MCDonald Electraflow User manual

Installation & Technical Manual
ELECTRAflow
Thermal Store
Tel: [phone]
www.mcdonaldwaterstorage.com
April 2022
ELECTRA flow Thermal Store Tank, Installation & Technical Manual
Manual must be completed by Installer and left with Home Owner

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Contents
Preface............................................................................................................2
Handling & Storage..........................................................................................2
What is a Thermal Store?.................................................................................3
Design .............................................................................................................3
Mains Water Supply ........................................................................................4
Immersion Heaters..........................................................................................4
Water Treatment.............................................................................................5
Pipework .........................................................................................................6
Discharge/Overflow Requirements ..................................................................6
Showers...........................................................................................................7
ELECTRAflow Cylinder: General Schematic.......................................................8
ELECTRAflow Cylinder: Description & Heights ..................................................9
ELECTRAflow Rectangular Tank: General Schematic.......................................10
ELECTRAflow Rectangular Tank: Description & Heights..................................11
Technical Data ...............................................................................................12
Installation Schematic....................................................................................13
ELECTRAflow Controller.................................................................................14
Commissioning ............................................................................................148
Troubleshooting ............................................................................................20
Warranty.......................................................................................................21
Ancillary Descriptions ....................................................................................23
Commissioning Checklist................................................................................24

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Preface
An early adopter of the principal of domestic thermal stores, McDonald Water Storage
first started manufacturing thermal stores in early 1990s. Manufactured by our trained
coppersmiths and designed based upon the experiences of our technical team. The
McDonald Water Storage ELECTRAflow provides the perfect electric only solution to
both mains pressure hot water and wet central heating.
This information provided is intended to provide support with the installation of the
ELECTRAflow thermal storage system. Responsibility for selection and specification of
our equipment remains that of our customer and any experts or consultants concerned
with the installation(s). Our full Terms & Conditions of Sale are available on request.
The ELECTRAflow thermal storage system is required to be fitted by a competent
installer, in accordance with Building Regulations G, Gas Safety Regulations, and the
Water Fitting Regulations (England and Wales),Water Fitting Regulations (Northern
Ireland) or Water Byelaws (Scotland).
(Please note that while the ELECTRAflow overcomes Safety implications within Building
Regulations G3 relating to pressure and temperature discharge requirements, the installation of
the ELECTRAflow may be notifiable to the relevant building control.)
Handling & Storage
It is important the ELECTRAflow is handled with care and stored the correct way up in a
dry place at all times prior to, during and after installation.
Carrying handles are provided in the back of the rectangular cased products to assist
with lifting and positioning. DO NOT LIFT BY THE PIPEWORK as this can loosen off the
pre-tested pipework andmayresult in leaks. It is good practice to check the joints before
filling with water in case anything has been loosened in transit. Any manual lifting will
need to comply with the requirements of the Manual Handling Operations Regulations
issued by the Health & Safety Executive. For installations on higher levels of properties
such as the 4th floor it is recommended as best practice for the ELECTRAflow to be
moved vertically within a lift.

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What is a Thermal Store?
•Initially the Thermal Store is filled through the ball-valve that is sited in the feed
and expansion tank to the cold working level. This primary water stays within
the unit.
•The primary store of water is then heated directly via the use of immersion
heaters.
•The hot water is generated via a secondary heat exchanger that draws its heat
from the primary store of water.
Design
The copper ELECTRAflow Thermal Store is a bespoke primary store that is very well
insulated to ensure minimum Heat Loss and optimally designed to meet the stringent
requirements of ERP. In addition, the rectangular tank variant will hold 25% more water
than a cylinder in a given space, and the dimensions can be altered to make the best
use of the available space.
Cold water at mains pressure passes through a High Efficiency Coil, which is specifically
designed to draw heat from the thermal store at mains pressure. This heated water is
subsequently blended with cold mains water through a Thermostatically Controlled
Mixing Valve, to provide mains pressure water at 55°C to the taps and showers.
If the length of the hot water draw off pipework is excessive, and delivery time to the
outlet is greater than 60 seconds, you may consider using a secondary pipework loop.
The Secondary Pipework Loop (DHW Coil & External Pipework) can contain a total of
3 - 5 Litres of water, and incorporates an expansion bottle to accommodate the thermal
expansion of the heated mains water. If the volume of the secondary pipework loop
exceeds 15 Litres, then the installer must fit suitable relief valves and appropriately
sized expansion vessels.
The open vented wet central heating system is supplied directly from the store whereas
a sealed heating system is supplied via an internal heating coil. The installer must
appropriately size the heating expansion vessel for any sealed heating system.
Being a thermal store that is vented, it is inherently safe and requires no annual
maintenance. Its benefits go one step further as being a primary store there is no
legionella risk, and having a blending valve ensures in-built scald protection.

