OSO HOTWATER Multipoint-W Series User manual

11008565-142234-00 - 11-2022
Multipoint - W
30-50-80-100 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 identification...................................... 5
2.2. Intended use........................................................ 5
2.3 UKCA marking.................................................... 5
2.4 Technical data...................................................... 5
2.5. ErP data (TDS)...................................................... 5
2.6 Spare parts............................................................. 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 .. 8
3.5. Pipe installation................................................... 9
3.6. Electrical installation........................................ 11
4. Commissioning........................................................... 13
4.1. Commissioning and filling.......................... 13
4.2. Turning on the power ................................... 13
4.3. Temperature adjustment of tap water. 13
4.4 Control points.................................................... 13
4.5. Draining................................................................. 14
4.6 System flushing.................................................. 14
4.7 Handover to end-user................................... 14
5. User Guide, safety and servicing ................... 15
5.1. Safety cut out...................................................... 15
5.2 Settings.................................................................. 15
5.3 Intermittent discharge from tundish...... 16
5.4 Continous very hot water discharge
from tundish........................................................ 16
5.5 Expansion vessel maintenance.................. 16
5.6 Warranty................................................................ 16
5.7 Service procedure............................................. 16
5.8 Discharge............................................................... 16
5.9 Annual inspection of T&P valve................ 17
6. Troubleshooting ....................................................... 18
6.1. Faults and fixes.................................................. 18
7. Service records and warranty .......................... 19
Installation, Commissioning and
Service Record Log Book.............................. 19
Warranty.............................................................. 22
7.1. Customer service............................................. 22
Service interval records................................ 23
8. Removing the product ........................................ 22
8.1. Removal............................................................... 22
8.2. Returns scheme............................................... 22

3
1. SAFETY INSTRUCTIONS
1.1 General information
• Read the following safety instructions care-
fully before installing, maintaining or ad-
justing the water heater.
• Personal injury or material damage may re-
sult 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 future
reference.
• The manufacturer assumes compliance (by
the end-user) with the safety, operating
and maintenance instructions supplied and
(by the installer) with the fitting manual
and relevant standards and regulations 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
The overflow from the safety valve must NOT be sealed or plugged.
!
The unit must be connected to a minimum 16 amp dedicated permanent supply complying
with current IET Wiring regulations.
!
Discharge must comply with current building regulations.
!
The electrical supply to the heater shall be done in accordance with current local regula-
tions and best practice by a qualified electrician. The product is intended for permanent
supply.
!
The mains cable shall withstand 90°C. A strain reliever shall be fitted.
!
The product shall be filled 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
The overflow from the safety valve must NOT be sealed or plugged.
The product front and electric junction box shall NOT be covered
The product must NOT be modified or changed from its original state.
Children must NOT play with the product or go near it without supervision.
!
The unit must be connected to a minimum 16 amp dedicated permanent supply complying
with current IET Wiring regulations.
!
The product shall be filled with water before the power is switched on.
!
Maintenance/settings shall be carried out by persons over 18 years of age, with adequate
technical understanding.
!
CAUTION
The product must not be exposed to frost, over-pressure, over-voltage or chlorine treat-
ment. See warranty provisions.
Maintenance/settings shall not be carried out by persons of diminished physical or men-
tal capacity, unless they have been instructed in the correct use by someone responsible
for their safety.
!
CAUTION
Do not use the balanced cold connection to feed any outlets other than mixer showers.
Under no circumstances use the balanced cold connection to feed all cold water outlets as
this practice contravenes Section 10 of water regulations.
!
The cylinder must be installed in compliance with current building regulations. Liability for
consequential damage will only apply if this is followed.
!
The product shall be properly aligned vertically and horizontally, on a floor or wall suitable
for the total weight of the product when in operation. See type plate.
!
The product shall have a clearance for servicing of 400 mm in front of the cover / 100 mm under
the base plate when wall-mounted.

