Unvented Direct & Indirect
Hot Water Cylinders
Megaflo Product Guide
Contents
Product Specification .....................................................................................................................................................................Page 3
Installation and Commissioning Instructions ..............................................................................................................................Page 11
Maintenance and Servicing...........................................................................................................................................................Page 27
User Guide ......................................................................................................................................................................................Page 37
PRODUCT SPECIFICATION (1)
DIRECT, EXPLODED VIEW
• Introduction
• Checklist
• General Requirements
• Water Supply
• Power Supply
• The Environment
• Specification and Dimensions
Unvented Hot Water Cylinder
PRODUCT SPECIFICATION (1)
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 and relevant electrical qualifications. 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.
IMPORTANT NOTE TO USER: PLEASE REFER TO THE USER GUIDE SECTION, PAGE 37 FOR IMPORTANT INFORMATION WITH RESPECT
TO THE BENCHMARK SCHEME
Introduction
Congratulations on your purchase of a MEGAFLO Eco unvented water heater. The MEGAFLO Eco is 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 Lifetime guarantee*. Its performance and insulation levels exceed the latest requirements of
Building Regulation Part L.
The MEGAFLO Eco 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, electric immersion heater(s) and, for indirect units, a
cylinder thermostat, thermal cut - out, 2-port motorised valve and wiring centre.
Generally its pressure and flow rate performance will far exceed that from a comparable vented system, thermal store, instantaneous gas heater or
combination boiler.
The MEGAFLO Eco requires no separate expansion vessel as any expanded water is accommodated within an internal air gap.
Please read and understand this product guide before starting work.
Please leave this product guide with the user following installation.
Component Checklist
Before commencing installation, check that all the components for your MEGAFLO Eco unit are contained in the package. The following
components are supplied as standard with your MEGAFLO Eco unit:
• Factory fitted immersion heater(s) and thermal controls
• Cold water inlet control kit, comprising of:
• 3 bar Pressure Reducing Valve (Figure 4, p.12)
• 8 bar Pressure Relief Valve (Figure 5, p.13)
• Stop cock (Figure 6, p13)
• Factory fitted Temperature and Pressure Relief Valve (set at 90ºC / 1 Mpa (10bar))
• Tundish (included in cold water combination valve pack)
• Factory fitted indirect thermostat and thermal cut-out
• T&P relief valve insulation set
• Drain valve
• Wiring centre
• 2-port motorised valve
• Lifting handle
* See Terms and Conditions of guarantee on page 39
Unvented Hot Water Cylinder
Important: Please read and understand this product guide before installing the MEGAFLO Eco water heater. Incorrect installation may invalidate
the guarantee. This appliance is not intended for use by persons (including children) with reduced physical, sensory or mental capabilities, or lack
of knowledge and experience, unless they have been given supervision or instruction concerning the use of the appliance by a person responsible
for their safety. The MEGAFLO Eco must be Installed (Section 2), Commissioned (Section 2) and Maintained (Section 3) 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).
For installations outside of the UK, contact the local authority for: local legislation, legal requirements, regulations, building regulations.
Following installation and commissioning, the operation of the heater should be explained to the user (Section 4) and this product guide left with
them for future reference.
PRODUCT SPECIFICATION (1)
General Requirements
Storage and Handling
Please take care when handling a packaged MEGAFLO Eco. 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.
Siting the MEGAFLO Eco (see Figure 1 below)
The MECAFLO Eco 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 of sufficient strength to support the
“full” weight of the unit (refer to Tables 3 and 4 on 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.
Please do not install valves or pipework (except discharge pipe) within 50mm (2”) of the T&P relief valve to allow your insulation set to be fitted.
The insulation set is important to ensure heat and energy conservation. See page 16 for more information.
To aid installation, the MEGAFLO Eco is provided with lifting points located in the base moulding and a lifting handle. The lifting handle should
be fully threaded onto the outlet boss before use. Once the MEGAFLO Eco is suitably positioned the lifting handle should be removed to allow
connection of the outlet pipework. The weights of the units are noted in the Tables 3 and 4, (p.9).
Figure 1 - Schematic Installation Details
BALANCED COLD WATER
CONNECTION (IF REQUIRED)
TO HOT OUTLET
3 BAR PRESSURE
REDUCING VALVE
STOP COCK (IF USED
IN THIS POSITION)
MAINS WATER
SUPPLY
SECONDARY RETURN
TAPPING (IF REQUIRED,
INDIRECT CYLINDERS
ONLY)
8 BAR PRESSURE RELIEF VALVE
T&P VALVE
TUNDISH
ELEMENT/CONTROLS
HOUSING
PRIMARY
RETURN
DRAIN COCK
DISCHARGE PIPE
PRIMARY
FLOW
Unvented Hot Water Cylinder
PRODUCT SPECIFICATION (1)
Outlet / Terminal Fittings (Taps, Etc.)
The MEGAFLO Eco can be used in conjunction with most types of terminal fittings. It is advantageous in many mixer showers to have balanced hot
and cold water supplies, in these instances the balanced cold water supply should be teed off the supply to the MEGAFLO Eco immediately after
the cold water combination valve (see Figure 7 p.14). Branches to cold drinking outlets should be taken before the valve.
Outlets situated higher than the MEGAFLO Eco unit will give outlet pressures lower than that at the heater, a 10m height difference will result in a
0.1 Mpa (1 bar) pressure reduction at the outlet fitting.
NOTE: Accessories should have a rated operating pressure of at least 0.8 MPa (8 bar).
Limitations
The MEGAFLO Eco 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.
NOTE: A high mains water pressure will not always guarantee high flow rates.
Wherever possible the main supply pipe should be in 22mm. The minimum mains water supply requirements should be 0.15 MPa (1.5 bar) working
pressure and 20 litres per minute flowrate.
At these values outlet flowrates may be poor if several outlets are used simultaneously, the higher the available pressure and flowrate the better the
system performance will be.
The MEGAFLO Eco has an operating pressure of 3 bar which is controlled by the 3 Bar Pressure Reducing Valve. The 3 Bar Pressure Reducing Valve
can be connected to a maximum mains supply pressure of 1.6 MPa (16 bar). The water supply must be of wholesome water quality (Fluid Category
1 as defined by the Water Supply Regulations 1999).
The MEGAFLO Eco is to be used for the storage of wholesome water (max. 250mg/l chloride).
Electrical Supply
WARNING: THIS APPLIANCE MUST BE EARTHED. IT IS SUITABLE FOR A.C. SUPPLY ONLY. ELECTRICAL INSTALLATION MUST BE CARRIED
OUT BY A COMPETENT ELECTRICIAN AND BE IN ACCORDANCE WITH THE LATEST I.E.E. WIRING REGULATIONS.
ENSURE THE ELECTRICAL SUPPLY IS SWITCHED OFF BEFORE MAKING ANY CONNECTIONS TO THE MEGAFLO Eco.