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Mains Water Supply
•The mains supply to the unit should ideally be in a minimum of 22mm diameter
but will work with 15mm if there is adequate pressure and flow rate.
•The ELECTRAflow will operate with a minimum incoming mains pressure of 1.0
Bar and a minimum flow rate of 10 Litres/minute.Careful consideration should
be made to ensure the pressure of hot and cold supplies are balanced.
•An incoming pressure of 2.1 Bar is the most optimal for performance.
•If the incoming pressure exceeds 3 Bar, then a pressure reducing valve must be
fitted after the stopcock of where the incoming cold supply enters the property.
•No Pressure Reducing Valve or Check Valve should be fitted within 2 metres of
the Cold Inlet to the ELECTRAflow Coil.
•If the flow rate exceeds 18 Litres per minute at any tap, it should be restricted
to maintain the performance of the system as a whole.
Immersion Heaters
•The temperature of the store is controlled by the ELECTRAflow controller. This
has been preset to 85°C, but can be adjusted to between 75°C and 90°C to suit
user requirements, see separate controller instructions regards how to change
the setting. The temperature is monitored through the PT1000 sensor at the
top of the unit and will control the power to the immersions.
•The Immersion Heater high limit thermostats are preset at 90°C.
•If in any doubt of how to set the Immersion or what temperature we would
advise for specific installations, please contact us on 01592 611123.
•All Immersion Heaters should be wired by a qualified electrician as shown
below, for further information refer to literature provided with the immersion;

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Water Treatment
In accordance with the Building Regulations L1A: New Dwellings/ L1B: Existing
Dwellings, the requirements set out in the Domestic Building Services Compliance
Guide specify that “where the mains water hardness exceeds 200ppm provision should
be made to treat the feed water to water heaters and the hot water circuit of
combination boilers to reduce the rate of accumulation of lime scale”. In most instances
of this water condition, an inline Water Conditioner/Scale Inhibitor would be fitted to
the incoming mains.
The water quality shall be in accordance with European Council Directive 98/83/EC, or
revised version at the date of installation, and is not fed with water from a private
supply. Particular:
•Chloride content: Max. 200 mg/l
•Sulphate content: Max. 200 mg/l
•Combination chloride/sulphate: Max. 300 mg/l (in total)
The ELECTRAflow is part of the primary system and other parts of the primary circuit
will require the application of a protective scale and corrosion inhibitor such as Fernox
to ensure adequate protection. This should avoid having corrosive material in the
primary system and remove any build-up of sludge which can reduce the performance
of the High Efficiency Heat Exchanger Coil.
The volumes and concentration of inhibitor required should be calculated in accordance
with the manufacturer’s instructions. Please ensure that the thermal store volume is
also included as well as the radiator and pipework volume.
An inhibitor is optional where a sealed heating coil is specified. However if there are
doubts regarding the quality of water being used to fill the ELECTRAflow, an inhibitor
should be added to the appliance when filling in line with the manufacturer’s
instructions for these products.
Please note that in all ELECTRAflow models, the primary water within the thermal store
water is used as primary storage and the domestic hot water is heated instantaneously
by means of the High Efficiency Heat Exchanger Coil. Therefore, treating the primary
water will not have an effect on the domestic hot water supply.

