Unvented Direct & Indirect
Hot Water Cylinders
(400L - 2500L)
Important
Please read & understand all these instructions before commencing installation.
Please leave this manual with the customer for future reference
MEGAFLO Commercial Product Guide
PRODUCT SPECIFICATION (1)
Contents
Product Specification3
Introduction3
General requirements3
THE BENCHMARKtm SCHEME3
Checklist4
Storage and handling5
Operational summary
6
Technical data8
Thermostat control schematics
13
Limitations14
Water supply14
Installation & Commissioning
15
General Installation15
Cold Water Supply15
Discharge Pipe work20
Indirect Model22
Commissioning23
Maintenance & Servicing25
Maintenance requirements25
Clean the strainer25
Fault finding27
Benchmark log book28
Spares30
Servicing30
Spares drawings32
User Guide32
Lifetime Guarantee Terms and Conditions
2
Unvented Hot Water Cylinder
38
Introduction
Congratulations on your purchase of a MEGAFLO Commercial unvented water heater. The MEGAFLO
Commercial products are manufactured in the UK from top quality materials and meets all the
latest relevant safety and constructional standards. The high grade Duplex stainless steel cylinder
offers exceptional strength and corrosion resistance which is backed by a 25 year guarantee* Its
performance and insulation levels exceed the latest requirements of Building Regulation Part L.
The MEGAFLO Commercial unvented water heater can be fed directly from the cold water mains
supply to the property without the need for separate feed cisterns or vent pipes. It is supplied
complete with all its necessary inlet and safety controls.
The MEGAFLO Commercial cylinder range all require a separate expansion vessel to accommodate
any expanded water.
PRODUCT SPECIFICATION (1)
Product specification
General Requirements
IMPORTANT: Please read and understand this product guide before installing the MEGAFLO
Commercial water heater. Incorrect installation may invalidate the guarantee*.
The MEGAFLO Commercial must be Installed, Commissioned and Maintained by a competent
installer in accordance with Building Regulation G3 (England and Wales), Technical Standard P3
(Scotland) or Building Regulation P5 (Northern Ireland) and the Water Fitting Regulations (England
and Wales) or Water Byelaws (Scotland).
THIS APPLIANCE CAN BE USED BY CHILDREN AGED FROM 8 YEARS AND ABOVE AND
PERSONS WITH REDUCED PHYSICAL, SENSORY OR MENTAL CAPABILITIES OR LACK OF
EXPERIENCE AND KNOWLEDGE IF THEY HAVE BEEN GIVEN SUPERVISION OR INSTRUCTION
CONCERNING USE OF THE APPLIANCE IN A SAFE WAY AND UNDERSTAND THE HAZARDS
INVOLVED. CHILDREN SHALL NOT PLAY WITH THE APPLIANCE. CLEANING AND USER
MAINTENANCE SHALL NOT BE MADE BY CHILDREN WITHOUT SUPERVISION
WARNING: Do not switch on if there is a possibility that the water in the heater is frozen.
THE BENCHMARKtm SCHEME
Benchmarktm places responsibilities on both manufacturers and installers. The purpose is to ensure that
customers are provided with the correct equipment for their needs, that it is installed, commissioned
and serviced in accordance with the manufacturer’s instructions by competent persons and that it
meets the requirements of the appropriate Building Regulations. The Benchmarktm Checklist can be
used to demonstrate compliance with Building Regulations and should be provided to the customer
for future reference.
Installers are required to carry out installation, commissioning and servicing work in accordance with
the Benchmarktm Code of Practice which is available from the Heating and Hotwater Industry Council
who manage and promote the Scheme. Visit www.centralheating.co.uk for more information.
* See Terms and Conditions of guarantee on page 38
Note: This Megaflo commercial cylinder needs a minimum 100L/min water supply at open outlet.
Unvented Hot Water Cylinder
3
PRODUCT SPECIFICATION (1)
Checklist
Before commencing installation check that all the components for your MEGAFLO Commercial
unit are contained in the package. The following components are supplied as standard with your
MEGAFLO Commercial unit:
• Table 1: Cold Water Inlet Control Kit (as below, depending on model)
Commercial Cylinder
Volume (ltr)
400 - 500
800
1000
1250 - 1450
2000 - 2500
Pressure Reducing Valve
Pressure Relief Valve
S i n g l e
Check Valve
1” Integrated inlet control valve
1.25” (1.5 - 6 bar) or (5 -10 bar)
1” x 1.25” (8 bar) or (13 bar)
1.25” (1.5 - 6 bar) or (5 -10 bar)
1” x 1.25” (8 bar) or (13 bar)
1.5” (1.5 - 6 bar) or (5 -10 bar)
1” x 1.25” (8 bar) or (13 bar)
2” (1.5 - 6 bar) or (5 -10 bar)
1.25” x 1.5” (8 bar) or (13 bar)
• Table 2: Expansion Vessel (as below)
Commercial Cylinder
Expansion Vessel
Volume (ltr)
Size (ltr)
400 - 500
60
800
100
1000 - 1250
150
1450
200
2000 - 2500
300
1.25”
1.25”
1.5”
2”
Mounting Kit
Weights
Floor Mounted
Floor Mounted
Floor Mounted
Floor Mouinted
Floor Mounted
12kg
17kg
24kg
38.5kg
41kg
• Factory fitted Temperature & Pressure Relief Valve, set at 90ºC / 1 MPa (10bar) or factory fitted
Temperature & Pressure Relief valve set at 90ºC / 1.5MPa (15bar) Depending on model.
Connection size 1 1/4”BSP to cylinder, 28mm compression fitting out.
• Tundish 1 1/4” inlet/ 1 1/2” outlet
• Thermostat and Thermal cut-out (Indirect units only)
• Isolating Valve (1”, 1.25”, 1.5” or 2”) Depending on model
• 1” Drain Valve
• 2-Port Motorised Valve (Indirect units only)
• All connections BSP female
Notes:
1” Integrated inlet control valve is not assembled.
4
Unvented Hot Water Cylinder
Please take care when handling a packaged MEGAFLO Commercial. The unit is heavy and must
only be moved manually within safe working practices. If the unit is to be stored before installation,
it must be placed on a secure, level surface and in a dry, frost free environment.
Precautions to be carried out prior to commencement of work:
1.
2.
3.
4.
5.
6.
Tidy area ensuring there is safe access and egress to installation place, free from trip hazards.
Be aware of other people who may be in the area
Operate any machinery in accordance with training and operating instructions
Visually inspect the equipment prior to use, do not use damaged equipment.
Safe working practices are adopted for manual handling of appliances/parts
Correct PPE to be worn.
PRODUCT SPECIFICATION (1)
Storage and Handling
The MEGAFLO Commercial unit must be vertically floor mounted. It can be placed anywhere
convenient provided the discharge pipe(s) from its safety valves can be correctly installed. Areas that
are subject to freezing must be avoided. Ensure that the floor is level and of sufficient strength to
support the “full” weight of the unit when filled with water (refer to Table 4 on page 8 or Table 6,
page 9 for unit weights). Pipe runs should be kept as short as possible for maximum economy. Access
to associated controls, immersion heaters and indirect controls should be possible for servicing and
maintenance of the system.
To aid installation, the MEGAFLO Commercial is provided with lifting points located at the top of
the unit. To access the lifting eyes please remove the top cover. The weights of the units are noted
on Table 4, page 8 or Table 6, page 9.
