MCDonald POWERflow Series Installation and maintenance instructions
BESPOKE RANGE OF
UNVENTED HOT WATER CYLINDERS
Installation & Service Instructions
Hot Water Storage Solutions
Page 2
Issue 4: March 2020
Section Page
DESIGN
Introduction 3
Storage and Handling 4
Equipment Supplied 5
Mains Cold Water Supply 6
Positioning The Cylinder 6
Schematic Diagram 7
Technical Data 8
INSTALLATION
Cold Mains Pipe Work 10
Temperature and Pressure Relief Valve 11
Expansion Vessel 11
Secondary Return Circulation 11
Boiler and Soalr Connection 11
Electric Immersion Heaters and Connections 12
Discharge Pipe Arrangement 13
Wiring Diagram Two 2 Port Valves (S-Plan) 16
Wiring Diagram 3 Port Mid Position Valve (Y-Plan) 16
COMMISSIONING
Filling the Cylinder 17
Storage Temperature 17
Safety Valve Checks 17
SERVICING AND MAINTENANCE
Service The POWERow Range 18
How to Drain the Cylinder 18
Annual Inspection & Maintenance 18
Troubleshooting 19
Scale Protection 20
Short Parts List 21
Product Warranty 22
Commissioning Checklist 24
Service Record 26
Page 3
INTRODUCTION
The POWERow
designed to fully optimise the performance of the heat source it is connected to
whether that is a conventional boiler, electric immersion heater or solar thermal.
and heat up performances possible along with unrivalled thermal loss protection
from the high density foam insulation.
All unvented cylinders come with all necessary safety and control devices required
to connect to the cold water mains and are compliant with G3 building regulations.
All McDonald Water Storage products are manufactured under a ISO9001:2015
Quality Management System.
IMPORTANT
Please ensure that these instructions are left with the householder.
Failure to install and maintain this system in accordance with these instructions will
invalidate the manufacturers warranty. Extended warranty card to be completed and
returned.
Installers are required to carry out installation, commissioning and servicing work in
accordance with the Benchmark Code of Practice which is available from the Heating
and Hot Water Industry Council who manage and promote the Scheme. Visit www.
centralheating.co.uk for more information.
For further information on the HWA Charter Statement, please refer to the HWA
website hotwater.org.uk.
DESIGN
Page 4
MANUFACTURER: MCDONALD WATER STORAGE
Maximum inlet pressure to ressure reducing valve 12 bar
Operating pressure (PRV setting) 2.1 bar
Expansion vessel charge pressure 2.1 bar
Expansion relief valve setting 3.5 bar
Opening pressure of P & T Relief Valve 4.5 bar
Opening temperature of P & T Relief Valve 90°C
Energy cut-out thermostat setting 80°C
Max. working pressure - Primary heat exchanger (Indirect models) 3.5 bar
Max. working pressure - Solar heat exchanger (Solar models) 6 bar
Immersion heater rating 3kW, 240V AC
The table above and throughout this manual, we refer to the settings associated
with the standard 2.1 bar operating pressure unit. For other operating pressures
supplied, please see below.
Operating pressure of the cylinder 1.5 bar 3 bar
Max inlet pressure to pressure reducing valve 12 bar 12 bar
Operating pressure (PRV setting) 1.5 bar 3 bar
Expansion vessel charge pressure 1.5 bar 3 bar
Expansion relief valve setting 3 bar 5 bar
Opening pressure of P & T Relief Valve 4.5 bar 7 bar
All cylinders are manufactured in accordance with the requirements of BS EN 12897
The tundish must be positioned so that it is visible to the occupant and is away from
electrical devices.
STORAGE & HANDLING
McDonald Water Storage must be stored in an upright orientation and should be
stored in a dry environment.
When lifting or carrying the cylinder, please handle with care. Do not use any factory
tted pipe work or connections as these can be damaged.
Safe manual handling and lifting procedures must be used when carrying any
cylinder.
