andrews Maxxflo CWH30/200 User manual

M6500 Rev B
INSTALLATION OPERATION AND MAINTENANCE MANUAL
MAXXflo
High Efficiency Condensing Stainless Steel Storage Water heaters
High Efficiency Condensing Stainless Steel Storage Water heaters
Please read and understand these instructions before commencing installation and leave this manual with the customer for future reference
CWH30/200, CWH30/300, CWH60/200, CWH60/300,
CWH90/200, CWH90/300, CWH120/200, CWH120/300
E281B

MAXXflo Water Heater
22
Reproduction of any information in this publication by any method is not permitted unless prior
written approval has been obtained from Andrews Water Heaters.
Andrews Storage Water Heaters have been designed and manufactured to comply with current
international standards of safety. In the interests of the health and safety of personnel and the
continued safe, reliable operation of the equipment, safe working practices must be employed at
all times. e attention of UK users is drawn to their responsibilities under the Health and Safety
Regulations.
All installation and service on Andrews Water Heaters must be carried out by competent qualified
personnel and, therefore, no liability can be accepted for any damage or malfunction caused as a
result of intervention by unauthorised personnel.
Andrews Water Heaters’ policy is one of continuous product improvement and, therefore, the
information in this manual, whilst completely up to date at the time of publication, may be subject
to revision without prior notice.
Further information and assistance can be obtained from:
Andrews Water Heaters
Wood Lane, Erdington,
Birmingham B24 9QP
Tel: [phone]
Fax: [phone]
Email: [email protected]
Website: www.andrewswaterheaters.co.uk
Twitter: @AndrewsWH
THE ANDREWS WATER HEATERS COVERED IN THIS MANUAL
ARE FOR USE WITH NATURAL GAS OR LPG (PROPANE) GAS ONLY
Copyright Andrews Water Heaters

MAXXflo Water Heater
33
PAGE
SECTION 1 GENERAL AND SAFETY INFORMATION
General Information 4
British Standards and Codes of Practice 4
Health and Safety Regulations 1993 4
Legionellae in Water Heaters 5
SECTION 2 TECHNICAL DETAILS
Technical Details – CWH30/60/90/120 5
Technical Parameters 6
Product Fiche 7
Heater Dimensions – 200 litre model 7
Heater Dimensions – 300 litre model 8
SECTION 3 INSTALLATION
Description 10
Location 10
Water Quality and Treatment 11
Water Connections 11
Condense Drain 12
Typical Installations – CWH30/60 & CWH90/120 13
Gas Supply – Natural Gas 14
Gas Supply – Propane 14
Typical Bulk Storage Vessel Installation 15
Typical Cylinder Installation 15
Electrical Supply 16
Electrical Connection 16
Wiring Diagram 17
Temporary Water Heater Temperature Change 18
Circulation Pump and Storage Tanks 18
HWST Tank Dimensions and Wiring Diagram 19
Flue Systems 20
Flue Systems – CWH 30 & 60 21
Alternative Flue Systems – CWH 30 & 60 22
Standard Flue System Dimensions – CWH 30 & 60 23
Flue Systems – CWH 90 & 120 24
Alternative Flue Systems – CWH 90 & 120 25
Standard Flue System Dimensions – CWH 90 & 120 26
Flue System Positions and Distances 27
Flue System – Horizontal and Vertical Terminations 28
Air supply and ventilation – Concentric Flue Systems 28
Air supply and ventilation – concentric and conventional flue systems 30
Air supply and ventilation – conventional flue systems 31
Heat exchanger configuration 32
Control panel 32
SECTION 4 WATER TEMPERATURE SETTINGS
Temperature setting 33
Adjusting temporary temperature change 33
SECTION 5 INSTRUCTIONS FOR COMMISSIONING
Filling the water heater 34
Commissioning – natural gas and propane 34
CO2adjustment 34
Control and adjustment at full load 35
Control and adjustment at low load 35
Decommissioning 35
SECTION 6 FAULT CODES
Fault codes 36
Blocking faults 36
Lockout faults 36
SECTION 7 MAINTENANCE
Annual maintenance checks 37
SECTION 8 PARTS LIST
External, Internal & cylinder spares 38
Flue and old issue spares 40
SECTION 9 DISMANTLING DISPOSAL AND RECYCLING 43
CONTENTS

