andrews BUFFER-GL200-8 Manual

Important
Please read & understand all these instructions before commencing installation.
This buffer range does not incorporate an internal heat exchanger.
Please leave this manual with the customer for future reference
Andrews. Built toperform.
INSTALLATION AND SERVICE MANUAL
Glass Lined Buffers
10 bar, 2”-2.5”
8 bar

Contents
Installation & Commissioning
General Installation 12
Cold Water Supply 12
Secondary circulation and De-Stratification 13
Discharge Pipe work 15
Commissioning 19
Maintenance & Servicing
Maintenance requirements 19
Warranty
Warranty Termsand Conditions 20
Product Specification
Introduction
3
General requirements
3
Installation standards
3
Storage and handling
4
Before Installation
4
ErP data information
4
8 bar Buffer dimensions
5
10 bar Buffer dimensions
8
Weights
11
Standing Heatloss
11
Limitations
12

Product specification
Introduction
Congratulations on your purchase of an Andrews buffer vessel. The Andrews buffer products
are manufactured from top quality materials and meet all the latest relevant safety and
constructional standards.
General Requirements
IMPORTANT: Please read and understand this product guide before installing the Andrews
buffer vessel. Incorrect installation may invalidate the warranty*.
The Andrews buffer vessel 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).
* See Terms and Conditions of warranty
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 use if there is a possibility that the water in the buffer vessel is frozen.
Important Notice:
When installed with a KIWA approved unvented kit the Andrews buffer vessels are
approved as meeting current water regulations.
To satisfy these regulations when the kit is not supplied it will be required that the installer ensures
that all of the system components meet the required standards.
BS 6700 : Design, Installation, Testing and Maintenance for Domestic use within Buildings and
their Curtilages.
BS 7206 : Specification for Unvented Hot Water Storage Units and Packages.
BS EN 806 : Specifications for Installations inside Buildings Conveying Water for Human
Consumption.
BS EN 12897 : Specification for Indirectly Heated Unvented Storage.
3

Storage and Handling
Please take care when handling a packaged Andrews buffer vessel. 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 freeenvironment.
Precautions to be carried out prior to commencement of work:
1. Tidyareaensuringthereis safeaccessandegresstoinstallation place, freefrom triphazards.
2. Be aware of other people who may be in thearea
3. Operate any machinery in accordance with training and operatinginstructions
4. Visually inspect the equipment prior to use, do not use damaged equipment.
5. Safe working practices are adopted for manual handling of appliances/parts
6. Correct PPE to be worn.
The Andrews buffer vessel unit must be vertically floor mounted. 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. Pipe runs should be kept as short as possible for
maximum economy. Access to associated controls and indirect controls should be possible for
servicing and maintenance of the system.
ErP data
Model(s)
200
300
500
800
1000
Energy efficiency class
B B C B C
Standing loss (kWh/24h)
1.34 1.61 2.23 2.14 2.76
Storage volume V in Litres
197
292
490
780
970
Table 3: ErP Data Information
Technical parameters in accordance with European Commission regulations 814/2013
and 812/2013
4

8 bar Glass Lined Buffers
200 & 300 Ltr
5

500 Ltr
6

800 & 1000 Ltr
7

10 bar Glass Lined Buffers
300 Ltr

8
500 Ltr

9
800 Ltr

10
N o m i n a l
Capacity
(Litres)
Unit Weight (kg)
Empty Full
200
61
261
300
77 377
500
125 625
800
168
968
1000
198
1198
Table 5: Weights
N o m i n a l
Capacity
(Litres)
Per Day
(kWh/24h)
Per Year
kWh/24h)
200
1.34
489
300
1.61 587
500
2.23 813
800
2.14
781
1000
2.76
1007
Table 6: Standing heat-loss
Testing is carried out to BS EN12897
11

Limitations
• The Andrews buffer vessel 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.
• Watersuppliesthathaveeitherinadequatepressureorwherethesupplymaybe
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).
Installation & Commissioning
General
installation
Pipe fittings
All pipe connections to the Andrews buffer are made via BSP threaded pipe connection
directly to the unit.
Installation
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 buffer and
will invalidate the warranty.
12