5
2.4 Technical data
Model no. Product code: IP
class Weight kg. Dia. x Height mm. Freight vol. m³ Heating time hours Dt 65°C Heat loss W
10800451 W 30 - 2.8 kW/1x240V IP21 14 ø435 x 542 0.11 0.7 22
10800452 W 50 - 2.8 kW/1x240V IP21 17 ø435 x 697 0.16 1.1 29
10800453 W 80 - 2.8 kW/1x240V IP21 24 ø435 x 1017 0.22 1.9 36
10800454 W 100 - 2.8 kW/1x240V IP21 28 ø435 x 1237 0.26 2.2 45
2.5 ErP data - Technical Data Sheet
Brand Manufacturer
product no. Model name Tap profile
ErP
Rating
Energy
eff. %
AEC
kWh/a
Thermo-
stat set-
ting °C
Volume
40°C
water
OSO Hotwater AS 11008568 Multipoint - W 30 S C 34.2 539 70 52
OSO Hotwater AS 11008569 Multipoint - W 50 M C 37.1 1384 70 84
OSO Hotwater AS 11008570 Multipoint - W 80 M C 36.4 1411 60 113
OSO Hotwater AS 11008571 Multipoint - W 100 L C 38.6 2653 60 142
Regulation: 2017/1369/EU - Regulation: EU 812/2013 Directive: 2009/125/EC - Regulation: EU 814/2013
Efficiency-tested according to standard: EN 50440: 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
The Multipoint W series is designed to supply
premises with domestic hot water. The product is
designed for wall installation, but can also be fitted
standing on the floor.
2.3 UKCA marking
The UKCA mark shows that the product complies
with the relevant Directives. See Declaration of
Conformity at www.osohotwater.co.uk for more
information.
2.6 Spare parts
Prod. no. Designation Product description: Dimension
71214 RGK 1” Element - 2.8 kW/1x230V - 1-tube - Inc 825 Length 320 mm.
80020 TS2 Thermostat - 59T/66T 40-70°C 1-phase 2-pole
801 5519 Connecting cable Internal cable - 2.5# ,180°C / Saga, fork+fork Length 205 mm
W91803 FLEX 27 Flexhose DN13, Bend G1/2F x straight G1/2F, L=400 mm. 1/2” x 1/2”
92025 T&P valve Temperature and pressure relief valve 7 bar/90-95°C 1/2”
92043 Inlet Group G3 Inlet Group with Tundish G3

6
3.2.1 G3 Inlet Group kit
The product is supplied with a G3 Inlet Group kit.
The kit contains the components shown in table
below and illustration (right).
3. INSTALLATION INSTRUCTIONS
3.1 Products covered by these instructions
10800451 Multipoint - W 30
10800452 Multipoint - W 50
10800453 Multipoint - W 80
10800454 Multipoint - W 100
3.2 Included in delivery
Ref.
no. Pcs. Description
1 1 T&P safety valve, 7 bar/90-95°C (factory fitted)
2 1 Stainless steel multipoint
3 1 Thermostat 40-70°C
4 1 Immersion heating element
5 1 Stainless steel wall bracket
6 1 Mains power cable (factory fitted)
7 1 Installation manual (this document)
8 2 CW/HW flexhose - 1/2” x 1/2” pipe thread
9 1 G3 Inlet Group kit (see pt. 3.2.1).
2
3
4
1
5
7
6
8
9
No. Description Dim.
A Cold water supply ø22 mm
B Balanced cold supply (optional) ø22 mm
C Expansion vessel 1/2”
D Multibloc valve 3/4”
E Discharge pipework 15-22 mm
FDrain cock (not supplied) N/A
GCold water inlet 1/2” M
HTundish 15-22 mm
IExpansion vessel connection point 3/4”
JLine strainer -
KExpansion relief valve 6 bar ø15 mm
LHot water outlet (DHW) 1/2” M
MExpansion overflow connection ø15 mm
NT&P safety valve 90-95°C - 7 bar 1/2”
H
AC B
F
GE
K
I
B
J
L
N
MD

7
3.3 Product dimensions
3.3.1 Delivery
The product shall be transported carefully as
shown, with packaging. Use the handles in the
box.
Product. A ø
W 30 542 435
W 50 697 435
W 80 1017 435
W 100 1237 435
Tolerance +/- 5 mm.
!
CAUTION
Pipe stubs, valves etc. shall not be used to lift the
product as this could cause malfunctions.
All dimensions in mm.
A
ø
45°

