DORCHESTER DR-RS Series, DR-RS 25, DR-RS 40, DR-RS 105, DR-RS 65 Installation, Commissioning And Servicing Instructions

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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 (2 LPG (3 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

FAMILY) I3+ (DR-RS 105 I3P). PLEASE ENSURE RELEVANT INFORMATION

FAMILY) I2H OR

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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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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

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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

Instruction manual DR-RS 5

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6 Instruction manual DR-RS

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1 Introduction

1.1 About the water heater

0063

1.2 What to do if you smell gas

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 C and C33. The information in this manual is applicable to water heater types: DRRS 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.

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!

1.3 Regulations and documents

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.

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:

Instruction manual DR-RS 7

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Introduction

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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

(End) user

Installer

Service and maintenance engineer

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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.

n Remark

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.

n Remark

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.

n Remark

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:

n Remark

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.

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Introduction

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1.7 Overview of this document

Table 1. 2 Contents of document

Chapter Target groups Description

2 Functioning of the water heater

3Installation

4 Filling and draining

Table 1.2 provides an overview of the contents of this document.

This chapter describes how the water heater functions.

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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.

This chapter describes how to fill and drain the water heater.

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5 Controls

6 Status of the water heater

7 Starting up and shutting down

8 Troubleshooting

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This chapter describes the water heater’s control panel and how to use it.

This chapter describes the status (mode or condition) that the water heater may have and possible actions to take.

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.

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

This chapter sets out the maintenance tasks to be carried out during a service.

n Remark

If the water heater is not regularly maintained, the warranty will become void.

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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

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2.2 Functional description of the water heater

Figure 2.1 shows a cut-away view of the water heater.

IMD-0240

Legend:

(1) flue gas discharge

(2) air supply

(3) fan

(4) top box

(5) anodes

(6) flue tubes

(7) flue baffles

(8) hot water tank

(9) insulation layer

12 Instruction manual DR-RS

(10) air restrictor

(11) cleaning opening

(12) cold water inlet

(13) drain valve

(14) combustion chamber with air

distribution plate

(15) bar burners/burner tray

(16) hot water outlet

(17) control thermostat

(18) air pressure switch

(19) high-limit thermostat

Figure 2.1 Cut-away view of the water heater

(20) high-limit thermostat sensor

(21) safety thermostat

(22) safety thermostat sensor

(23) frost thermostat

(24) burner control

(25) frost thermostat sensor

(26) control thermostat sensor

(27) flame probe

(28) pilot burner

(29) spark igniter

(30) gas control

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The water heater’s heating cycle

In this water heater, the cold water enters the bottom of the it via the cold water inlet (12). The heat of combustion is transferred to the water through the combustion chamber (14) and flue tubes (6). The heated tap water leaves the heater via the hot water outlet (16). 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 air required for combustion is forcibly delivered to the combustion chamber

by the fan. The gas required for combustion flows into the manifold via the gas control (30). The DR-RS 105 has a different gas control (see box). There are orifices in the manifold. The gas enters the bar burners (15) via these orifices. The bar burners together form the burner tray. As the gas is injected into the bar burners, the primary air required for combustion is also drawn in from the combustion chamber steps. The pilot flame is first ignited by a spark igniter. This pilot flame then ensures the complete ignition.

The flue gases generated by this combustion are led through the flue tubes (6). There are flue baffles (7) fitted inside the flue tubes. These slow down the flue gas exhaust, improving the heat transfer efficiency. The flue gases leave the water heater via the top box (4). A different top box is used on the DR-RS 85 and 105 (see box). Below the burner tray there is an air distribution plate (14), that also serves as a radiation shield. When condensation forms, the water runs off to the siphon via the air distribution plate.

The insulation layer (9) prevents heat loss. The inside of the hot water tank is enamelled to protect against corrosion. The anodes (5) provide additional protection.