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.
Unvented Hot Water Cylinder
PRODUCT SPECIFICATION (1)
Specifications and Dimensions
Outline Specifications
Maximum mains water supply pressure (to 3 bar Pressure Reducing Valve)
1.6 MPa (16 bar)
Operating pressure (Pressure Reducing Valve set pressure – non adjustable) 0.3 MPa (3 bar)
Pressure Relief Valve
0.8 MPa (8 bar)
Temperature and Pressure Relief Valve set temp and pressure
90ºC / 1MPa (10 bar)
Immersion heater rating (a.c. supply only)
3kW @ 240V
2.8kW @ 230V
Outer casing:
White textured plastic coated corrosion resistant steel
Water container:
Duplex stainless steel. 100% pressure tested to 1.5 MPa (15 bar).
Thermal insulation:
CFC/HCFC free fire retardant expanded polyurethane foam with zero ozone depletion potential. It has a Global Warming Potential (GWP) of
3.1. Nominal thickness 60mm.
Pipe connections:
All connections accept 22mm outside diameter pipe – compression nuts and olives supplied. Thread rate is 3/ ” BSP male parallel to accept
standard 3/ ” BSP female fittings if required.
4
4
Safety features:
Direct units –
Manually resettable thermal cut-out on each heating element
Factory fitted Temperature and Pressure Relief Valve
Indirect units –
Manually resettable thermal cut-out on heating element
Manually resettable thermal cut-out for primary heating. Must be wired in conjunction with 2-port motorised valve supplied
Factory fitted Temperature and Pressure Relief Valve
The pace of product development is such that we reserve the right to change product specifications without
notice. We do, however, strive to ensure that all information in this leaflet is accurate at the time of publication.
Table 1 - Standing Heat-loss
STANDING HEAT LOSS
NOMINAL
CAPACITY
(LITRES)
70
125
145
170
210
250
300
PER DAY
(kWh/24h)
PER YEAR
(kWh/24h)
0.93
1.19
1.32
1.42
1.57
1.67
1.89
339.45
434.35
481.80
518.30
573.05
609.55
689.85
Unvented Hot Water Cylinder
29
PRODUCT SPECIFICATION (1)
Ø 579
Figure 2 - MEGAFLO Eco Direct
Temperature and Pressure
Relief Valve
D
74
30°
B
375
E
C
45°
Ø 579
29
Figure 3 - MEGAFLO Eco Indirect
Temperature and Pressure
Relief Valve
D
74
Unvented Hot Water Cylinder
B
A
393
F
C
27°
47°
30°
45°
TYPE
DIMENSIONS (mm)
B
C
A
D
E
70L
307
N/A
495
802
N/A
355
70L
i
802
316
495
N/A
125L
794
307
D
N/A
1102 649
i
125L
794
1102 N/A
316
355
895
1229 680
145L
307
D
N/A
145L
895
i
1229 N/A
316
355
307
N/A
D
170L
1020 1384 805
170L
i
1020 1384 N/A
316
355
307
210L
D
N/A
1095 1486 901
210L
355
1095 1486
i
316
*
D
1323 1738 1109
307
250L
N/A
250L
i
1323 1738
355
316
*
307
1574 2053 1413
D
N/A
300L
1574 2053
i
316
355
300L
*
A
SECOND
ELEMENT
KIT
CAN
BE
PURCHASED,
KIT
NO
95970554
*
SIZE
DIRECT
D
INDIRECT
F
N/A
N/A
N/A
709
N/A
810
N/A
934
N/A
1011
N/A
1238
N/A
1526
PRODUCT SPECIFICATION (1)
Table 2 - Dimensions
Table 3 - Direct Units - Technical Specification
HEAT UP TIMES (RECOVERY 70% DRAW-OFF), MINS
UNIT WEIGHT (kg)
SIZE
MODEL D
(3kW)
MODEL DD MODEL DDD MODEL DDDD
(12kW)
(6kW)
(9kW)
EMPTY
FULL
70L
23
123
92
(63)
125L
25
174
142
(98)
71
145L
31
200
158 (109)
170L
34
228
210L
38
250L
300L
BOOST
(3kW)
N/A
N/A
N/A
(49)
N/A
N/A
66
79
(55)
N/A
N/A
72
186 (129)
93
(65)
N/A
N/A
79
249
204 (142)
102 (71)
68
(47)
51
(36)
85
46
296
245 (169)
121 (85)
81
(56)
60
(42)
92
56
356
292 (203)
146 (102)
97
(68)
73
(51)
97
N/A
Table 4 - Indirect Units - Technical Specification
UNIT WEIGHT (kg)
SIZE
COIL SPECIFICATIONS
EMPTY
FULL
SURFACE (SQ/M)
HEAT-UP (MINS)
RECOVERY (MINS)
RATING (kW)
70L
25
125
0.58
17
10
15.4
125L
31
180
0.58
23
15
18.3
145L
35
204
0.72
24
17
18.7
170L
39
233
0.79
22
16
24.3
210L
43
253
0.79
28
19
24.3
250L
50
300
0.79
34
23
23.9
300L
58
358
0.79
39
27
24.5
NOTE
Coil heating performance based on a primary flow rate of 15L/min at 80°C.
Temperature rise is from 15°C to 60°C.
Unvented Hot Water Cylinder
PRODUCT SPECIFICATION (1)
NOTES.
Unvented Hot Water Cylinder
PRODUCT
SPECIFICATION (1)
INSTALLATION AND
COMMISSIONING INSTRUCTIONS (2)
• General Installation
• Indirect Model
• Direct Model
• Commissioning
Unvented Hot Water Cylinder
General Installation
Pipe Fittings
All pipe connections to the MEGAFLO Eco are made via 22mm compression fittings directly to the unit (nuts and olives supplied). The fittings are
also threaded 3/ ” BSP male parallel should threaded pipe connections be required.
4
Cold Water Supply
A 22mm cold water supply is recommended, however, if a 15mm (1/ ”) supply exists which provides sufficient flow (see section1, p.6 “Water
Supply”) this may be used. More flow noise may be experienced from small bore pipes due to the increased water velocity through them.
2
INSTALLATION AND
COMMISSIONING INSTRUCTIONS (2)
The Cold Water Inlet Control kit supplied with the MEGAFLO Eco incorporates a full flow isolating valve which will enable the MEGAFLO Eco to be
isolated from the mains supply for maintenance or servicing. To close the valve the blue handle should be turned so that it lies at 90º to the direction
of flow. To open, turn the handle so that it lies parallel to the direction of flow.
3 Bar Pressure Reducing Valve (see Figure 4 below)
The 3 bar Pressure Reducing Valve can be connected anywhere on the cold water mains supply prior to the MEGAFLO Eco 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 3 bar Pressure Reducing Valve can be installed as a complete one-piece unit or incorporating the stopcock (see Figure 6, p.13). The valve
incorporates a factory set, non-adjustable Pressure Reducer and Strainer and a single Check Valve. 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 Eco heater.
