andrews R18 Series Guide

18IP22B
Technical documentation
R18
Water Heaters
Andrews Water Heaters
Wednesbury One
Black Country New Road, Wednesbury
West Midlands WS10 7NZ
Telephone: [phone]
Facsimile: 0121 506 7401

18IP22B
II
Edition B, 27-11-2000
© 2000 Andrews Water Heaters
All rights reserved.
No part of this publication may be reproduced, stored in a retrieval system, or transmitted in
any form or by any means, electronic, mechanical, photocopying, recording or otherwise,
without the prior permission in writing of Andrews Water Heaters.
We aim to achieve continuous improvement in our products. Therefore, specifications are
subject to change without prior notice.
Due to changes the product can deviate from the information specified in this document.
Therefore Andrews Water Heaters rejects any responsibility for the differences between the
product delivered and the information mentioned in this document.

18IP22B III
R18 WATER HEATER TECHNICAL DATA
Type 132 154 180 210 244 280
Nominal heat output kW 481 558 649 756 875 1002
Nominal heat input (nett. CV) kW 538 625 727 846 980 1122
Gas consumption
natural gas H (10,9 kWh/m ) m /h 49,3 57,9 67,4 78,4 90,8 104,0
3
propane m /h 19,0 22,1 25,7 29,9 34,7 39,7
3
3
Gas inlet pressure (min.) mbar 17 17 17 17 17 17
(max.) mbar 25 25 25 25 25 25
propane (max.) mbar 50 50 50 50 50 50
Water volume dm 22,0 23,2 24,6 26,3 28,1 30,1
Max. working pressure bar 11 11 11 11 11 11
3
Flue connection D mm 450 500 550 600 650 700
Gas connection G 2" 2" 2" 2" DN65 PN16 DN65 PN16
Water connections
cold water feed + hot water flow W DN80 PN16 DN80 PN16 DN80 PN16 DN80 PN16 DN80 PN16 DN80 PN16
recirculation DN80 PN16 DN80 PN16 DN80 PN16 DN80 PN16 DN80 PN16 DN80 PN16
Pressure relief valve connection 1¼” 1¼” 1¼” 1½” 1½” 1½”
relief connection 1½” 1½” 1½” 2" 2" 2"
standard setting bar 5 5 5 5 5 5
Electrical supply water heater 1N~ V 230 230 230 230 230 230
pump 3N~ V 400 400 400 400 400 400
Frequency Hz 50 50 50 50 50 50
Fuse A666666
Max. electrical consumption
water heater kW 0,04 0,04 0,04 0,04 0,04 0,04
pump kW 0,75 0,75 0,75 0,75 0,75 0,75
Dimensions B mm 1430 1430 1430 1430 1400 1400
H mm 1795 1795 1795 1795 1895 1895
L mm 1461 1636 1842 2080 2350 2636
Weight, empty, ± 5 % kg 620 660 705 760 820 885
Table 1 Technical Data
- Heat output measured with : 60 - 80 °C
- Gas consumption at : 1013 mbar, 15 °C, dry
- Gas specification : II2H3P
- Appliance category : B11
- Protection degree : IP30
Changes in specifications and dimensions
The manufacturer reserves the right to change the above mentioned dimensions without prior
notice.
Because of manufacturing tolerances, the above mentioned dimensions can vary slightly.

18IP22B
IV
Fig. 1 Dimensions
Dimensions
The water heater is available as either:
Top and side clearances are 600 mm MINIMUM.

18IP22B V
Fig. 2 Dimensions 500 litre tank
R18 SUPA FLO PLUS with BT 500 litre tank