8
3.4 Requirements for installation location and
positioning
!
CAUTION
!
The cylinder must be installed in compliance with current building regulations. Liability for
consequential damage will only apply if this is followed.
!
The product shall be placed in a dry and permanently frost-free position.
!
The product shall be fixed to a wall structure or placed on a floor surface suitable for the total
weight of the product in operation.
!
The minimum distance from the ceiling to the centre of the upper screw hole on the wall
bracket is 250 mm. because of the space required for fitting. See diagram below.
!
The product shall have a clearance for servicing of 400 mm in front of the cover / 100 mm under
the base plate when wall-mounted.
!
The product shall be easily accessible in the home for servicing and maintenance.
3.3.2 Wall bracket
The product can be mounted on the wall or floor
and is supplied with a wall bracket (7). The sup-
plied wall bracket must be used for wall installation.
Ensure that the wall or floor will withstand the full
weight of the product in operation. The minimum
distance from ceiling to wall bracket is 250 mm., see
section 3.4 and illustration below.
Wooden wall: Bracket should preferably be fixed
with four screws to wall studs/beams, or at least two
screws vertically above each other into stud/beam.
Use ø8 mm. wood screws. For other types of wall,
suitable fastening materials must be selected for any
given wall design.
Installation of heater on bracket:
The product should be tilted down slightly on the
bracket before turning it against the wall, see illus-
tration. Make sure that the product is lowered all the
way down onto the bracket and that the back of the
product is in full contact with both bracket and wall.
7
7
!
WARNING
Ensure that the product is lowered completely
onto the bracket and that the back of the pro-
duct is in full contact with both the bracket and
the wall.
Min. 100 mm when
wall mounted
Min. 250 mm
Min. 400 mm

9
Component Torque
Hose nut on CW/HW connection 20 Nm (+/- 3)
Compr. ring clamp on safety valve 20 Nm (+/- 3)
Product. COLD WATER
(conn. 1) HOT WATER (conn. 2) P&T overflow (conn. 3)
W 30-100 1/2” ext.
BSPP
1/2” ext.
BSPP
ø15mm comp.
fitting / 1/2” int.
pipe thread
3.5.4 Torque settings
3.5.1 Incoming water pressure
The efficiency of the product depends on the inlet
cold water pressure. The water pressure should
always be between min. 2 bar and max. 6 bar. Ex-
cessive water pressure can be adjusted by install-
ing a pressure reduction valve.
3.5.2 Fitting cold and hot water hoses
Remove the front and base vanity cover (D) from
the product by gently pulling them off. The sup-
plied cold and hot water flexible hoses (H) should
be fitted to their respective connections and tight-
ened to the correct torque (see 3.5.4).
The cold water hose is connected to the cold wa-
ter connection (1).
The hot water hose is fitted to the hot water con-
nection (2).
3.5.3 Fitting the P&T valve discharge pipe
A discharge pipe (5) of suitable dimension (see ta-
ble 3.5.5) is run to the overflow connection (3) on
the top mounted P&T safety valve (6):
• Connect to overflow outlet (3) - ø15 mm ring
clamp or 1/2” internal thread - unscrew ring
clamp nut (4).
• Ensure the discharge pipe (5) is fitted uninter-
ruptable and frost free sloping to a suitable
drain, see illustration on next page and pt. 5.8.
All pipe connections should be checked for leak-
age when water is turned on and again after ap-
prox. 3 months of operation, then annually. Tight-
en connections if necessary.
Refit front and base vanity covers (D) after pipe
fitting is finalised.
3.5 Pipe installation
The product is designed to be permanently con-
nected to the mains water supply. Approved pipes of
the correct size must be used for installation. The rel-
evant standards and regulations must be followed.
3
4
5
6
1
H
D2
3

