Dimp-15278-SCx_Instructions 31/3/06 9:32 am Page 1
DIMPLEX
UNVENTED WATER HEATERS
INSTALLATION MANUAL
Marketing Department, Millbrook House, Grange Drive, Hedge End, Southampton, SO30 2DF. Telephone: 0870 077 7117 Fax: 0870 727 0109
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Dimp-15278-SCx_Instructions 31/3/06 9:32 am Page 5
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1 Element on IDH indirect models up to 305 litres and 80
litre DH direct model
CONNECTINGTHE WATER SUPPLY
DRAINTAP
STANDARD ENERGY LOSSES
●
●
Pipework is not supplied
A drain tap to drain the unit must be fitted to the cold-water inlet
pipe somewhere between the SCx unit and the cold water
valve assembly and at as low a level as possible, see fig. 1.
The heat loss of each SCx Unvented Unit while maintaining
the temperature of the stored water at 65 degrees Celsius.
(See performance table below).
2 Elements on DH direct models from 130 up to 305 litres.
Additional elements from 215 to 305 litres are available on
request.
All pipework should be installed using good plumbing
practice. We recommend 22mm mains cold water supply
is used.
1) Tests carried out by BBA. Slight variations may occur with
changes to water mains supply pressure
●
Install a Stop Cock Valve before the cold water inlet
assembly on the incoming mains water supply so the unit
can be isolated if required.
●
Cold-water control valve comprising line strainer, check
valve, pressure reducing valve set to 2.1 bar
PIPEWORKTOTAPS
Ideally a 22mm pipe run should supply the outlets throughout
the property with short lengths (max 1 metre) runs of 15mm
going to baths, showers, and basin taps. Smaller bore pipe
can be used to suit taps.
SCx Performance
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●
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Expansion relief valve with non return valve set at 6 bar
Tundish 15mm x 22mm F x F
Nominal
Heat up
Heat up
Reheat
Reheat
Heat loss in
24 hrs
Capacity Model IDH Model DH Model IDH Model DH
Litres
80
Mins
33
28
33
27
35
42
50
Mins
64
Mins
23
21
24
24
30
35
42
Mins
53
kw/hr
COLD WATERVALVE
1.12
1.50
1.82
2.10
2.64
2.73
2.88
Temperature / Pressure relief valve set at 90 degrees
Celsius and 7 bar pressure relief (factory fitted)
130
150
175
215
255
305
115
138
167
212
263
313
90
The combined cold water valve (supplied) can be connected
anywhere on the cold water mains prior to the unit. It can even
be located at a point near to where the mains supply enters the
premises if this is more convenient. When installing the cold water
valve, ensure that the arrow is pointing in the same direction as
the mains water supply flow when connecting, see fig 2.
SECONDARY CIRCULATION
104
124
153
184
220
This is particularly easy to fit on the SCx units; a Swept Tee (not
supplied) is needed for all indirect models if secondary
circulation is required, see page 6 fig. 3 for fitting. A non-return
valve (not supplied) must be fitted to prevent backflow. You
will need a pump to circulate the hot water (not supplied). The
return feed is in 15mm pipe and all work can be done on site.
●
●
Motorised valve (indirect units only)
Cylinder thermostat-factory fitted to cylinder, maximum
setting 85 degrees Celsius (indirect units only)
●
●
Thermal cut out set to operate at 87 degrees Celsius plus
or minus 3 degrees (indirect units only)
2) These figures relate to a 45 degree differential between
the stored water and ambient temperature
The cold water balancing port, on the valve, allows you to
connect the cold water mains to the rest of the property thus
giving balanced pressure throughout. If this facility is not
required leave the cap on.
Option – Expansion vessel with capacity as below: -
WITH AN SCx UNVENTED CYLINDER THE
FOLLOWING IS SUPPLIED AS STANDARD
Typical Indirect Tank installation using external expansion vessel option
Tank Size
ExpansionTank Required
12 Litres
Before commencing installation check that all the
components of your SCx Unit are contained in the kit.