DESIGN
Page 5
EQUIPMENT SUPPLIED
cylinders safely to the cold mains. G3 building regulation should always be considered
when installing unvented systems.
See the table below for components are supplied with the unvented cylinder.
DESIGN
COMPONENT Direct Indirect Direct Solar Indirect
Solar
Pressure Reducing Valve
Temperature and Pressure
Relief Valve (Fitted)
Expansion Relief Valve (Fitted)
Tundish (Fitted)
Check Valve
3kW Immersion Heater -
Primary Heat Source (Fitted)
3kW Immersion Heater - Back
Up Heat Source (Fitted)
Expansion Vessel
Dual Control and Overheat
Thermostat
Overheat Thermostat
Two Port Motorised Zone Valve
Flexible Hose For Connection
to Expansion Vessel
Page 6
MAINS COLD WATER SUPPLY
The POWERow range operates at 2.1 bar (see page 4 for other model settings),
which is controlled by the pressure reducing valve.
The water demand requirements of a property need to be assessed and care should
be made to take into account that hot and cold services are supplied simultaneously
from the mains cold water feed.
of the property. Installers should ensure that the incoming mains pressure is less
than 12 bar and that local authority approval for Installation of Unvented Systems is
granted.
existing ½”(15mm) cold mains pipe work may need to be increased in size.
POSITIONING THE CYLINDER
The POWERow range must be installed vertically on a stable base which must be
capable of supporting the weight when the cylinder is full of water.
of the cylinder. Additional considerations should be made to allow space to mount
dimensions of the product range are provided in this booklet.
Access for maintenance of all equipment should be considered when positioning the
unvented cylinder. Care should be taken that the immersion heater can be withdrawn
for servicing if required these are 375mm long. Building regulation G3 should always
be followed when installing discharge pipe work from the safety valves.
Any hot outlets which are higher than the cylinder will reduce in pressure by 0.1 bar
for every 1m of height difference.
All exposed pipe work should be insulated and additional considerations should be
taken to protect the unit from frost damage. Particular care is needed if the cylinder is
to be installed in an exposed location such as an outhouse or garage.
DESIGN
Page 7
DIRECT
INDIRECT
DIRECT SOLAR
INDIRECT SOLAR
DESIGN
A Hot Water Draw Off
B Secondary Return *
C T&P Valve
DDual Thermostat Control
E Expansion Relief Valve
F Tundish
G Immersion Heater
H Boiler Coil Flow
I Boiler Coil Return
J Solar Coil Flow
K Solar Coil Return
L Solar High Limit Thermostat
M Cold Feed
N Drain
O Solar Probe Pocket
* Selected models only
A A
A
A
BB
B
B
CC
C
C
FF
F
F
H
I
NN
N
J
J
K
K
N
G
G
D
G
MM
M
L
G
L
D
O
O
I
G
M
EE
E
O
O
G
H
E
Page 8
DESIGN
Direct / Direct Solar Model Size 75 120 150 180 210 250 300
Capacity (Litres) 75 120 150 180 210 250 300
Height (mm) 950 950 1150 1350 1550 1550 1850
Diameter (mm) 450 550 550 550 550 600 600
Approximate Weight (KG)
Direct Model
Empty 24 33 39 49 55 64 80
Full 99 153 189 229 265 314 380
Approximate Weight (KG)
Direct Solar Model
Empty 29 38 44 54 60 69 85
Full 104 158 194 234 270 319 385
Surface Area Of Solar Coil (m2)1.0 1.2 1.2 1.2 1.2 1.5 1.5
Pressure Loss Across Solar Coil (bar) 0.15 0.15 0.15 0.15 0.15 0.2 0.2
Dedicated Solar Volume 31 50 62 75 87 104 125
Heat Up Time 15-600C (mins)
(Primary heat source only) 79 126 157 189 220 262 314
Immersion Heater 3KW Single Phase - 230V - 50hz
Cylinder Material Copper
Insulation Type White Cased Polyurethane (PU) insulation with CO2Blowing Agent
Insulation Thickness (mm) 50 50 50 50 50 50 50
Model Size 75 120 150 180 210 250 300
Standing Heat Loss Watts 45 52 56 59 63 68 75
ErP Rating CCCCCCC
POWERFLOW DIRECT AND DIRECT SOLAR
TECHNICAL DATA
ERP DATA
DIRECT DIRECT SOLAR
Please note all data shown above is based on the white cased models with 50mm insulation.