10
RECOMMENDATION
!
Min. distance from ceiling to upper screw on wall bracket is 330 mm to allow space for instal-
lation on wall bracket. See diagram in section 3.4.
3.5.5 Fitting instructions
3.5.6 Installation recommendation
!
CAUTION
!
The cylinder must be installed in compliance with current building regulations. Liability for
consequential damage will only apply if this is followed.
!
The product shall be properly aligned vertically and horizontally. The product shall be fixed to a
wall structure or placed on floor suitable for the total weight of the product when in operation.
!
The product shall have a clearance for servicing of 400 mm in front of the cover / 100 mm under
the base plate when wall-mounted.
!
WARNING
!
The product shall be filled with water before the power is switched on.
!
Discharge must comply with current building regulations.
Safety device
(e.g. temperature
relief valve)
Metal discharge pipe (D1) from
temperature relief valve to tundish
600 mm.
maximum
Tundish
300 mm.
minimum
Discharge pipe (D2) from tundish,
with continous fall. See table and
worked example.
Discharge below
fixed grating
(see text for alternative
points of discharge)
Fixed grating
Trapped gulley
5
!
WARNING
The tundish shall be installed away from any
electrical devices.

11
3.6.3 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
G 1” heating element 38 Nm (+/- 5)
Thermostat screws 2 Nm (+/- 0.1)
Screw on the element head 2 Nm (+/- 0.1)
A) Live wire (L) is connected to point ‘1’ on the
safety thermostat.
B) Neutral wire (N) is connected to point ‘3’ on
the safety thermostat.
C) Earth wire, yellow with green stripe is con-
nected to the earth terminal on the inner tank;
see illustration.
D) Internal wires from the element to the ther-
mostat are connected to point ‘4’ on the safety
thermostat and point ‘2’ on the work thermostat.
See illustration.
3.6.1 Electrical components
Component Note
Safety thermostat 85°C thermal cut-out
Work thermostat 40-70°C adjustable
Heating element 1-phase 240 V
Mains cable with plug Heat-resistant
Internal wires Heat-resistant
3.6 Electrical installation
The unit must be connected to a minimum 16
amp dedicated permanent supply complying
with current IET Wiring regulations, isolation is
required via a minimum 20 amp double pole iso-
lation switch with a minimum 3 mm separation
required. All electrical wiring shall be carried out
by a competent electrician, using a heat resist-
ant flexible cable (minimum 90°C), and be in ac-
cordance with the latest IET Wiring Regulations.
A mains cable is supplied with the product. The
relevant standards and regulations must be fol-
lowed.
3.6.2 Electrical connections in the junction box
Electrical connection, diagram
R
E
S
E
T
R
E
S
E
T
M2
1
2
3
4
THERM-O-DISC
1
2
L N
70 40

12
RECOMMENDATION
- The mains cable supplied (heat-resistant) should be used with fixed electric fittings.
-Mains cable for wall connection should be laid where it is not exposed to any harmful contact.
-For products with ≤ 3kW capacity, a >20A fuse / >2.5# wire shall be used.
This product is not suited for connection to a 3-pin plug.
3.6.4 Fitting instructions
3.6.5 Fitting recommendation
!
WARNING
!
The unit must be connected to a minimum 16 amp dedicated permanent supply complying
with current IET Wiring regulations.
!
The product shall be filled with water before the power is switched on.
!
The electrical supply to the heater shall be done in accordance with current local regula-
tions and best practice by a qualified electrician. The product is intended for permanent
supply.
!
The mains cable shall withstand 90°C. A strain reliever shall be fitted (supplied).
!
CAUTION
!
The product shall have a clearance for servicing of 400 mm in front of the cover / 100 mm under
the base plate when wall-mounted.
!
In case of damage to the mains cable it shall be replaced with a specially adapted mains
cable from the manufacturer.