MAXXflo Water Heater
44
GENERAL AND SAFETY INFORMATION
e Andrews Water Heater has been designed for use with NATURAL GAS OR LPG and is manufactured to give an efficient,
reliable and long service life.
To ensure the continued, trouble-free operation of your heater at maximum efficiency, it is essential that correct installation,
commissioning, operation and service procedures are carried out strictly in accordance with the instructions given in this
manual. By law, installation and commissioning of the heater must be carried out by properly qualified personnel.
e heater(s) must be installed in accordance with the following requirements:
• e current GAS SAFETY (INSTALLATION AND USE) REGULATIONS
• e current BUILDING REGULATIONS
• e WATER SUPPLY (WATER FITTINGS) REGULATIONS
•
Additionally, installation should be performed in accordance with all relevant requirements of the Gas Supplier, Local
Authority and recommendations of the British Standards and Codes of Practice which should include the following:
• BS EN 806 (Parts 1 - 5) Specifications for installations inside buildings conveying water for human consumption.
General design, pipe sizing, installation, operation and maintenance.
• BS 5440-1 Flueing and ventilation for gas appliances of rated input not exceeding 70 kW net. Specification for
installation of gas appliances to chimneys and for maintenance of chimneys.
• BS 5440-2 Flueing and ventilation for gas appliances of rated input not exceeding 70 kW net. Specification for the
installation and maintenance of ventilation provision of gas appliances.
• BS 5546 Specification for installation of gas hot water supplies for domestic purposes. Using gas-rated appliances of
rated input not exceeding 70 kW net.
• BS 6891 Installation of low pressure gas pipework of up to 35mm in domestic premises.
• BS 6644 Installation of gas fired water boilers of rated inputs between 70kW and 1.8MW
• BS EN 12897 Water supply. Specification for indirectly heated unvented (closed) storage water heaters
• IGE/UP/1A, 1B Strength/tightness testing and direct purging
• IGE/UP/2 Installation pipework
• IGE/UP/10 - 1 (Edition 4): Installation of gas appliances in industrial and commercial premises.
Andrews Water Heaters accepts no liability for any damage resulting from failing to accurately follow the instructions.
When replacing parts during maintenance, only original parts from Andrews Water Heaters should be used; these can be
recognised by the name of the manufacturer printed on them.
HEALTH AND SAFETY REGULATIONS
It is the duty of manufacturers and suppliers of products for use at work to ensure, so far as is practicable, that such products
are safe and without risk to health when properly used, and to make available to users adequate information about their safe
and proper operation.
Andrews Water Heaters should only be used in the manner and purpose for which they are intended and in accordance with
the instructions in this manual. Although the heaters have been manufactured with paramount consideration to safety, certain
basic safety precautions highlighted in this manual must be observed by the user.
It is imperative that all users of the heaters must be provided with all the information and instruction necessary to ensure
correct and safe operation.
EFFECTIVENESS IN COMBATING LEGIONELLA
Water systems in buildings have been associated with outbreaks of Legionnaires’ Disease, particularly in health care facilities
where occupants are significantly more susceptible to infection.
In recognition of the risks in hospitals, a Code of Practice for the Control of Legionella in Health Care premises has been issued
by the Department of Health. Codes of Practice applicable to other premises have been published by other organisations,
principally the Health and Safety Executive and the Chartered Institute of Building Services Engineers (CIBSE).
All Codes of Practice draw attention to the design and operation of water systems with reference to avoidance of factors that
favour colonisation by Legionella bacteria. ese factors include stagnation, lukewarm conditions (20°C to 45°C) and the
accumulation of debris, scale and corrosion in the base of tanks and calorifiers.
e MAXXflo range has a Legionella flushing programme – see page 15 (terminals BTI – BT2)
SECTION 1 • GENERAL AND SAFETY INFORMATION