Secondary Circulation
If a secondary circulation system is required it is recommended that it be connected to the
Andrews buffer similar to Figure 9. The secondary return pipe should be in 28mm pipe and
incorporate a check valve to prevent back flow, smaller pipe diameters can be used but may
have a reduced flow. A suitable WRAS approved 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 10litres.
De-stratification kits
The correct size of de-stratification kit must be used with your buffer to ensure the volume
can be circulated in 1 hour. The pump instructions will need to be reviewed for information on
the cor- rect setting. Please follow the installation schematic (Figure 9) for guidance. When
the system circulates it needs to be specified by the installer to ensure water is not drawn off
during the de-stratification process. If a hot water demand is required during this period cold
water may be discharged from the hot outlet. It is recommended that a check valve be
installed before the pump to stop any risk of cold water draw off through the pump when it is
not in use. For guidance on installation please refer to Figure 9.
Unvented systems
If the cylinder is being used for storage of domestic hot water on an unvented system
additional Temperature and Pressure valve must be fitted to the cylinder hot outlet
connection with the use of a T-piece and ensuring the probe from the Temperature and
Pressure valve is fully immersed in water in the top of the cylinder.
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)
13

The following extract is taken from latest G3 Regulations
Discharge pipes from safety
Devices Discharge pipe D1
3.50 Safety devices such as temperature relief valves or combined temperature and
pres- sure 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 safety device, e.g. temperature relief valve.
3.52 Where a manifold is used it should be sized to accept and discharge the total discharge
from the discharge pipes connected to it.
3.53 Where valves other than a 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
orpackage.
Tundish
3.54 The tundish should be vertical, located in the same space as the unvented hot water
stor- age system and be fitted as close as possible to, and lower than, the safety device, with
no more than 600mm of pipe between the valve outlet and the tundish (see Diagram1).
Note: To comply with the Water Supply (Water Fittings) Regulations, the tundish should
incorpo- rate 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 mo- bility, consideration should be given to the installation of a suitable safety
device to warn when discharge takes place, e.g. electronicallyoperated.
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 of at least 1 in 200thereafter.
3.57 The discharge pipe (D2) should be madeof:
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 per- formance standard (e.g. as specified in the relevant part of BS 7291-
1:2006 Thermostatic pipes and fittings for hot and cold water for domestic purposes and
heating installations in buildings. General requirements).
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 3.1 and the workedexample.
14

Note: An alternative approach for sizing discharge pipes would be to follow Annex D, section
D.2 of BS 6700:2006 + A1:2009 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 beconnected.
3.60 The discharge pipe should not be connected to a soil discharge stack unless it can be
demonstrated that the soil discharge stack is capable of safely withstanding temperatures of the
water discharged, in which case, itshould:
a. 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 thetundish;
b. be a separate branch pipe with no sanitary appliances connected toit;
c. if plastic pipes are used as branch pipes carrying discharge from a safety device, they
should be either polybutalene (PB) or crosslinked polyethylene (PE-X) complying with national
stand- ards such as Class S of BS 7291-2:2006 or Class S of BS 7291-3:2006 respectively;and
d. be continuously marked with a warning that no sanitary appliances should be connected
to the pipe.
Notes:
1. 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 1043-1:2002 Plastics. Symbols and abbreviated
terms. Basic polymers and their special characteristics.
2. Where pipes cannot be connected to the stack it may be possible to route a dedicated pipe
alongside or in close proximity to the dischargestack.
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 thedischarge.
3.62 Examples of acceptable discharge arrangementsare:
a. to a trapped gully with the end of the pipebelow
a fixed grating and above the water seal;
b. 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,
c. discharges at high level: e.g. into a metal hopper and metal downpipe with the end of the
dis- charge pipe clearly visible or onto a roof capable of withstanding high temperature
discharges of water and 3 m 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.
15