If a balanced pressure cold water supply is required to a thermostatic shower mixer valve this may be teed off the supply to the MEGAFLO Eco
immediately after the 3 bar Pressure Reducing Valve (see Figure 7, p. 14).
Figure 4 - 3 bar Pressure Reducing Valve
Pressure Reducing Valve
Cartridge (3 bar)
Take note of flow
direction
Mains in
Outlet to MEGAFLO Eco
22mm compression connection
Unvented Hot Water Cylinder
8 Bar Pressure Relief Valve (see Figure 5 below)
This should be installed between the 3 bar Pressure Reducing Valve and the MEGAFLO Eco cylinder. Should a balanced pressure cold water draw off supply be
required for the cold water outlets, this should be taken off between the 3 bar Pressure Reducing Valve and 8 bar Pressure Relief Valve (see Figure
7, p. 14). Branches to drinking water outlets should be taken BEFORE the 8 bar Pressure Relief Valve to avoid the possibility of warm
expanded water being drawn from the tap.
Figure 5 - 8 bar Pressure Relief Valve
Take note of flow
direction
From cold water
combination valve
Outlet to MEGAFLO Eco
Pressure Relief Valve
“TEE” ( incorporates
Check Valve )
INSTALLATION AND
COMMISSIONING INSTRUCTIONS (2)
Pressure Relief Valve
discharge connection
22mm compression connection
Figure 6 - Valve set can be grouped two ways
Stopcock can be grouped with either
3 bar Pressure Reducing Valve or
8 bar Pressure Relief Valve on the
inlet to either valve only
8 bar Pressure Relief
Valve
3 bar Pressure
Reducing Valve
Stopcock
Unvented Hot Water Cylinder
Unvented Hot Water Cylinder
KEY
MCWS =
HWS =
SC =
DOC =
Mains Cold Water Supply
Hot Water Service
Stop Cock / Isolating Valve
Drain Off Cock
Isolating / Regulating
Valves, as required
Balanced HWS and
MCWS to bathrooms,
showers, cloakrooms,
etc
DOC
Tundish
Temperature and Pressure
Relief Valve
Balanced cold water
draw-off
Discharge pipe to atmosphere
(see page 18 “Discharge Pipework”
DOC DOC
MEGAFLO Eco
HWS supply
SC
DOC
SC
Mains Cold Water
Supply
MCWS to Kitchen
(unbalanced cold
mains supply)
3 bar Pressure Reducing
Valve incorporating
Pressure Reducing Valve,
Strainer, and Check Valve.
(Stop cock can be fitted
here)
8 bar Pressure Relief
Valve (combined
Expansion Relief
Valve / Check Valve)
INSTALLATION AND
COMMISSIONING INSTRUCTIONS (2)
Figure 7 - Schematic installation diagram using 3 bar Pressure Reducing
Valve in conjunction with 8 bar Pressure Relief Valve
Drain Tap
A drain tap is supplied and should be installed in the cold water supply to the MEGAFLO Eco unit between the 8 bar Pressure Relief
Valve and the heater at as low a level as possible (see Figure 1, p. 5). 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 tap outlet spigot). The drain tap
supplied provides very good water flow control and blanking cap for extra security.
Outlet Pipework
Ideally the pipework from the MEGAFLO Eco to the outlet fittings should be in 22mm pipe with short runs of 15mm pipe to showers
and basin taps. 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.
The secondary return pipe should be in 15mm pipe and incorporate a check valve to prevent backflow. 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.
Indirect models
If a secondary circulation system is requiredon on an indirect model, it is recommended that it be connected as shown in Figure 8a
below.
Direct models
If a secondary circulation system is required on a direct model, it is recommended that it be connected to the MEGAFLO Eco as shown in
Figure 8b below via a swept tee (spare code 95605812). Particular attention should be paid by the installer to maintain the return water
temperature (guidelines state that a minimum of 55° C is advisable). Factors such as, but not limited to secondary circulation flow rates,
minimising heat loss of all secondary pipework and timed operation during periods of high demand are critical to the correct operation
and longevity of the heating element(s) and thermostats.
Pipe capacities (copper)
15mm o/d = 0.13 litres per metre run (10 litres = 77m)
INSTALLATION AND
COMMISSIONING INSTRUCTIONS (2)
Secondary Circulation
22mm o/d = 0.38 litres per metre run (10 litres = 26m)
28mm o/d = 0.55 litres per metre run (10 litres = 18m)
Secondary Circulation Connection
To Hot Outlets
Cold Water
Inlet
To Hot
Outlets
Check Valve
Secondary Return
Cold Water
Inlet
WRAS Approved
Bronze Pump
Swept Tee
Secondary
Circulation Pump
Secondary
Return
Check Valve
Figure. 8a Indirect models
Figure. 8b Direct models
Unvented Hot Water Cylinder
T&P Relief Valve insulation
A set of insulating components is supplied with the MEGAFLO Eco water heater and should be installed to gain maximum heat and energy
saving benefits. See Figure 9 below, for installation instructions.
Warnings
i) Under no circumstances should the factory fitted Temperature and Pressure Relief Valve be removed other than by authorised Heatrae
Sadia personnel. To do so will invalidate any guarantee or claim.
ii) The Cold Water Combination Valve must be fitted to the Mains Cold Water Supply to the MEGAFLO Eco unit.
iii) No control or safety valves should be tampered with or used for any other purposes.
iv) Water may drip from the discharge pipe of the Pressure Relief Valve (expansion valve) and this pipe must be left open to atmosphere. The
discharge pipe should not be blocked or used for any other purpose.
INSTALLATION AND
COMMISSIONING INSTRUCTIONS (2)
v) The tundish must be installed so that it is visible to the end user.
vi) The tundish, drain valve and motorised valves (indirect units only) must be installed away from any electrical components.
vii) No valve should be fitted between the 8 bar Pressure Relief Valve and the MEGAFLO Eco unit.
Figure 9 - Installation of T&P Insulation Set
IMPORTANT INFORMATION:
HOW TO INSULATE YOUR T&P RELIEF VALVE
TO SAVE HEAT AND ENERGY A SET OF INSULATING PARTS FOR
THE T&P RELIEF VALVE HAVE BEEN SUPPLIED WITH THIS WATER
HEATER. INSTALL THE HEATER FIRST THEN FIT THE INSULATING
PARTS BY FOLLOWING THE DIAGRAMS BELOW.
B
A
T&P RELIEF
VALVE
DISCHARGE
PIPEWORK
LEFT HAND
INSULATING PIECE
RIGHT HAND
INSULATING PIECE
TUNDISH
D
C
PLASTIC COVER
Unvented Hot Water Cylinder
DISCHARGE PIPE
CLIP INTO
PLACE !
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
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.