FIGURE 1: Lifting
Unvented Hot Water Cylinder
5
PRODUCT SPECIFICATION (1)
OPERATIONAL SUMMARY (Indirect models in conformance with BS EN 12897:2006)
Maximum mains water supply pressure 2.5MPa (25 bar)
Operating pressure/PRV (low pressure system)
Operating pressure/PRV (high pressure system)
0.60MPa (6. bar)
1.00MPa (10 bar)
Expansion vessel pressure (low pressure system)
Expansion vessel pressure (high pressure system)
1.0MPa (10 bar max)
1.6MPa (16 bar max)
Expansion relief valve setting (low pressure system)
Expansion relief valve setting (high pressure system)
0.8MPa (8 bar)
1.3MPa (13 bar)
Maximum design pressure (low pressure system)
Maximum design pressure (high pressure system)
0.80MPa (8 bar)
1.3MPa (13 bar)
T&P relief valve setting
T&P relief valve setting
1.0MPa/90 °C (10 bar)
1.5MPa/90 °C (15 bar)
Primary coil operating pressure (max)
0.30MPa (3 bar)
Immersion heater rating (a.c. supply only) single phase
Immersion heater rating (a.c. supply only) 3 phase
(See Accessories on page 35 for full range)
6kW & 9kW 50/60Hz ~
12kW - 54kW 50/60Hz ~
Primary Coil ratings
See Table 10, page 10
Pressure drop across coils
See table 11, page 10
Storage weights (empty and full)
See Table 4, Page 8
See Table 6, Page 9
Coil surface area
6
Unvented Hot Water Cylinder
See table 10, page 10
PRODUCT SPECIFICATION (1)
Unvented Hot Water Cylinder
7
D
OUTLET
T&P VALVE
SENSOR
POCKETS
A
PRODUCT SPECIFICATION (1)
FIGURE 2: Indirect dimensions
SECONDARY
RETURN
35°
30°
C
E
F
INLET
G
B
PRIMARY
FLOW
PRIMARY
RETURN
Table 3: Indirect measurements
Direct Connection 400l
500l Connection 800l 1000l Connection 1250l 1450l Connection 2000l 2500l
A
N/A
1535 1804
N/A
1906 2301
N/A
1936 2253
N/A
2014 2419
B
N/A
1264 1416
N/A
1487 1882
N/A
1408 1693
N/A
1410 1515
C
1 1/4” BSP
400
D
N/A
872
872
E
1 1/4” BSP
418
418
F
1 1/4” BSP
593
593
G
1” BSP
1 1/2” BSP 437
399
N/A
1 1/4” BSP
1008 1108
437
1024 1024
443
618
618
1 1/2” BSP 707
8
Unit Weight (kg)
Empty
Full
400
105
505
500
110
610
800
164
964
1000
188
1188
1250
319
1569
1450
322
1872
2000
445
2445
2500
450
2950
Unvented Hot Water Cylinder
1” BSP
527
1224 1224
1 1/2” BSP 527
NOTE: All connections BSP female threads
Size
(Litres)
N/A
443
1 1/4” BSP
1” BSP
1183 1433
Table 4: Indirect weights
1 1/2” BSP 523
527
707
1172 1373
2” BSP
N/A
606
605
1470 1470
1 1/2” BSP 599
599
1 1/2” BSP 779 779
1” BSP 1225 1474
°
15
PRODUCT SPECIFICATION (1)
FIGURE 3: Direct dimensions
D
OUTLET
T&P VALVE
SECONDARY
RETURN
A
SENSOR
POCKETS
35°
°
15
B
30°
C
E
INLET
Table 5: Direct measurements
Direct Connection 400L 500L Connection 800L 1000L Connection 1250L 1450L Connection 2000L 2500L
A
N/A
B
N/A
C
1 1/4” BSP
D
N/A
E
1” BSP
1535 1804
N/A
1264 1416
N/A
400
399
872 872
1008 1108
1906 2301
N/A
1487 1882
N/A
1 1/2” BSP 437
437
N/A
1024 1024
1” BSP
1183 1433
1936 2253
N/A
2014 2419
1408 1693
N/A
1410 1515
1 1/2” BSP 523
N/A
1” BSP
527
2” BSP
606
605
1224 1224
N/A
1470 1470
1172 1373
1” BSP
1225 1474
NOTE: All connections BSP female threads
Table 6: Direct weights
Size
(Litres)
Unit Weight (kg)
Empty
Full
400
95
495
500
100
600
800
153
953
1000
178
1178
1250
297
1547
1450
304
1754
2000
415
2415
2500
421
2921
Unvented Hot Water Cylinder
9
PRODUCT SPECIFICATION (1)
Table 9: Standing heat-loss
NOMINAL
CAPACITY
(LITRES)
400
500
800
1000
1250
1450
2000
2500
STANDING HEAT LOSS
PER DAY
PER YEAR
(kWh/24h)
(kWh/24h)
1.72
627
2.14
781
2.74
1000
3.33
1215
3.60
1314
4.17
1522
4.30
1569
4.50
1642
Table 10: Indirect coil kW ratings
NOMINAL
CAPACITY
(LITRES)
400
500
800
1000
1250
1450
2000
2500
PRIMARY FLOW RATE l/min
15
30
60
29.4kW
28.7kW
31.3kW
32.9kW
35.0kW
30.1kW
40.2kW
37.5kW
43.6kW
41.8kW
52.7kW
51.4kW
63.6kW
61.2kW
98.4kW
86.4kW
59.7kW
55.8kW
76.9kW
76.5kW
97.9kW
91.7kW
132.2kW
126.4kW
COIL
SURFACE
AREA
2m²
3m²
5m²
7.5m²
Table 11: Pressure drop across coils
NOMINAL
CAPACITY
(LITRES)
400
500
800
1000
1250
1450
2000
2500
PRIMARY FLOW RATE l/min
15
30
60
0.02bar
0.02bar
0.01bar
0.01bar
0.01bar
0.01bar
0.01bar
0.01bar
0.04bar
0.04bar
0.08bar
0.08bar
0.06bar
0.06bar
0.07bar
0.07bar
0.32bar
0.32bar
0.44bar
0.44bar
0.25bar
0.25bar
0.30bar
0.30bar
Table 12: Indirect heat-up times (based on a 45°C temperature rise)
NOMINAL
CAPACITY
(LITRES)
400
500
800
1000
1250
1450
2000
2500
PRIMARY FLOW RATE l/min
15
43 min
55 min
80 min
91.min
112 min
130 min
180 min
225 min
30
29 min
38 min
48 min
59 min
62min
72 min
99 min
124 min
60
21 min
28 min
32 min
39 min
40min
50 min
48 min
62 min
Testing is carried out to BS EN12897:2006
Primary flow rates are based on a flow temperature of 80°C +/- 2°C
10
Unvented Hot Water Cylinder
NOMINAL
CAPACITY
(LITRES)
400
500
800
1000
1250
1450
2000
2500
Maximum kW ratings
Upper
boss
9
12
18
36
30
36
36
36
Lower
boss
30
45
45
45
54
54
54
54
Total
kW
39
57
63
81
84
90
90
90
PRODUCT SPECIFICATION (1)
Table 13: Maximum kW ratings for Direct Cylinders
Table 14: Water delivered to 40°C (Indirect cylinders only)
NOMINAL
CAPACITY
(LITRES)
Water delivered to 40°C
(Litres)
400
384
500
482
776
961
1206
1399
1930
2482
800
1000
1250
1450
2000
2500
Table 15: Direct heat up times based on maximum kW per cylinder
NOMINAL
CAPACITY
(LITRES)
400
500
800
1000
Heat-up times
Heat-up times
NOMINAL
CAPACITY Maximum Heat up
Maximum Heat up
kW
Time (mins)
kW
Time (mins) (LITRES)
47
1250
32
84
39
51
90
1450
28
57
70
90
2000
40
63
87
90
2500
39
81
Times based on nominal volume
Times based on a 45°C temperature rise
Direct heat up times are based on the formula below:
Time =
Volume of water to be heated (litres) x Temperature rise
kW loading of cylinder x 14.3
Worked Example:
Volume of water= 500Litres
Temperature rise = 45°C
kW loading = 57
500 x 45
57 x 14.3
22500
Time =
815.1
Time =
Time = 27.6 minutes
Unvented Hot Water Cylinder
11
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400
500
800
1000
1250
1450
2000
2500
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
94110301
6
Upper
Lower
400
500
800
1000
1250
1450
2000
2500
Element
Kw
Location
Direct
Indirect
12
Unvented Hot Water Cylinder
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94110302
9
Upper
Lower
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94110303
12
Upper
Lower
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94110304
18
Upper
Lower
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94110305
24
Upper
Lower
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94110306
30
Upper
Lower
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94110307
36
Upper
Lower
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94110308
45
Upper
Lower
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94110309
54
Upper
Lower
PRODUCT SPECIFICATION (1)
Element Allocation Table
Note:
The element/elements are not factory fitted.
