5. User Guide..................................................................... 13
5.1 Settings.................................................................. 13
5.2 Annual inspection............................................ 13
5.3 Maintenance....................................................... 13
6. Troubleshooting ....................................................... 14
6.1 Faults and fixes.................................................. 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

3
1. SAFETY INSTRUCTIONS
1.1 General information
• Read the following safety instructions
carefully before installing, maintaining or
adjusting the hot water cylinder
• 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
documents where they are accessible for
future reference.
• The manufacturer assumes compliance
(by the end-user) with the safety, oper-
ating and maintenance instructions sup-
plied and (by the installer) with the fitting
manual and relevant standards and regu-
lations in effect 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
This document should be kept in a suitable place where it is accessible for future reference.

4
1.3 Safety instructions for installers
WARNING
If a PT safety valve is fitted (included), the valve overflow shall NOT be sealed or plugged.
Any overflow pipe from the safety valve shall be in a suitable dimension and must be
uninterruptable, undamaged and frost-free with a fall to a suitable drain or gulley.
The relevant regulations and standards, and this installation manual, must be followed.
1.2 Safety instructions for users
WARNING
If a safety valve is fitted, the valve overflow shall NOT be sealed or plugged.
The product shall NOT be modified or changed from its original state.
Children shall NOT play with the product or go near it without supervision.
Maintenance/settings shall only be carried out by persons over 18 years of age, with sufficient
understanding
CAUTION
The product shall not be exposed to frost, over-pressure, over-voltage or chlorine treatment.
See warranty provisions.
Maintenance/settings shall not be carried out by persons of diminished physical or mental
capacity, unless they have been instructed in the correct use by someone responsible for their
safety.
CAUTION
The product shall be placed in a room with a drain, in accordance with current local rules
and regulations. Alternatively, fit an automatic stop valve with sensor and overflow from
safety valve to drain.
Liability for consequential damage will only apply if this is followed.
The product shall be properly aligned vertically and horizontally, on a floor 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 junction boxes / 10 cm
over the top connection.

5
2.4 Technical data
NRF no. Product code: IP class-
ification
Capacity,
persons Weight, kg. Packaging dimensions
LxWxH mm.
Freight
vol. m³ Heating time, hours Dt 65°C Actual vol. l.
800 2551 MS 300 - 15 kW (2x7,5) / 3x230V IP44 -57 595x595x1765 0,62 -280
800 2552 MS 400 - 15 kW (2x7,5) / 3x230V IP44 -77 595x595x2225 0,79 -372
2.5 ErP data - Technical Data Sheet
Brand Model-no. Model name ErP
profile
ErP
rating AEC - kWh/a Thermostat setting °C
Volume
40°C
water
Heat
loss W
OSO Hotwater AS 11009861 MS 300 - C - 75 - 83
OSO Hotwater AS 11008985 MS 400 - C - 75 - 90
Regulation: 2017/1369/EU - Regulation: EU 812/2013 Directive: 2009/125/EC - Regulation: EU 814/2013
Heat loss tested acc. to standard: EN 12897: 2015
2. PRODUCT DESCRIPTION
2.1 Product identification
Identification details for your product can be found
on the type plate fixed 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 certified for
• Quality ISO 9001
• Environment ISO 14001
• Work environment ISO 45001
2.2 Intended use
Maxi is designed for use as a buffer for tap water
and is fitted with electrical peak load elements.
2.3 UKCA marking
The UKCA 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
The safety valve(s) used must be CE marked and
conform to PED 2014/68/EU.

6
3.3 Product dimensions
Product. A B C (HW) D
(CW) ø
MS 300 0-40 1685 1366 286 595
MS 400 0-40 2175 1856 286 595
Tolerance +/- 5 mm. (not dimension A).
3. INSTALLATION INSTRUCTIONS
3.1 Products covered by these instructions
800 2551 Maxi Standard - MS 300
800 2552 Maxi Standard - MS 400
3.2 Included in delivery
Ref no. Pcs. Description
1 1 Hot water cylinder
2 1 PT valve 10 bar/99°C (supplied)
3 1 Installation manual (this document)
4 1 Center support foot with base (supplied)
5 2 Junction box with element / thermostat
6 3 Adjustable feet, factory fitted
All dimensions in mm.
3
4
2
1
5
6
D
B C
ø
A