3.55
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
3.56
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)
( d)
INSTALLATION AND
COMMISSIONING INSTRUCTIONS (2)
3.54
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.
Note:
1.
2.
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
Discharge Pipework
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 (p. 17) are reproduced in the following 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 and 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.
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 INSTRUCTIONS (2)
Notes:
1) Discharge pipe-work D2 can now be a plastic pipe but only pipes that have been tested to a
minimum110°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.
VALVE OUTLET
SIZE
MINIMUM SIZE OF
DISCHARGE PIPE D1
MINIMUM SIZE OF
DISCHARGE PIPE D2
FROM TUNDISH
MAXIMUM RESISTANCE
ALLOWED, EXPRESSED
AS A LENGTH OF
STRAIGHT PIPE (I.E. NO
ELBOWS OR BENDS
RESISTANCE CREATED BY
EACH ELBOW OR BEND
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
Figure 10 - Schematic discharge pipe arrangement
Safety device
(e.g. Temperature
relief valve)
Metal discharge pipe (D1) from
Temperature relief valve to tundish
600mm maximum
Tundish
300mm
minimum
Discharge pipe (D2) from tundish,
with continuous fall. See Building
Regulation G3 section 3.56,
Table 4 and worked example
Discharge below
fixed grating
(Building Regulation
G3 section 3.61 gives
alternative points
of discharge)
Fixed grating
Trapped
gully
Unvented Hot Water Cylinder
Worked example of discharge pipe sizing
The example on page 18 is for a G½ 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 22mm copper discharge pipe (D2) from a G1/ Temperature Relief Valve is 9m.
2
Subtract the resistance for 4 No. 22mm elbows at 0.8m each = 3.2m
Therefore the permitted length equates to: 5.8m
5.8m is less than the actual length of 7m therefore calculate the next largest size.
Maximum resistance allowed for a straight length of 28mm pipe (D2) from a G1/ Temperature Relief Valve equates to 18m.
2
Subtract the resistance of 4 No. 28mm elbows at 1m each = 4m
As the actual length is 7m, a 28mm (D2) copper pipe will be satisfactory.
INDIRECT MODEL
Boiler Selection
The MEGAFLO Eco 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 pipework close to the MEGAFLO Eco 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 Eco unit.
Indirect Thermal Cut-Out And 2-Port Motorised Valve
To comply with Building Regulations, and to prevent the MEGAFLO Eco from overheating the 2-port motorised valve supplied MUST be fitted
to the primary flow to the indirect coil (see Figure 11 below).
Figure 11 - Primary connections to indirect units
INSTALLATION AND
COMMISSIONING INSTRUCTIONS (2)
Therefore the maximum permitted length equates to: 14m
To Hot Outlets
Cold Water Inlet
Air Vent
(Must be at the highest
point of the system)
Primary Return
Two Port Motorised Valve (Supplied)
Primary Flow
Unvented Hot Water Cylinder
Wiring
All electrical wiring should be carried out by a competent electrician and be in accordance with the latest I.E.E. wiring regulations.
!
"
#
$
%
&
'
(
)
*
!
&
The MEGAFLO Eco indirect combined thermostat and thermal cut-out are factory pre-wired. The 2-port motorised valve supplied MUST be wired in series
with the indirect controls such that the power supply to the valve is interuppted should eithet the thermostat or thermal cut-out operate. Figures 13 and
14, (p. 21) detail the wiring between these controls and the motorised valve. Wiring to external controls is made via the terminal block fitted. The cable
should be routed through the aperture in the terminal cover and secured using the cable grip provided. The indirect thermal cut-out MUST NOT be
bypassed.
Heating System Controls
The controls provided with the MEGAFLO Eco will ensure the safe operation of the MEGAFLO Eco within a central heating system. Other controls will be
necessary to control the space heating requirements and times that the system is required to function. Depending on the boiler selected, heating circuit
design and controls used, it may be beneficial to incorporate a system bypass in the heating system pipework.
INSTALLATION AND
COMMISSIONING INSTRUCTIONS (2)
The MEGAFLO Eco is compatible with most heatig controls, examples of electrical circuits are given in Figures 13 and 14, (p. 21). However, other systems
may be suitable, refer to controls manufacturers’ instructions supplied with the controls selected, for alternative system wiring schemes.
Immersion heater(s)
The MEGAFLO Eco indirect units are supplied with an immersion heater which can be used as an alternative heat source should the boiler supply need to
be isolated from the MEGAFLO Eco unit.The immersion heater is located within the controls housing, refer to, sections “Wiring and Operation”(see p. 22)
for details of wiring and operation of the immersion heater. 210 litre models and above are supplied with a second blanked off boss which can be used
for the connection of a second immersion heater should this be required.
To remove the blanking plug:
Ensure the cylinder is drained of water. Open the cover to the upper immersion heater boss. Unscrew the backnut using the key spanner provided with the
unit. Remove the blanking plug and sealing gasket from the boss.
Fitting additional immersion heater:
Insert the immersion heater and sealing gasket into the upper boss. Ensure that the sealing gasket is not displaced when inserting. It may be helpful
to support the immersion heater using a round shafted screwdriver inserted into one of the thermostat pockets.Hand tighten the backnut. Secure the
immersion heater in position by tightening with the key spanner provided. If an additional immersion heater and thermostat assembly is required, order
part no. 95:970:554.
Figure 12- Indirect wiring layout
Control Housing Details
Element Connections
Indirect control
wiring
Unvented Hot Water Cylinder
1
2
3
L
N
1.5mm² 3 Core
HOFR sheathed
cable
Figure 13 - 2 port valve in conjunction with a 3 port mid-position valve system (“Y” Plan)
MEGAFLO ECO INDIRECT
THERMAL CONTROLS
(SUPPLIED FITTED)
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
INSTALLATION AND
COMMISSIONING INSTRUCTIONS (2)
(SUPPLIED)
L
N
1
3
2
ROOM STAT
O
GY
N
3-PORT MID POSITION VALVE
N
L
L
PUMP
BOILER
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. USE COPPER LINKS SUPPLIED TO MAKE CONNECTIONS BETWEEN TERMINALS.
5. DO NOT MOUNT WIRING CENTRE ON CYLINDER.
6. 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.
Figure 14 - 2 x 2 port valve system (“S”Plan)
MEGAFLO ECO INDIRECT
THERMAL CONTROLS
(SUPPLIED FITTED)
PROGRAMMER
KEY
Bl
Br
G
O
GY
DHW
HTG
L
N
1
2
HTG
ON
DHW
ON
4
5
1
2
MEGAFLO ECO (DHW)
ZONE VALVE
(SUPPLIED)
Bl
3
Br
G
O GY
BLUE
BROWN
GREY
ORANGE
GREEN/YELLOW
DOMESTIC HOT WATER
HEATING
3
6
7
8
9
10 11 12 13 14 15 16
Bl
Br
G
O GY
WIRING CENTRE
(SUPPLIED)
L
N
1
3
2
ROOM STAT
ZONE VALVE (HTG)
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. USE COPPER LINKS SUPPLIED TO MAKE CONNECTIONS BETWEEN TERMINALS.
