DORCHESTER DR-LA 45 User manual

Dorchester DR-LA Range
of Hot Water Storage Heaters
Open Flue, Direct Gas Fired Hot Water Storage Heaters
with Automatic Ignition
for Domestic Hot Water Installations
Installation, Commissioning
and Servicing Instructions
DORCHESTER DR-LA 30, 40, 45, 60, 75, 95, 110 Models
NATURAL GAS I2H LPG I3+
NOTE: THESE INSTRUCTIONS MUST BE READ AND UNDERSTOOD BEFORE
INSTALLING, COMMISSIONING, OPERATING OR SERVICING EQUIPMENT.
THIS WATER HEATER IS FOR USE ON GROUP H NATURAL GAS (2ND FAMILY) I2H OR
LPG (3RD FAMILY) I3+. PLEASE ENSURE RELEVANT INFORMATION REQUIRED WITHIN
DOCUMENT IS FOUND RELATING TO SPECIFIC GAS TO BE FIRED BEFORE FIRING
HEATER.
THIS WATER HEATER COMPLIES WITH ALL RELEVANT EUROPEAN DIRECTIVES.
PUBLICATION NO. 500001137
ISSUE ‘A’
SEPTEMBER 2005
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Table of contents
1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - 7
1.1 About the water heater - - - - - - - - - - - - - - - - - - - - - - - - - - - 7
1.2 What to do if you smell gas - - - - - - - - - - - - - - - - - - - - - - - - - 7
1.3 Regulations and documents - - - - - - - - - - - - - - - - - - - - - - - - 7
1.4 Target groups - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 8
1.5 Maintenance - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 9
1.6 Forms of notation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 9
1.7 Overview of this document - - - - - - - - - - - - - - - - - - - - - - - - 10
2 Functioning of the water heater - - - - - - - - - - - - - - - - 11
2.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 11
2.2 Functional description of the water heater - - - - - - - - - - - - - - - - 12
2.3 The water heater’s heating cycle - - - - - - - - - - - - - - - - - - - - - 13
2.4 Protection for the water heater - - - - - - - - - - - - - - - - - - - - - - 13
2.4.1 Water temperature protection - - - - - - - - - - - - - - - - - 13
2.4.2 Combustion products discharge safety device - - - - - - - - - 14
2.4.3 flame probe - - - - - - - - - - - - - - - - - - - - - - - - - - 14
2.5 Safety of the installation - - - - - - - - - - - - - - - - - - - - - - - - - 14
2.5.1 Unvented installation - - - - - - - - - - - - - - - - - - - - - 14
2.5.2 Vented installation- - - - - - - - - - - - - - - - - - - - - - - 14
2.5.3 Temparature and Pressure valve (T&P valve) - - - - - - - - - 14
2.6 Indicators and Alarms - - - - - - - - - - - - - - - - - - - - - - - - - - 14
2.6.1 Volt Free Contacts - - - - - - - - - - - - - - - - - - - - - - 14
2.7 Options - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 15
2.7.1 LPG- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 15
2.7.2 Unvented Supply - - - - - - - - - - - - - - - - - - - - - - - 15
2.7.3 Top to Bottom Circulation - - - - - - - - - - - - - - - - - - - 15
3 Installation - - - - - - - - - - - - - - - - - - - - - - - - - - - 17
3.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 17
3.2 Packaging - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 17
3.3 Environmental conditions- - - - - - - - - - - - - - - - - - - - - - - - - 17
3.3.1 Humidity and ambient temperature- - - - - - - - - - - - - - - 18
3.3.2 Maximum floor loading - - - - - - - - - - - - - - - - - - - - 18
3.3.3 Working clearances - - - - - - - - - - - - - - - - - - - - - - 18
3.4 Technical specifications - - - - - - - - - - - - - - - - - - - - - - - - - 20
3.5 Installation diagram - - - - - - - - - - - - - - - - - - - - - - - - - - - 24
3.6 Water connections, Unvented - - - - - - - - - - - - - - - - - - - - - - 25
3.6.1 Cold water side - - - - - - - - - - - - - - - - - - - - - - - - 25
3.6.2 Top to bottom recirculating pump - - - - - - - - - - - - - - - 25
3.6.3 Hot water side- - - - - - - - - - - - - - - - - - - - - - - - - 25
3.6.4 Drain valve - - - - - - - - - - - - - - - - - - - - - - - - - - 25
3.6.5 Circulation pipe - - - - - - - - - - - - - - - - - - - - - - - - 25
3.7 Water connections, Vented- - - - - - - - - - - - - - - - - - - - - - - - 26
3.7.1 Cold water side - - - - - - - - - - - - - - - - - - - - - - - - 26