Thermostat/Cut-out
All immersion heaters are fitted with a thermostat which is fitted in the centre of the heater
plate and a cut-out which is fitted to the side of the thermostat. These MUST be wired
in series with the operating coil circuit of the contactor (not supplied). See figures 4,
5 & 6, below.
Maximum working temperature is 80°C/176°F. In very hard water areas limit
to 60/65°C (140/150°F).
60
80
80
40
Notes:
The 2 external contactors must be approved
components certified for 10,000 cycles of
operation for the contactor controlled by the
thermostat and at least 30 for the contactor
controlled by the non-self-resetting thermal
cut-out.
7
0
50
DO NOT
BREAK SEAL
FACTORY
SET
7
0
50
60
A
FIGURE 5: Single phase wiring
schematic
B
INSTALLATION AND
COMMISSIONING (2)
40
FIGURE 4: Thermostat and thermal
For optimal working conditions the
thermal cut-out should be set to 80°C cut-out settings
and the thermostat should be set to 70°C
Thermostat
Cut-out
max. If the thermostat is set above 70°C
A
there could be instances of nuisance
tripping of the thermal cut-out.
B
FIGURE 6: 3 phase wiring schematic
Neutral
L1
L2
L3
Fuse
Neutral
(not
Live
supplied)
Fuse
(not supplied)
Contactors
(not supplied)
Contactor
(not supplied)
Line terminal
marked L2
Live
marked ‘L’
Line terminal
marked L1
Line terminal
marked L3
80
80
40
40
0
7
0
60
60
Earth
Neutral terminal
marked 'N'
Typical wiring diagram for single phase heater
7
0
5
5
0
Earth
Neutral terminal
marked 'N'
Typical wiring diagram for three phase heater
Unvented Hot Water Cylinder
13
INSTALLATION AND
COMMISSIONING (2)
Limitations
• The MEGAFLO Commercial unvented water heater should not be used in any of the following
instances:
• Solid fuel boilers or any other boiler in which the energy input is not under effective thermostatic
control unless additional and appropriate safety measures are installed.
• Gravity circulation primaries.
• Steam heating plant unless additional and appropriate safety devices are installed.
• Ascending spray type bidets or any other Class 5 back syphonage risk requiring that a Type AA,
AB, AD or AG air gap be employed.
• Water supplies that have either inadequate pressure or where the supply may be intermittent.
• Situations where it is not possible to safely pipe away any discharge from the safety valves.
• Areas where the water consistently contains a high proportion of solids, eg. suspended matter
that could block the strainer, unless adequate filtration can be ensured.
• The installation must be carried out in accordance with the relevant requirements of the
appropriate Building Regulations: either The Building Regulations (England), The Building
Regulations (Scotland) or Building Regulations (Northern Ireland), The Water Fittings Regulations
(England and Wales) or Water Byelaws (Scotland).
Water supply
Bear in mind that the mains water supply to the property will be supplying both the hot and cold
water requirements simultaneously. It is recommended that the maximum water demand be assessed
and the water supply checked to ensure this demand can be met. A minimum flow rate of 100l/min
is required for the MEGAFLO Commercial range of cylinders
NOTE: A high mains water pressure will not always guarantee high flow rates.
Wherever possible the main supply pipe should be in 28mm. The minimum mains water supply
requirements should be 0.15 MPa (1.5 bar) working pressure and minimum 100 litres per minute
flow rate. At these values outlet flow rates may be poor if several outlets are used simultaneously,
the higher the available pressure and flow rate the better the system performance will be.
The water supply must be of wholesome water quality (Fluid Category 1 as defined by the Water
Supply Regulations 1999). The MEGAFLO Commercial is to be used for the storage of wholesome
water (max. 250mg/l chloride).
Water container:
Duplex stainless steel. 100% pressure tested to 2.25 MPa (22.5 bar).
14
Unvented Hot Water Cylinder
Installation & Commissioning
General installation
Pipe fittings
All pipe connections to the MEGAFLO Commercial are made via BSP female parallel threaded pipe
connection directly to the unit.
Cold water supply
A 28mm cold water supply is recommended, however, if a smaller supply exists which provides
sufficient flow this may be used. More flow noise may be experienced from small bore pipes due
to the increased water velocity through them. A minimum flow rate of 100l/min is required for the
MEGAFLO Commercial range of cylinders
INSTALLATION AND
COMMISSIONING (2)
High flow cold water control pack 1” & 1½” (Low and high pressure)
The control pack consists of a pressure reducing valve with integral strainer, check valve, core unit
and expansion relief valve. The pressure settings are adjustable for the low or high pressure valve
sets. For the“low” pressure valve set the pressure reducing valve can be set between 1 and 6 bar.
For the “high” pressure valve set the pressure can be set between 5 and 10 bar. For optimum
performance the following installation instructions should be complied with.
Note: The expansion vessel pressure must be set in accordance with the inlet pressure set
on the pressure reducing valve.
Installation:
Cold water supply to be 28mm minimum. Flush supply pipe work before connection to remove all
flux and debris prior to fitting the inlet controls. Failure to do this may result in irreparable damage
to the controls and will invalidate the warranty.
The pressure reducing valve can be fitted in any orientation to suit the installation as long as it is
fitted in the correct flow direction. Check the flow arrows on the side of the body.
The expansion relief valve should be installed with the discharge pipe work in either the horizontal
position or facing downwards, if the discharge pipe is facing upwards debris may be deposited on
the seat of the valve when in operation.
The blank plastic plugs in the body of the pressure relief valve are pressure gauge connections to
enable pressure monitoring to be carried out, should the system develop a fault. It is recommended
that these be accessible (the pressure reducing valve has two – only one need be accessible).
Expansion relief discharge pipe work must be connected to a safe visible discharge point via a
tundish and the pipe work must have a continuous fall. If site conditions allow, the expansion relief
discharge pipe work can be connected to the T&P valve discharge pipe work before the tundish.
Pressure reducing valve:
The pressure reducing valve can be connected anywhere on the cold water mains supply prior to the
MEGAFLO Commercial unit. There is no requirement to site it close to the unit, it can be located at
a point where the mains supply enters the premises if this is more convenient but you must install a
non-return valve just after the reducing valve for ease of maintenance.
The pressure reducing valve incorporates a adjustable pressure reducer / strainer. The valve can be
fitted in any orientation to suit the installation, however, ensure that the valve is installed with the
direction of flow arrows (stamped on the side of the brass body) pointing towards the MEGAFLO
Commercial heater.