80 to 130 Litres
150 to 215 Litres
255 to 305 Litres
WATER FLOW
HOT WATER OUTLET
1
●
3KW Incoloy 825 heating element-incorporating
thermostat to 70 degrees Celsius and resetable safety cut
out set at 80 degrees Celsius
18 Litres
EXPANSION VESSEL
7 BAR / 90 DEGREES
(WALL MOUNTED)
PRESSURE &
25 Litres
TEMPERATURE
RELIEF VALVE.
WATER FLOW
TO COIL INLET
PRIMARY FLOW
TUNDISH
WATER FLOW TO
MANIFOLD VIA
FLEXIBLE HOSE
SCx UNVENTED INSTALLATION INSTRUCTIONS
PRIMARY RETURN
WATER FLOW
FROM COIL INLET
TWIN
THERMOSTAT
SECONDARY
RETURN FLOW
PRESSURE
REDUCING VALVE
SET AT 3 BAR
6 BAR
EXPANSION
RELIEF
WARNING: Under no circumstances must the factory fitted temperature pressure relief valve be removed. This will totally invalidate
any guarantee or claim. The cold-water inlet valve assembly must be fitted or the SCx unit will not perform satisfactorily.
VALVE
WATER FLOW
TO OVERFLOW
IMMERSION
HEATER
DO NOT ATTEMPT TO VENT THE PRIMARY CIRCUIT THROUGH THE SCx UNIT.
WATER INLET
WATER FLOW
INLET SIDE OF TANK
All boilers should be installed to manufacturers instructions and the primary circuit through the SCx unit must be pumped.
SWEPT TEE
WATER FLOW
FROM EXPANSION
TANK TO 22MM
FEMALE THREAD
BEHIND COVER
DRAIN
COCK
BLANKED
PORT
BALANCED
COLD WATER
OUTLET
SITINGTHE SCx UNIT
CHECK WATER PRESSURE & FLOW RATES
Cold water inlet valve assembly
We suggest 1.5 bar pressure & 15 litres / minute flow rate to
be the minimum requirements for satisfactory operation. Less
than this the unit will still operate but you will not be able to run
two, or more, outlets at the same time. 85% of all U.K homes
have more than 2-bar pressure.
6 BAR
EXPANSION
RELIEF
The unit can be placed anywhere convenient. Because it is
connected directly to the mains water supply it is equally
efficient on any floor – ground, first or second. Avoid areas
that may be subject to frost. Try to keep pipe runs as short as
possible for maximum economy, especially hot water
discharge pipes running down from the SCx unit.
VALVE
PRESSURE REDUCING
VALVE SET
AT 3 BAR
2
The mains supply must not exceed 16 bar. If it does a special
pressure-reducing valve will be required.
WATER FLOW INLET SIDE OF TANK
The unit can be fitted into a conventional airing cupboard
and does not require any additional insulation.
WATER FLOW FROM EXPANSION
TANK TO 22MM FEMALE THREAD BEHIND
COVER
Important Note: - Stainless Steel Tectile push fit elbows are
fitted as standard to all SCx Cylinders.
BLANKED
PORT
ALL SCx UNITS MUST BE STORED VERTICALLY
4
5
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Dimp-15278-SCx_Instructions 31/3/06 9:32 am Page 7
2 PORT VALVE + 3 PORT MID POSITION
VALVE (Y-PLAN) SYSTEM
GUIDANCE LAYOUT ONLY
SECONDARY CIRCULATION
CONNECTION DIAGRAM
Fig.5
Fig.3
As our heating element is Incoloy 825 and is fitted with a cut-
WIRING
3
/
4
out and thermostat for safety, a non-standard 1 " boss is fitted
to the unit. Replacements can only be obtained from your
authorised Dimplex Service Agent.
All electrical wiring should be carried out by a registered electrical
contractor and must conform to the latest IEE wiring regulations
Do not switch the power on until the unit has been filled with
water and all wiring has been earthed, see Fig. 4 and 5.
All our heating elements have a built in manual reset cut-out.
This will operate if the immersion heater thermostat fails.