3.7.2 Top to bottom recirculating pump - - - - - - - - - - - - - - - 26
3.7.3 Hot water side- - - - - - - - - - - - - - - - - - - - - - - - - 26
3.7.4 Circulation pipe - - - - - - - - - - - - - - - - - - - - - - - - 26
3.8 Gas connection - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 26
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4Instruction manual DR-LA
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3.9 Flue gas discharge - - - - - - - - - - - - - - - - - - - - - - - - - - - - 27
3.9.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 27
3.9.2 Fitting the draught diverter - - - - - - - - - - - - - - - - - - - 27
3.9.3 Flue gas thermostat assembly - - - - - - - - - - - - - - - - - 28
3.10 Electrical connection - - - - - - - - - - - - - - - - - - - - - - - - - - - 29
3.10.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 29
3.10.2 Preparation- - - - - - - - - - - - - - - - - - - - - - - - - - - 29
3.10.3 Mains power - - - - - - - - - - - - - - - - - - - - - - - - - - 30
3.11 Checking the supply pressure and burner pressure - - - - - - - - - - - - 31
3.12 Conversion to a different gas category - - - - - - - - - - - - - - - - - - - 33
3.12.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 33
3.12.2 Conversion to a different gas category DR-LA 30 through 95 - - 34
3.12.3 Conversion to a different gas category, DR-LA110 - - - - - - - 36
4 Filling and draining - - - - - - - - - - - - - - - - - - - - - - - 39
4.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 39
4.2 Filling the water heater - - - - - - - - - - - - - - - - - - - - - - - - - - 40
4.2.1 Filling unvented installations - - - - - - - - - - - - - - - - - - 40
4.2.2 Filling vented installations- - - - - - - - - - - - - - - - - - - - 40
4.3 Draining the water heater - - - - - - - - - - - - - - - - - - - - - - - - - 40
4.3.1 Draining unvented installations - - - - - - - - - - - - - - - - - 40
4.3.2 Draining vented installations - - - - - - - - - - - - - - - - - - 41
5 Controls- - - - - - - - - - - - - - - - - - - - - - - - - - - - - 43
5.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 43
5.2 Control panel - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 43
5.3 Explanation of the symbols - - - - - - - - - - - - - - - - - - - - - - - - 44
5.4 ON/OFF switch - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 44
5.5 Control thermostat - - - - - - - - - - - - - - - - - - - - - - - - - - - - 44
5.6 Burner control reset button - - - - - - - - - - - - - - - - - - - - - - - - 44
5.7 Flue gas thermostat reset button - - - - - - - - - - - - - - - - - - - - - 44
6 Status of the water heater - - - - - - - - - - - - - - - - - - - 47
6.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 47
6.2 Operating states - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 47
6.3 Error states - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 47
7 Starting up and shutting down - - - - - - - - - - - - - - - - - 49
7.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 49
7.2 Starting up - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 49
7.3 Shutting down- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 49
7.3.1 Shut the water heater down for brief periods ("OFF mode") - - - 49
7.3.2 Isolate the water heater from the power supply - - - - - - - - - 49
7.3.3 Shut the water heater down for a longer period - - - - - - - - - 49
7.4 Heating cycle - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 50
8 Troubleshooting - - - - - - - - - - - - - - - - - - - - - - - - 51
8.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 51
8.2 Troubleshooting table for general errors - - - - - - - - - - - - - - - - - - 52
8.3 Troubleshooting table "no hot water"- - - - - - - - - - - - - - - - - - - - 53
8.4 Troubleshooting table "insufficient hot water’" - - - - - - - - - - - - - - - 55
9 Maintenance - - - - - - - - - - - - - - - - - - - - - - - - - - 57
9.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 57