Unvented Hot Water Cylinder
15
Figure 07: Cold water combination valve (for 400 & 500ltr)
3.5 bar Pressure
reducing valve
INSTALLATION AND
COMMISSIONING (2)
8 bar Pressure
relief valve
direction
direction
Pressure relief
discharge
Mains water in
To cylinder
Pressure gauge
connections (one
each side)
28mm compression connections
Figure 08: Schematic installation
To hot outlets
T&P relief
valve
Expansion
vessel
Pressure relief
valve
Balanced cold
water connection
Pressure reducing
valve
Mains water
supply
Secondary
return
Element/
controls
housing
Primary flow
Tundish
Primary return
Discharge pipe
Inlet
16
Unvented Hot Water Cylinder
Drain valve
Pressure Relief Valve
This should be installed between the Pressure Reducing Valve and the MEGAFLO Commercial
cylinder. Should a balanced pressure cold water draw off supply be required for the cold water
outlets, this should be taken off between the Pressure Reducing Valve and Pressure Relief Valve.
Branches to drinking water outlets should be taken before the Pressure Relief Valve to avoid the
possibility of warm expanded water being drawn from the tap.
Drain valve
It is recommended that the drain valve (supplied) be incorporated into the cold water inlet system,
Fig 08, page 16. It is recommended that the outlet point of the drain pipe work be at least 1 metre
below the level of the heater (this can be achieved by attaching a hose pipe to the drain valve outlet
spigot).
Secondary Circulation
If a secondary circulation system is required it is recommended that it be connected to the MEGAFLO
Commercial as shown in Figure 010, Page 18. The secondary return pipe should be in 28mm pipe
and incorporate a check valve to prevent back flow. A suitable WRAS approved bronze circulation
pump will be required. On large systems, due to the increase in system water content, it may be
necessary to fit additional expansion volume to the secondary system by fitting an external expansion
vessel to the circuit. This should be done if the capacity of the secondary circuit exceeds 10 litres.
INSTALLATION AND
COMMISSIONING (2)
Outlet Pipe work
Ideally the pipe work from the MEGAFLO Commercial to the outlet fittings should be in 2” pipe,
smaller bore pipe can be used but it could impact on the performance of the unit. Small bore pipe
can also be used to suit some taps, but runs should be of minimum length. Pipe sizes may vary due
to system design.
Pipe capacities (copper)
22mm o/d = 0.38 litres per metre run (10 litres = 26m)
28mm o/d = 0.55 litres per metre run (10 litres = 18m)
35mm o/d = 0.83 litres per metre run (10 litres = 12m)
42mm o/d = 1.23 litres per meter run (10 litres = 8m)
Warnings
1. Under no circumstances should the factory fitted Temperature /Pressure Relief Valve be removed
other than by authorised Heatrae Sadia personnel. To do so will invalidate any guarantee or claim.
2. The Cold Water Combination Valve must be fitted to the mains water supply to the MEGAFLO
Commercial unit.
3. No control or safety valves should be tampered with or used for any other purposes.
4. Water may drip from the discharge pipe of the pressure relief device (Expansion Valve) and this
pipe must be left open to atmosphere. The discharge pipe should not be blocked or used for any
other purpose.
5. The tundish must be installed so that it is visible to the end user.
6. The tundish, drain valve and motorised valves (indirect units only) must be installed away from
any electrical components.
7. No valve should be fitted between the 8 bar or 13 bar pressure relief valve and the MEGAFLO
Commercial unit.
Unvented Hot Water Cylinder
17
Figure 09: Pressure reducing valve - 800L - 2500L
Pressure reducing cartridge
INSTALLATION AND
COMMISSIONING (2)
Take note of flow direction
Mains in
Outlet to cylinder
Figure 10: Secondary circulation
To hot outlets
Check valve
WRAS approved
pump
Secondary
return
Air vent
(not supplied)
Cold water inlet
18
Unvented Hot Water Cylinder
The following extract is taken from the latest G3 Regulations
Discharge pipes from safety devices
Discharge pipe D1
3.50
Safety devices such as temperature relief valves or combined temperature and pressure and pressure relief valves (see
paragraphs 3.13 or 3.18) should discharge either directly or by way of a manifold via a short length of metal pipe (D1) to a tundish.
3.51
The diameter of discharge pipe (D1) should be not less than the nominal outlet size of the temperature relief valve.
3.52
Where a manifold is used it should be sized to accept and discharge the total discharge form the discharge pipes connected to it.
3.53
Where valves other than the temperature and pressure relief valve from a single unvented hot water system discharge by way of the
same manifold that is used by the safety devices, the manifold should be factory fitted as part of the hot water storage system unit or
package.
Tundish
3.54
The tundish should be vertical, located in the same space as the unvented hot water storage system and be fitted as close as possible
to, and lower than, the valve, with no more than 600mm of pipe between the valve outlet and the tundish
(see Diagram 1).
Note:
To comply with the Water Supply (Water Fittings) Regulations, the tundish should incorporate a suitable air gap.
3.56
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 pipework
(see Diagram 1); and
(b) be installed with a continuous fall thereafter of at least 1 in 200.
3.57
The discharge pipe (D2) should be made of:
(a) metal; or
(b) other material that has been demonstrated to be capable of safely withstanding temperatures of the water discharged
and is clearly and permanently marked to identify the product and performance standard (e.g. as specified in the
relevant part of BS 7291).
3.58
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. for discharge pipes between 9m and 18m the 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 the flow resistance.
See Diagram 1, Table 1 and the worked example.
Note:
An alternative approach for sizing discharge pipes would be to follow Annex D, section D.2 of BS 6700:2006 Specification
for design, installation, testing and maintenance of services supplying water for domestic use within buildings and their
curtilages.
3.59
Where a single common discharge pipe serves more than one system, it should be at least one pipe size larger than the largest individual
discharge pipe (D2) to be connected.
3.60
The discharge pipe should not be connected to a soil discharge stack unless it can be demonstrated that that the soil discharge stack is
capable of safely withstanding temperatures of the water discharged, in which case, it should:
(a)
(b)
(c)
Note:
( d)
1.
2.
INSTALLATION AND
COMMISSIONING (2)
Any discharge should be visible at the tundish. In addition, where discharges from safety devices may not be apparent, e.g. in dwellings
occupied by 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.
Discharge pipe D2
3.55
contain a mechanical seal, not incorporating a water trap, which allows water into the branch pipe without allowing
foul air from the drain to be ventilated through the tundish;
be a separate branch pipe with no sanitary appliances connected to it;
if plastic pipes are used as branch pipes carrying discharge from a safety device they should be either polybutalene
(PB) to Class S of BS 7291-2:2006 or cross linked polyethylene (PE-X) to Class S of BS 7291-3:2006; and
be continuously marked with a warning that no sanitary appliances should be connected to the pipe.
Plastic pipes should be joined and assembled with fittings appropriate to the circumstances in which they are used as set out in
BS EN ISO 1043-1.
Where pipes cannot be connected to the stack it may be possible to route a dedicated pipe alongside or in close proximity to the
discharge stack.
Termination of discharge pipe
3.61
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.
3.62
Examples of acceptable discharge arrangements are:
b) to a trapped gully with the end of the pipe below a fixed grating and above the water seal;
(c) downward discharges at low level; i.e. up to 100mm above external surfaces such as car parks, hard standings,
grassed areas etc. are acceptable providing that a wire cage or similar guard is positioned to prevent contact,
whilst maintaining visibility; and
(d) discharges at high level: e.g. into a metal hopper and metal downpipe 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 system that would collect such discharges.
3.63
The discharge would consist of high temperature water and steam. Asphalt, roofing felt and non-metallic rainwater goods may be
damaged by such discharges.
Unvented Hot Water Cylinder
19
G3 Requirement
“...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”.
INSTALLATION AND
COMMISSIONING (2)
Discharge Pipe work
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 2 (page 17) are reproduced
in the previous sections.
For discharge pipe arrangements not covered by G3 Guidance advice should be sought from your
local Building Control Officer. Any discharge pipe connected to the pressure relief devices (Expansion
Valve and Temperature / Pressure Relief Valve) must be installed in a continuously downward direction
and in a frost free environment.