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
+
,
DIRECT MODEL
Immersion Heater(s)
The MEGAFLO Eco is supplied with either one (D model), two (DD models), three (DDD models) or four (DDDD models) factory fitted immersion heaters.
Each immersion heater is rated 3kW at 240V~.
To remove the immersion heater:
Open the cover to the upper immersion heater. Unplug the thermostat from the element by gently pulling the thermostat outwards. Unscrew the
backnut using the key spanner provided. Remove the immersion heater assembly and sealing gasket from the boss.
Replacement:
Insert the immersion heater and sealing gasket into the required boss. Ensure that the sealing gasket is not displaced when inserting. It may be helpful
to support the immersion heater using a round shafted screwdriver inserted into one of the thermostat pockets. Hand tighten the backnut . Secure the
immersion heater in position by tightening with the key spanner provided. Insert the blanking plate into the remaining boss, ensuring the sealing gasket
is not displaced when inserting. Hand tighten the backnut. Secure in position by tightening with the key spanner provided.
INSTALLATION AND
COMMISSIONING INSTRUCTIONS (2)
If an additional immersion heater is required, order part no. 95:970:554.
Wiring (see Figure 16, p.23)
All electrical wiring should be carried out by a competent electrician and be in accordance with the latest I.E.E. wiring regulations. Each circuit must be
protected by a suitable fuse and double pole isolating switch with a contact separation of at least 3mm in both poles.
The immersion heater(s) should be wired in accordance with Figure 15, p.23. The immersion heaters MUST be earthed. The supply cable should be
1.5mm² 3-core HOFR sheathed and must be routed through the cable gland provided with the outer sheath of the cable firmly secured by tightening
the screw on the cable gland. Replace the immersion heater cover(s) before operating, ensuring that the threaded edge clip is in position to provide a
suitable thread for the cover screw.
DO NOT OPERATE THE IMMERSION HEATER(S) UNTIL THE MEGAFLO Eco HAS BEEN FILLED WITH WATER.
Operation
See Figure 16, p.23 for details on how to adjust the temperature setting of the heater. The thermostat incorporates a thermal cut-out that will switch off
the immersion heater in the event of a thermostat failure. The thermal cut-out reset button position is indicated on Figure 16, page 23.
DO NOT BYPASS THE THERMAL CUT-OUT IN ANY CIRCUMSTANCES.
Access to Control Unit:
LUGS
Disconnect from mains supply before removing any covers.
Removing the Control Cover:
• Unscrew the large screw using a flat ended screw driver.
• Lift from bottom of cover at point indicated until cover comes
away freely
Replacing the Control Cover:
LIFT OFF
• Tilt and align the top 2 lugs in the holes indicated
• Firmly press the cover until it “snaps” back in place.
• Tighten the large screw ( DO NOT OVER TIGHTEN ).
LIFT FROM THIS POINT
REPLACE
-
-
Unvented Hot Water Cylinder
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 MEGAFLO Eco SPARE PART.
Figure 15- Schematic wiring diagram - Direct immersion heater with adjustment details
Direct Wiring Layout
INSTALLATION AND
COMMISSIONING INSTRUCTIONS (2)
N
L
1.5mm² 3 Core
HOFR sheathed
cable
Figure 16 - Adjustment details
THERMAL CUT-OUT RESET BUTTON
SPINDLE POSITIONS
= MINIMUM TEMP
= MAXIMUM TEMP
= APPROX 60 °C
ROTATE SPINDLE CLOCKWISE
FOR TEMPERATURE INCREASE
AND COUNTER CLOCKWISE
FOR TEMPERATURE DECREASE
TEMPERATURE ADJUSTING
SPINDLE
Unvented Hot Water Cylinder
.
/
Commissioning
Ensure that all fittings and immersion heaters are correctly fitted and tightened. An immersion heater key spanner is provided to aid in tightening
the immersion heater(s).
(i) Open the hot tap furthest from the MEGAFLO Eco.
(ii) Open the isolating valve on the 3 bar Pressure Reducing Valve by turning the blue handle on the stop cock (if fitted in this position) so that it lies
parallel to the direction of flow. Open the mains stop cock to fill the unit. When water discharges from the tap, alow to run for a few minutes to
thoroughly flush through any residue, dirt or swarf, then close the tap.
INSTALLATION AND
COMMISSIONING INSTRUCTIONS (2)
(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 3 bar Pressure Reducing Valve should be cleaned to remove any debris that may have been flushed through the
mains supply pipe. Refer to, p. 28 ‘Clean the strainer’ for instructions on how to do this.
WARNING: If the installation is to be left unused following installation and commissioning, e.g. unoccupied
properties, the water heater should be drained or regularly flushed through with fresh mains water once a
week.
When placing the unit into service, the procedure for filling the unit and the system checks above should be
observed.
Check the operation of the safety valves
(i) Slowly, manually open (turn black knob on end counter-clockwise for a few seconds, the Temperature and Pressure Relief Valve (T & P valve)
situated on the MEGAFLO Eco unit (see Figure 1, p. 5). Check water discharged runs freely away through the tundish and discharge pipework.
Close valve, ensure water flow stops and valve re-seats correctly.
(ii) Repeat for the 8 bar Pressure Relief Valve (see Figures 5 & 6, p.13.)
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. 60°C is recommended. If necessary, the temperature can be adjusted by inserting a flat bladed screwdriver in the adjustment
knob on top of the immersion heater thermostat and rotating clockwise (see Figure 16, p. 23). The full adjustment represents a temperature range
of between 12°C and 68°C. Check that no water is discharged from either the Expansion Valve or Temperature and Pressure Relief Valve during the
heating cycle.
Indirect Units
Fill the indirect (primary) circuit following the boiler manufacurer’s commissioning instructions. To ensure the primary heating coil in the MEGAFLO
Eco is filled, the 2-port motorised valve (supplied) should be manually operated by moving the lever to the MAN OPEN position. When the primary
circuit is full, return the lever to AUTO position. Vent any trapped air by opening the air bleed.
Switch on the boiler, ensure the programmer is set to Dometic Hot Water. Allow the MEGAFLO Eco unit to heat up and check that the indirect
thermostat and 2-port motorised valve operate correctly. A storage temperature of approx. 60°C is recommended. If necessary, the temperature can
be adjusted by inserting a flat bladed screwdriver in the adjustment knob on top of the immersion heater thermostat and rotating clockwise (see
Figure 16, p.23). The full adjustment represents a temperature range of between 12°C and 68°C. Check that no water is discharged from either the
Expansion Valve or Temperature and Pressure Relief Valve during the heating cycle.