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9.2 Preparing for maintenance - - - - - - - - - - - - - - - - - - - - - - - - 57
9.3 Water-side maintenance - - - - - - - - - - - - - - - - - - - - - - - - - 58
9.3.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 58
9.3.2 Checking the anodes - - - - - - - - - - - - - - - - - - - - - 58
9.3.3 Descaling and cleaning the heater - - - - - - - - - - - - - - - 58
9.4 Gas-side maintenance - - - - - - - - - - - - - - - - - - - - - - - - - - 59
9.4.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 59
9.4.2 Cleaning the burners - - - - - - - - - - - - - - - - - - - - - 59
9.4.3 Cleaning the orifices- - - - - - - - - - - - - - - - - - - - - - 60
9.4.4 Checking the flue baffles - - - - - - - - - - - - - - - - - - - 60
9.5 Finalising maintenance- - - - - - - - - - - - - - - - - - - - - - - - - - 60
A Appendices- - - - - - - - - - - - - - - - - - - - - - - - - - - 61
1.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 61
1.2 Electrical diagram DR-LA - - - - - - - - - - - - - - - - - - - - - - - - 62
1.2.1 Electrical diagram DR-LA 30 through 95 and 110 (natural gas) - 62
1.2.2 Electrical diagram DR-LA 110 (LP gas) - - - - - - - - - - - - 63

6Instruction manual DR-LA
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About the water heater
Instruction manual DR-LA 7
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1 Introduction
1.1 About the water
heater
This manual describes how to install, service and use an DR-LA-water heater.
An DR-LA water heater is a gas-fired open water heater without a fan. DR-LA
water heaters are fitted with a combustion products discharge safety device.
The DR-LA belongs to water heater category B11BS. The information in this
manual is applicable to types: DR-LA 30, DR-LA 40, DR-LA 45, DR-LA 60, DR-
LA 75, DR-LA 95 and DR-LA 110.
The manner of construction and features of the water heater are in conformance
with the European standard for gas-fired storage water heaters for the
production of domestic hot water (EN 89). The water heaters are therefore
compliant with the European Directive for Gas Appliances and have the right to
bear the CE mark.
Warning
Read this manual carefully before starting up the water heater. Failure to
read the manual and to follow the printed instructions may lead to personal
injury and damage to the water heater.
1.2 What to do if you
smell gas Warning
Whenever there is a smell of gas:
No naked flames! No smoking!
Avoid causing sparks! Do not use any electrical equipment or switch, i.e. no
telephones, plugs or bells!
Shut off the mains gas supply!
Open windows and doors!
Warn occupants and leave the building!
After leaving the building, alert the gas distribution company or installation
engineer.
1.3 Regulations and
documents
Gas Safety Installations and Use Regulations 1998, (As amended). It is law
that all gas appliances are installed by competent persons, in accordance with
the above regulations. Failure to install appliances correctly could lead to
prosecution. It is in your own interest, and that of safety, to ensure that this law
is complied with.
The installation of the boiler MUST be in accordance with the relevant
requirements of the Gas Safety Regulations, Building Regulations, IEE
Regulations and the Water Supply (water fittings) Regulations.
The installation should also be in accordance with any relevant requirements of
the HSE, local gas region and local authority and the relevant recommendations
of the following documents:
0063
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Introduction
8Instruction manual DR-LA
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British Standards
•BS 6891: Specification for installation of low pressure gas pipework of up to
28 mm (R1) in domestic premises (2nd family gas). For larger installations
see IGE/UP/2 below.
•BS 6798: Specification for installation of gas-fired boilers of rated input not
exceeding 70 kW net.
•BS 6644: Specification for installation of gas-fired hot water boilers of rated
inputs between 60 kW and 2 MW (2nd and 3rd family gases).