18IP22B
VI

18IP22B VII
INDEX
R18WaterHeaterTechnicaldata ...............III
Dimensions ............................... IV
Index .................................... VII
1 INTRODUCTION ............................ 1
1.1 General ................................... 1
1.2 Supplier ................................... 1
1.3 This manual ................................ 1
1.4 Service .................................... 2
1.5 Reservation ................................ 2
2 DESCRIPTION ............................. 3
2.1 General information .......................... 3
2.2 Main components ............................ 4
2.3 Principleofregulation ........................ 9
2.3.1 EMControloption ........................... 9
2.3.2 EWControloption .......................... 10
2.4 Water heater protection ...................... 12
3 SAFETY.................................. 14
4 DELIVERYANDTRANSPORT ................ 17
4.1 Delivery .................................. 17
4.2 Unitprotectivepackaging..................... 17
4.3 Transport ................................. 17
5 INSTALLATION............................ 19
5.1 Boilerroom................................ 19
5.1.1 Siting .................................... 19
5.1.2 Boilerroomventilation ....................... 19
5.1.3 Air supply and ventilation ..................... 20
5.2 Unit connections ........................... 21
5.2.1 Gas supply ................................ 21
5.2.2 Electrical supply ............................ 22
5.2.3 Hydraulic connections ....................... 23
5.2.3.1 Watersystem.............................. 24
5.2.3.2 Pumpinformation........................... 24
5.2.4 Flues .................................... 25
5.3 General recommendations .................... 26
5.4 Watertemperature.......................... 27
5.5 Demand for hot water for sanitary use ........... 27
5.6 Waterquality .............................. 28
5.7 Formulatocalculatehotwaterrequirements ...... 30
5.8 Asmallselectionofapplications ............... 32
5.8.1 Singletemperaturesystem ................... 32
5.8.2 Dualtemperaturesystem..................... 32
5.8.3 Industrial application ........................ 33
5.8.4 High peak demand use ...................... 33

18IP22B
VIII
6 COMMISSIONING .......................... 34
6.1 General .................................. 34
6.2 Pre-lighting checks and dry run ................ 35
6.2.1 Check1 .................................. 35
6.2.2 Check2 .................................. 35
6.2.3 Check3 .................................. 36
6.3 Liveruncheck ............................. 39
6.4 Instructionstouser.......................... 41
7 OPERATION AND FAULT INDICATION ......... 42
7.1 Function .................................. 42
7.2 Regulation ................................ 42
7.3 Control panel .............................. 42
7.4 Faultindications ............................ 43
7.5 Start-up .................................. 44
7.6 Shut-down ................................ 44
7.7 Warnings ................................. 44
7.8 Faultfindingtable........................... 45
8 MAINTENANCE............................ 47
8.1 Safety.................................... 47
8.2 General information ......................... 47
8.3 Inspection ................................ 47
8.4 Cleaning .................................. 49
8.5 Servicing ................................. 49
8.6 Component replacement ..................... 53
8.7 Service ................................... 57
9 LISTOFSERVICEABLEPARTS .............. 58
SUPPLEMENT ............................ 59

18IP22B 1
1 INTRODUCTION
1.1 General Through their unique construction, these water heaters are
renowned for their:
1.2 Supplier Andrews Supa Flo water heaters are sold throughout the
1.3 This manual This documentation has been produced to aid the following
- high thermal efficiency
- environmental friendliness
- light weight and small dimensions
- durability
- low noise production
- large regulating range
- available with many different options.
Continual research and development means that Andrews
remains at the forefront of boiler and water heater technology.
United Kingdom by:
Andrews Water Heaters
Wednesbury One
Black Country New Road, Wednesbury
West Midlands WS10 7NZ
Telephone: [phone]
Facsimile: 0121 506 7401
For advice or more information with regard to our products
contact Andrews Water Heaters.
target groups:
- the consulting engineer
- the heating installer
- the service engineer
- the user.
Because these target groups require mostly similar information
and also specific information, our technical documentation has
been integrated to provide these target groups with the neces-
sary general and specific information to install, service and
operate this product.
The supplier (see 1.2) will be able to provide any further or
supplemental information.