Page 9 DESIGN
Indirect / Indirect Solar Model Size 75 120 150 180 210 250 300
Capacity (Litres) 75 120 150 180 210 250 300
Height (mm) 950 950 1150 1350 1550 1550 1850
Diameter (mm) 450 550 550 550 550 600 600
Approximate Weight (KG)
Indirect Model
Empty 26 37 44 55 61 70 86
Full 101 157 194 235 271 320 386
Approximate Weight (KG)
Indirect Solar Model
Empty 31 42 49 60 66 75 91
Full 106 162 199 240 276 325 391
Surface Area Of Boiler Coil (m2)1.2 0.62 0.7 0.88 0.97 1.06 1.23
Pressure Loss Across Boiler Coil (bar) 0.1 0.3 0.4 0.4 0.5 0.5 0.6
kW Rating Of Boiler Coil (kW)12 19 24 28 33 39 47
Surface Area Of Solar Coil (m2)1.0 1.2 1.2 1.2 1.2 1.5 1.5
Pressure Loss Across Solar Coil (bar) 0.15 0.15 0.15 0.15 0.15 0.2 0.2
Dedicated Solar Volume 31 50 62 75 87 104 125
Heat Up Time 15-600C (mins)
(Primary heat source only) 20 20 20 20 20 20 20
Immersion Heater 3KW Single Phase - 230V - 50hz
Cylinder Material Copper
Insulation Type White Cased Polyurethane (PU) insulation with CO2Blowing Agent
Insulation Thickness (mm) 50 50 50 50 50 50 50
Model Size 75 120 150 180 210 250 300
Standing Heat Loss Watts 45 52 56 59 63 68 75
ErP Rating B B B C C C C
TECHNICAL DATA
ERP DATA
POWERFLOW INDIRECT AND INDIRECT SOLAR
INDIRECT INDIRECT SOLAR
Please note all data shown above is based on the white cased models with 50mm insulation.
Page 10
INSTALLATION
COLD MAINS PIPEWORK
Fit to the pressure reducing valve set at 2.1 bar (see page 4 for other model settings),
which includes a serviceable strainer.We would strongly recommend this valve is
the installation, between the stopcock and the cylinder.
also providing potable water throughout the property. Outdoor taps for hoses should
be taken before the pressure reducing valve.
and before the expansion vessel on the cold feed. Any balanced cold draw off should
INSTALLATION
Non
Return
Valve
Pressure
Reducing
Valve
(With Strainer)
Check
Valve
Expansion
Vessel
Tee
Compression
2 Port
Valve
Pump
Secondary Return Circuit
(180 litre models and larger) Hot Water Draw Off
Cold Feed
Drain
Discharge Pipework
Tundish
Expansion
Relief Valve
Boiler Flow
Immersion
Heater
Boiler Return
Dual
Thermostat
Temperature and
Pressure Relief Valve
Page 11
TEMPERATURE AND PRESSURE RELIEF VALVE
The temperature and pressure relief valve is set at 900C and 4.5 bar, and the expansion
opposite). Note, the relief valves are only used for relief discharge purposes.
EXPANSION VESSEL
The expansion vessel should be set the same as the pressure reducing valve.
It is recommended that the expansion vessel be installed in the vertical orientation so
that the expansion vessel is:-
• bottom fed and upright; and
- rises continuously
- is kept to a minimum
provided. Please remember that the vessel will get much heavier once it is full of
water. Access must be available to the bottom of the vessel.
The expansion vessel should be connected to the tee. No isolating valve is permitted
between the expansion vessel and cold feed.