The water may drip from the discharge pipe of the pressure relief device and that this pipe must be
left open to the atmosphere. The pressure relief device is to be operated regularly to remove lime
deposits and to verify that it is not blocked.
Worked example of discharge pipe sizing (Taken from Building Regulations 2000, G3, 2010
edition)
The example below is for a G1” temperature relief valve with a discharge pipe (D2) having 4 No.
elbows and length of 7m from the tundish to the point of discharge.
From Table 5:
Maximum resistance allowed for a straight length of 35mm copper discharge pipe (D2) from a G1”
temperature relief valve is 9m.
Subtract the resistance for 4 No. 35mm elbows at 1.4m each = 5.6m
Therefore the permitted length equates to: 3.4m
3.4m is less than the actual length of 7m therefore calculate the next largest size.
Maximum resistance allowed for a straight length of 42mm pipe (D2) from a G1” temperature relief
valve equates to 18m.
Subtract the resistance of 4 No. 42mm elbows at 1.7m each = 6.8m
Therefore the maximum permitted length equates to: 11.2m
As the actual length is 7m, a 42mm (D2) copper pipe will be satisfactory.
Note:
The tundish must be installed away from any electrical devices
20
Unvented Hot Water Cylinder
Notes:
1) Discharge pipe-work D2 can now be a plastic pipe but only pipes that have been tested to a minimum 110°C must be used.
2) Discharge pipe D2 can now be plumbed in the soil stack but only soil stacks that can handle temperatures of 99°C or greater should be used.
Table 5 Sizing of copper discharge pipe “D2” for common T&P Relief Valve sizes.
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
G 1/2
15mm
G 3/4
22mm
G1
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
INSTALLATION AND
COMMISSIONING (2)
VALVE OUTLET
SIZE
Figure 11: Typical discharge pipe arrangement (Extract from Building Regulations G3
Guidance section 3.5 to 3.63)
Safety device
(e.g. Temperature
relief valve)
Metal discharge pipe (D1) from
Temperature relief valve to tundish
Tundish
600mm maximum
300mm
minimum
Discharge below
fixed grating
(Building Regulation
G3 section 3.61 gives
alternative points
of discharge)
Fixed grating
Discharge pipe (D2) from tundish,
with continuous fall. See Building
Regulation G3 section 3.56,
Table 1 and worked example
Trapped
gully
Unvented Hot Water Cylinder
21
Indirect Model
INSTALLATION AND
COMMISSIONING (2)
Boiler Selection
The MEGAFLO Commercial Indirect models are suitable for use with most gas or oil fired boilers
compatible with unvented systems i.e. fitted with a temperature control thermostat and thermal
cut-out. If in doubt consult the boiler manufacturer. Solid fuel boilers or any other boiler in which
the energy input is not under effective thermostatic control, unless additional and appropriate safety
measures are installed, SHOULD NOT be used. The boiler used can either be a sealed system or open
vented type, maximum primary circuit pressure 3 bar. The primary flow from the boiler MUST be
pumped. Gravity circulation will not work due to the special design of the primary heat exchanger.
It is recommended that an air bleed point or automatic air vent is incorporated in the primary return
pipe work close to the MEGAFLO Commercial unit. The boiler flow temperature should usually be
set to 82ºC (maximum flow temperature to primary heat exchanger 89ºC). The boiler cannot be
vented through the MEGAFLO Commercial unit.
Indirect Thermal Cut-Out And 2-Port Motorised Valve
To comply with Building Regulations, and to prevent the MEGAFLO Commercial from overheating
the 2-port motorised valve supplied MUST be fitted to the primary flow to the indirect coil. It must
be wired such that in the event of the cylinder over heating it will close the primary circuit.
Wiring
All electrical wiring should be carried out by a competent electrician and be in accordance with the
latest I.E.E. Wiring Regulations BS 7671.
IT IS RECOMMENDED THAT ALL WIRING TO THE IMMERSION HEATERS IS OF A FIXED TYPE.
DO NOT OPERATE THE IMMERSION HEATER(S) UNTIL THE MEGAFLO COMMERCIAL HAS
BEEN FILLED WITH WATER.
Safety
DO NOT BYPASS THE THERMAL CUT-OUT(S) IN ANY CIRCUMSTANCES
DISCONNECT FROM THE MAINS SUPPLY BEFORE REMOVING ANY COVERS
NEVER ATTEMPT TO REPLACE AN IMMERSION HEATER OTHER THAN WITH THE
RECOMMENDED HEATRAE SADIA MEGAFLO COMMERCIAL SPARE PART
Figure 12: Indirect controls
Unvented Hot Water Cylinder
50 40
22
°C 70 60
Thermal cut-out
reset under cap
30
0
Temperature control
clockwise to increase,
counter-clockwise to
decrease
Figure 13: 2 port valve in conjunction with a 3 port mid-position valve system (“Y” Plan)
PROGRAMMER
KEY
Bl
Br
G
O
GY
DHW
HTG
L
N
1
2
MEGAFLO ECO (DHW)
ZONE VALVE
(SUPPLIED)
MEGAFLO INDIRECT
THERMAL CONTROLS
HTG
ON
DHW
ON
4
5
1
2
3
7
8
9
10 11 12 13 14 15 16
Bl
Br
G
O GY
Bl
Br
O GY
G
BLUE
BROWN
GREY
ORANGE
GREEN/YELLOW
DOMESTIC HOT WATER
HEATING
3
6
WIRING CENTRE
L
N
3
2
ROOM STAT
N
N
L
PUMP
BOILER
ZONE VALVE (HTG)
L
NOTES:
1. A DOUBLE POLE ISOLATING SWITCH MUST BE INSTALLED IN THE MAINS SUPPLY.
2. ALL EARTH CONNECTIONS MUST BE LINKED BACK TO THE MAINS EARTH SUPPLY.
3. DO NOT MOUNT WIRING CENTRE ON CYLINDER.
4. THE ABOVE DIAGRAM IS FOR GUIDANCE ONLY, HEATRAE SADIA ACCEPT NO LIABILITY FOR ANY LOSS OR DAMAGE ARISING FROM ANY ERRORS OR OMISSIONS.
THAT MAY BE INADVERTENTLY CONTAINED WITHIN THIS DIAGRAM. THE VARIOUS EQUIPMENT MANUFACTURERS SHOULD BE CONSULTED TO CONFIRM THE
CORRECT OPERATION OF THEIR PRODUCTS WITHIN THE SYSTEM.
INSTALLATION AND
COMMISSIONING (2)
1
Figure 14: 2 x 2 port valve system (“S” Plan)
MEGAFLO INDIRECT
THERMAL CONTROLs
PROGRAMMER
KEY
Bl
Br
G
O
GY
DHW
HTG
L
N
1
2
HTG
ON
DHW
ON
DHW
OFF
4
5
6
MEGAFLO ECO (DHW) 2-PORT
VALVE (SUPPLIED)
Bl Br G O GY
1
2
3
7
8
9 10 11 12 13 14 15 16
Bl
W G
BLUE
BROWN
GREY
ORANGE
GREEN/YELLOW
DOMESTIC HOT WATER
HEATING
3
WIRING CENTRE
L
N
1
3
2
ROOM STAT
O GY
3-PORT MID POSITION VALVE
N
L
BOILER
N
L
PUMP
NOTES:
1. A DOUBLE POLE ISOLATING SWITCH MUST BE INSTALLED IN THE MAINS SUPPLY.
2. ALL EARTH CONNECTIONS MUST BE LINKED BACK TO THE MAINS EARTH SUPPLY.
3. ASSUMES BASIC BOILER WITH EXTERNAL PUMP.
4. DO NOT MOUNT WIRING CENTRE ON CYLINDER.
5. THE ABOVE DIAGRAM IS FOR GUIDANCE ONLY, HEATRAE SADIA ACCEPT NO LIABILITY FOR ANY LOSS OR DAMAGE ARISING FROM ANY ERRORS OR OMISSIONS.