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Pipework
It is imperative to achieve balanced supply of hot and cold water in a mains pressure
system, and that the piping in a dwelling should be sized in accordance with BS 6700.
However, the following rule of thumb guide lines should be adequate for most of the
smaller property types as long as water pressures are within the recommended range.
•The cold feed from the main incoming stop tap to the ELECTRAflow should be run
in 22mm pipe. The cold main and hot draw-off should also be run in 22mm as far
as the branch to the bath tap. 
•A 15mm copper or equivalent external service may be sufficient for a small 1
bathroom dwelling (depending upon the flow rate available), but the minimum
recommended size for new dwellings is 22mm (25mm MDPE).
•The internal branches to the hand basins and sinks should be in 10mm and to the
baths and showers in 15mm. (1 metre minimum) 
•A pressure reducing valve must be fitted after the stopcock if above 3 bar,
where the incoming cold supply enters the property and at least 2 metres from
the unit.
•To drain DHW system, cold mains to unit must be isolated with a hot tap
opened. Place a bucket or similar below the compression elbow and remove to
drain the water from the coil and DHW System. Once cold mains has been
connected, the compression elbow should be tightened both sides.
Discharge/Overflow Requirements
The ELECTRAflow is a Vented Thermal Store and therefore does not require safety
discharge from a Pressure and Temperature Relief Valve as highlighted in Part G of the
Building Regulations.
The Manual Fill version of the ELECTRAflow Thermal Store can be sited anywhere within
the property as no discharge pipework is required, however we do supply an Overflow
pipe to the Feed & Expansion tank. (On the Multifuel model, if an open vented central
heating is to be run, ensure a minimum 500mm from the highest point of the radiator
circuit and the bottom of the Feed & Expansion Tank.) Once the unit is filled through
the pipework, close off the isolation valve and disconnect the flexible hose from the
pipework and cap the pipe to avoid any dead legs.

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If an Automatic Fill version is to be installed then the overflow must be run to a suitable
drain point. A tundish is supplied if the overflow termination is difficult to see. The
tundish must be fitted vertically, with continuous fall of the overflow pipe.
The overflow should be run in either 22mm copper tube or high temperature overflow
pipe with suitable supports. Ensure that the overflow is capable of coping with a ball-
valve fail situation and restrict flow to the ball-valve accordingly.
Showers
•ELECTRAflow is compatible with all showers.
•Most commonly used are of the Thermostatic Mixing type. All mains pressure
systems are subject to dynamic changes particularly when other hot and cold
taps/showers are opened and closed. This will cause changes in the inlet hot
water temperature and pressure at mixed water outlets such as showers.
•Careful consideration should be taken in selecting specification of the shower
valve to ensure the correct mixed water temperature and pressure is
maintained and that it is suitable for the type of people using it.
•Some showers in the TMV2 range have about a 10 degree differential between
the hot inlet temperature and the mixed outlet temperature, allowing
showering temperatures of up to 48 degrees.
•Other valves such as TMV3 only allow maximum temperatures of 41 degrees.
•Commissioning should ensure that the hot draw off from the thermal store is
set taking this into account.
•Please ensure that the shower head is capable of taking mains pressure.
•Please ensure that the shower tray drain is capable of handling the shower
head flow rate. A flow restrictor may be required in the shower outlet hose.
•The hot water supply to a shower-mixing valve should be fed wherever
practical directly from the ELECTRAflow or be the first draw-off point on the
hot circuit.
•The cold supply to a shower-mixing valve should wherever practical be fed
directly from the incoming mains. To ensure balanced pressure for the shower
mixing valve, a pressure reducing valve must be fitted after the stopcock of
where the incoming cold supply enters the property.
•The shower must incorporate or be fitted with the necessary check valves to
provide back-syphonage protection in accordance with the Water Regulations.