18IP22B
2
1.4 Service For commissioning and assistance in maintenance matters,
1.5 Reservation It is the law that the installation be carried out by a competent
The following aspects will be explained:
- general description
- technical specifications
- necessary services for system design and unit installation
- example systems
- maintenance instructions.
Operating instructions for the user can be found on the unit.
See also chapter 7.
please contact your supplier’s service department. For more
details see section 1.2.
person. The water heater should be installed in accordance
with the British Standards and Codes of Practice referred to in
this manual, the Gas Safety (installation & use) Regulations
1994, Building Regulations, Water Bye-laws and any Require-
ments of the Local Gas Supplier, Local Authority, Water and
Fire Authorities and I.E.E. Regulations.
Health & Safety at Work Act, 1974
Under Section 6 of the above Act, it is the duty of manufactur-
ers and suppliers of products for use at work to ensure, so far
as it is reasonable practicable, that such products are safe and
without risk to health when properly used and to make available
to users of such products adequate information about their safe
and proper operation.
Andrews water heaters should only be used in the manner and
purpose for wich they were intended, and in accordance with
the recommendations detailed in this manual. Our heaters have
been designed, produced and inspected with safety in mind,
but there are certain basic precautions, wich should be taken by
the user and, in particular attention is drawn to the safety pre-
cautions in this manual and to the operating instructions on the
heater.
It is imperative, therefore, that all persons who make use of our
heaters have all the information and instructions they require to
ensure that they are fully aware of any hazard, and that they
know both the purpose and correct manner of use of our heat-
ers.
The manufacturer can alter its products without any pre-
ceding notification and is therefore not obliged to adapt
earlier delivered products.

18IP22B 3
2 DESCRIPTION
2.1 General information The R18 series water heaters are atmospheric open flued, low
The R18 series is CE approved for the following countries:
thermal capacity gas-fired water heaters.
These high efficiency water heaters are designed to provide hot
water to various industrial and commercial applications where
there can be varying demands and fluctuating loads.
Several models are available with heat inputs from 538 kW to
1122 kW and recovery rates from 10.513 litres per hour to
21.926 litres per hour, based upon a temperature rise of 44 K
or 8.260 litres per hour to 17.226 litres per hour, based upon a
temperature rise of 56 K.
The R18 series of water heaters are available in 6 types:
132, 154, 180, 210, 244 and 280.
The last three digits of the type number indicate the number of
burner bars present in the burner assembly. The load at nett
calorific value is approx. 3,6 kW per burner.
All water heater types are fitted with a 18-tube heat exchanger
of the 2 pass type including stainless steel manifolds.
The use of extruded copper fin pipes in the heat exchanger
leads to higher efficiency.
The R18 water heater is supplied with a primary pump, to
ensure the optimum flow rate (to prevent the precipitation of
lime scale) and a bypass.
Thermal radiation losses are minimized by the optimal con-
struction of the combustion chamber in which high-grade insu-
lation is integrated.
The advanced construction of the R18 enables swift assembly
and dismantle, which simplifies maintenance and inspection.
All water heaters have full sequence automatic control with
overheat cut off, water flow switch, modulating turn down on
gas and combustion air (for improved efficiency at varying heat
loads) and fault indicators.
The R18 has an electronic protection and ignition system,
indicated by E.
The electronic PID version controlled by a simple to operate
regulator is indicated in the M version.
Appliance category B11.
Great Britain, Belgium, Denmark, France, Ireland, Italy, Spain
and Sweden under Product Identification Number 0063AQ6600.

18IP22B
4
Fig. 3 View of the R18 series
2.2 Main components
1. Flue outlet socket 24. Gas governor
3. Draught diverter 25. Main gas valve
6. Cover for electrical connection tray 26. Solenoid valve for pilot burner
7. Connection tray 27. Pressure test points
11. Servomotor (air damper/gas input) 28. Temperature control unit
13. Modulating gas valve 29. Safety system control box
15. Modulating air damper 30. Control panel
19. Safety valve 33. Gas connection
20. Water flow switch 34. Water connections
21. Pressure gauge/thermometer 35. Cover
22. Flow temperature sensor 36. Fill/drain cock
23. Pilot governor 37. High limit thermostat

18IP22B 5
Fig. 4 Cross-section of the R18 series
1. Flue outlet socket 10. Modulating gas valve
2. Deflector 11. Servo motor
3. Draught diverter 12. Front adjustment limit stop
4. Air in-take 13. Linkage assembly
5. Heat exchanger 14. Adjustment screw
6. Connection tray 15. Lock screw for air damper
7. Combustion chamber 16. Rear adjustment screw for air damper
8. Sight glass 17. Modulating air damper
9. Burner assembly 18. Air deflector

18IP22B
6
Fig. 5 Draught diverter
Fig. 6 Combustion chamber
Draught diverter
The R18 is fitted with a draught diverter. It is possible to con-
nect the flue outlet connection on the top cover with a standard
flue pipe. The inside of the draught diverter is insulated. The
mantle is easily removed without the use of any special tools by
means of a click system.
Combustion chamber
The chassis consists of two side frames with steel supports.
Dura blanket type thermal insulation is sandwiched between the
vermiculite refractory blocks and front, rear and side panels of
the combustion chamber housing. These vermiculite refractory
blocks are mounted so as to allow freedom of expansion. The
refractory blocks backed with the Dura blanket insulation form
the combustion chamber.