THAT MAY BE INADVERTENTLY CONTAINED WITHIN THIS DIAGRAM. THE VARIOUS EQUIPMENT MANUFACTURERS SHOULD BE CONSULTED TO CONFIRM THE
CORRECT OPERATION OF THEIR PRODUCTS WITHIN THE SYSTEM.
Unvented Hot Water Cylinder
23
Direct Model
Immersion Heater(s)
The MEGAFLO Commercial can be fitted with a selection of single phase and three phase immersion
heaters (see Table 13 and element allocation table, page 12 for details). The immersion heaters
must be installed in accordance with the installation instructions supplied with the immersion heater
(supplied separately)
INSTALLATION AND
COMMISSIONING (2)
Warning: Before starting any work on the Megaflo commercial immersion heaters switch off
all electrical supplies to such immersion heaters including thermostatic controls, these may
be on a separate circuit.
To remove the immersion heater:
Drain down the cylinder before any work is carried out on the Immersion heaters. Remove the
immersion heater cover and disconnect all wiring from the Immersion and thermostatic controls.
Remove the 8 nuts (or bolts) and withdraw the immersion heater from the cylinder. Take care when
lifting the immersion out of the cylinder and work within safe working practices.
Replacement:
Make sure the Immersion heater gasket face is clean and if necessary replace the gasket (spare part
number 95607396). Replace the Immersion heater and make sure the 8 nuts (or bolts) are correctly
torqued (20Nm or 14.75 ft/lbf) as per the Megaflo commercial immersion heater fitting instructions
(36006161). Wire up the immersion heater as per Fig 5, page 13 or Fig 6, page 13 or Megaflo
commercial immersion heater fitting instructions. Refill the cylinder and check for leaks. Turn on
the supply and set the thermostat temperature to the desired water temperature (60°C - 65°C is
recommended).
Wiring (See Figures 4, 5 & 6)
All electrical wiring should be carried out by a competent electrician and be in accordance with the
latest I.E.E. Wiring Regulations BS 7671.
DO NOT OPERATE THE IMMERSION HEATER(S) UNTIL THE MEGAFLO Commercial HAS BEEN
FILLED WITH WATER.
Operation
See Fig 4, page 13 for details on how to adjust the temperature setting of the heater.
DO NOT BYPASS THE THERMAL CUT-OUT IN ANY CIRCUMSTANCES.
24
Unvented Hot Water Cylinder
Notes:
INSTALLATION AND
COMMISSIONING (2)
Unvented Hot Water Cylinder
25
Commissioning
INSTALLATION AND
COMMISSIONING (2)
Filling and flushing the MEGAFLO Commercial
Ensure that all fittings and immersion heaters are correctly fitted and tightened.
i)
Open a hot tap furthest from the MEGAFLO Commercial.
ii)Open the mains stop cock to fill the unit. When water issues from the tap, allow to run for a few
minutes to thoroughly flush through any residue, dirt or swarf, then close tap.
iii)
Open successive hot taps to purge any air from the system.
iv)
Check all connections for leaks and rectify as necessary.
v)The Strainer housed within the Pressure Reducing Valve should be cleaned to remove any
debris that may have been flushed through the main supply pipe.
Check the operation of the Safety Valves
i)Slowly, manually open for a few seconds, the Temperature and Pressure Relief Valve (T&P
Valve) situated on the MEGAFLO Commercial unit. Check water discharged runs freely away
through the tundish and discharge pipe work. Close valve, ensure water flow stops and valve
reseats correctly.
ii)Repeat for the Pressure Relief Valve.
NOTE: The water discharged may be very hot.
Direct Units
Switch on the electrical supply to the immersion heater(s) and allow the unit to heat up. Check that
the thermostat operates correctly. A storage temperature of approx. 60ºC is recommended, install
and set up immersions as per immersion heater fitting instructions (36006161) . Check that no water is discharged from either the Expansion Valve or Temperature and Pressure Relief Valve during the
heating cycle. The thermal cut-out should be set for 85°C max for direct heating
Indirect Units
Fill the indirect (primary) circuit following the boiler manufacturer’s commissioning instructions. To
ensure the primary heating coil in the MEGAFLO Commercial indirect is filled the 2-port motorised
valve (supplied) should be manually opened by moving the lever on the motor housing to the MAN
OPEN position. When the primary circuit is full return the lever to the AUTO position. Vent any
trapped air by opening the air bleed. If necessary the cylinder water temperature can be adjusted
by turning the knob located on front of the thermostat housing, see fig 12, page22. The minimum
thermostat setting is 30°C. The maximum thermostat setting is 70°C, it is recommended that the
water temperature setting is between 60°C and 65°C for optimum working conditions. The thermostatic controls contain a thermal cut-out which is set 82°
Benchmarktm Log Book
On completion of the installation and commissioning procedures detailed in this Product Guide
the BenchmarkTM “Installation, Commissioning and Service Record Log” should be completed and
signed off by the competent installer or commissioning engineer in the relevant sections. The various
system features, location of system controls, user instructions and what to do in the event of a system failure should be explained to the customer. The customer should then countersign the BenchmarkTM commissioning checklist to accept completion. The Service Record should be filled in when
any subsequent service or maintenance operation is carried out on the MEGAFLO Commercial unit.
26
Unvented Hot Water Cylinder
Maintenance & Servicing
Maintenance requirements
To ensure the continued optimum performance of the MEGAFLO Commercial it should be regularly
maintained. This is of particular importance in hard water areas or where the water supply contains
particulate matter. Maintenance should be carried out by a competent person and any replacement
parts used should be authorised MEGAFLO Commercial spare parts. It is recommended that
maintenance is carried out every 12 months and includes the checks detailed below.
In hard water areas consideration should be given to periodically descaling the immersion heater elements.
To do this the MEGAFLO Commercial unit will need to be drained.
Check operation of Safety Valves
Slowly open the Temperature and Pressure Relief Valve by twisting its cap for a few seconds. Check water
is discharged and that it flows freely through the tundish and discharge pipe work. Check valve reseats
correctly when released.
NOTE: The water discharged may be very hot.
Repeat the procedure for the Pressure Relief Valve.
Inspection
The immersion heater boss can be used as an access for inspecting the cylinder internally.
Draining the MEGAFLO Commercial unit
Switch off the electrical supply to the immersion heater(s) and shut down the boiler on indirect units.
Turn off the mains water supply to the MEGAFLO Commercial unit. Attach a hosepipe to the drain valve
having sufficient length to take water to a suitable discharge point below the level of the unit, at least
one metre below the unit is recommended. Open hot water tap nearest to the MEGAFLO Commercial
to relieve the system pressure. Open drain valve. If water fails to drain from the MEGAFLO Commercial
vent the unit by manually opening the Temperature / Pressure Relief Valve.
MAINTENANCE AND
SERVICING (3)
Clean the strainer
The strainer is incorporated within the Pressure Reducing Valve housing of the Valve. To inspect and clean
the strainer:
1. Turn off the isolating valve prior to the Pressure Reducing Valve or the main stop cock to the
system.
2. Open the lowest hot tap in the system to relieve the system pressure.
3. Using a spanner unscrew the pressure reducing cartridge and remove the moulded housing. The
strainer will be removed with the cartridge.
4. Wash any particulate matter from the strainer under clean running water.
5. Replace the strainer and screw the Pressure Reducing Valve cartridge into the moulded housing.
6. Close hot tap, turn on isolating valve or main stop cock to the system. Check for leaks.
Refilling system
DO NOT switch on the immersion heater(s) or boiler until the system has been completely refilled.