(1)

. The ignition of the gas/air mixture takes place in two

2.3 The water heater’s

heating cycle

2.4 Protection for the

water heater

The water heater is controlled by the burner control (24) and the control thermostat (17) or frost thermostat (23). The control thermostat and frost thermostat both independently measure the water temperature (T water heater’s heating cycle is activated as soon as T specified threshold value (T for the water heater, see paragraph 6.2 Operating modes. 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 T close and the burner control will register a heat demand. The gas control (30) will open and the gas will mix with the air it draws in. This mixture is ignited by the spark igniter (29) and the water becomes heated. A soon as T

, the thermostat will open once more. The heat demand will cease and the

set

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.

The burner control monitors the water temperature by means of thermostats and ensures a safe combustion. This is achieved by:

•the Water temperature protection;

•the flame probe;

•the Pressure switch.

falls below T

water

). The value for T

set

, the relevant thermostat (control or frost) will

set

depends on the status chosen

set

falls below the

water

). The

exceeds

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).

Instruction manual DR-RS 13

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2.4.1 Water temperature protection

Table 2. 1 Temperature protection

Protection Description

Functioning of the water heater

By means of the frost, high-limit and safety thermostats, the burner control monitors three temperatures related to safety. Table 2.1 explains the operation of the thermostats with sensors.

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Frost thermostat If the frost thermostat sensor (25) detects a temperature of 20°C or lower, the

High-limit thermostat If the high-limit thermostat sensor (20) detects a temperature greater than

Safety thermostat If the safety thermostat sensor (22) detects a temperature greater than 93°C,

2.4.2 flame probe

2.4.3 Pressure switch

water heater’s heating cycle will start. See paragraph 2.3 The water heater’s

heating cycle.

84°C, the high-limit thermostat will open. The heat demand will cease 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.

the safety thermostat will open. The heat demand will cease and the burner control will immediately stop the heating cycle. A lockout error of the burner control takes place. This must be manually reset, before the water heater can be put back into operation.

To ensure that no gas can flow when there is no combustion, an flame probe (27) has been fitted. The burner control uses this rod for flame detection, by means of ionisation detection. The burner control cuts in immediately, as soon as it detects that gas is flowing, but there is no flame.

The pressure switch guarantees the discharge of the flue gases and the supply of air. The default position of the pressure switch is open. If there is sufficient pressure difference across the air restrictor (10), the air pressure switch (18) will close. However, in the event of a fault, the pressure switch will be tripped open and the heating cycle will be interrupted.

Table 2.2 shows the trip point per water heater.

Table 2. 2 Pressure switch trip points

Appliance Pressure differential [Pa]

Closing Opening

DR-RS 25 > 200 < 170

DR-RS 40 > 270 < 240

DR-RS 65 > 255 < 225

DR-RS 85 > 610 < 580

DR-RS 105 > 220 < 190

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2.5 Safety of the installation

2.5.1 Unvented installation

2.5.2 Vented installation

2.5.3 Temparature and Pressure valve (T&P valve)

Safety of the 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.

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.

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.

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.

Instruction manual DR-RS 15

Page 16

Functioning of the water heater

gis

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.

16 Instruction manual DR-RS

Page 17

3 Installation

Warning

The installation should be carried out by an approved installer 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;

• Air supply and flue gas discharge;

• Electrical connections;

• Checking the supply pressure and burner pressure;

• Conversion to a different gas category.

n Remark

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

The DR-RS water heater is a room-sealed water heater. Installation types possible with this water heater are C13 and C33. This makes it possible to install the water heater in either a closed or an open boiler room.

Instruction manual DR-RS 17

Page 18

Installation

3.3.1 Humidity and ambient temperature

The boiler room must be frost-free or be protected against frost. Ta bl 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.