•BS 6700: Specification for design, installation, testing and maintenance of
services supplying water for domestic use within buildings and their
curtilages.
•BS EN 806-2: Specification for installations inside buildings conveying water
for human consumption. Part 2: Design.
•BS 5546: Specification for installation of hot water supplies for domestic
purposes, using gas-fired appliances of rated input not exceeding 70 kW.
•BS 5440: Installation and maintenance of flues and ventilation for gas
appliances of rated input not exceeding 70 kW net (1st, 2nd and 3rd family
gases). Part 1: Flues. Part 2: Ventilation.
Institute of Gas Engineers and Managers Publications
• IGE/UP/1 Soundness testing and purging of industrial and commercial gas
installations.
• IGE/UP/1A Soundness testing and direct purging of small low pressure
industrial and commercial natural gas installations.
• IGE/UP/2 Gas installation pipework, boosters and compressors on industrial
and commercial premises.
• IGE/UP/10 Installation of gas appliances in industrial and commercial
premises. Part 1: flued appliances.
CIBSE Publications:- "CIBSE Guide"
Section B4 : Water Service Systems.
1.4 Target groups The three target groups for this manual are:
• (end) users;
• installation engineers;
• service and maintenance engineers.
Symbols on each page indicate the target groups for whom the information is
intended. See Table 1.1.
Table 1.1 Target group symbols
Symbol Target group
g(End) user
iinstallation engineer
sService and maintenance engineer

Maintenance
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1.5 Maintenance A service should be carried out at least once a year, both on the water side and
on the gas side. Maintenance frequency depends, among other things, on the
water quality, the average burning time per day and the set water temperature.
nCaution
To determine the correct maintenance frequency, it is recommended to
arrange for the service and maintenance engineer to check the water heater
on both the water and gas side, three months after installation. Based on this
check, the best maintenance frequency can be determined.
nCaution
Regular maintenance extends the service life of the water heater.
Both the end user and the service and maintenance engineer are responsible
for regular maintenance. They will need to establish clear agreements on this.
nCaution
If the water heater is not regularly maintained, the warranty will become void.
1.6 Forms of notation The following notation is used in this manual:
nCaution
Important information
cNote
Ignoring this information can lead to the water heater being damaged.
Warning
Failure to carefully read this information may lead to danger of personal
injury and serious damage to the water heater.

Introduction
10 Instruction manual DR-LA
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1.7 Overview of this
document
Table 1.2 provides an overview of the contents of this document.
Table 1.2 Contents of document
Chapter Target groups Description
2 Functioning of the water
heater gis This chapter describes how the water heater functions.
3Installation is This chapter describes the installation activity to be completed
before you actually start up the water heater.
4 Filling and draining gis This chapter describes how to fill and drain the water heater.
5 Controls gis This chapter describes the water heater’s control panel and
how to use it.
6 Status of the water heater gis This chapter describes each status (state) that the water
heater may be in and how to respond, if necessary.
7 Starting up and shutting
down gis This chapter describes how to start up the water heater and
how to shut it down for a brief or long period of time. The
general heating cycle of the water heater is also described.
8 Troubleshooting gis This chapter is mainly intended for the installation engineer
and the service and maintenance engineer. It describes water
heater errors. These errors are indicated on the display. A
table of possible causes and solutions is provided. End users
may also refer to this chapter for additional information about
the water heater.
9 Maintenance sThis chapter sets out the maintenance tasks to be carried out
during a service.

Introduction
Instruction manual DR-LA 11
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2 Functioning of the
water heater
2.1 Introduction Topics covered in this chapter:
•Functional description of the water heater;
•The water heater’s heating cycle;
•Protection for the water heater;
•Safety of the installation.
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Functioning of the water heater
12 Instruction manual DR-LA
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2.2 Functional
description of the
water heater
Figure 2.1 shows a cut-away view of the water heater.
In this water heater the cold water enters the bottom of the it via the cold water
inlet B. The heat of combustion is transferred to the water through the
combustion chamber land flue tubes d. The heated tap water leaves the
heater through the hot water outlet r. Once the water heater is completely filled
with water, it remains constantly under water supply pressure. As hot water from
the water heater is consumed, it is continuously replenished with cold water.