SECONDARY RETURN CIRCULATION
a secondary circulation loop is greater than 15% of the unit capacity, an extra expansion
vessel may be required to ensure expansion of the additional volume is absorbed.
A non-return valve MUST be FITTED near the return connection. No valve or terminal
BOILER AND SOLAR CONNECTION
On indirect units, the two port motorised zone valve and dual thermostat controller
units are suitable for oil, gas or electric boilers on a pumped, gravity or sealed system.
(We would recommend 28mm coil connections and zone valve on gravity systems.)
The solar controller should be wired using the high limit thermostat to ensure power
is cut to the solar pump in the event of an overheat situation. Please refer to the solar
equipment instructions for further details.
INSTALLATION
Page 12
ELECTRIC IMMERSION HEATERS AND CONNECTIONS
cut out at 800C) to the power supply and earth them in accordance with the current
IEE wiring regulations. The fuse rating should be 13 Amps.
Do not at any time t immersion heaters without a thermal cutout.
Immersion heaters and the dual thermostat controller supplied with the indirect units
should be set to no greater than 600C and the internal high limit thermostats are
factory set no higher than 800C.
All electrical wiring to thermostats, zone valves and immersion heaters must be
earthed and to current IEE Wiring Regulations. The fuse should generally be 3 Amps
but refer to component instructions to conrm this.
All wiring should be carried out by a qualied electrician.
INSTALLATION
E
N
L
Control
Stat
Reset
Stat
EARTH (GREEN/YELLOW)
LIVE (BROWN)
NEUTRAL (BLUE)
Twin Stat Immersion
E
N
L
EARTH (GREEN/YELLOW)
LIVE (BROWN)
NEUTRAL (BLUE)
Combined Stat Immersion
Page 13
DISCHARGE PIPE ARRANGEMENT
Position the inlet control group so that the discharge from both safety valves can be
joined together via a 15mm end feed Tee. Connect the tundish and route the discharge
pipe. The discharge pipe work must be routed in accordance with Part G3 of schedule
1 of the Building Regulations. The information that follows is not exhaustive and if
you are in doubt you should seek advice. The two safety valves will only discharge
water under fault conditions. When operating normally water will not be discharged.
The tundish should be vertical, located in the same space as the unvented hot water
with no more than 600mm of pipe between the valve outlet and the tundish.
Any Discharge should be visible at the tundish. The tundish should be located such
that any discharge is visible. In addition, where discharges from safety devices may
not be apparent, e.g. people with impaired vision or mobility, consideration should
be given to the installation of a suitable safety device to warn when discharge takes
place, e.g. electronically operated.
The discharge pipe (D2) from the tundish should:
A) Have a vertical section of pipe at least 300mm long, below the tundish before any
elbows or bends in the pipe work.
B) Be installed with a continuous fall of at least 1 in 200 thereafter.
INSTALLATION
Page 14
and non-metallic rainwater goods may be damaged by such discharges
Note: D2 pipe from tundish is now allowed to be installed in soil stacks within
premises. This activity is not recommended as discharge from T&P may continue for
long periods of time. It is the installer’s responsibility to ensure the discharge pipe
work can support the discharge for prolonged periods. If used follow guidance on
mechanical seal without water trap given in G3 Building Regulations. As discharge
can be in excess of 90ºC discharge into plastic pipe work is also not recommended.
The discharge pipe (D2) from the tundish should be of metal or other material that
has been demonstrated to be capable of withstanding temperatures of the water
discharged. The discharge pipe (D2) should be at least one pipe size larger than the
nominal outlet size of the safety device unless its total equivalent hydraulic resistance
exceeds that of a straight pipe 9m long i.e. 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.
1, Table 1 and the worked example. An alternative approach for sizing discharge
maintenance of services supplying water for domestic use within Buildings.
The discharge pipe (D2) should terminate in a safe place where there is no risk
to persons in the vicinity of the discharge. Examples of acceptable discharge
arrangements are:
water seal.