FITTING IMMERSION HEATERS
WARNING: Ensure that the immersion heater thermostat is set
at 60 degrees Celsius.
These are supplied as standard
2 * 2 PORT (S-PLAN) VALVE SYSTEM
GUIDANCE LAYOUT ONLY
E N L
An ’O’ ring is supplied as the seal and must be fitted against
the flange of the element. Take care not to cross thread and
DO NOT USE any other type of seal.
Fig.4
FITTINGTHETHERMAL CUT-OUT &
PRIMARY CONNECTIONS
ROOM
HTG
ON
DHW
ON
PROGRAMMER
GY 1
3
2
L
N
1
E
THERMOSTAT
The motorised valve supplied and the thermal cut-out (Hi
limit stat) must be fitted to the primary flow. Use
compression fittings only.
1
2
3
2 PORT MID
POSITION VALVE
Br BI
G O GY
4
Operation of the cut-out and motorised valve
5
TWIN
C
2 C
1
2 GY
THERMOSTAT
To comply with BBA regulations and to prevent the
temperature reaching 100 degrees Celsius the thermal
cut-out supplied must be fitted.
6
7
E
8
BOILER
PUMP
The thermal cut-out is wired in series to the cylinder
thermostat. When the thermal cut-out senses an abnormal
rise in temperature in the primary flow the electrical supply
to the motorised valve will be cut, and the valve will be in
the closed position thus cutting of the primary water from
the boiler to the indirect coil in the cylinder. If this occurs it
must be reset manually. If the thermal cut-out operates
check the cylinder stat and / or boiler stat.
L
L
N
N
E
E
9
L
N
10
MOTOR ON/OFF
VALVE
Br BI G
GY
O
6
7
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Dimp-15278-SCx_Instructions 31/3/06 9:32 am Page 9
standings, grassed areas etc. are acceptable providing
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.
TUNDISH
DRAINING
G3 REQUIREMENT
The tundish supplied must be fitted visible to the occupier. The
discharge pipe must be 22mm copper pipe. Regulations do
not permit more than 3 x 90-degree bends between the SCx
unit and the outflow. Between the temperature & pressure
relief valve and the first 90-degree bend there must be a fall
of at least 300mm. The fall of the pipework must be
continuous and the pipe should terminate in the gully or be
bent backwards onto an outside wall, in a place where
discharge cannot be injurious to persons.
Switch off electrical power to immersion heaters and/or shut
‘…there shall be precautions…to ensure that the hot water
discharged from safety devices is safely conveyed to where it is
visible but will not cause danger to persons in or about the building.’
down the boiler. Close the stopcock valve to isolate the SCx unit.
Attach hosepipe to the drain cock having sufficient length to
take water to a suitable discharge point.
iii) discharges at high level; e.g 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 3m from any plastics guttering system that
would collect such discharges (tundish visible.)
G3 GUIDANCE SECTION 3.9
Open drain cock
The discharge pipe (D1) from the vessel up to and including
tundish is generally supplied by the manufacturer of the hot
water storage system. Where otherwise the installation should
include the discharge pipe (s) (D1) from the safety device(s).
In either case the tundish should be vertical located in the
same space as the unvented hot water storage system and
be fitted as close as possible and within 500mm of the safety
device e.g the temperature relief valve.
Open hot water tap nearest SCx unit.
If water fails to drain from SCx unit, vent the system by
If you need to site the SCx unit In the middle of the house your
discharge pipe to the tundish can be as far away as 9m, which
in most cases is enough to run the final discharge point. After 9m,
increase the pipe size to a greater diameter than 22mm and
accordingly for subsequent 9m lengths, see table 1 on page 10.
opening the temperature pressure relief valve.
iv) where a single pipe serves a number of discharges, such as
in blocks of flats, the number served should be limited to not
more than 6 systems so that any installation discharging can
be traced reasonably easily. The single common discharge
pipe should be at least one pipe size larger than the largest
individual discharge pipe (D2) to be connected. If unvented
hot water storage systems are installed where discharges
from safety devices may not be apparent i.e. in dwellings
occupied by blind, infirm or disabled people, consideration
should be given to the installation of an electronically
SCHEMATIC DISCHARGE
PIPE ARRANGEMENT
COMMISSIONINGTHE SCx UNIT
The discharge pipe (D2) from the tundish should terminate in
a safe place where there is no risk to persons in the vicinity of
the discharge, preferably be of metal and:
Switch on electricity to the immersion heater(s) (Direct system)
or switch on the boiler (Indirect system). Refer to the boiler
manufacturers instructions on commissioning.