MAXXflo Water Heater
55
TECHNICAL DETAILS • SECTION 2
Model Reference CWH 30/200 60/200 90/200 120/200
30/300 60/300 90/300 120/300
Input gross Hs min/max 6.7–31.1 kW 13.4–62.2 kW 20.1–93.3 kW 26.8-124.4 kW
Input nett Hi min/max 6.0–28.0 kW 12.0–56.0 kW 18.0-84.0 kW 24.0-112.0 kW
Output (tank set point : 60°C) 6.5–30.5 kW 13.0–61.0 kW 19.5-91.6 kW 26.0-122.1 kW
Natural Gas, G20
Gas Consumption 2.96 m3/h 5.93 m3/h 8.89 m3/h 11.85 m3/h
Minimum Gas Supply Pressure 18 mbar 18 mbar 18 mbar 18 mbar
Propane, G31
Gas Consumption 2.18 Kg/h 4.35 Kg/h 6.53 Kg/h 8.71 Kg/h
Minimum Gas Supply Pressure 37 mbar 37 mbar 37 mbar 37 mbar
Efficiency (gross) 98% 98% 98% 98%
Efficiency (nett) 109% 109% 109% 109%
Standby Heat Loss 780 Mj per month
NOxlevel @ 0% O225ppm 25ppm 25ppm 25ppm
NOxlevel @ 0% O244mg/kWh 44mg/kWh 44mg/kWh 44mg/kWh
Noise level LWA 49dB 49dB 49dB 49dB
Ionisation current – max 6.0A 6.0A 6.0A 6.0A
Ionisation current – min 4.0A 4.0A 4.0A 4.0A
HSI resistance 1.0 – 1.4 k1.0 – 1.4 k1.0 – 1.4 k1.0 – 1.4 k
Max recovery thru 50°C 480 l/h 960 l/h 1440 l/h 1920 l/h
Max recovery thru 56°C 429 l/h 856 l/h 1284 l/h 1712 l/h
Time to recover tank thru 50°C rise
200 litre capacity 25 mins 13 mins 9 mins 7 mins
300 litre capacity 38 mins 19 mins 13 mins 10 mins
Flue size (concentric) Int/External 80/125 80/125 130/200 130/200
Flue Size (conventional) 80 80 130 130
Max flue run – concentric * 14 12 14 14
Max flue run – conventional ** 50 20 50 40
Max flue static pressure 140 Pa 140 Pa 140 Pa 140 Pa
Inlet/Outlet connections 1½” BSP 1½” BSP 1½” BSP 1½” BSP
Return connection 1” BSP 1” BSP 1” BSP 1” BSP
Nominal operating water pressure 3.5 bar 3.5 bar 3.5 bar 3.5 bar
Maximum water pressure 6.0 bar 6.0 bar 6.0 bar 6.0 bar
Minimum water pressure 1.0 bar 1.0 bar 1.0 bar 1.0 bar
Gas connection (gas cock supplied) 3/4” 3/4” 3/4” 3/4”
Electrical supply All models: 230/50V/Hz
Power consumption 170 W 340 W 510 W 680 W
Weight – empty (200 litre) 155 kg 170 kg 185 kg 200 kg
Weight – empty (300 litre) 165 kg 180 kg 195 kg 210 kg
Weight – full (200 litre) 355 kg 370 kg 385 kg 400 kg
Weight – full (300 litre) 465 kg 480 kg 495 kg 513 kg
Shipping weight (200 litre) 178 kg 193 kg 208 kg 213 kg
Shipping weight (300 litre) 188 kg 203 kg 218 kg 233 kg
Shipping depth 1040 mm 1040 mm 1040 mm 1040 mm
Shipping width 880 mm 880 mm 880 mm 880 mm
Shipping height (200 litre) 1653 mm 1653 mm 1653 mm 1653 mm
Shipping height (300 litre) 2077 mm 2077 mm 2077 mm 2077 mm
* Reduce flue length by 1.2m for 90° bend, 0.7m for 45° bend and 1.5m for condensate trap
** Reduce flue length by 4m for 90° bend, 2m for 45° bend and 4m for condensate trap
e MAXXflo range features stainless steel tanks with external heat exchanger(s) and fully automatic electronic control with
BEMS interface as standard. e heaters must be installed with a minimum water pressure of 1 bar. e heaters are factory
fitted with temperature and pressure relief valve(s). A gas cock, water draw-off cock and comprehensive instruction manual are
also included. e water heaters can be fitted with concentric flue for room sealed applications; horizontal or vertical flue kits
must be ordered separately – see pages 20 and 25.
Conventional flue, suitable for condensing applications can be used if the plantroom is ventilated.