The gas required for combustion flows into the manifold via the gas control n.
Orifices are located within the manifold. Via these orifices, the gas enters the
bar burners C. Together, the bar burners constitute the burner tray. As the gas
is injected into the bar burners, the primary air required for combustion is also
drawn in(1). Additional air is drawn through the openings in the burner tray. The
Legend
aflue gas discharge
bdraught diverter
canodes
dflue tubes
eflue baffles
fflue gas thermostat
gflue gas thermostat sensor
hinsulation layer
ihot water tank
jcleaning opening
kdrain valve
lcombustion chamber
mradiation shield/condensation
tray
ngas control
osafety thermostat sensor
phigh-limit thermostat sensor
qburner control
rhot water outlet
scontrol panel
tcontrol thermostat
uhigh-limit thermostat
vsafety thermostat
wfrost thermostat
xcontrol thermostat sensor
yfrost thermostat sensor
zhot surface igniter
Aflame probe
Bcold water inlet
Cbar burners/burner tray
Figure 2.1 Cut-away view of the water heater
IMD-0133
a
c
d
e
f
g
h
j
k
l
m
r
o
u
x
B
z
C
i
b
n
p
q
v
s
t
w
y
A
1. The narrow opening in the orifices accelerates the gas flow. This causes a partial vacuum. The
effect of this partial vacuum is to draw the air into the flow (the Venturi effect).

The water heater’s heating cycle
Instruction manual DR-LA 13
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hot surface igniter zensures the ignition of the gas/air mixture. The flue gases
generated by this combustion are led through the flue tubes d. There are flue
baffles elocated in the flue tubes. These slow down the flue gas exhaust,
improving the heat transfer efficiency. The flue gases leave the water heater via
the draught diverter b. A radiation shield/condensation tray mis mounted under
the burner tray. This prevents overheating of the floor surface under the water
heater and serves as a collection tray for condensate.
The insulation layer hprevents heat loss. The inside of the hot water tank is
enamelled to protect against corrosion. The anodes cprovide additional
protection.
2.3 The water heater’s
heating cycle
The water heater is controlled by the burner control qand the control
thermostat tor frost thermostat w. The control thermostat and frost thermostat
both independently measure the water temperature (Twater). The water heater’s
heating cycle is activated as soon as Twater falls below the specified threshold
value (Tset). The value for Tset depends on the status chosen for the water
heater, see paragraph 6.2 Operating states. If the water heater is in the 'OFF
mode' (frost protection), then this value is determined by the frost thermostat
(threshold value = 20°C). If the water heater is in the 'ON mode', then the
threshold value is selectable via the control thermostat (40°C - 70°C).
As soon as Twater falls below Tset, the relevant thermostat (control or frost) will
close and the burner control will register a heat demand. The gas control nwill
open and the gas will mix with the air it draws in. This mixture is ignited by the
hot surface igniter zand the water becomes heated. A soon as Twater exceeds
Tset, the thermostat will open once more. The heat demand will cease and the
burner control will stop the heating cycle.
The thermostats have a certain margin both when closing and opening. We refer
to this margin as the hysteresis. The hysteresis cannot be adjusted.
2.4 Protection for the
water heater
The burner control monitors the water temperature by means of thermostats
and ensures a safe combustion. This is achieved by:
•theWater temperature protection;
•theCombustion products discharge safety device;
•theflame probe.
2.4.1 Water temperature protection
By means of the frost, high-limit and safety thermostats, the burner control
monitors three temperatures related to safety. Ta b le 2.1 explains the operation
of the thermostats with sensors.
Table 2.1 Temperature protection
Protection Description
Frost thermostat If the frost thermostat sensor ydetects a temperature of 20°C or lower, the
water heater’s heating cycle will start. See paragraph 2.3 The water heater’s
heating cycle.