Close the drain valve. With the hot tap open, turn on mains water supply. When water flows from the hot
tap allow to flow for a short while to purge air and to flush through any disturbed particles. Close hot tap
and then open successive hot taps in system to purge any air. The electrical supply can now be switched
on.
Unvented Hot Water Cylinder
27
BenchmarkTM
On completion of any maintenance or service of the MEGAFLO Commercial, the BenchmarkTM
“Installation, Commissioning and Service Record”, Pages 30 & 31, should be filled in to record the actions
taken and the date the work was undertaken.
Maintenance
Under normal circumstances the control valves should not require any maintenance. However, annual
inspection and/or cleaning of the integral strainer , pressure reducing valve cartridge, expansion
relief valve cartridge and seating may be necessary depending on local water conditions.
Pressure reducing valve
Isolate cold water supply and drain system if necessary
Unscrew the retaining nut of the valve. The complete operating mechanism, including the strainer
can be removed. Clean the filter mesh and cartridge ensuring that the strainer is correctly located
and reassemble the unit.
Expansion Valve
Isolate cold water supply
Unscrew expansion relief cartridge from body and clean the filter mesh and cartridge.
Clean valve seat face and seating – do not scratch or damage either seal face or seating,
Refit in reverse order. Do not over tighten.
MAINTENANCE AND
SERVICING (3)
Warnings
28
IF WATER DISCHARGES FROM THE TEMPERATURE / PRESSURE RELIEF VALVE ON THE MEGAFLO
COMMERCIAL UNIT REFER TO FAULT FINDING TABLE FIRST FOR GUIDANCE. IF THIS DOES
NOT RECTIFY THE FAULT SWITCH OFF ELECTRICAL SUPPLY TO THE IMMERSION HEATER(S)
[ DIRECT UNITS ] OR SHUT DOWN THE BOILER [ INDIRECT UNITS ]. DO NOT TURN OFF THE
WATER SUPPLY. CONTACT A COMPETENT INSTALLER FOR UNVENTED WATER HEATERS TO
CHECK THE SYSTEM.
DO NOT TAMPER WITH ANY OF THE SAFETY VALVES FITTED TO THE MEGAFLO COMMERCIAL
SYSTEM, IF A FAULT IS SUSPECTED CONTACT A COMPETENT INSTALLER.
Unvented Hot Water Cylinder
Fault finding
The Fault Finding chart will enable operational faults to be identified and their possible causes rectified.
Any work carried out on the MEGAFLO Commercial unvented water heater and its associated
controls MUST be carried out by a competent installer for unvented water heating systems. In case
of doubt contact the MEGAFLO Commercial Service Department.
Table 3: Fault Finding guide
Fault
No hot water flow
Possible Cause
Remedy
Mains water supply off
Check and open stop cock/isolating valve
Strainer blocked
Turn off water supply, remove strainer and clean
Cold water combination valve incorrectly Check and refit as required
fitted
Direct immersion heater not switched on
Check and switch on
Direct immersion heater thermal cut-out Check, reset by pushing button on thermal cuthas operated
out
Indirect programmer set to central heating Check, set to domestic hot water programme
only
Water from hot tap Indirect boiler not working
is cold
Indirect thermal cut-out has operated
Check boiler operation. If fault is suspected consult
boiler manufacturer’s instructions
Check, reset by pushing button on thermal cutout
Check operation of indirect thermostat
Indirect motorised valve not connected Check wiring and/or plumbing connections to mocorrectly
torised valve
INTERMITTENTLY
Check pressure from pressure reducing valve
Remove expansion relief cartridge from pressure
relief valve and check seating. If necessary fit new
cartridge
Water
discharges Expansion relief valve faulty
from the T&P relief
valve intermittently
Check valve and replace if necessary
Thermal control failure
Water
discharges
NOTE: Water will be very hot
from the T&P relief
valve continually
Switch off power to immersion heater(s) and shut
down boiler. DO NOT turn off water supply. When
discharge stops check all thermal controls, replace
if faulty
Unvented Hot Water Cylinder
MAINTENANCE AND
SERVICING (3)
Water
discharges
from overflow visual CONTINUALLY
indicator (tundish)
Incorrect pre-charge pressure for expansion vessel
29
Servicing
Important
i)Servicing should only be carried by authorised heateam engineers, Agents or by installers competent
in the installation and maintenance of unvented water heating systems.
ii)Any spare parts used MUST be authorised MEGAFLO Commercial parts.
iii)Disconnect the electrical supply before removing any electrical equipment covers.
iv)NEVER bypass any thermal controls or operate system without the necessary safety valves.
v)Water contained in the MEGAFLO Commercial unit may be very hot, especially following a thermal
control failure. Caution must be taken when drawing water from the unit.
Spares
Spare parts
A full range of spare parts are available for the MEGAFLO Commercial range. Refer to the Technical
Data label on the unit to identify the model installed and ensure the correct part is ordered.
MAINTENANCE AND
SERVICING (3)
KEY
DESCRIPTION SPARES NUMBER
30
1
IMMERSION HEATER GASKET
2
BLANKING PLATE KIT
4
EXPANSION VESSEL 60L 6 BAR
6
EXPANSION VESSEL 100L 6 BAR
7
EXPANSION VESSEL 150L 6 BAR
8
EXPANSION VESSEL 200L 6 BAR
9
EXPANSION VESSEL 300L 6 BAR
10
1” INTEGRATED INLET CONTROL VALVE 5-10BAR
11
ISOLATING BALL VALVE 1”
12
ISOLATING BALL VALVE 1 1/4”
13
ISOLATING BALL VALVE 1 1/2”
14
ISOLATING BALL VALVE 2”
15
ISOLATING DRAIN VALVE 1”
16
TUNDISH 1 1/2” x 2”
17
PRV 1 1/4” SET PRESSURE 1.5 TO 6 BAR MAX IP 16 BAR
18
PRV 1 1/4” SET PRESSURE 5 TO 10 BAR MAX IP 16 BAR
19
PRV 1 1/2” SET PRESSURE 1.5 TO 6 BAR MAX IP 16 BAR
20
PRV 1 1/2” SET PRESSURE 5 TO 10 BAR MAX IP 16 BAR
21
PRV 2” SET PRESSURE 1.5 TO 6 BAR MAX IP 16 BAR
22
PRV 2” SET PRESSURE 5 TO 10 BAR MAX IP 16 BAR
23
SINGLE CHECK VALVE 1 1/4”
24
SINGLE CHECK VALVE 1 1/2”
25
SINGLE CHECK VALVE 2”
26
EXPANSION RELIEF VALVE 1” x 1 1/4” SET PRESSURE 8 BAR
27
EXPANSION RELIEF VALVE 1” x 1 1/4” SET PRESSURE 13 BAR
28
EXPANSION RELIEF VALVE 1 1/4” x 1 1/2” SET PRESSURE 8 BAR
29
EXPANSION RELIEF VALVE 1 1/4” x 1 1/2” SET PRESSURE 13 BAR
30
TEMPERATURE AND PRESSURE RELIEF VALVE - SET PRESSURE 10 BAR
31
TEMPERATURE AND PRESSURE RELIEF VALVE - SET PRESSURE 15 BAR
32
DUAL CONTROL THERMOSTAT
Unvented Hot Water Cylinder
95611025
95607396
95607445
95607458
95607461
95612723
95612724
95605176
95605178
95605179
95605180
95605181
95605182
95607452
95605183
95605184
95605185
95605186
95605187
95605188
95605189
95605190
95605191
95605192
95605193
95605194
95605195
95605196
95605197
95612650
Spares
KEY
DESCRIPTION SPARES NUMBER
33
CUT-OUT THERMOSTAT
95612652
34
ROD THERMOSTAT
95980025
35
2 PORT MOTORISED VALVE (DN 32)
95605198
36
2 PORT MOTORISED VALVE (DN 40)
95605199
37
PUMP 3 SPEED CIRCULATION UP 20-30N