18IP22B 7
Fig. 7 Heat exchanger
Fig.8 Pump and bypass with water connections
Heat exchanger
The heat exchanger (type 2-pass) is mounted on the chassis.
To ensure proper heat transfer of the combustion gases, the
copper fin tubes are arranged side by side and expanded
laterally into a mounting plate. The baffles on the copper fin
tubes optimize the efficiency of the heat exchanger. The stain-
less steel supply and return pipes together with the water mani-
folds form the heat exchanger and is pressure tested at 16
bar. The R18 water heater is supplied with a primary pump,
to ensure the optimum flow rate and a bypass (see fig. 8).
Primary pump
The primary circulating pump is sized to prevent the depositing
of limescale in the water heater under the following conditions.
Water hardness in ppm Maximum temperature in °C
0 - 80 90
80 - 250 85
250 - 350 80
350 - 500 60
Table 2 Maximum temperature

18IP22B
8
Fig. 9 Burner
Fig. 10 Combustion air damper
Burner
The burner is mounted under the combustion chamber in the
chassis. The burner bars, mounted in the burner trolley are
manufactured from stainless steel. Each burner bar is supplied
by its own injector nozzle mounted on the gas manifold.
Combustion air damper
A combustion air damper is situated underneath the burners.
Gas train
The principal components of the gas train are a main governor
and two main gas valves or combined main governor and main
gas valve. The quantity of gas is adjusted in proportion of the
quantity of air being supplied by the air damper opening. The
pilot flame has a separate pilot line with pilot governor and gas
valve.

18IP22B 9
2.3 Principle of regulation The flow temperature can be adjusted continously as a function
2.3.1 EM Control option Electronic Modulating version
of hot water demand and water hardness (see table 2 and 3).
Several boilers can be connected by using cascade switching.
With the EM or EW Control option you can reduce electricity
consumption, both boiler and boiler primary pump can be
switched off by the cascade control box.
This type of boiler control regulation (indicated by the EM
control option) uses a built-in PID regulator to maintain a con-
stant flow temperature to within a minimum temperature devia-
tion of +1 to -1 K. This system allows the user to fine-tune the
reaction of the boiler to the heating system or application pro-
cess. An added bonus with this “EM” control system is that it
allows a Building Management system to influence the flow
temperature using a 0 - 10 VDC control signal.
Boiler temperature controller RWF40
A Process value (actual temperature)
B Set point (temperature)
C Burner enable (not applicable)
D Mod. indicator (decrease fire rate)
E Mod. indicator (increase fire rate)
F Two-stage firing (not applicable)
G Limit comparator
H Manual operation
The keys K-L-M-N are used for displaying
values and changing parameters in the
temperature controllers configuration.
K Down key (reduce value)
L Up key (increase value)
M Programme key
N Exit key
Assignment of levels
All levels can be accessed from the basic
display via the button, as shown in
PGM
the diagram. The upper actual value dis-
play (red) indicates the actual value and
the parameter values for the various levels.
The setpoint and the parameters are
indicated in the lower setpoint display
(green).
1. After using *PGM+to step through all
the parameters of a level, an automatic
return occurs after the last parameter has
been confirmed.