• Downward discharges at a low level; i.e. up to 100mm above external surfaces
such as car parks, hard standings, grassed areas etc. are acceptable providing
that where children play or otherwise come into contact with discharges, a wire
cage or similar guard is positioned to prevent contact whilst maintaining visibility.
• Discharges at a high level; e.g. in to metal hopper and metal down pipe with the
end of the discharge pipe clearly visible or onto a roof capable of withstanding
high temperature discharges of water and 3m from any plastic guttering systems
that would collect such discharges.
• Device to warn when discharge takes place.
INSTALLATION
Page 15
Worked Example
having 4 No. elbows and length of 7m from the tundish to the point of discharge.
Maximum resistance allowed for a straight length of 22mm copper discharge pipe
22mm elbows at 0.8m each = 3.2m.
Therefore the maximum permitted length equates to: 5.8m. 5.8m is less than the
actual length of 7m therefore calculate the next largest size.
temperature relief valve equates to: 14m. As the actual length is 7m, a 28mm (D2)
copper pipe will be satisfactory.
INSTALLATION
Sizing of copper discharge pipe ‘D2’ for a temperature relief valve
with a G1/2 outlet size (as supplied)
Size of discharge
pipework
Maximum length of
straight pipe
(no bends or elbows)
from the maximum length
for each bend or elbow in
the discharge pipe
22mm Up to 9m 0.8m
28mm Up to 18m 1m
35mm Up to 27m 1.4m
Page 16
INSTALLATION
8
FOR SPARES VISIT WWW.MCDONALDWATERSTORAGE.COM OR CALL 01592 611123
WIRING DIAGRAM TWO 2 PORT ZONE VALVE (S-PLAN)
DUAL THERMOSTAT WIRING
INDIRECT POWERflow WIRING DIAGRAM
2 PORT (HTG)
HIGH LIMIT
CUTOUT
CONTROL
STAT 2 PORT (DHW)
Br G Bl C
E E
1 1 2 C GBr Bl 0
1
0
10 WAY WIRING CENTRE 1 2 3 4 5 6 7 8 9 10
1234
ROOM STAT
L N HTG
ON
DHW
ON
DHW
OFF
PROGRAMMER
LSL N
BOILER
L
N
PUMP
5A SUPPLY
KEY: Bl=Blue, Br=Brown, C=Common Terminal, E=Earth, G=Grey, G/Y=Green/Yellow, L=Live, N=Neutral, O=Orange, SL=Switched Live, W=White
Note: The programmer and boiler power can be taken either from the Wiring Centre or from elsewhere as appropriate.
EE
E
3 PORT
Mid Position
HIGH LIMIT
CUTOUT
CONTROL
STAT 2 PORT (DHW)
W G Bl C
E E
1 1 2 C GBr Bl 0
2 12
0
10 WAY WIRING CENTRE 1 2
LN
3 4 5 6 7 8 9 10
1234
2
ROOM STAT
L N HTG
ON
DHW
ON
DHW
OFF
PROGRAMMER
LSL N
BOILER
L
N
3
2
PUMP
5A SUPPLY E
2 12
LN
2
3
2
E
EE
E
WIRING DIAGRAM 3 PORT MID POSITION VALVE (Y-PLAN) + 2 PORT VALVE
DUAL THERMOSTAT WIRING
Page 17
FILLING THE CYLINDER
the same as the setting of the pressure reducing valve (see page 4 for other model
settings).
Please check all connections including any which are factory made for tightness
such as the immersion heater, temperature and pressure relief valve before lling.
Firstly ensure the drain at the base of the cylinder is closed. The hot tap furthest away
from the Cylinder should be opened to allow the air in the pipe work to be forced out.
through any dirt or pipe jointing residue. Once this is completed close the furthest tap
and open all others to remove all remaining air.
Check the control thermostats on the immersion heater(s) and the dual thermostat
are set at no higher than 600C and that the high limit thermostats are set no higher
than 850C.
STORAGE TEMPERATURE
The recommended storage temperature for a POWERow cylinder is 60-65C.