Table 3. 1 Humidity and ambient temperature specifications

Humidity and

Humidity max. 90% RH at +40°C

Ambient temperature Functional: 0 ≤ t ≤ 60°C

3.3.2 Maximum floor loading

In connection with the water heater’s weight, take account of the maximum floor loading, see Tab le 3 . 2.

Table 3. 2 Weight specifications related to maximum floor loading

Weight of the water heater filled with water

DR-RS 25 DR-RS 40 DR-RS 65 DR-RS 85 DR-RS 105

554 kg 557 kg 560 kg 585 kg 585 kg

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.

ambient temperature

18 Instruction manual DR-RS

Page 19

Environmental conditions

If the available clearance is less than 100 cm, flexible magnesium anodes may be ordered from Hamworthy, the installer / supplier.

n Remark

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

Instruction manual DR-RS 19

Page 20

Installation

3.4 Technical specifications

DR-RS 25, 40, 65

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

Table 3.3.

DR-RS 85, 105

IMD-0057

Figure 3.2 Plan and elevation of the water heater

20 Instruction manual DR-RS

Page 21

Technical specifications

Tab le 3.3 Dimensions

Description Unit DR-RS 25 DR-RS 40 DR-RS 65 DR-RS 85 DR-RS

men sion

A Total height mm 2000 2000 2020 2020 2020

105

B Height water heater top

mm 1800 1800 1820 1820 1820

surface

D Appliance diameter mm 710 710 710 710 710

E Depth mm 1000 1000 1000 1000 1000

F Width mm 755 755 755 755 755

G Diameter of flue gas discharge mm 80/125 100/150 130/200 2x 130 2x 130

K Height of gas connection mm 600 600 600 600 760

M Height of cold water supply mm 600 600 590 590 590

N Height of hot water outlet mm 1640 1640 1655 1655 1655

P Height of cleaning opening mm 770 770 760 760 760

R Height of drain valve

mm 550 550 540 540 540

connection

S Height of T&P valve

mm 1600 1600 1600 1600 1600

connection

1 Cold water supply connection

-R1

(external thread)

2 Hot water outlet connection

-Rp1

(internal thread)

3 Gas control connection

-Rp

(internal thread)

4 Drain valve connection

-Rp1

(internal thread)

5 T&P valve connection (internal

thread)

6 Cleaning/inspection openings mm

R11/

Rp11/

Rp 3/

Rp11/

R11/

Rp11/

Rp 3/

Rp11/

R11/

Rp11/

Rp 3/

Rp11/

R11/

Rp11/

Rp1

Rp11/

1" NPT

Ø 100 Ø 100 Ø 100 Ø 100 Ø 100

Tab le 3.4 General and electrical specifications

DESCRIPTION Unit DR-RS

DR-RS 40

DR-RS 65

DR-RS 85

DR-RS 105

Storage capacity litres 324 312 265 265 265

Maximum operating pressure bar 8 8 8 8 8

Maximum operating pressure

bar 5.5 5.5 5.5 5.5 5.5

unvented

Nomimnal operating pressure

bar 3.5 3.5 3.5 3.5 3.5

unvented

Empty weight kg 265 275 340 350 350

Heating time ∆T = 45

minutes 35 25 12 9 8

Number of anodes - 2 2 4 4 4

Instruction manual DR-RS 21

Page 22

Table 3. 4 General and electrical specifications (Continued)

Installation

DESCRIPTION Unit DR-RS

Number of bar burners/orifices - 3 5 7 7 7

Number of flue tubes/flue baffles - 5 7 16 16 16

Diameter of air restrictor mm 36 42 54 48 64

Electrical power consumption W 100 100 100 275 300

Supply voltage VAC 230 (-15% +10%)

Mains frequency Hz 50

DR-RS 40

DR-RS 65

DR-RS 85

DR-RS 105

Table 3. 5 Gas data

Gas category data Unit DR-RS

Gas categories: DR-RS 25, 40, 65, 85: II

Specifications for natural gas: G20 - 20 mbar

Orifice diameter mm 2.60 2.50 2.70 3.20 3.30

Diameter of pilot flame orifice mm 0.56 / 0.41 0.56 / 0.41 0.56 / 0.41 0.56 / 0.41 0.56 / 0.41