95607366
38
PUMP 3 SPEED CIRCULATION UPS 15-50N 130
95607404
39
28mm PUMP ISOLATING VALVE95605177
40
1/2” BLANKING STAT POCKET95607690
41
1” BLANKING STAT POCKET95607691
43
EXPANSION VESSEL 60L 10 BAR95607446
44
EXPANSION VESSEL 100L 10 BAR95607459
45
EXPANSION VESSEL 150L 10 BAR95607462
46
EXPANSION VESSEL 200L 10 BAR95612725
47
EXPANSION VESSEL 300L 10 BAR95612726
48
1” INTEGRATED INLET CONTROL VALVE 1-6BAR
95605109
49
OVER TEMPERATURE ROD THERMOSTAT95980009
50
PUMP ISOLATION VALVE 28mm COMPRESSION TO 1 1/2”
95605110
Accsessories
94110301
94110302
94110303
94110304
94110305
94110306
94110307
94110308
94110309
De-Stratification loop kit - 400-500 litre
De-Stratification loop kit - 800-1450 litre
De-Stratification loop kit - 2000-2500 litre
95970140
95970157
95970158
MAINTENANCE AND
SERVICING (3)
6kW Commercial Immersion - Single phase
9kW Commercial Immersion - Single phase
12kW Commercial Immersion - Three phase
18kW Commercial Immersion - Three phase
24kW Commercial Immersion - Three phase
30kW Commercial Immersion - Three phase
36kW Commercial Immersion - Three phase
45kW Commercial Immersion - Three phase
54kW Commercial Immersion - Three phase
Temperature gauge95970141
Pressure gauge95970142
Temperature gauge (calibrated)95970017
Pressure gauge (calibrated)95970016
Unvented Hot Water Cylinder
31
2
1
Part
No:
95:611:025
4-9
43-47
MAINTENANCE AND
SERVICING (3)
95:607:396
10-48
Part
No:
95:607:_ _ _
Part
No:
95:605:_ _ _
Part
No:
95:605:182
15
11-14
Part
No:
95:605:_ _ _
17-22
16
Part
No:
32
Part
No:
95:607:452
Unvented Hot Water Cylinder
Part
No:
95:605:_ _ _
23-25
Part
No:
26-29
95:605:_ _ _
95:605:_ _ _
Part
No:
95:612:650
Part
No:
95:980:053
32
30-31
Part
No:
Part
No:
95:605:_ _ _
34
Part
No:
95:612:652
35&36
Part
No:
MAINTENANCE AND
SERVICING (3)
33
37&38
95:605:_ _ _
Part
No:
95:607:_ _ _
Unvented Hot Water Cylinder
33
40
39
Part
No:
95:605:177
MAINTENANCE AND
SERVICING (3)
95:607:690
Part
No:
95:980:009
49
41
34
Part
No:
Part
No:
95:607:438
Part
No:
95:605:110
50
Unvented Hot Water Cylinder
MAINTENANCE AND
SERVICING (3)
Unvented Hot Water Cylinder
35
MAINTENANCE AND
SERVICING (3)
36
Unvented Hot Water Cylinder
MAINTENANCE AND
SERVICING (3)
Unvented Hot Water Cylinder
37
User Guide
Lifetime Guarantee Terms and Conditions
WARNING: Should the factory fitted temperature and pressure relief valve be tampered with or
removed your guarantee will be invalidated. Neither the Distributor nor Manufacturer shall be
responsible for any consequential damage howsoever caused.
Guarantee Terms
Heatrae Sadia guarantees the MEGAFLO Commercial cylinder against faulty manufacture or
materials for a period of two years from the date of purchase including parts and labour. This two
year guarantee is extended to five years for the cold water control valve and to 25 years (from the
date of installation) for the stainless steel inner vessel.
These guarantees are valid provided that:
• The MEGAFLO Commercial has been installed by a competent engineer and as per the instructions
contained in the installation manual and all relevant Codes of Practice and Regulations in force
at the time of installation.
• Any disinfection has been carried out in accordance with BS EN 806-5:2012
• Should the factory fitted temperature and pressure relief valve be tampered with or removed your
guarantee will be invalidated.
• The MEGAFLO Commercial unit has not been modified in anyway other than by heateam
approved engineers.
• The MEGAFLO Commercial unit has only been used for the storage of wholesome sanitary
water (max 250mg/l chloride).
• Only stainless steel dummy plugs are to be used.
• The MEGAFLO Commercial unit has not been subjected to excessive pressure beyond the
guidelines detailed in the installation instructions.
• The MEGAFLO Commercial unit has not been subjected to frost, nor has it been tampered with
or been subject to misuse or neglect.
• No factory fitted parts have been removed for un-authorised repair or replacement
• Regular maintenance has been carried out by a competent person in accordance with the
requirements set in the maintenance section of the installation manual and any replacement
parts used should be approved MEGAFLO Commercial spare parts.
• The guarantee is not valid outside of the United Kingdom.
The warranty does NOT cover:
USER GUIDE (4)
Consequential damages or profit loss which may arise from a defect.
Warranty claims have no delaying effect on the payment dates and other demands
38
Your MEGAFLO Commercial warranty covers you for a direct replacement and labour in the event
that the unit fails prematurely as a result of a proved manufacturing defect.
In order that this can be achieved, full access to replace the unit is essential. If it is found that access
can not be achieved the warranty will be limited to the replacement of the unit only and subsequent
labour charges would not be met under the warranty.
Unvented Hot Water Cylinder
For installations outside of the United Kingdom, please contact either the Megaflo Export Department
on Tel: +44 1603 420271 or Baxi International on Tel: +44 1926 478323 for further details of the
guarantee terms and conditions applicable. This guarantee does not affect your statutory rights.
The unit is not guaranteed against damage due to frost. This guarantee does not affect your statutory
rights.
The Environment
This product is made from many recyclable materials, therefore at the end of its useful life it should be
disposed of at a Local Authority Recycling Centre in order to realise the full environmental benefits.
Insulation is by means of an approved HCFC/CFC free polyurethane foam.
Spares Stockists
megafloservice@heateam.co.uk
Electric Water Heating Co.
2 Horsecroft Place
Pinnacles
Harlow
Essex
CM19 5BT
Tel: 0845 0553811
E-Mail: sales@ewh.co.uk
SPD
Special Product Division
Units 9 & 10
Hexagon Business Centre
Springfield Road
Hayes
Middlesex
UB40 0TY
Tel: 0208 5730574
Newey & Eyre
Specialist Products Division
Please Contact your Local Branch
UK Spares Ltd
Unit 1155
Aztec West
Almondsbury
Bristol
BS32 4TF
Tel: 01454 620500
William Wilson Ltd
Unit 3A
780 South Street
Whiteinch
Glasgow
G14 0SY
Tel: 0141 434 1530
USER GUIDE (4)
Parts Center
Network 65 Business Park
Bentley Wood Way
Burnley
Lancashire
BB11 5ST
Telephone
0844 8711535 (option 5)
Facsimile
0844 8711528
E mail
Tel: 01282 834403
www.partscenter.co.uk
Unvented Hot Water Cylinder
39
Customer Service
Telephone
0845 070 1058
Facsimile
0845 070 1059
E mail
heateam.commercial@baxicommercialdivision.com
Megaflo
Hurricane Way
Norwich
Norfolk
NR6 6EA
© 2011
40
Unvented Hot Water Cylinder
36006144_issue _W
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