MAXXflo Water Heater
66 SECTION 2 • TECHNICAL DETAILS
Product name MAXXflo
CWH 30/200 MAXXflo
CWH 30/300 MAXXflo
CWH 60/200 MAXXflo
CWH 60/300 MAXXflo
CWH 90/200 MAXXflo
CWH 90/300 MAXXflo
CWH 120/200 MAXXflo
CWH 120/300
Daily electricity consumption Qelec kWh 0.289 0.318 0.291 0.320 0.292 0.321 0.563 0.682
Declared load profile XXL XXL XXL XXL XXL XXL XXL XXXL Sound power level, indoors LWA dB 49 49 49 49 49 49 49 49
Daily fuel consumption Qfuel kWh 27.945 28.201 28.222 28.189 29.529 29.660 30.979 56.402
Emissions of nitrogen oxides NOXmg/kWh 44 44 44 44 44 44 44 44
Weekly fuel consumption with smart controls Qfuel, week, smart kWh--------
Weekly electricity consumption with smart controls Qelec, week, smart kWh-------- Weekly fuel consumption without smart controls Qfuel, week kWh-------- Weekly electricity consumtion without smart controls Qelec, week kWh-------- Storage volume Vl--------
Mixed water at 40 °C V40 l448 718 fffff
686
Harmonised standards applied Specific precautions that shall be taken when the water heater is assembled, installed or maintained:
EN: 13203-2
Before any assembly, installation or maintenance the installation and operation manual has to be read attentively and to be followed
MAXXflo
Technical parameters

MAXXflo Water Heater
77
TECHNICAL DETAILS • SECTION 2
Product name MAXXflo
CWH 30/200 MAXXflo
CWH 30/300 MAXXflo
CWH 60/200 MAXXflo
CWH 60/300
Declared load profile XXL XXL XXL XXL Water heating energy efficiency class Water heating energy efficiency %86 85 85 85 Annual energy consumption kWh(1)
GJ(2)
63 25 70
25 63
25 70
25
Other load profiles for which the water heater is suitable to use and the corresponding water heating energy efficiency and annual electricity consumption(3) ---- Thermostat temperature setting °C 60 60 60 60 Sound power level LWA indoors dB 49 49 49 49 Ability to off-peak hours functioning(3) ---- Enables smart control settings(4) ---- (1) Electricity (2) Fuel (3) If applicable. (4) If smart control settings value is "1", the water heating energy efficiency and annual electricity and fuel consumption only relate to enabled smart control settings.
A A
MAXXflo
A A
Product Fiche

MAXXflo Water Heater
88
INSPECTION HATCH INSPECTION HATCH
SECTION 2 • TECHNICAL DETAILS

MAXXflo Water Heater
99
TECHNICAL DETAILS • SECTION 2
INSPECTION HATCH INSPECTION HATCH

MAXXflo Water Heater
1010
DESCRIPTION
e MAXXflo series is a direct fired condensing storage
water heater which has a stainless steel tank that is heated
by up to four burner modules placed outside the tank. A
burner module consists of a stainless steel heat exchanger
in which the burner is placed.
e water heater works according to the loading principle:
e water in the bottom of the tanks is led directly through
the heat exchanger, heated up and carried back to the top
of the tank. e temperature of the water at the bottom
of the tank (return temperature) is representative of the
input heat; the burner modulates on the basis of this
return temperature. e temperature at which the water
is supplied to the tank from the heat exchanger (supply
temperature) is kept at the set water heater temperature
using pump modulation.
An important advantage of bringing the heat transfer
from outside the tank is that the output is not influenced
by the temperatures that prevail in the tank. As long as
draw off occurs, the water from the bottom of the tank
to the heat exchanger is almost the same as the supply
cold water temperature. is means the maximum output
is maintained during the heating up period. On the final
heating period, when the tank is almost completely heated
up, the return temperature will increase and the burner
modulates. Because the water is pumped round from the
lowest point in the tank, the whole tank is heated up and
there are no cool zones.
e water heater is equipped with a maximum of four
burner modules dependent on the model. Each burner
module produces a maximum of 30.5 kW output for a set
water heater temperature of 60°C.
Important Note:
• Minimum water pressure = 1 bar
THE LAW REQUIRES THAT THE INSTALLATION IS CARRIED
OUT BY A COMPETENT QUALIFIED PERSON
Installations must be carried out in accordance with
Gas Safety (Installation and Use) Regulations , Building
Regulations, e Water Supply (Water Fittings) Regulations
and any requirements of the local Gas Authority, Local
Authority, Water and Fire Authorities and the current
British Standards and Codes of Practice listed in Section 1.
LOCATION
e location selected for installation of the heater must
allow the provision of a satisfactory flue, adequate air
supply, drain facilities and must be well illuminated.
A purpose built water heater room or compartment is
strongly recommended.
A manual valve for isolation of the water heater room
should be installed in the gas supply. It should be clearly
identified and readily accessible for use at all times.
If a purpose built water heater room is not available,
measures should be taken to protect the heater from
damage and prevent any extraneous matter from being
stored on or around the heater. See BS6644 for details.
e heater must not be installed in any location which
contains a bed, bath or shower. ere must be easy access
to the water heater room and heater at all times.
e water heater must be located in an area where leakage
from the tank, water connections or the combination
temperature and safety valve will not result in damage to
the area adjacent to the water heater. When such locations
cannot be avoided, a suitable drain tray must be installed
under the water heater. e drain tray must be no deeper
than 38mm and must be 100mm wider and longer than the
heater. e drain tray must be piped to an adequate drain
using 20mm (0.75in) diameter pipe, angled for proper
drainage.
Access must be provided to the front of the water heater
and adequate clearance for its servicing and operation.
e floor on which the heater is installed must be flat,
level and of sufficient strength to withstand the weight of
the heater when filled with water, and should satisfy the
requirements of the Local Authority & Building Regulations.
Any combustible material adjacent to the heater must be
so placed and shielded as to ensure that its temperature
does not exceed 66°C (150°F).
Place the water heater on a flat floor in a frost-proof area.
See pages 5, 6 and 7 for recommended service clearances.
INSTALLATION
SECTION 3 • INSTALLATION