18IP22B
10
Fig. 11 Parallel displacement of the heating curve
2.3.2 EW Control option Electronic Modulating version with outside temperature
compensation and night-time temperature reduction
This system (indicated by the EW control option) uses the
above mentioned PID regulator to regulate the boiler. The “EW”
control system maintains the advantages of the “EM” type boiler
and adds to it the possibility of automatically changing the flow
temperature according to the outside temperature and the
required heating curve. The unit’s built-in week-clock also
means that a night-time and weekend temperature reduction is
possible with a “EW” control system.
Weather-dependent setpoint shift
The RWF40 can be configured in such a way that, if a Ni1000
outside sensor (e.g. QAC22) is connected, a weather-depen-
dent setpoint shift is implemented.
The minimum and maximum setpoint values can be set by the
lower setpoint limit *SPL+and the upper setpoint limit *SPH+.
Parameter *P+can be used to apply a parallel displacement to
the heating curve.
*Each RWF40 must have its own separate outside
sensor connected (no parallel connection)!
Heating curve slope
Slope *H+of the heating curve can be used to adjust the set-
point in response to the outside temperature, as shown in the
diagram. The common origin of the heating curves is set at
(20 °C / 20 °C). The effective range of the weather-adjusted
setpoint is restricted by the setpoint limits *
**
*SPH+
++
+and *
**
*SPL+.

18IP22B 11
Fig. 12 Heating curve slope
*
**
*HYS1+
++
+is the switch-on point for the burner, and *
**
*HYS3+
++
+is the
switch-off point. As already described, they act with the set shift
relative to the weather-controlled setpoint.
Process data
Parameter Display Value range Factory setting
Setpoint 1 SP1 SPL-SPH 0
1
Setpoint 2 (option) SP2 SPL-SPH 0
1
Digital setpoint shift (option) dSP SPL-SPH 0
1
Outside temperature (option) tA *C111 Inputs+-
1
Predefinition of external setpoint SP.E SPL-SPH -
1
Parameter level
Parameter Display Value range Factory setting
Limit value of limit comparator AL -1999...+9999 digit 0
1
Switching differential for limit comparator HYSt 0...999,9 digit 1
1
Proportional band Pb.1 0,1...999,9 digit 10
1
Derivative time dt 0...9999 s 80
Integral action time rt 0...9999 s 350
Contact spacing db 0,0...999,9 digit 1
1
Actuator running time tt 10...3000 s 15 s
Switch-on threshold burner/stage II H Y S 1 0,0...-199,9 digit -5
1
Switch-off level stage II H Y S 2 0,0... HYS3 digit 3
1
Upper switch-off threshold H Y S 3 0,0...999,9 digit 5
1
Response threshold q0,0...999,9 0
Heating curve slope H0,0...4,0 2
Parallel displacement P-90...+90 0
1

18IP22B
12
2.4 Water heater protection
Configuration level
Parameter Display Factory setting
Analog input 1, 2 and 3; setpoint changeover / shift C111 9930
Limit comparator; controller type; setpoint 1; locking C112 5010
Unit address; decimal place / unit signal for out-of-range C113 0
Measurement range start analog input 1 SCL 0
1
Measurement range analog input 1 SCH 100
1
Measurement range analog input 2 SCL2 0
1
Measurement range analog input 2 SCH2 100
1
Lower setpoint limit SPL 30
1
Upper setpoint limit SPH 95
1
Actual value correction, analog input 1 OFF1 0
1
Actual value correction, analog input 2 OFF2 0
1
Actual value correction, analog input 3 OFF3 0
1
Filter time constant for digital filter, analog input 1 dF1 1
These parameters are affected by the setting for the decimal place.
1
The R18 is protected by the following systems:
minimum water flow switch
The water flow switch is installed in the flow manifold and
continuously monitors the minimum water flow. If the water flow
falls below a preset level, the burner is shut down and will go to
lock-out. The water flow switch is factory set and should not be
adjusted.
high limit thermostat (E.C.O.)
In the event of failure of the control thermostat, a preset high
limit thermostat will shut down the burner and go to lockout.
pressure relief valve
The maximum operating pressure of the R18 water heater is 10
bar. The standard safety valve supplied is set to 5 bar. If a
different pressure setting is required this should be specified
and will be set at the factory.
gas burner control
The burner control unit provide control and supervision of the
atmospheric burner. The sequence controller is coupled to the
spindle of the control circuit and to the flame supervision unit
displaying the status, the symbol appearing above the reading
mark indicates the firing sequence or lock-out condition. The
pilot flame is supervised by ionisation current detection.