DORCHESTER DR-RS Series User guide

Dorchester DR-RS Range
of Hot Water Storage Heaters
Room Sealed, Direct Gas Fired Hot Water Storage
Heaters with Automatic Ignition
for Domestic Hot Water Installations
Installation, Commissioning
and Servicing Instructions
DORCHESTER DR-RS 25, 40, 65, 85, 105 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+ (DR-RS 105 I3P). 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. 500001138
ISSUE ‘A’
OCTOBER 2013
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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 - - - - - - - - - - - - - - - - - 14
2.4.2 flame probe - - - - - - - - - - - - - - - - - - - - - - - - - - 14
2.4.3 Pressure switch - - - - - - - - - - - - - - - - - - - - - - - - 14
2.5 Safety of the installation - - - - - - - - - - - - - - - - - - - - - - - - - 15
2.5.1 Unvented installation - - - - - - - - - - - - - - - - - - - - - 15
2.5.2 Vented installation- - - - - - - - - - - - - - - - - - - - - - - 15
2.5.3 Temparature and Pressure valve (T&P valve) - - - - - - - - - 15
2.6 Indicators and Alarms - - - - - - - - - - - - - - - - - - - - - - - - - - 15
2.6.1 Volt Free Contacts - - - - - - - - - - - - - - - - - - - - - - 15
2.7 Options - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 15
2.7.1 LPG- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 15
2.7.2 Unvented Supply - - - - - - - - - - - - - - - - - - - - - - - 15
2.7.3 Top to Bottom Circulation - - - - - - - - - - - - - - - - - - - 16
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 - - - - - - - - - - - - - - - - - - - - - - - - - - - 23
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
3.6.6 Condensation drainage - - - - - - - - - - - - - - - - - - - - 26
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
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4Instruction manual DR-RS
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3.8 Gas connection - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 27
3.9 Air supply and flue gas discharge - - - - - - - - - - - - - - - - - - - - - 27
3.9.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 27
3.9.2 Fitting flue gas discharge and air supply for DR-RS 25, 40, 65 - - 27
3.9.3 Fitting flue gas discharge and air supply for DR-RS 85 and 105 - 30
3.10 Electrical connections - - - - - - - - - - - - - - - - - - - - - - - - - - - 33
3.10.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 33
3.10.2 Preparation- - - - - - - - - - - - - - - - - - - - - - - - - - - 33
3.10.3 Mains - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 34
3.11 Checking the supply pressure and burner pressure - - - - - - - - - - - - 35
3.12 Conversion to a different gas category - - - - - - - - - - - - - - - - - - - 39
3.12.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 39
3.12.2 Conversion - - - - - - - - - - - - - - - - - - - - - - - - - - - 39
3.12.3 Replacing orifices - - - - - - - - - - - - - - - - - - - - - - 40
3.12.4 Replacing burner pressure regulator or flat plate
(DR-RS 25-40-65-85)- - - - - - - - - - - - - - - - - - - - - - 42
4 Filling and draining - - - - - - - - - - - - - - - - - - - - - - - 43
4.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 43
4.2 Filling the water heater - - - - - - - - - - - - - - - - - - - - - - - - - - 44
4.2.1 Filling unvented installations - - - - - - - - - - - - - - - - - - 44
4.2.2 Filling vented installations- - - - - - - - - - - - - - - - - - - - 45
4.3 Draining the water heater - - - - - - - - - - - - - - - - - - - - - - - - - 45
4.3.1 Draining unvented installations - - - - - - - - - - - - - - - - - 45
4.3.2 Draining vented installations - - - - - - - - - - - - - - - - - - 45
5 Controls- - - - - - - - - - - - - - - - - - - - - - - - - - - - - 47
5.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 47
5.2 Control panel - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 47
5.3 Explanation of the symbols - - - - - - - - - - - - - - - - - - - - - - - - 48
5.4 ON/OFF switch - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 48
5.5 Control thermostat - - - - - - - - - - - - - - - - - - - - - - - - - - - - 48
5.6 Burner control reset button - - - - - - - - - - - - - - - - - - - - - - - - 48
6 Status of the water heater - - - - - - - - - - - - - - - - - - - 49
6.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 49
6.2 Operating modes - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 49
6.3 Error conditions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 49
7 Starting up and shutting down - - - - - - - - - - - - - - - - - 51
7.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 51
7.2 Starting up - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 51
7.3 Shutting down- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 51
7.3.1 Shut the water heater down for a brief period (’OFF mode’) - - - 51
7.3.2 Isolate the water heater from the power supply - - - - - - - - - 51
7.3.3 Shut the water heater down for a longer period - - - - - - - - - 51
7.4 The water heater’s heating cycle - - - - - - - - - - - - - - - - - - - - - 52
8 Troubleshooting - - - - - - - - - - - - - - - - - - - - - - - - 53
8.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 53
8.2 Troubleshooting table for general errors - - - - - - - - - - - - - - - - - - 54
8.3 Troubleshooting table ’insufficient hot water’ - - - - - - - - - - - - - - - - 55
8.4 Troubleshooting table ’no hot water’ - - - - - - - - - - - - - - - - - - - - 56

Instruction manual DR-RS 5
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9 Maintenance - - - - - - - - - - - - - - - - - - - - - - - - - - 59
9.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 59
9.2 Preparing for maintenance - - - - - - - - - - - - - - - - - - - - - - - - 59
9.3 Water-side maintenance - - - - - - - - - - - - - - - - - - - - - - - - - 60
9.3.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 60
9.3.2 Checking the anodes - - - - - - - - - - - - - - - - - - - - - 60
9.3.3 Descaling and cleaning the heater - - - - - - - - - - - - - - - 60
9.4 Gas-side maintenance - - - - - - - - - - - - - - - - - - - - - - - - - - 61
9.4.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 61
9.4.2 Cleaning the burners - - - - - - - - - - - - - - - - - - - - - 61
9.4.3 Cleaning the orifices- - - - - - - - - - - - - - - - - - - - - - 62
9.4.4 Checking the flue baffles - - - - - - - - - - - - - - - - - - - 62
9.5 Finalising maintenance- - - - - - - - - - - - - - - - - - - - - - - - - - 62
A Electrical diagram DR-RS - - - - - - - - - - - - - - - - - - - 63

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Instruction manual DR-RS 7
1 Introduction
1.1 About the water
heater
This manual describes how to install, service and use the DR-RS water heater.
A DR-RS water heater is a gas-fired closed water heater with a fan in the air
supply. Depending on the water heater type, the chimney connections are
parallel or concentric. Installation types possible with this water heater are C13
and C33. The information in this manual is applicable to water heater types: DR-
RS 25, DR-RS 40, DR-RS 65, DR-RS 85 and DR-RS 105.
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 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 your installer.
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-RS
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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;
•installers;
• 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
iInstaller
sService and maintenance engineer

Maintenance
Instruction manual DR-RS 9
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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.
nRemark
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.
nRemark
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.
nRemark
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:
nRemark
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-RS
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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. Instructions are
also provided for the installation and/or service and
maintenance engineer on converting the water heater to other
types of gas.
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 the status (mode or condition) that the
water heater may have and possible actions to take.
7 Starting up and shutting
down gisgis 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 installer and the service
and maintenance engineer. It describes water heater errors.
These errors are indicated on the display. A troubleshooting
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.
nRemark
If the water heater is not regularly maintained, the warranty
will become void.