13
4. COMMISSIONING
4.1 Commissioning and filling
1. Check all connections for correct fitment
and tightness.
2. Open the hot water tap furthest away
from the OSO water heater. Leave open.
3. Open the mains cold water supply stop
cock to fill the water heater. When water
flows evenly from the open tap without
any air locks, allow to run for a few min-
utes to flush through any dirt, swarf or
residue. Close the tap. Open successive
remaining hot taps to purge any remain-
ing air.
4. Check all water connections for leaks and
rectify if necessary.
5. For test purposes manually operate Tem-
perature and Pressure relief valve (1) to
ensure free water flow through discharge
pipe by turning knob counter-clockwise.
Ensure that the water flows freely to drain.
To close valve continue to turn knob
counter-clockwise until the valve shuts.
4.2 Turning on the power
When the cylinder has been filled with water,
the power can be switched on. Turn on power
switch/circuit breaker.
4.3 Temperature adjustment of tap water
The outgoing hot water temperature from the
product to the outlets is mixed automatically.
The home is supplied with water that maintains
a temperature approx. 10°C lower than the set
temperature of the thermostat. For tempera-
ture adjustment, see section 5.1.1.
4.4 Control points (min. annually)
A) Check that all pipe connections to/from the
product are tight and not leaking. Tighten if
necessary.
B) Check that the power supply to the product
is not at risk of exposure to mechanical, ther-
mal or chemical damage.
C) Check that any discharge pipe (3) from the
safety valve overflow (2) is kept uninterrupt-
able, undamaged and frost-free sloping to the
drain.
D) Check that the product is hanging securely
on its wall bracket and is positioned level verti-
cally and horizontally.
2
3
1
3
Drain valve
(not supplied)
2

14
4.7 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 in the Installation, Com-
missioning and Service Record Log Book at the
back of this manual.
4.5 Draining
A) Disconnect the power supply and ensure it
can not be turned back on while work is in pro-
gress.
B) Shut off incoming cold water supply.
C) Open a hot tap to the maximum – leave
open (prevents vacuum lock).
D) Connect hose pipe to drain valve, then open
drain valve discharging contents to a drain.
Note that the water can be very hot, take nec-
essary precautions.
Close drain valve and all open taps. The wa-
ter heater must be refilled with water before
power is turned on, see pt. 4.1.
4.6 System flushing
System flushing will not be necessary under
normal circumstances as the line strainer will
prevent ingress of foreign materials, however
if flushing is required, run at least 50 litres of
water from the cylinder at the highest possible
flowrate. Close the taps and follow draining
procedure described in pt. 4.5.
!
WARNING
The water temperature in the product can be up
to 90°C and could cause scalding. Before drain-
ing, a hot tap should be opened to maximum
pressure/temperature for min. 3 minutes.

15
!
WARNING
Constant voltage present in the junction box. Be-
fore any electrical work is done, the power supply
must be disconnected and secured against acti-
vation while the work is in progress.
Maintenance must be carried out by a compe-
tent person.
5.1 Safety cut out
1. The safety cut-out operates if:
a.) Wiring is incorrect.
b.) The immersion heater thermostat or
cylinder thermostat fails.
2. Important: Before resetting the safety cut-
out or altering the thermostat setting, isolate
electrical supply to the unit prior to removal
of the electric junction box cover (1) by un-
screwing the retaining screw (2).
3. Lower the thermostat setting by adjust-
ing the dial (4) using a flathead screwdriver.
Then press the RESET button (3). After ad-
justments are completed, the junction box
cover (1) must be refitted before the power is
switched back on.
4. If still out of operation, contact installer.
5.2 Settings
5.1.1 Thermostat setting
The factory fitted thermostat is adjustable from
40-70°C. The thermostat should not be set lower
than 60°C to prevent bacteria growth.
To adjust the temperature disconnect power sup-
ply and remove the junction box cover (1) by un-
screwing the retaining screw (2). Adjust the ther-
mostat temperature setting as desired by turning
the dial (4) using a flathead screwdriver.
The junction box cover (1) must be refitted before
the power is switched back on.
Changing the temperature setting on the thermo-
stat changes the temperature of the water inside
the vessel. Increasing the temperature in the vessel
will result in a higher available hot water volume .
The product is designed with automatic mixing of
the outgoing tap water and will supply the prem-
ises with hot water at a temperature approx. 10°C
below the set temperature of the thermostat.
5.1.2 Resetting the safety thermostat
The safety thermostat on the product cuts out
when there is a risk of overheating. It can be reset
by disconnecting the power supply and remov-
ing the junction box cover (1) by unscrewing the
fastening screw (2) . Press the RESET button (3). A
noticeable click should be heard when the ther-
mostat resets. If the thermostat cuts out repeat-
edly, contact the installer.
The junction box cover (1) must be refitted before
the power is switched back on.
5. USER GUIDE, SAFETY AND SERVICING
R
E
S
E
T
R
E
S
E
T
M2
1
2
3
4
THERM-O-DISC
1 3
2
4
3
1
2