7
3.3.1 Delivery
The product should be transported carefully as
shown, with packaging. Use the handles in the
box.
CAUTION
Pipe stubs, valves etc. shall not be used to lift the
product as this could cause malfunctions.
3.4 Requirements for installation location and
positioning
CAUTION
The product shall be placed in a room with a drain, in accordance with current local laws
and regulations. Alternatively, fit an automatic stop valve with sensor and overflow from
safety valve to drain.
The product shall be placed in a dry and permanently frost-free position.
The product shall be placed on a level floor 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 junction boxes / 10 cm
over the top connection.
The product shall be easily accessible for servicing and maintenance.
Min. 10 cm
Min. 40 cm
Min.
40 cm

8
No. Dimension Connection description
1 G 3/4” F Ventilation / hot water (plugged)
2 G 1 ½” F Hot water out
3 G 3/4” F PT valve
4 G 3/4” F Hot water circulation / thermometer
5 G 3/4” F Anode
6 G 1 ½” F Cold water in
7
G 3/4” F Draining/safety valve
3.6.1 Incoming water pressure
The efficiency 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 adjusted
by installing a pressure reduction valve.
2
3
4
5
7
6
1
A. Unpack the heater and lay it on its side. Use
the packaging cardboard as a substrate,
take care so that the product does not suffer
cosmetic damage.
B. Two adhesive pads are included with the
center support foot. Remove the protective
paper on one side and fit the adhesive pads
as shown (1).
C. Remove the second protective paper of the
adhesive pads and fit the center support (2)
with the foot (3) in the center hole in the bot-
tom of the product (see illustration). Press the
support firmly into place.
D. Unscrew the support foot (3) to the desired
height. Raise the boiler so that it stands on
the foot of the central support and place the
boiler in the desired position in the room.
E. Adjust the three outer feet (4) until the prod-
uct is plumb and level. Middle support foot
MUST be in full contact with the floor after
the adjustment.
F. Install pipes to the product and fill up with
water according to the pipe installation
instructions in this manual.
3.6 Pipe installation
The product is designed to be permanently con-
nected to the mains water supply. Approved pipes
of the correct size should be used for installation.
The relevant standards and regulations must be
followed.
1
4
44
2
3
3
3.5 Installation of center support foot

9
RECOMMENDATION
-If the maximum water pressure exceeds 6 bar in a 24-hour period, a reduction valve and expansion
vessel shall be fitted.
3.6.4 Fitting instructions
3.6.5 Fitting recommendation
CAUTION
The product shall be placed in a room with a drain, in accordance with current local laws
and regulations. Alternatively, fit an automatic stop valve with sensor and overflow from
safety valve to drain.
The product shall be properly aligned vertically and horizontally, on a floor 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 junction boxes / 10 cm
over the top connection.
9
9
8
CAUTION
Any discharge pipe shall be suited for the supplied
safety equipment and must withstand up to 90°C.
3.6.2 Fitting pipes
A) Run a pipe of suitable size to the connections
shown, and affix with suitable sealant. Unused
connections must be plugged securely.
B) The product can connected in series for in-
creased capacity in the system. Use OSO pre-
fabricated SRS manifolds, see illustration.
3.6.3 Fitting of discharge pipe
An discharge pipe (9) in a suitable dimension is
run to the safety valve;
• Connects to the discharge (8) on the safety
valve (3/4”inside thread).
• Must be fitted uninterruptable, undamaged
and frost-free with a fall to a suitable drain.

10
RECOMMENDATION
-
An authorized electrician should calculate the correct supply cable and fuse according to the applica-
ble standards and regulations. Make sure all wires are undamaged and are not pinched..
3.7.5 Fitting instructions
3.7.6 Fitting recommendation
WARNING
The product should be filled with water before the power is switched on.
Fixed electrical fittings must be used for installation according to the regulations. Any electric
fittings must be installed by an authorised electrician. Components for disconnection must be
integrated in the electric connection in accordance with current standards and regulations.
The mains cable should withstand 90°C continously. A suitable strain reliever must be fitted.
CAUTION
The product must have a clearance for servicing of 40 cm in front of the electric junction box
cover/10 cm over the highest point.
In case of damage to the power supply cable, this should be replaced with new cable with
the correct specifications for the installation. All electrcal work should be performed by an
authorised electrician.
WARNING
Constant voltage present at the terminals. Be-
fore any electrical work is done, the power sup-
ply must be disconnected and secured against
activation while the work is in progress.
A) Supply cable connected to terminal (1) as
shown. Supply wires should be secured
with suitable strain relievers.
B) Internal wires from connection piece (1) to
thermostats and the wires from thermo-
stats to elements are pre-connected from
the factory.
C) Make sure that the earth wire (yellow wire
with green stripe) is connected to the
Fixed electrical fittings must be used for instal-
lation. Any electric fittings must be installed by
an authorised electrician. The relevant standards
and regulations must be followed.
3.7.1 Electrical components
Component Note
Safety thermostat 85°C thermal cut-out
Work thermostat 50-75°C adjustable
Heating element 3-phase 230 V
Internal wires Heat-resistant
3.7.2 Electrical connections in the junction box
3.7.3 Torque settings
Component Torque
G1.1/4” heating element 60 Nm (+/- 5)
Thermostat screws 2 Nm (+/- 0,1)
Screw on the element head 2 Nm (+/- 0,1)
Screws on terminal (1) 2,5-16 mm²: 3 Nm
25-35 mm²: 6 Nm
3.7.4 Reduced electric power output 2.5 - 5 kW
The electric output from each 7.5 kW el. junction
box can be reduced by removing jumpers from the
element, see illustration. The product is equipped
with two identical junction boxes which both can
be altered individually. All electrical installation
shall be performed by approved installer.
3.7 Electrical installation
earthing point
Cover of junction box should be correctly
mounted before the power is switched on. The
power must not be switched on until the prod-
uct has been filled with water.
Reduction of electric power output
The power output can be reduced in each
electric junction box to 2.5 or 5 kW if desired.
See pt. 3.7.4. All electrical installation shall be
performed by approved installer.