Fig.6
a. be at least one pipe size larger than the nominal outlet size
of the safety device unless it’s total equivalent hydraulic
resistance exceeds that of a straight pipe 9m long ie.
discharge pipes between 9m and 18m equivalent resistance
length should be at least two sizes larger, than the nominal
outlet size of the safety device between 18 and 27m, at least
3 sizes larger and so on. Bends must be taken into account in
calculating flow resistance. Refer to Table 1 overleaf and fig. 6.
Bring the unit to its maximum temperature setting of approx.
60 degrees Celsius. You should, on operating the water taps,
have a good flow of hot and cold water assuming adequate
water is supplied to the SCx unit.
operated device to warn when discharge takes place.
Note: The discharge will consist of scalding water and steam.
Asphalt, roofing felt and non-metallic rainwater goods may be
damaged by such discharges.
Check the water does not discharge via the tundish pipework
during heating.
WORKED EXAMPLE OF DISCHARGE PIPE SIZING
Recheck all fittings/joints for possible leaks.
An alternative approach to sizing discharge pipes would
be to follow BS 6700:1987 specification for design
installation, testing and maintenance of services supplying
water for domestic use within buildings and their curtilages,
Appendix E, section E2 and table 21.
The example below is for a G1/2 temperature relief valve with
a discharge pipe (D2) having 4 No elbows and length of 7m
from the tundish to the point of discharge.
On completion of the installation, before turning on the mains
water supply ensure that all residual materials are removed by
means of flushing the system with a suitable cleaner.
From table 1: (overleaf)
EXTERNAL EXPANSIONVESSEL – OPTIONAL
Maximum resistance allowed for a straight length of 22mm copper
discharge pipe (D2) from G1/2 temperature relief valve is 9.0m
b. have a vertical section of pipe at least 300mm long, below
the tundish before any elbow or bends in the pipework.
This smaller tank is connected to the cold-water inlet side of
the vessel. Mount the tank according to separate manufacturers
instructions provided with the External Expansion vessel.
See fig 1 page 5.
Subtract the resistance for 4 No 22mm elbows at
0.8m each = 3.2m
c. be installed with a continuous fall.
DISCHARGE PIPEWORK
Therefore the permitted length equates to 5.8m
d. have discharges visible at both the tundish and the final
point of discharge but where this is not possible or is
practically difficult there should be clear visibility at one or
other of these locations.
It is a requirement of Building Regulations that any discharge
from an unvented system is conveyed to where it is visible, but
will not cause danger to persons in or about the building. The
tundish and discharge pipes should be fitted in accordance
with the requirements and guidance notes of Building
Regulations. Building Regulation G3 Requirements and
guidance section 3.9 reproduced in the following sections.
5.8m is less than the actual length of 7m therefore calculate
the next largest size.
SCALE
In hard water areas lower water temperatures can result in
less scale being deposited.
Maximum resistance allowed for a straight length of 28mm pipe
(D2) from a G1/2 temperature relief valve equates to 18m
If water softener is used it should be capable of flows of
approx. 50 lt/min, this will maintain maximum performance
of the SCx unit.
Examples of acceptable discharge arrangements are:
Subtract the resistance of 4 No 28mm elbows at
1.0m each = 4.0m
i) ideally below a fixed grating and above the water seal in
a trapped gully.
Therefore the maximum permitted length equates to 14m
If no descaler or softener is used then the heating element(s)
will need descaling periodically for maximum efficiency.