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ELECTRAflow Cylinder
PT1000 Sensor
Pocket
3kW
Heating Return
Drain
Cold Mains
Secondary Water
Hot Out
c/w Thermostatic
Mixing Valve
Expansion
Chamber
High Efficiency
Secondary Coil
Ball-valve
HW Boost
Immersion
Store (CH)
Immersions x2
Overflow
3kW
3kW
Flexi-Hose
& Isolator
Heating Flow

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ELECTRAflow Cylinder: Description & Heights
The ELECTRAflow Combination Cylinder is an electrically heated Thermal Store
cylinder. This unit is suitable for use with off peak electricity tariffs, such as Economy 7
and Economy 10.
These dimensions and the diagrams shown above are indicative to provide guidance to
approximate sizes. The ELECTRAflow Thermal Store units are bespoke designed to suit
the specific installation and will be supplied with a sketch prior to manufacturing.
Capacity (Litres)
180
210
250
300
Diameter (mm)
550
550
600
600
Height (mm)
1500
1700
1700
2050
Heating Expansion (l)
25
25
25
25
Allow 100mm clearance on any face of the unit with pipework / connections and allow
225mm between the top of the tank and ceiling to allow access to service the ball-
valve if ever required.
The ELECTRAflow is a bespoke designed product with indicative sizes for reference
shown above. Larger volumes and different configurations other than shown are
available to suit the available space and application.
The units are also available in a cylinder variant, with indicative sizes shown below.
Capacity (Litres)
180
210
250
300
Diameter (mm)
550
550
550
600
Height (mm)
1350
1550
1850
1850
The selection chart below provides a guideline to sizing the ELECTRAflow, but please
note that this will incorporate both the heating and hot water demand.
Capacity (Litres)
Property Type
180
1 Bed with shower
210
1 Bed with bathroom
250
1 –2 Bed with bathroom & en suite shower
300
2 –3 Bed with bathroom & en suite shower

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ELECTRAflow Rectangular Tank
Overflow
Ball-valve
Hot Out
c/w Thermostatic
Mixing Valve
Store (CH)
Immersions x2
Drain
Heating Flow
Heating Return
Expansion
Bottle
Cold Mains
DHW Coil
3kW
Flexi-Hose
& Isolator
3kW
3kW
HW Boost
Immersion
PT1000 Sensor
Pocket

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ELECTRAflow Rectangular Tank: Description & Heights
The ELECTRAflow Tank is an electrically heated Thermal Store tank. This unit is suitable
for use with off peak electricity tariffs, such as Economy 7 and Economy 10.
These dimensions and the diagrams shown above are indicative to provide guidance to
approximate sizes. The ELECTRAflow Thermal Store units are bespoke designed to suit
the specific installation and will be supplied with a sketch prior to manufacturing.
Capacity (Litres)
180
210
250
300
Depth (mm)
540
570
600
640
Width (mm)
540
585
600
640
Height (mm)
1285
1285
1260
1285
Heating Expansion (l)
20
20
20
20
Allow 100mm clearance on any face of the unit with pipework / connections and allow
225mm between the top of the tank and ceiling to allow access to service the ball-
valve if ever required.
The ELECTRAflow is a bespoke designed product with indicative sizes for reference
shown above. Larger volumes and different configurations other than shown are
available to suit the available space and application.
The selection chart below provides a guideline to sizing the ELECTRAflow, but please
note that this will incorporate both the heating and hot water demand.
Capacity (Litres)
Property Type
180
1 Bed with shower
210
1 Bed with bathroom
250
1 –2 Bed with bathroom & en suite shower
300
2 –3 Bed with bathroom & en suite shower