16
5.3 Intermittent discharge from tundish
1. Turn off the electrical supply to the immer-
sion heater.
2. Turn off cold water supply valve.
3. Open a hot tap.
4. Turn the knob (K) on the Temperature and
Pressure Relief Valve clockwise and hold in
this position for 30 seconds (see below).
5. Check pre-charge on vessel and adjust
pressure if necessary.
6. Open cold water supply valve.
7. When water flows through open tap, close
tap. Turn on electrical supply to the immer-
sion heaters.
5.4 Continous 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 off the electri-
cal supply to the immersion heater.
Contact the installer or competent engineer.
5.5 Expansion vessel maintenance
The expansion vessel require annual mainte-
nance by a competent person and the precharge
pressure 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
pressure is different 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 wa-
ter from the drain valve at the base of the cylinder
5.6 Warranty
Cylinder should be serviced annually (as below)
and logbook should be updated in order to vali-
date warranty. Logbook and service records act
as warranty document. For terms of warranty see
Service logbook at rear of manual.
5.7 Service procedure
The following maintenance work has to be car-
ried out annually by a competent person:
1. Inspection of pressure/temperature relief
valve and expansion relief valve.
2. Manually operate each valve by twisting the
operating cap, and check if water flows un-
obstructed via the tundish to the discharge
point.
3. Ensure that both valves re-seat satisfactorily.
4. Turn off mains water supply and open near-
est hot water tap to depressurise the DHW
system.
5. Check the expansion vessel.
6. If the pressure is below 3 bar, top up with
a suitable air pressure pump to pressure
shown on vessel label.
7. Complete the service section of the Cylinder
Commissioning Checklist included in the in-
side back pages of these instructions.
8. Remove , clean and replace line strainer.
9. The immersion heater element must be
removed for inspection on service after 5
years. The threads must be checked for cor-
rosion. If signs of corrosion are evident, the
element must be replaced. Subsequently
the element must be removed and exam-
ined every 3 years. Failure to do so in ar-
eas of aggressive water may result in the
element separating from the cylinder with
consequential escape of water.
10. Visual inspection of all valves, external fit-
tings, immersion heaters and electrical con-
nections.
5.8 Discharge
Discharge pipes must be metal or suitably temper-
ature rated as defined by G3 building Regulations.
The pipe should have a continuous fall and should
terminate in a safe and visible place.
Downward discharges at low level, i.e. up to 100
mm above external surfaces such as car parks, hard
standings, grassed areas etc. are acceptable pro-
viding that where children may play or otherwise
come into contact with discharges, a wire cage
or similar guard is positioned to prevent contact,
whilst maintaining visibility.
Discharge at high level, i.e. into a metal hopper and
metal down pipe with the end of the discharge
pipe clearly visible (tundish visible or not) or onto
a roof capable of withstanding high temperature
discharges of water and 3 m from any plastics gut-
tering system that would collect such discharges
K

17
5.9 Annual inspection of T&P valve
MAINTENANCE INSTRUCTIONS
!
Maintenance shall be carried out by persons over 18 years of age, with adequate techni-
cal understanding.
!
Annual inspection of T&P valve:
- Open valve for 1 min. by turning the knob (1) approx. 90 degrees to the open position.
- Visually check that the water is flowing freely to the drain.
-
YES = OK. Close the valve by turning the knob (1) a further 90 degrees to the closed
position.
- NO = NOT OK. Disconnect power supply / shut off water supply. Contact installer.
1
Valve Outlet size
Minimum size
of discharge
pipe D1
Minimum size of
discharge pipe D2
from tundish
Maximum resistance allowed
expressed as a length of straight
pipe (i.e. no elbown or bends)
Resistance created by each
elbow or bend
G 1/2 15 mm
22 mm
28 mm
35 mm
up to 9 m
up to 18 m
up to 27 m
0.8 m
1.0 m
1.4 m
Safety device
(e.g. temperature
relief valve)
Metal discharge pipe (D1) from
temperature relief valve to tundish
600 mm.
maximum
Tundish
300 mm.
minimum
Discharge pipe (D2) from tundish,
with continous fall. See table and
worked example.
Discharge below
fixed grating
(see text for alternative
points of discharge)
Fixed grating
Trapped gulley
(tundish visible).
Where a single common discharge pipe serves
more than one system, it should be at least one
pipe size larger than the largest individual dis-
charge pipe (D2) to be connected.
For further information contact your Building
Control Office.
!
WARNING
The tundish shall be installed away from any
electrical devices.