Information Sheet No. 33 available from the British Board of
Agreement gives further advice on discharge pipe installation.
ii) downward discharges at low level; i.e. up to 100mm
above the external surfaces such as car parks, hard
As the actual length is 7m a 28mm (D2) copper pipe will
be satisfactory.
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Dimp-15278-SCx_Instructions 31/3/06 9:32 am Page 11
TABLE 1 – SIZING OF COPPER DISCHARGE PIPE (D2) FOR COMMONT&P RELIEFVALVE SIZES
MAINTENANCE
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 elbows or bends)
Resistance created by
each elbow or bend
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To keep the cylinder in good operating order the cylinder should be serviced once a year by a Dimplex service engineer.
If water is seen dripping through the tundish, please contact your installer or Dimplex service agent.
To receive the 25 year guarantee please complete and return the guarantee card within 30 days of purchase / install
– please read Terms and Conditions on the guarantee card.
G1/2
G3/4
G1
15mm
22mm
28mm
22mm
28mm
35mm
28mm
35mm
42mm
35mm
42mm
54mm
up to 9m
up to 18m
up to 27m
up to 9m
up to 18m
up to 27m
up to 9m
up to 18m
up to 27m
0.8m
1.0m
1.4m
1.0m
1.4m
1.7m
1.4m
1.7m
2.3m
GUIDANCE INTHE EVENT OF A PROBLEM
●
If you have a problem, in the first instance contact the plumber who fitted the unit. There after contact the plumber
who carries out the annual servicing for you.
Check current amps drawn by the heater, should be approx.
15 amps. If heating element fails to operate, change the
complete heating element assembly.
PROBLEM SOLVING
No water in tap from the SCx Unit
Check that mains supply is on.
Important. In the event of an over heat situation reset all
thermal cutouts.
Check that the line strainer is not blocked
Check that the combination valve has been fitted so that the
arrow on it faces in the direction of the water flow.
If hot water discharges from Tundish
If the water at the hot tap is cold
WARNING: Do not turn the mains water supply off - switch off
(1) power to immersion heaters (Direct) or (2) shut down
heating boiler (Indirect)
Boiler (indirect): Ensure that the boiler has been switched on
and working correctly.
If hot water discharges from the tundish on indirect models there
could be a fault with the thermal cut out, cylinder thermostat or
temperature pressure relief valve. On a direct model the fault
could lie with the heating element thermostat. We recommend
you call your installer or Dimplex Service Agent.
Check that no air blocks have occurred in the primary system
Check the following are all connected correctly
Cylinder Stat
Thermal cut out (Reset by pushing red button)
Motorised valve
SPARES
Boiler thermostat (max setting 82 degrees Celsius)
Boiler thermal cut out (if fitted)(Reset by pushing red button)
Direct (Electric) Models
When ordering replacement parts the serial number on the
unit should be quoted.
PART/COMPONENT REFERENCES
WARNING: Isolate unit at main electric supply before opening
heating element cover.
Tundish 15mm to 22mm -
Expansion Vessel Kit (12 Litre) -
Expansion Vessel Kit (18 Litre) -
Expansion Vessel Kit (25 Litre) -
Motorised Valve -
SC06006
SC06001
SC06002
SC06003
SC06007
SC06009
SC06005
SC06008
SC06004
Ensure that power is available to the element from the electric
mains and that the isolator is on. If there is power to the
element and the element fails to operate check as follows:
Check that the thermal cut out on the elements have not
operated. If they have, reset by pressing the red button. If they
cut out again as the water heats up the cylinder thermostat
has failed and needs replacing. Fit a new thermostat and
reset the thermal cut out.
Immersion Heater -
Temp/pressure Relief Valve -
Twin Thermostat -
Inlet valve assembly -
WARNING: Should the factory fitted temperature and pressure
relief valve be tampered with your guarantee will be
invalidated. Neither the distributor nor manufacturer shall be
responsible for any consequential damage howsoever caused.
With power on and the thermal cut out reset check the output
terminal on the thermostat. If the circuit cannot be
completed, the thermostat and/or cut out needs replacing.
10
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