BenchmarkTM Log Book
On completion of the installation and commissioning procedures detailed in this manual, the BenchmarkTM ‘Installation, Commissioning and Service
Record Log’, pages 34 and 35 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 (page 34) to accept completion. The Service Record
should be filled in when any subsequent service or maintenance operation is carried out on the MEGAFLO Eco unit (see Maintenance and Servicing,
p.35).
0
1
Unvented Hot Water Cylinder
NOTES.
INSTALLATION AND
COMMISSIONING INSTRUCTIONS (2)
3
2
Unvented Hot Water Cylinder
INSTALLATION AND
COMMISSIONING INSTRUCTIONS (2)
NOTES.
4
5
Unvented Hot Water Cylinder
INDIRECT, EXPLODED VIEW
MAINTENANCE AND
SERVICING (3)
• Maintenance
• Fault Finding
• Servicing
• Spares
• Benchmark
Unvented Hot Water Cylinder
6
7
Maintenance
Maintenance requirements
To ensure the continued optimum performance of the MEGAFLO Eco 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 MEGALO Eco 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 Eco unit will
need to be drained, details below list how to drain the unit and remove the immersion heater(s).
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 pipework. Check valve reseats correctly when released.
NOTE: The water discharged may be very hot.
Repeat the procedure for the 8 bar Pressure Relief Valve.
Clean the strainer
The strainer is incorporated within the Pressure Reducing Valve housing of the Cold Water Combination Valve (see Figure 17, p.31). To inspect and
clean the strainer:
i) Turn off the isolating valve on the 3 bar Pressure Reducing Valve by turning the blue handle (if fitted in this position) so it lies 90º to the direction
of flow or the main stop cock to the house.
ii) Open the lowest hot tap in the system to relieve the system pressure.
iii) Using a spanner unscrew the Pressure Reducing Cartridge and remove the moulded housing. The strainer will be removed with the cartridge.
iv) Wash any particulate matter from the strainer under clean running water.
v) Replace the strainer and screw the Pressure Reducing Valve Cartridge into the moulded housing.
vi) Close hot tap, turn on isolating valve by turning handle so it lies parallel to the direction of flow. Check for leaks.
MAINTENANCE AND
SERVICING (3)
Draining the MEGAFLO Eco 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 Eco unit. Attach a hosepipe to the drain cock 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 Eco to relieve the system pressure.
Open drain cock. If water fails to drain from the MEGAFLO Eco vent the unit manually by opening the Temperature and Pressure Relief Valve.
Descaling immersion heater(s)
Open the cover(s) to the immersion heater housing(s) and disconnect wiring from immersion heater(s). Remove the thermostat capillaries, 2 or
4 depending on which unit being serviced. Unscrew immersion heater backnut(s) and remove immersion heater from the unit. A key spanner is
supplied with the MEGAFLO Eco unit for easy removal and tightening of the immersion heater(s). Over time the immersion heater gasket may
become stuck to the mating surface. To break the seal insert a round shafted screwdriver into one of the pockets on the immersion heater and
gently lever up and down.
Carefully remove any scale from the surface of the element(s). DO NOT use a sharp implement as damage to the element surface could be
caused. Ensure sealing surfaces are clean and seals are undamaged, if in doubt fit a new gasket.
Replace immersion heater(s) ensuring the lower (right angled) element hangs vertically downwards towards the base of the unit. It may be helpful
to support the immersion heater using a round shafted screwdriver inserted into one of the thermostat pockets whilst the backnut is tightened.
Replace the thermostat(s) by carefully plugging the two male spade terminations on the underside of the thermostat head into the corresponding
terminations on the element.
Rewire the immersion heater(s) in accordance with Figure 12, p.20 or Figure 15, p.23. Close and secure terminal cover(s).
Refilling system
DO NOT switch on the immersion heater(s) or boiler until the system has been completely refilled.
Close the drain tap. With the hot tap open, turn on the 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 the hot tap and then open successive hot taps in system to purge any air. The electrical
supply can now be switched on.
BenchmarkTM
On completion of any maintenance or service of the MEGAFLO Eco, the BenchmarkTM “Installation, Commissioning and Service Record” should
be filled in to record the actions taken and the date the work was undertaken.
8
9
Unvented Hot Water Cylinder
Fault Finding
The Fault Finding Chart (Table 6. below) will enable operational faults to be identified and their possible causes rectified. Any work carried out on
the MEGAFLO Eco 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 Eco Service Division, (p. 40).
Table 6 - Fault Finding Chart
F AUL T
P O S S IB L E CAUS E
1. M a in s w a t e r s u pp ly o ff.
2. S tra in er bloc k e d.
N o ho t w ate r flow
3. C old Water Com bination
V alve inc orrec tly fitted .
R E ME DY
1 . C h ec k and op en s top c oc k .
2 . Turn o ff w a ter s u pp ly . R em ove s tra in er
a nd c le an (s ee p.28).
3 . C h ec k and refit as re qu ired .
1. B A C K U P im m e rs ion h ea te r
1 . C h ec k and s w itc h o n.
no t s w itc hed on.
2. B A C K U P im m e rs ion h ea te r
2 . C h ec k . R e s e t b y pu s h in g bu tto n.
(Figure 16, p.23)
the rm al c ut-ou t h as ope rated .
W a ter from hot tap s is c o ld
3. IN D IR E C T prog ram m e r s et
to cen tra l hea tin g on ly .
3 . C h ec k . S e t to a do m e s tic hot wa te r
p ro gra m m e.
4. IN D IR E C T boiler no t
w ork ing .
4 . C h ec k boiler op eration . If fau lt is
s us pec ted c on s ult bo iler m an ufac turer's
ins tru c tions .
5. IN D IR E C T th erm a l c ut-ou t
ha s op era te d.
5 . C h ec k . R e s e t b y pu s h in g bu tto n on c u to ut. C h ec k op eration of ind ire c t therm o s ta t
(Figure 16, p.23 ).
6. IN D IR E C T m oto ris e d va lve
no t c on ne c ted c orrec tly .
6 . C h ec k w iring a nd/o r p lu m bin g
c on nec tio ns to m otoris e d valve (s e e F ig u r e s
13 & 14, p.21).
1. IN TE R M ITTE N TL Y
Air Volume in MEGAFLO
Eco has reduced.
W a ter dis c harg es from
8 b a r P r e s s u r e R e l i e f Valve
a. 3 b a r P r e s s u r e R e d u c i n g
Valve not working correctly
2 a. C hec k pre s s ure from 3 bar Pressure
Reducing Valve. If grea ter than 3 b ar
rep lac e Pre s s ure Red uc er c artridge .
b. E x p an s ion valve s ea t
da m ag ed .
2 b. R em o ve Pressure Relief c artrid ge from
8 bar pressure Relief Valve and check seating. If
necessary fit new cartridge.