11
Electrical connection diagram 2 factory
supplied
9 kW - 3x230V - Factory standard layout.
For UK single phase and Uk 3 phase 400v see
illustration 2.
1
Electrical connection, diagram 2 - UK wiring
9 kW - 3x400V - NB: Neutral wire is NOT pos-
sible.
1
R
E
S
E
T
R
E
S
E
T
M2
1
2
3
4
THERM-O-DISC
1
2
R
E
S
E
T
R
E
S
E
T
M2
1
2
3
4
THERM-O-DISC
1
2
N
L
L
N
1
R
E
S
E
T
R
E
S
E
T
M2
1
2
3
4
THERM-O-DISC
1
2
R
E
S
E
T
R
E
S
E
T
M2
1
2
3
4
THERM-O-DISC
1
2
NN
L
N
L
1
2.5 kW 2x230V effect:
Wire from the right thermostat to the element is
removed. The jumpers on the element are removed
as shown Wiring should be connected from single
phase supply. Supplied via a 20 amp double pole
5 kW 2x230V effect:
Wire from the right thermostat to the element is
removed. The jumpers on the element is arranged
as shown. Wiring should be connected from single
phase supply. Supplied via a 25 amp double pole
12

12
4.1 Filling with water
First check that all pipes are connected correctly.
Then fill the tank according to the needs/
requirements of the system. Make sure that the
tank is vented during filling to prevent air pockets.
4.2 Turning on the power
When the cylinder has been filled with water, the
power can be switched on.
A) Switch on breaker/fuse.
4.3 Control points
A) Check that all pipe connections to/from the
product are tight and not leaking.
B) Check that the power supply to the product is
not at risk of exposure to mechanical, thermal or
chemical damage.
C) Check that any overflow pipe from the safety
valve is clear, undamaged and frost-free with a
fall to a suitable drain or gulley.
D) Check that the product is standing firmly
vertically and horizontally.
4.5 Handover to end-user
4. INITIAL COMMISSIONING
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.
WARNING
The water temperature in the product is 75°C and
could cause scalding. Before emptying, a hot tap
shall be opened to the max. pressure/tempera-
ture for min. 3 minutes.
A) Disconnect the power supply.
B) Shut off incoming cold water supply.
C) Open a hot tap to the maximum
– leave open (prevents a vacuum).
D) The product is emptied via the drain pipe (5).
After emptying, close the drain pipe (5). Close
all open taps.
4.4 Emptying of water
5
6
22