MAXXflo Water Heater
1111
INSTALLATION • SECTION 3
WATER QUALITY AND TREATMENT
When installing Andrews Water Heaters we would
recommend the inclusion of water treatment and that
a water treatment specialist is consulted to ensure
the selection of the most appropriate system for each
particular installation.
In hard water areas in particular, scale formation can occur
in all hot water systems and various factors can influence
this such as water temperature, amount of water used and
the quality of the local water supply. B.S. 7953 states that
provision should be made for water treatment where the
local water hardness exceeds 200 parts per million (14
degree Clark).
For further information please refer to our Technical Data
Sheet - T/D027 Water Quality and Treatment Data Sheet
(available from www.andrewswaterheaters.co.uk).
WATER CONNECTIONS
An unvented system must be fitted by an approved
installer.
e pressure reducing valve C1 will regulate the mains
water pressure at 3.5 bar (provided there is sufficient
mains water pressure available). e maximum test
pressure should be 6 bar. e expansion vessel C3 supplied
is suitable for the stored volume of the heater and a
comparative pipe work system.
e temperature and pressure relief valve(s) are factory
fitted. FOR SYSTEMS WITH LARGER PIPE VOLUMES OR
ADDITIONAL STORAGE, EXPANSION VESSELS WITH MORE
CAPACITY ARE AVAILABLE.
We do not recommend the use of galvanised pipework
due to issues such as galvanic attack (British Standard
BS6644). e MAXXflo has a number of copper and brass
components.
e cold water connection and the hot water connection
can be found on the top of the appliance, see Fig 1A and
1B. An extra connection is available for the benefit of a
circulation line. Please note that a stop valve should be
fitted in the circulation line.
e MAXXflo range of storage water heaters are designed
to work from a mains fed unvented system. An unvented kit
to regulate the cold feed is supplied with each heater and
should be installed as Fig. 1, 1a and 1b plus drawings on
pages 5, 6 and 7.
e temperature and pressure relief valves are supplied
factory fitted for external connection to a tundish
(supplied) and suitable drain. e MAXXflo can also
operate on vented systems providing the minimum water
pressure is one bar.
Expansion Vessel
Fig 1