1. Air volume in MEGAFLO Eco has 1 . S e e p. 3 8 ‘ O p e r a t i o n a l F a u l t s ’
(for re-c h arging )
reduced
2. 8 bar Pressure Relief Valve
faulty
W a ter dis c harg es from the
Temperature and Pressure Relief
Valve continually
M ilk y w ater
1. Th erm a l c ontro l failu re
N O TE w ater w ill b e ve ry ho t.
1. O x y ge na te d w ate r.
2. C h e c k v a l v e a n d r e p l a c e i f n e c e s s a r y
1 . S w itc h off pow e r to im m e rs ion h ea te r(s )
a nd s hu t d ow n b oile r. D O N O T turn o ff
w ate r s up ply . W h en d is c h arge s top s
c he c k a ll th erm a l c on tro ls , rep lac e if fa ulty .
MAINTENANCE AND
SERVICING (3)
W a ter dis c harg es from t h e
Temperature and Pressure
Relief valve intermittently
2. C O N TIN U A L LY
1 . S e e p. 3 8 ( o p e r a t i o n a l f a u l t s
s e c tio n for re-c h arging )
1 . W ate r from a p res s uris e d s y s tem
rele as e s ox y g en b ub bles w h en flow in g. Th e
m ilk ine s s w ill dis a ppe ar after a s hort w hile .
Unvented Hot Water Cylinder
:
;
Servicing
Important
i) Servicing should only be carried by authorised Baxi Customer Support 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 Eco 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 Eco unit may be very hot, especially following a thermal control failure. Caution must be taken when
drawing water from the unit.
Spares
MAINTENANCE AND
SERVICING (3)
Spare parts
A full range of spare parts are available for the MEGAFLO Eco range. Refer to the technical data label on the unit to identify the model installed
and ensure the correct part is ordered.
<
=
Description
Cold Water Inlet Control Kit - Complete
3 Bar Pressure Reducing Valve - Complete
Strainer Mesh
3 Bar Pressure Reducing Valve Cartridge
8 Bar Pressure Relief Valve - Complete
8 Bar Expansion Relief Cartridge
Stopcock
Part no.
95:605:894
95:605:886
95:605:889
95:605:891
95:605:893
95:605:888
95:605:885
Immersion Heater Backnut
Immersion Heater Gasket
Immersion Heater Key
Immersion Heater Blanking Plug
Terminal Shroud
Titanium Immersion Heater - Upper
Titanium Immersion Heater - Lower
Direct Combined Thermostat / Thermal Cut-Out
Tundish
95:607:940
95:611:822
95:607:861
95:605:881
95:606:993
95:606:989
95:606:988
95:612:717
95:605:838
Direct Titanium Control Cover
Mounting Plate (Direct)
3 way Terminal Block
95:614:119
95:607:929
95:607:932
Insulation Set ( T & P Relief Valve )
Mounting Plate (Indirect)
Indirect Control Cover
6 way Terminal Block
2 Port Motorised Valve (22mm Connections )
Incoloy Immersion Heater - Lower
Indirect Combined Thermostat and Cut-out
95:607:922
95:607:931
95:614:118
95:607:933
95:605:819
95:606:984
95:612:716
Temperature and Pressure Relief Valve
Set of Compression Nuts and Olives
Drain Valve 1/4 Turn
Swept tee (secondary return)
95:605:810
95:607:838
95:605:051
95:605:812
Unvented Hot Water Cylinder
Figure 17 - Exploded View of 3 Bar Inlet Control Valve
Pressure Reducing
Valve Cartridge (3 Bar)
95:605:891
Strainer Mesh
95:605:889
3 Bar Pressure Reducing Valve - Complete
95:605:886
Figure 18 - Exploded View of 8 Bar Pressure Relief Valve
Expansion Relief Cartridge
95:605:888
MAINTENANCE AND
SERVICING (3)
8 Bar Pressure Relief Valve, Complete
95:605:893
Figure 19 - Exploded View of Stopcock
Stopcock, Can Be Used Either with
3 Bar Inlet Control Valve or 8 Bar
Pressure Relief Valve
95605885
Unvented Hot Water Cylinder
>
?
Figure 20: Indirect Exploded View
Indirect Control Assembly
For 210 Litre and above a further
Boost Immersion Heater (direct control
assembly) accessory
is available 95:970:554
See diagram A on page 33
Terminal Cover (indirect)
95:614:118
MAINTENANCE AND
SERVICING (3)
Mounting PLate
95:607:931
Backnut
95:607:940
Terminal Shroud
95:606:993
Indirect Combined
Thermostat and
Thermal Cut-Out
95:612:716
Direct Combined
Thermostat and
Thermal Cut-Out
95:612:717
Gasket
95:611:822
Incoloy Immersion
Heater - Lower
95:606:984
6 Way Terminal Block
95:607:933
@
A
Unvented Hot Water Cylinder
Figure21: Direct Exploded View
Direct Control Assembly
Mounting PLate
95:607:929
Terminal Cover (direct)
95:614:119
Terminal Shroud
95:606:993
A
Direct Combined Thermostat
and Thermal Cut-Out
95:612:717
Gasket
95:611:822
Backnut
95:607:940
3 Way Terminal Block
95:607:932
Titanium Immersion
Heater - Upper
95:606:989
MAINTENANCE AND
SERVICING (3)
Spare components are comman to Upper and
Lower Direct Control Assemblies Except for
the Upper elements 95:606:989 and Lower
element 95:606:988
A
B
B
Titanium Immersion
Heater - Lower
95:606:988
Unvented Hot Water Cylinder
B
B
MAINTENANCE AND
SERVICING (3)
C
D
Unvented Hot Water Cylinder
MAINTENANCE AND
SERVICING (3)
Unvented Hot Water Cylinder
E
F
Spares Stockists
Advanced Water Co.Ltd.
Unit D5 Enterprise Way
Vale Park, Evesham
Worcs WR11 1GS
Tel: 01386 760066
Fax: 01386 760077
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 UB4 0TY
Tel: 020 8606 3567
Parts Center
Tel: 0845 270 9800
www.partscenter.co.uk
Newey & Eyre
Unit 3-5 Wassage Way
Hampton Lovett Ind. Estate
Droitwich, Worcestershire WR9 0NX
Tel: 01905 791500
Fax: 01905 791501
USER GUIDE (4)
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
Alternatively contact your local supplying merchant or wholesale branch
G
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Unvented Hot Water Cylinder
USER GUIDE (4)
• User Instructions
• Guarantee
• Customer Service
Unvented Hot Water Cylinder
I
J
IMPORTANT LEGAL REQUIREMENT FOR INSTALLERS
MEGAFLO Eco, is a trading name of Heatrae Sadia, is a licensed member of the BenchmarkTM Scheme which aims to
improve the standards of installation and commissioning of domestic heating and hot water systems in the UK and to
encourage regular servicing to optimise safety, efficiency and performance. is managed and promoted by the Heating
and Hotwater Industry Council. For more information visit www.centralheating.co.uk. Please ensure that the installer
has fully completed the checklist on page 34 of this manual and that you have signed it to say that you have received
a full and clear explanation of its operation. The installer is legally required to complete a commissioning checklist
as a means of complying with the appropriate Building Regulations (England and Wales). All installations must be
notified to Local Area Building Control either directly or through a Competent Persons Scheme. A Building Regulations
Compliance Certificate will then be issued to the customer who should, on receipt, write the notification number on
the checklist. This product should be serviced regularly to optimise its safety, efficiency and performance. The service
engineer should complete the relevant service record on the checklist after each service. The checklist may be required
in the event of any warranty work.