18
6.1 Faults and fixes
If problems arise when the product is in use, check
for possible faults and fixes in the flow chart. If the
problem is not shown in the flow chart or you are
unsure what is wrong, contact the installer (see
6. FAULT FINDING GUIDE
Installation, Commissioning and Service Record
Log Book at the back of this manual.) or OSO
Hotwater AS - see pt. 7.1 (page 22).
No water from
hot taps
Water from taps
is cold
Intermittent
water discharge
Continous
water discharge
Mains supply off
Strainer blocked
Immersion heaters
not switched on
Cylinder thermal
cutout has
operated
Immersion heater
thermal cutout has
operated
Reduced expansion
vessel charge
Thermal control
failure (note: water
will be hot
Expansion relief
valve not working
properly
Cold water inlet
pressure reducing
valve not working
Temperature and
pressure relief valve
faulty
Check and open stopcock
Turn off water supply, remove and clean strainer
Check and switch on
Check and press reset button
Check and press reset button
Follow instructions 5.2 Intermittent or slow discharge
from tundish
Switch off power to immersion heater(s). When dis-
charge has stopped check thermal controls, replace if
faulty
Check and replace if faulty
Check pressure from valve, if greater
than 3 bar - replace
Drain 10 litres from cylinder and replace valve
Problem Possible cause Possible solution

19
The code of practice for the installation,
commissioning & servicing of mains pressure hot water storage
Installation,CommissioningInstallation,Commissioning
and Service Record Log Bookand Service Record Log Book
CUSTOMER DETAILS
NAME
ADDRESS
TEL No.
IMPORTANT
1. Please, keep the Log Book in a safe place for future reference.
2. This Log Book is to be completed in full by the competent person(s) who
commissioned the equipment and then handed to the customer. When this is done,
the Log Book is a commissioning certicate that can be accepted as evidence of
compliance with the appropriate Building Regulations.
3. Failure to install and commission this appliance to the manufacturer’s
instructions may invalidate the guarantee.
The above does not a󰀨ect your statutory rights.
For full details on the HWA charter please visit http://www.hotwater.org.uk/
© HEATING AND HOTWATER INFORMATION COUNCIL
IT IS THE RESPONSIBILITY OF THE INSTALLER TO COMPLETE THIS
LOG BOOK AND PASS IT ON TO THE CUSTOMER. FAILURE TO DO
SO MAY INVALIDATE THE CYLINDER GUARANTEE
HWA charter members agree to:
• To supply t for purpose products clearly and honestly described
• To supply products that meet, or exceed appropriate standards and building and water regulations
• To provide pre and post sales technical support
• To provide clear and concise warranty details to customers

20
INSTALLER & COMMISSIONING ENGINEER DETAILS
INSTALLER DETAILS
COMPANY NAME DATE
ADDRESS
INSTALLER NAME TEL No.
REGISTERED OPERATIVE ID CARD No.
(IF APPLICABLE)
REGISTRATION DETAILS
COMMISSIONING ENGINEER (IF DIFFERENT)
NAME DATE
ADDRESS
TEL No.
REGISTERED OPERATIVE ID CARD No.
(IF APPLICABLE)
REGISTRATION DETAILS
IT IS THE RESPONSIBILITY OF THE INSTALLER TO COMPLETE THIS LOGBOOK AND PASS IT
ON TO THE CUSTOMER. FAILURE TO DO SO MAY INVALIDATE THE CYLINDER GUARANTEE
APPLIANCE & TIME CONTROL DETAILS
MANUFACTURER OSO HOTWATER (UK) MODEL
CAPACITY
TYPE
TIME CONTROL
UNVENTED
PROGRAMMER
litres MANUFACTURE date
TIME SWITCH
or