MAXXflo Water Heater
1212
CONDENSE DRAIN
Condensation is formed in the heater and this must be
continuously discharged into a drain. A trap is supplied
which should be connected into a drain via a tundish or
air break. e condense flow must not be allowed to block
otherwise the heater will fail to work correctly. NOTE: AN
AIR BREAK IS REQUIRED DOWNSTREAM
OF THE TRAP TO PROTECT THE WATER HEATER FROM
BLOCKAGES AND SUBSEQUENT DAMAGE. Each 30kW
module could produce up to 3 litres of condense per hour
while at full load.
SECONDARY RETURN CIRCULATION PUMP
An additional connection for a secondary circulation is
available in the top of the heater that is located between
the hot flow and cold feed ports. We would recommend that
a non-return valve is fitted in the return line.
If a secondary return circuit is fitted with a secondary
pump, please ensure that the flow-rate or heat loss does
not exceed the heater maximum flow-rate or minimum
load. An excessive flow in the secondary circuit could result
in a temperature mixing effect in the heater storage vessel
resulting in a stored water temperature less than the set
temperature (see table below).
Model Type CWH30 CWH60 CWH90 CWH120
Maximum 0.9 1.8 2.7 3.6
flow rate m3/h
Minimum load
kW 6 12 18 24
Circulation Pump
Secondary
Return Line
Cold Water
Fig 2
SECTION 3 • INSTALLATION

MAXXflo Water Heater
1313
INSTALLATION • SECTION 3
Fig 3A – Typical installation
Fig 3B – Typical installation

MAXXflo Water Heater
1414
GAS SUPPLY – NATURAL GAS
e installation of the gas supply must conform, depending
on its size, to the requirements of British Standards and
Codes of Practice listed in Section 1 of this manual.
A gas meter will be connected to the service pipe by British
Gas plc or its authorised contractor.
e meter and service pipe should be checked by British
Gas or its authorised contractor to ensure that they are
adequate to deal with the gas supply to the water heater(s)
in addition to any existing or additional requirements.
Fit the service gas cock (supplied) to the gas connection on
top of the water heater using a suitable jointing compound
and connect to the gas supply.
Where the water heater(s) is(are) installed in a water
heater house or purpose built compartments, a manually
operated valve for the water heater house must be fitted
in accordance with the Gas Safety (Installation and Use)
Regulations. e valve must be easily identified and readily
accessible.
After installation, the system should be pressure tested for
soundness and purged in accordance with BS6891 or IM/2
and IM/5 as appropriate.
Please note that the minimum dynamic gas pressure for
Natural Gas must not fall below 18 mbar.
GAS SUPPLY – PROPANE
Contact your provider or supplier who will provide the
appropriate type and size of LPG supply vessel and ensure
its safe location and installation.
e installation of the gas supply must confirm to LGPA
Code of Practice, 22 LPG Piping Systems: Design and
Installation plus the requirements of British Standards and
Codes of Practice listed in Section 1 of this manual.
Andrews Water Heaters are unregulated and a second stage
regulator must be installed to give an inlet pressure to the
appliance as follows: (see fig 2)
PROPANE 37 mbar (14.86 in wg)
When using propane cylinders, connect a minimum of 47kg
cylinders as listed below, together with a manifold before
connecting to the union.
Use a minimum pipe size of ¾” bore.
Two 47kg Cylinders LCWH30 and LCWH60
ree 47kg Cylinders LCWH90
Four 47kg Cylinders LCWH120
WARNING!
PROPANE CYLINDERS MUST BE USED AND STORED IN
ACCORDANCE WITH ‘THE HIGHLY FLAMMABLE LIQUIDS
AND LIQUIFIED PETROLEUM GASES REGULATIONS AND
SHOULD COMPLY WITH LPGA CODE OF PRACTICE 7:
‘STORAGE OF FULL AND EMPTY LPG CYLINDERS AND
CARTRIDGES’.
Also please note that for Propane the minimum
dynamic gas pressure to the unit must not fall below 37
mbar.
SECTION 3 • INSTALLATION

MAXXflo Water Heater
1515
INSTALLATION • SECTION 3
Important
ese drawings show a schematic representation only and should not be used for installation purposes.
Contact your gas supplier for authorised installation drawings.
Fig 4: Typical Bulk Storage Vessel Installation
Fig 5: Typical Cylinder Installation