User Instructions
Warnings
IF WATER DISCHARGES FROM THE TEMPERATURE and PRESSURE RELIEF VALVE ON THE MEGAFLO Eco UNIT REFER TO
PAGE 29 (TABLE 6) 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 Eco SYSTEM, IF A FAULT IS SUSPECTED
CONTACT A COMPETENT INSTALLER.
Immersion Heaters
A combined thermostat and thermal cut-out is provided for each immersion heater. The thermostat is factory set to give a water
storage temperature of approx. 60ºC, however it can be set to control between 12ºC and 68ºC. This will usually have been done
during installation. Adjustments can only be made by opening the terminal cover(s), DO NOT remove the cover(s) without first
switching off the electrical supply. The temperature adjustment is made by inserting a flat bladed screwdriver in the slot in the
disc on top of the thermostat and rotating (see Figure 16, p. 23).
If in any doubt consult a competent electrician.
Indirect units are fitted with an indirect thermostat which controls a 2-port motorised valve and hence the temperature of the water
in the MEGAFLO Eco unit. The thermostat is factory set to give a water storage temperature of approx. 60ºC, however it can be set
to control between 12ºC and 68ºC, this will usually have been done during installation. Adjustments can only be made by opening
the terminal cover. DO NOT REMOVE THE COVER WITHOUT FIRST SWITCHING OFF THE ELECTRICAL SUPPLY. Temperature
adjustment is made by inserting a flat bladed screwdriver in the adjustment knob located on the front of the thermostat mounting
bracket (see Figure 16, p. 23 ) and rotating. At the minimum position the temperature will be approx. 12ºC.
If in any doubt consult a competent electrician.
Flow Performance
When initially opening hot outlets a small surge in flow may be noticed as pressures stabilise. This is quite normal with unvented
systems and does not indicate a fault. In some areas a cloudiness may be noticed in the hot water. This is due to aeration of the
water, is quite normal and will quickly clear.
Operational Faults
Operational faults and their possible causes are detailed in Table 6, p.29 . It is recommended that faults should be checked by a
competent installer.
The air volume within the MEGAFLO Eco unit will periodically require recharging to ensure any expanded water is accommodated
within the unit. A discharge of water INTERMITTENTLY from the Pressure Relief Valve will indicate the air volume has reduced to a
point where it can no longer accommodate the expansion. To recharge the air volume:-
USER GUIDE (4)
i) Turn off the heat source to the cylinder via programmers / immersion isolation switch(es).
ii) Turn off the water supply to the MEGAFLO Eco unit by turning off the isolating valve on the 3 bar Pressure Reducing Valve if fitted
at this point or at the 8 bar Pressure Relief Valve if fitted there. Turn the blue handle so that it lies at 90º to the direction of flow
(see Fig 6, p.13 for options on valve set) .
iii) Open the lowest hot tap supplied by the MEGAFLO Eco.
iv) Hold open the Temperature and Pressure Relief Valve until water ceases to run from the tap and gurgling noise at the valve stops.
v) Close Temperature and Pressure Relief Valve.
vi) Turn on the isolating valve at the Cold Water Combination Valve by turning the blue handle so it lies parallel to the direction of
flow, when water flows from the hot tap, close tap.
vii) The air volume will be automatically recharged as the unit refills. If after following the above actions water still discharges from
the Pressure Relief Valve, further advice should be sought from a competent installer or the MEGAFLO Eco Service Division.
Alternatively you can watch a video clip on how to replenish the air gap on:
http://www.heateam.co.uk/replenishing-the-air-gap-on-a-megaflo-cylinder.htm
K
L
Unvented Hot Water Cylinder
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 Eco 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
lifetime* for the stainless steel inner vessel in domestic properties and to 30 years for the stainless steel inner vessel in commercial
buildings.
These guarantees are valid provided that:
The MEGAFLO Eco has been installed by a competent installer 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 6700.
The MEGAFLO Eco has not been modified in any way other than by BAXI CUSTOMER SUPPORT approved engineers.
The MEGAFLO Eco has only been used for the storage of wholesome water (max. 250mg/l chloride).
The MEGAFLO Eco has not been subjected to frost, nor has it been tampered with or been subjected to misuse or neglect.
No factory fitted parts have been removed for unauthorised repair or replacement.
The BenchmarkTM commissioning checklist service record included in this product guide has been completed.
Regular maintenance has been carried out by a competent person in accordance with the requirements set out in the maintenance section of the
installation manual and any replacement parts used should be authorised MEGAFLO Eco spare parts. Annual services are available from the service
division of Heatrae Sadia. Please contact BAXI CUSTOMER SUPPORT on Tel: 0844 871 1535 for further details.
Within 60 days of purchase the owner completes and returns the certificate supplied to register the product. Evidence of purchase and date of
supply must be submitted upon making a claim.
*Lifetime is defined as for as long as the original owner who purchased the MEGAFLO Eco / New Home continues to own the
property. If the owner sells the property, the new owner (and any future owners) will receive a 30 year warranty from the time the
original owner purchased the MEGAFLO Eco or new property with MEGAFLO Eco installed.
This guarantee is not valid for installations outside the United Kingdom.
This guarantee does not affect your statutory rights.
For installations outside of the United Kingdom
For further details of the guarantee terms and conditions please contact:
Export Sales
T: +44 1603 420271
F: +44 1603 420199
E: export.sales@heatraesadia.com
USER GUIDE (4)
Unvented Hot Water Cylinder
M
N
Customer service
Telephone:
0844 8711535
Facsimile:
0844 8711528
Megaflo
Hurricane Way
Norwich
Norfolk
NR6 6EA
E-mail:
megafloservice@heateam.co.uk
Important notice to installations outside of the UK.
References to legislation, legal requirements, regulations, building regulations benchmark, spares stockists, guarantees and warranty are
ONLY APPLICABLE WITHIN THE UK.
For local legislation, legal requirements, regulations, building regulations outside of the UK, contact your local Authority.
For spares stockists, guarantees and warranty outside the UK, contact your local supplier or,
Export Sales
T: +44 (0)1603 420271
F: +44 (0)1603 420199
E: export.sales@heatraesadia.com
© 2014
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