13
WARNING
Constant voltage is present in the junction box.
Before any electrical work is done, the power sup-
ply must be disconnected and secured against
activation while the work is in progress.
5.3 Maintenance
5.1 Settings
5.1.1 Thermostat setting
The product’s thermostats are adjustable from 50-
75°C. The thermostat should not be set lower than
60°C to prevent bacteria growth. To adjust the tem-
perature:
A) Disconnect the power supply.
B) Remove the cover (2) with a screwdriver.
C) Adjust the temperature on the thermostats (3) with
a screwdriver.
Fit the cover (2) before connecting the power supply.
5.1.2 Resetting the safety thermostat
The safety thermostats on the product cut out when
there is a risk of overheating. These are reset by switch-
ing off the power supply, removing the cover (2) and
pressing the red ‘RESET’ button (4). If the thermostat
cuts out repeatedly, contact the installer.
5.2 Annual inspection
All components fitted in or to the product must be
inspected annually. Inspection must be performed by
person older than 18 years of age, with appropriate
qualifications. Annual inspection includes:
• Checking all connections for leaks. Tighten or
maintain properly if required..
• Tighten all connections in the electric junction
box:
A) Disconnect power supply and ensure against
activation while work is in progress.
B) Remove junction box cover (2) and tighten all
connections to the correct torque as shown in
table 3.6.3. The junction box cover must be refit-
ted before power is turned back on.
• Inspection of safety valve operation, see pt. 5.3.
• Annual inspection of anode (6):
a)Turn off el. power and water supply.
b) Release water pressure by fully opening a hot
water tap. Leave tap open.
c) Drain unit through drain connection (5).
d) Unscrew anode (6). If it is depleted (7) replace
with new (8). Fasten to set torque, see pt. 5.2.1.
e) Open water supply, wait until water flows
evenly out of open tap. Close tap. Electric power
can now be turned on.
5. USER GUIDE
MAINTENANCE INSTRUCTIONS
Maintenance shall be carried out by persons over 18 years of age, with sufficient understanding.
Annual inspection of safety valve:
-Open valve for 1 min. by turning knob (1) approx. 90 degrees counterclockwise to the open
position.
-Visually check that the water is flowing freely to the drain.
-YES = OK. Close the valve by turning knob (1) further counterclockwise.
-NO = NOT OK. Disconnect power supply / shut off water supply. Contact installer.
1
3
4
78
5.2.1 Torque settings
Component Torque
Anode 30 Nm (+/- 3)

14
6.1 Faults and fixes
If problems arise when the product is in use,
check for possible faults and fixes in the table.
If you are unsure what is wrong, contact the
6. TROUBLESHOOTING
TROUBLESHOOTING
Problem Possible cause of fault Possible solution
There is leakage/
dripping from the safety
valve/there is often
water on the floor by the
cylinder in the morning
Pressure reduction valve, water meter
or blocked non-return valve on the
water intake.
Water pressure into the system is too
high.
Fit AX expansion vessel which absorbs
expansion during heating, and fit pressure
reduction valve for stable water pressure
inside the system. The pressure reduction
valve is adjusted in according to the
pressure in the expansion vessel. Contact
auth. installer.
The safety valve is worn or there
are particles stuck between the
membrane and the valve seat because
the water is dirty
Try to flush with water through the safety
valve. Open valve for approx. 1 minute. See
section 5.2. If the valve still leaks, it must be
replaced. Contact auth. installer.
Leak from heating element.
Verify as follows: a) cut the electric supply,
b) unscrew the cover, c) visually check
whether there is a leak from the heating
element. If so, replace the gasket/heating
element. Contact auth. installer.
No hot water
Power supply interrupted. Verify that the fuse is on / the plug is plugged in to the wall contact / the earth
breaker has not tripped.
Thermostat has cut out. Press the ‘RESET’ button on the safety
thermostat; see ‘User guide’.
Heating element is defective. Replace heating element. Contact auth.
installer.
Leak in hot water pipe
Verify as follows: a) close the water
supply, b) wait 2-3 hours, c) feel the tank
to see whether it is hot. If so, there is a
leak in the hot water pipe or elsewhere.
Contact auth. installer.
Not enough hot water High consumption in the system. Switch to a larger OSO water heater.
Contact auth. installer.
Not high enough
temperature
The thermostat is set for low
temperatures. Check the thermostat settings. Turn up to 75°C; see ‘User guide’.
Change from cold to hot water in
taps. Contact auth. installer.
Fuse/earth breaker trips
repeatedly
Possible fault in the heater’s
electrical system.
Verify as follows: a) cut the electric supply,
b) unscrew the cover, c) visually check
the junction box for any problems. If so,
contact auth. installer to check. Fit the
cover.
Long time before the
water reaches the tap
Long stretch of pipe from water
heater to tap.
Fit circulation wire or heating cable to
HW pipe. Or fit an auxiliary heater by
the tap. Contact auth. installer.
Knocking in the pipes
when the hot tap is
closed
Large pressure increase when the
tap is closed quickly.
Completely normal. Fit AX expansion
vessel if troublesome. Contact auth.
installer.
installer (see data plate on product) or OSO
Hotwater AS - see section 7.1.

15

OSO Hotwater AS
Industriveien 1
3300 Hokksund - Norway
Tel: + 47 32 25 00 00
[email protected]
www.osohotwater.com
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and may be reproduced or distributed only with written consent from the manufacturer.
We reserve the right to make changes without notice.