MAXXflo Water Heater
1616
ELECTRICAL SUPPLY
External wiring to the water heater(s) must be installed in
accordance with current I.E.E. Regulations for the wiring of
buildings and to any Local Regulations that may apply.
e MAXXflo range is designed to operate from a
permanent 230v/50Hz single phases sup e fuse rating
is 5 amps.
Maximum Electrical Loading
Model Type Watts Amps
30 kW 170 0.74
60 kW 340 1.48
90 kW 510 2.22
120 kW 680 2.96
e method of connection to the mains electricity
supply should facilitate complete electrical isolation
of the appliance, preferably by use of a fused double
pole switch or fused spur box serving only the heater.
e disconnection of the supply shall have a contact
separation of 3mm on all poles.
e point of connection to the mains electricity supply
should be readily accessible and adjacent to the appliance.
ELECTRICAL CONNECTION
A terminal block can be found above the control panel (Fig
4, below). is becomes accessible by first removing the
front cover.
e following connections can be made on the terminal
block (see Fig. 5 – Wiring diagram, on next page)
Terminals Terminal Function
AL1 – AL2 Alarm volt-free contacts (24 volt 1
amp max.)
EN1 – EN2 Enable or disable contacts volt-free
(link fitted to enable)*
BT1 – BT2 Secondary set point temp. enable (40
– 75°C)*
LS1 – LS2 Secondary return temp. sensor for
pasteurisation function
TH1 – TH2 Secondary pump control enable*
Pump L – Pump N Secondary pump power supply
(0.7 amp max)
*To activate, place a contact across the terminals
M5910 G
AL1
AL2
TH1
TH2
BT1
BT2
LS1
LS2
TS1
TS2
TS3
TS4
EN1
EN2
gy
gn
bk
or
y
r
y
bk
r
r/bl
bk
bk
bk
gy
br
br
br
br
gy
gy
gy
gy
br
bl
r
r
r
r
wh
wh
wh
wh
bl
br
bl
bl
bl
bl
br
br
br
br
br
br
br
br
bl
bl
bl
bl
SECONDARY PUMP
Fig 6 – Terminal block connections
SECTION 3 • INSTALLATION

MAXXflo Water Heater
1717
INSTALLATION • SECTION 3
master
230V/50Hz
br wh
br
br br
wh wh
gr
gr
gr
gr
r
r r
r
wh
comm. 2
comm. 3
comm. 4
comm. 1
y
gy
r
br
bl
br bl
rr
bl
wh
bk
bl
br
bl
y
or
y
br gy
br
bl
br gy
br
bl
gy
bk
y
AL1
AL2
TS1
TS2
TS3
TS4
br
bl
br
bl
br br
br
bl
bl
bl
br br
br
bl bl
bl
gy
gn
bk
or
y
r y
bk
r
bk
gr
or
AL1-AL2 = Alarm
BT1-BT2 = Activate Second Setpoint TH1-TH2 = Activate Secondary Pump
LS1-LS2 = Secondary Sensor
TS1-TS2 = Tank sensor, low position EN1-EN2 = enable / disable
bl = blue
br = brown
y = yellow gn = green
gy = grey
or = orange
br
bl
BT1
BT2
LS1
LS2
TH1
TH2
LN
br bl
br bl
br
r = red
wh = white bk = black
pi = pink
bl
bk
pi
or
flow sensor 2
flow sensor 1
return sensor
slave 1
fan
ionisation rod
gasvalve
primary
pump
glow plug
tank sensor, low position
mains 1 mains 2 mains 3
mains 4
pump
pump L
secondary
pump
pump N
M5879D
wh
(Max24V1.0Amp)
E
g/y
g/y = green & yellow
EN1
EN2
tank sensor, high position
TS3-TS4 = Tank sensor, high position
r/bl
bk
gy
r/bl
r
bk
}
gn
Fig. 7 – Wiring Diagram
Make sure that the phase (L) and the neutral (N) are connected to the correct terminals on the connector. e appliance is
phase sensitive therefore swapping the phase and neutral will lead to a fault in the appliance.