Considerations should be made for the prevention of legionella control - For details
please consult the HSE legionella approved code of conduct and guidance document.
SAFETY VALVE CHECKS
The safety valve correct operation should be checked prior to cylinder heat up.
To do this turn the tops of both valves independently and ensure water passes
point make sure that your discharge pipe work is free from debris and is transporting
the water away to waste effectively.
The valves can then be released and a check should be made to ensure they have
re-seated correctly.
If water begins to discharge from either of the pressure relief valves during heat up
there is a problem and heat up should be stopped immediately.
COMMISSIONING
Page 18
SERVICING THE POWERow RANGE
hot water cylinder, any spare parts required must be purchased from McDonald Water
Storage. Safety devices should not be bypassed under any circumstances.
Please note, the warranty on the cylinder is void if the service is not completed by a
G3 qualied engineer.
HOW TO DRAIN THE CYLINDER
Before draining the cylinder the immersion heater should be isolated to prevent the
element from burning out. Shut the cold feed ball valve to isolate the cylinder from the
mains cold feed. Securely connect a hose pipe to the drain connection on the cylinder
and take the other end to a nearby waste or soak-away. The drain point should be
below the level of the cylinder to ensure that the maximum amount of water is drained
from the cylinder. The nearest hot tap should be opened to allow air back into the
system and prevent a vacuum being pulled in the cylinder. Care must be taken as the
draining water may be hot.
ANNUAL INSPECTION & MAINTENANCE
The POWERow range requires an annual service to ensure continued safe operation
at least 5 seconds. Upon release make sure it re-seats fully. Carry out the same
the discharge pipe work is carrying the water away adequately. If not check for
any potential blockages and clear them where necessary.
WARNING: THE DISCHARGING WATER MAY BE HOT!
• Check that the factory installed immersion heater is working and the internal
thermostat is controlling the water at the required temperature.
• Test the air pressure in the expansion vessel with the pressure in the Cylinder
dropped, this should be at 2.1 bar (see page 4 for other model settings). If this is
low the pressure can be topped up with a standard bicycle pump.
at the stopcock, remove cartridge, clean and replace.
• The POWERow log book supplied with this unit must be completed on every
service visit.
SERVICE & MAINTENANCE
Page 19
TROUBLESHOOTING
Discharge from either of the relief valves is an indication of a malfunction in the
system and must be investigated immediately.
OVERHEATED HOT WATER DISCHARGE
In the unlikely event of overheated (900C) water being discharged, the heat source
i.e. immersion heaters or boiler should be switched off immediately and a competent
operative called out. Ensure that the discharge of hot water or steam at the tundish or
Do not shut off the cold water supply to the unit or re-use until checked and repaired.
Once cold water has entered the unit and displaced the overheated water, check
the thermostats and energy cut out in the immersion heater, thermostat and boiler.
Identify the faulty component and replace with the correct component as supplied by
the manufacturer, and ensure that it works before re-commissioning the system. Do
not, for any reason, bypass an energy cut-out.
WATER DISCHARGE
If water is occasionally being discharged as the water is heated, this would indicate
that the expansion vessel needs recharging. Switch off all power to the cylinder and
recharge vessel as below.
allowed through the pressure reducing valve does not exceed 2.1 bar (see page 4 for
Next check the charge in the expansion vessel. If recharge is required, close the mains
stopcock and open a tap. Connect the pump with gauge to the air inlet on top of the
vessel and charge to the same as the pressure reducing valve. If after recharging
If any component has failed, it should only be substituted with a replacement part
from McDonald water Storage.
IMMERSION HEATER FAILURE
If the immersion heater is not heating the water, there may be an issue with the
or replaced, the immersion heater can be re-set by taking off the cap and depressing
the button on the high limit thermostat.
SERVICE & MAINTENANCE
Page 20
SCALE PROTECTION
requirements set out in the Domestic Heating 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”.
To comply with this requirement the hardness of the mains water should be checked
SERVICE & MAINTENANCE
This manual suits for next models
41
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