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Technical Data
Combination Cylinder ERP / Heat Loss Data
Capacity (Litres)
180
210
250
300
Insulation Thickness (mm)
50
50
50
50
ERP Class
C
C
C
C
Standing Heat Loss (Watts)
59
65
72
80
Standing Heat Loss (kWh/day)
1.43
1.52
1.64
1.82
Rectangular Tank ERP / Heat Loss Data
Capacity (Litres)
180
210
250
300
Insulation Thickness (mm)
50
50
50
50
ERP Class
C
C
C
C
Standing Heat Loss (Watts)
73
78
85
94
Standing Heat Loss (kWh/day)
1.75
1.87
2.04
2.26
Thermal Store ELECTRAflows have been tested in accordance with EN 50440. Heat losses should not be
directly compared with heat losses from unvented/vented tanks, because unvented/vented tanks are tested
at 65°C and thermal stores at 75°C, so they are treated differently in SAP.
Draw Off Profile (L)
Capacity
@50⁰C
@45⁰C
@40⁰C
180
135
171
198
210
158
200
231
250
188
238
275
300
225
285
330
•Store Temperature - 75⁰C
•Incoming Mains - 10⁰C
•Ambient Temperature - 20⁰C
•Tap Flow Rate - 12L/min

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Installation Schematic

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Controller
The ELECTRAflow unit is supplied complete with the controller and room thermostat.
The controller enables the following functionality for the homeowner;
•Set the heat up times for the thermal store inline with the available off-peak
tariffs at the property
•Set the heating times for the property
•Boost the store if it has been depleted of heat during the day
•Adjust the store temperature to suit the installation requirements
Controller Specification
The ELECTRAflow unit is supplied complete with the controller and room thermostat.
The controller enables the following functionality for the homeowner;
Purpose of control : Sensing control
Classification : Type 1.B Action, micro-disconnection on operation
Contact rating : 230VAC Suitable for heating element up to 3KW
Control power supply : 230V AC 50Hz 4W
Load power supply : 230V AC 50Hz 3 x 3KW + 700W (heating pump)
Boost duration : 30, 60 and 120 min
Operating temperature range : 0OC to 40OC
Control pollution situation : Pollution degree 2
Shock protection : Class II
Rated impulse voltage : 4000V
Ball pressure test : 75OC
Enclosure protection : IP30
Contacts : Micro-disconnection
Construction : Independently mounted control for surface mounting
Case material : Polystyrene, UL94-HB
Overall Dimensions : Width 235mm (including cable glands)
Height 182mm
Depth 63mm
Mounting : Surface mounting
Warning - Installation and connection should only be carried out by a suitably
qualified person and in accordance with the current edition of the IEE wiring
regulations. Warning: Isolate all the mains supplies before commencing installation.

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Controller Mounting
Fix the unit securely in place using the 4 off 5mm dia. mounting holes in the enclosure.
The mounting holes are located directly behind the enclosure lid screws. The drawing
above shows the location and fixing centres of the holes.
The Controller should be located in close proximity to the cylinder in a position where
it will remain dry. The unit should be mounted on a suitable solid surface (e.g. wall or
metal plate), however ensure that:
•the mounting surface is flat to avoid distortion of the case.
•clearance is provided for mounting the enclosure and that there is sufficient
access for wiring to the unit.
•ensure a minimum of 50mm free air space around the unit (excluding the rear
face). Do not mount directly to any heat source.
•avoid tight radius bends on all external cables to the unit.

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Controller Wiring Diagram
The supply circuit for each heater group should have an independent connection to
the power distribution equipment and be protected by a suitably rated HRC fuse or
circuit breaker. An appropriately rated isolation switch (minimum contact air gap of
3mm) should be used close to the control.
Three-core cable should be used for each of the heater connections, with a minimum
conductor size of 2.5mm2 for a 3KW heater. A three core cable should be used for the
mains supply to the controller, with a minimum conductor size of 6.0mm2. All cables
must pass through the cable glands provided and be secured on completion of wiring.
Note. The Controller must be powered from a single independently fused and
switched supply which is not derived from the heater circuits. This will allow the unit
to operate during programming with the heater supplies switched off for safety. The
supply must also always be present and cannot be powered by an externally switched
economy supply.
Please note, although there are three 3KW heaters attached the unit only requires a
6KW mains supply, as it is only possible for a maximum of two of these to be on at the
same time.