MAXXflo Water Heater
1818
TEMPORARY WATER HEATER TEMPERATURE
CHANGE
It is possible to change the water heater temperature
remotely via a timer programme. First of all, the new
desired water heater temperature is set at a value higher
or lower than the water heater temperature during normal
operation. is makes it possible, for example, to carry out
Legionella flushing. (See page 32).
e water heater temperature changes when the contacts
connected to terminals BT1 – BT2 are closed. e water
heater temperature goes back to normal operation when
these contacts are opened again.
If the temperature change is used for Legionella flushing,
it is possible to return the water heater temperature to
normal operation before the timer programme finishes.
is happens on the basis of a temperature measurement,
for example at the end of a circulation line (secondary
return). For this purpose, a 10K NTC temperature sensor
(part number E674) must be connected to the terminals
LS1 – LS2. e water heater temperature now goes back
to normal operation if the temperature is higher at the
measuring point than the secondary pre-set water heater
temperature minus 5°C for 20 minutes.
If, for example, the secondary pre-set water heater
temperature is set at 70°C, the water heater temperature
returns back to normal operation as soon as the
temperature at the secondary measuring point has been
above 65°C for more than 20 minutes.
CIRCULATION PUMP AND STORAGE TANKS
A circulation pump (maximum 0.7 A) can be connected at
the terminal pump L – pump N. e circulation pump can
then be controlled by a thermostat connected to terminals
TH1-TH2. Connecting the contacts of the thermostat then
activates the circulation pump.
e application can be used when the water heater is
combined with a separate storage tank.
As soon as the temperature in the tank gets too low, the
thermostat will activate the pump so the tank is heated
up again. Matching MAXXflo storage tanks are available in
200 and 300 litre sizes, models HWST200 and HWST300.
ese tanks are fitted with a thermostat for use as above.
See below for schematic system design and pages 16 & 18
for tank dimensions and wiring diagram.
FIG 8 – SCHEMATIC SYSTEM DESIGN
SECTION 3 • INSTALLATION

MAXXflo Water Heater
1919
INSTALLATION • SECTION 3
Fig 9 – HWST Tank Dimensions
Fig 10 – Wiring Diagram
1 1/2" Hot
water
supply
1" Return
1
1/2" Feedfrom
water heater
Tank inspection hatch
28 mm T&P outlets
1 or 2 Tundishes supplied
PLAN VIEW
47 T&P outlets
Thermostat
153
153
Drain access
28 mm valve
602 602
1528 (200 litre tank)
1952 (300 litre t ank)
HWST 200 HWST 300 STORAGE TANKS

MAXXflo Water Heater
2020
FLUE SYSTEMS
e versatile flueing options will provide a solution to most
flushing requirements. e heater, when fitted with
a concentric flue system, provides a room sealed
application. e concentric flue, supplied by Andrews,
is available for either horizontal or vertical installation
and the table below shows the basic kit supplied plus
optional extras. Alternatively, the heater can be fitted with
a conventional flue system, which can be obtained from
a specialist flue stockist. A flue system suitable for a
condensing pressurised system must be specified.
e table and the concentric flue component below show
the maximum allowable length of flue for both systems.
e following pages show standard kits and additional
items for concentric flue supplied by Andrews. Horizontal
and vertical flue kits must be ordered separately. Flue kits
are not included in the heater price.
GENERAL
Flue terminals must be installed in accordance with the
Clean Air Act to ensure the products of combustion are
properly dispersed. e drawing shows some minimum
clearances for the flue terminal; in addition, the flue
terminal should be positioned where it will not cause a
nuisance from noise or from the combustion products
accumulating. Please contact Andrews technical
department if advice is needed for a particular installation.
See drawings on page 26.
We recommend that a condensate trap be fitted when the
secondary flue length is over 1.5m.
If installed in a roof valley, the terminal should be at least
1m above the highest part of the roof structure and 2.5m
from any adjacent structure. e terminal must be fitted
with a guard if less than 2m above ground level or in a
position where it may cause injury to persons resulting
from touching a hot surface. Guards can be ordered with
flue components. See table on pages 20 and 23.
WARNING!
e flue system must be properly installed. Ensure the
inner flue is securely sealed at all the joints otherwise
incomplete combustion may result. Do not exceed
maximum flue lengths including elbows.
Model CWH30 CWH60 CWH90 CWH120
Flue size (concentric)
mm 80/125 80/125 130/200 130/200
Max. flue run – concentric (a) m 14 12 14 14
Max. flue run – conventional (b) m 50 20 50 40
Max. flue static pressure Pa 140 140 140 140
Max. flue gas volume m
3/h 41 82 123 164
Max. flue gas temperature °C 52 52 52 52
(a) For a concentric flue/room sealed, reduce flue length by 1.2m for 90° bend, 0.7m for 45° bend and 1.5m
for condense trap.
(b) For a conventional flue, reduce flue length by 4m for 90° bend, 2m for 45° bend and 4 m for condense trap.
e different ventilation requirements for room sealed or conventional flue systems are given on pages 28 – 30.
SECTION 3 • INSTALLATION