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.
G3 Requirement
“...there shall be precautions...to ensure that the hot water discharged from safety devices is
safelyconveyedtowhere it isvisible butwillnotcause danger topersons in oraboutthe
building”.
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.
16

Discharge below
fixed grating
(Building Regulation
G3 section 3.61 gives
alternative points
of discharge)
Fixed grating
Trapped
gully
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 canhandle
temperatures of 99°C or greater should be used.
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 22mm
28mm
35mm
UP TO 9m
UP TO 18m
UP TO 27m
0.8m
1.0m
1.4m
G 3/4 22mm 28mm
35mm
42mm
UP TO 9m
UP TO 18m
UP TO 27m
1.0m
1.4m
1.7m
G 1
28mm
35mm
42mm
54mm
UP TO 9m
UP TO 18m
UP TO 27m
1.4m
1.7m
2.3m
Table 10 Sizing of copper discharge pipe “D2” for common T&P Relief Valve sizes.
Safety device (e.g.
Temperature
relief valve) Metal discharge pipe (D1) from
Temperature relief valve to tundish
Discharge pipe (D2) from tundish,
with continuous fall. See Building
Regulation G3 section 3.56, Table 1
and worked example
Figure 10: Typical discharge pipe arrangement (Extract from Building Regulations G3
Guidance section 3.5 to 3.63)
17
Tundish
600mm maximum
300mm
minimum

Commissioning
NOTE: The water discharged may be very hot.
Primary Heat source (when fitted)
Connect up primary heat source as per manufacturers instructions. Fill up primary and secondary
circuits, bleeding any air that may be trapped and check for leaks. The Andrews range of buffers do not
have an internal heat ex- changer. Take care that the Primary Heat source can handle the working
pressure of the cylinder.
Maintenance & Servicing
Maintenance requirements
To ensure the continued optimum performance of the Andrews buffer 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 Andrews buffer 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 Andrews buffer unit will need to be drained.
NOTE: The water discharged may be very hot.
Draining the Buffer
Switch off the electrical supply to the primary heat source. Turn off the water supply to the 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 drain
valve. If water fails to drain from the Andrews buffer vent the unit by a suitable point on the
system.
Refilling system
DO NOT switch on the primary heat source until the system has been
completely refilled.
Close the drain valve, refill the system, and vent from suitable purge points on the system. When
water flows from the purge points allow to flow for a short while to purge air and to flush through
any disturbed particles. Close vent points and then open successive vents in system to purge any
air. The electrical supply can now be switched on.
18

Servicing
Important
i)Servicing should only be carried by an authorised Engineer, Agents or by installers competent
in the installation and maintenance of heating and hot water systems.
ii)Any spare parts used MUST be authorised Andrews buffer parts.
iii)NEVER bypass any thermal controls or operate system without the necessary
safetyvalves.
iv)Water contained in the Andrews buffer unit may be very hot, especially following a thermal
control failure. Caution must be taken when drawing water from theunit.
19

User Guide
Terms and Conditions
Warranty Terms
Andrews commercial guarantees the product against faulty manufacture or materials for a
period of one year from the date of purchase including parts and labour.
These guarantees are valid provided that:
` The Andrews buffer 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.
` The Andrews water heater unit has not been modified in anyway other than by approved
engineers.
` The Andrews water heater has not been subjected to excessive pressure beyond the
guidelines detailed in the installationinstructions.
` The Andrews water heater 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 unauthorised 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 spareparts.
` The original warranty period will apply to any parts replaced
The warranty does NOT cover:
Any consequential damages or profit loss which may arise from a defect.
Warranty claims have no delaying effect on the payment dates and other demands
Your Andrews 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.
Andrews is not responsible for any damage that has been caused by incorrect or defective
installation, commissioning, water treatment, service or maintenance. Our current technical
documentation can be taken as the basis for this.
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.
The Environment
This product is made from many recyclable materials, therefore at the end of its useful
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: Rigid mould-injected. PU
(CFC/HCFC-free, 0.025 W/m°K).
20