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Controller Circuit Board
Controller Repair and Service
The Controller is NOT user serviceable.
Do not dismantle the Controller.
In the unlikely event of a fault developing please contact your installer or qualified
electrician.
The control unit is protected by an internal 100mA fuse. Under abnormal load
conditions the fuse will blow and need replacing (230VAC T100mA).
The immersion heaters are protected by individual internal 15A HRC fuses.
In the event that a fuse should blow, the reason should be investigated as an
underlying problem may be overlooked. If the immersion heaters / pump are found to
be in good working order and the wiring shows no sign of damage the fuse should be
replaced with a new, identically rated, device. (230VAC F15A HRC)
Controller
Supply
Room Stat
CH Pump
RTD
(PT1000 Sensor)
STR2 Heater
(Str Immersion 2)
STR1 Heater
(Str Immersion 1)
Boost Heater
(HW Immersion)
Heater Supply

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Commissioning
The below is a recommended guide of actions and checks that should be undertaken
during commissioning:-
DO
✓During commissioning, complete all relevant sections of the Commissioning
Checklist (Page 22-24). This must be completed during commissioning and left
with product to meet the Warranty conditions.
✓Check the incoming mains water pressure. If the incoming mains pressure is higher
than 3.0 Bar, fit a Pressure Reducing Valve set at 3.0 Bar maximum –recommended
2.1 Bar where the cold supply enters the property as this will create balanced
pressure throughout.
✓Ensure that connections are fitted in accordance with the sketch supplied
✓Ensure the drain is connected to allow draining of the unit if required. If a drain-
cock is fitted, we recommend a DZR fitting.
✓Fit the Overflow with Copper piping or high temperature plastic to the thermal
store system where required.
✓Allow 100mm clearance on any face of the unit with pipework / connections and
allow 225mm between the top of the tank and ceiling to allow access to service the
ball-valve if ever required.
✓Check that all pipework connections on the ELECTRAflow are tight with pipes fully
inserted following transit and handling.
✓Fill the ELECTRAflow via the ball-valve in Feed & Expansion Tank
✓Ensure the system is inhibited correctly –see page 5.
✓Check the water level in the Feed & Expansion Tank, and adjust ball-valve so water
is at lowest level.
✓On the Automatic Fill version, turn down servicing valve once system is initially
filled to where the warning/overflow pipe will cope with the discharge from a ball-
valve failure.
✓On the Manual Fill version, once the unit is filled through the pipework, close off
the isolation valve, disconnect the flexible hose from the pipework and cap the pipe
to avoid any dead legs.
✓Check for leaks throughout the thermal storage system.
✓Run all taps and other hot outlets to remove all air from the system.
✓Ensure the store temperature is set to between 75⁰C and 90⁰C on the controller.
Consideration should be made for the temperature and pressure rise, caused by
“creeping”, where small draw offs are present.

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✓Electric only - Immersion Heater temperature is set by the ELECTRAflow controller
and is supplied at 85⁰C, but can be adjusted to between 75⁰C and 90⁰C to meet
users’ hot water requirements.
✓Temperature Controls must be fitted to ensure safe temperature of Thermal Store
✓Ensure PT1000 sensor is secure in the pocket (ie crimping the pocket)
✓On installs where open vented central heating is run from the ELECTRAflow, ensure
that 500mm height difference is in place between the highest point of the radiator
circuit and the bottom of the Feed & Expansion Tank.
✓Ensure that all exposed pipework on the ELECTRAflow is insulated to minimise any
heat losses.
✓Ensure the Thermostatic Mixing Valve is adjusted to control the hot water outlet
temperature between 50 - 55°C (take shower differential into consideration).
✓If required, chlorinate the hot and cold water system in accordance with BS 6700
and Water Regulations. Please note that the whole of the domestic hot and cold
water systems must be adequately flushed after chlorination. Failure to do so will
cause damage to the exchangers/immersion heaters etc.
DON’T
Use a combined feed and vent.
Place any clothing or other combustible materials against or on the ELECTRAflow.