High-limit thermostat If the high-limit thermostat sensor pdetects a temperature greater than 84°C,
the high-limit thermostat will open. The heat demand will be stopped and the
burner control will stop the heating cycle until the high-limit thermostat closes
again. At that moment, the burner control resets the water heater and the
heating cycle resumes. The high-limit safeguard serves to prevent
overheating and/or excessive formation of scale in the water heater.
Safety thermostat If the safety thermostat sensor odetects a temperature greater than 93°C, the
safety thermostat will open. The heat demand will be ended and the burner
control immediately stops the heating cycle. A lockout error will occur in the
burner control. This must be manually reset, before the water heater can be
put back into operation.

Functioning of the water heater
14 Instruction manual DR-LA
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2.4.2 Combustion products discharge safety device
The flue gases are channelled to the outside via the draught diverter band the
flue gas discharge a. To prevent the flue gases from flowing back into the boiler
room, the discharge ducting is monitored by a feature called the combustion
products discharge safety device. This uses a flue gas thermostat fwith flue
gas thermostat sensor gwhich are located in the draught diverter. Under
normal circumstances this sensor will register the ambient temperature.
However, if the chimney is not drawing sufficiently (for example, due to a
blockage in the chimney), the flue gases will flow back past the flue gas
thermostat sensor. The sensor will then detect an excessive temperature and
the flue gas thermostat will open. The heat demand will be ended and the burner
control immediately stops the heating cycle. The flue gas thermostat will also
lock out. This must be manually reset, before the water heater can be put back
into operation.
2.4.3 flame probe
To ensure that no gas can flow when there is no combustion, an flame probe A
has been fitted. The burner control uses this rod for flame detection, by means
of ionisation sensing. The burner control closes the gas valve as soon it detects
that gas is flowing and there is no flame.
2.5 Safety of the instal-
lation
2.5.1 Unvented installation
With an unvented installation, an expension valve and expansion vessel prevent
excessive pressure in the water heather. This prevents damage of the water
heater. A non-return valve prevents excessive pressure in the water supply
system. This valve also prevents water from flowing backwards from the heater
into the cold water supply system. The pressure reducing regulates the water
supply pressure to a normal operating pressure of 3.5 bar. The components are
fitted to the cold water pipe. See paragraph 3.6.1 Cold water side.
2.5.2 Vented installation
With a vented installation, excess pressure is taken up by the open water tank.
The level of the water determines the working pressure which may not exceed
8 bar.The installation must also be fitted with an open vent from the hot water
pipe. Ideally the vent pipe should be linked to a separate tundish/drain or else
to the cold water storage tank. A safety valve should also be fitted to the water
heather. See paragraph 3.6.3 Hot water side.
2.5.3 Temparature and Pressure valve (T&P valve)
A T&P valve is mandatory in an 'unvented' installation.
A T&P valve monitors the water pressure in the water heater and the water
temperature at the top of it. If the pressure in the water heater becomes
excessive (> 7 bar) or the water temperature is too high (>97°C), the valve will
open. The hot water will immediately flow out of the heater. Because the water
heater is under water supply pressure, cold water will automatically flow into it.
The valve remains open until the unsafe situation has been averted. A
connecting point for a T&P valve is standard on the water heater. See paragraph
3.6.3 Hot water side.
2.6 Indicators and
Alarms
2.6.1 Volt Free Contacts
Volt free contacts are supplied as standard to give remote indication/alarm of
'normal run' and 'lockout'. The 'lockout' indication includes shut down due to
operation of the safety thermostat, loss of flame and failure to ignite.

Options
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2.7 Options The heaters can be supplied with the following additional variations, either
ready fitted or for site fitting:
2.7.1 LPG
The heaters can be supplied adjusted for use on propane or butane, see section
3.12. It is most important that the heater is correctly adjusted for the gas to be
fired.
2.7.2 Unvented Supply
The heaters can be supplied with a purpose designed and sized unvented kit
comprising pressure reducing valve, non-return valve, expansion vessel,
expansion relief valve and pressure/temperature relief valve, to enable the
heater to be coupled directly to the mains water. For details see 2.5.1, 2.5.3 and
3.6.
2.7.3 Top to Bottom Circulation
In order to give enhanced temperature control to aid compliance with the HSE
guidance and the DHss Code of Practice for 'The Control of Legionellae in
Health Care Premises', a pump circulation kit can be supplied comprising 230
volt single phase pump, non-return valve, pipe work and sufficient fittings to
contact between the hot water flow and the bottom connection. For details see
section 3.5 of this manual.

Functioning of the water heater
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Introduction
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3 Installation
Warning
The installation should be carried out by an approved installation engineer
in compliance with the general and local regulations imposed by the gas,
water and power supply companies and the fire service.
The water heater may only be installed in a room which complies with the
requirements stated in national and local ventilation regulations.
Refer also to paragraph 1.3 Regulations and documents.
3.1 Introduction This chapter describes the installation activities to be carried out before the
water heater may be started up, namely:
•Packaging;
•Environmental conditions;
•Technical specifications;
•Water connections, Unvented;
•Water connections, Vented;
•Gas connection;
•Flue gas discharge;
•Electrical connection;
•Checking the supply pressure and burner pressure;
•Conversion to a different gas category.
nCaution
Starting up the water heater is described in chapter 7 Starting up and
shutting down.
3.2 Packaging To avoid damaging the water heater, remove the packaging carefully. We
recommend unpacking the water heater at or near its intended location.
cNote
The water heater may only be manoeuvred in an upright position. Take care
that the water heater is not damaged after unpacking.
3.3 Environmental
conditions cNote
The water heater may not be used in rooms where chemical substances are
stored or used due to the risk of explosion and corrosion to the water heater.
Some propellants, bleaching agents, degreasing agents etc. disperse
vapours which are explosive and/or which cause accelerated corrosion. If
the water heater is used in a room in which such substances are present,
the warranty will be void.
DR-LA water heaters are open water heaters and may only be placed in an
open boiler room. They fall under category B11BS.
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Installation
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3.3.1 Humidity and ambient temperature
The boiler room must be frost-free or be protected against frost. Tab l e 3.1
shows the environmental conditions that must be adhered to, for correct
functioning of the electronics present in the water heater to be guaranteed.
3.3.2 Maximum floor loading
In connection with the water heater’s weight, take account of the maximum floor
loading, see Table 3 . 2.
3.3.3 Working clearances
For access to the water heater it is recommended that the following
clearances are observed (see Figure 3.2):
• AA: around the water heater’s control column and cleaning openings:
100 cm.
• BB: around the water heater itself: 50 cm.
• Above the water heater (room to replace the anodes):
- 100 cm if using fixed anodes or
- 50 cm if using flexible anodes.
Table 3.1 Humidity and ambient temperature specifications
Humidity and ambient temperature
Humidity max. 93% RH at +25°C
Ambient temperature Functional: 0 ≤t ≤60°C
Table 3.2 Weight specifications related to maximum floor loading
Weight of the water heater filled with water
DR-LA 30 DR-LA 40 DR-LA 45 DR-LA 60 DR-LA 75 DR-LA 95 DR-LA 110
538 kg 611 kg 539 kg 613 kg 553 kg 543 kg 594 kg

Environmental conditions
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If the available clearance is less than 100 cm, flexible magnesium anodes
may be ordered from Hamworthy, the installation engineer / supplier.
nCaution
When installing the water heater, be aware that any leakage from the it and/
or connections can cause damage to the immediate environment or floors
below the level of the boiler room. If this is the case, then the water heater
should be installed above a wastewater drain or in a suitable metal leak tray.
The leak tray must have an appropriate wastewater drain and must be at
least 5 cm deep with a length and width at least 5 cm greater than the
diameter of the water heater.
Figure 3.1 Working clearances
IMD-0135a

Installation
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3.4 Technical specifica-
tions
The water heater is supplied without accessories. Check the dimensions and
other specifications for the accessories to be used, based on Figure 3.2 and
Tabel 3.5.
Figure 3.2 Plan and elevation of the water heater
10”
37” 45”
E
F
A
D
H
G
B
M
R
K
P
S
N
J
6
1
3
4
6
2
5
IMD-0135