(1) = Flat plate (2) = Burner pressure regulator

1 or 2 2 2 2 2 2

DR-RS 105: II

2H3+

2H3P

DR-RS 40

DR-RS 65

DR-RS 85

DR-RS 105

Nominal heat input (gross) kW 31.6 51.2 81.6 111.1 125.2

Nominal output kW 25.9 41.5 66.2 89.0 100.3

Supply pressure mbar 20 20 20 20 20

Burner pressure mbar 12.5 12.9 12.9 12.5 14.0

Gas consumption

Specifications for LP gas

General

Orifice diameter mm 1.45 1.40 1.50 1.95 2.30

Diameter of pilot flame orifice mm 0.25 0.25 0.25 0.25 0.25

(1) = Flat plate (2) = Burner pressure regulator

G30-30 mbar (butane)

Nominal heat input (gross) kW 30.9 48.9 79.7 108.4 N.A.

Nominal output kW 25.9 40.6 66.2 89.0

Supply pressure mbar 30 30 30 30

Burner pressure

Gas consumption

(1)

(2)

(1)

m3/h 3.1 5.0 7.9 10.8 12.2

1 or 2 1 1 1 1 2

mbar----

kg/h 2.3 3.6 5.9 8.0

1. Based on 1013.25 mbar and 15 °C.

2. If using a blank plate instead of a burner pressure regulator, it is assumed that the burner pressure is equal to the supply pressure. In practice however, the burner pressure will be lower.

22 Instruction manual DR-RS

Page 23

Table 3.5 Gas data

Installation diagram

Gas category data Unit DR-RS

G31 - 37 mbar (propane)(butane)

Nominal heat input (gross) kW 29.9 47.0 75.7 108.7 122.5

Nominal output kW 25.0 38.9 62.6 89.0 100.3

Supply pressure mbar 37 37 37 37 37

Burner pressure

Gas consumption

1. Based on 1013.25 mbar and 15 °C.

2. If using a blank plate instead of a burner pressure regulator, it is assumed that the burner pressure is equal to the supply pressure. In practice however, the burner pressure will be lower.

(2)

(1)

mbar - - - - 22.0

kg/h 2.2 3.4 5.5 7.9 8.9

DR-RS 40

DR-RS 65

DR-RS 85

DR-RS 105

3.5 Installation diagram Figure 3.3 shows the water and gas connection diagrams for unvented and

vented installations. The following paragraphs, describing the connections in detail, make reference to these diagrams

Instruction manual DR-RS 23

Page 24

Legend

a pressure-reducing valve

(mandatory whenever the mains water pressure exceeds 8 bar)

b expansion vessel (mandatory)

c T&P valve (mandatory)

ca) safety valve

d stop valve (recommended)

e non-return valve (mandatory)

ea) non-return valve

f circulation pump (optional)

g drain valve

h gas valve (mandatory)

i stop valve (mandatory)

j temperature gauge

(recommended)

k top to bottom recirculation

pump (optional)

l top box

m hot water draw-off points

n condensation drainage

o expension valve (mandatory)

p water tank

q float valve

r 3-way venting valve ()

s overflow pipe

a cold water supply

b hot water outlet

c circulation pipe

d gas supply

e flue gas discharge

Installation

UNVENTED

d f e d

VENTED

d k e d

eia

IMD-0066

dfed

IMD-0065

Figure 3.3 Installation diagrams

24 Instruction manual DR-RS

Page 25

3.6 Water connections, Unvented

3.6.1 Cold water side

3.6.2 Top to bottom recirculating pump

Water connections, Unvented

See a in Figure 3.3.

1. Fit an approved stop valve i on the cold water side as required by regulations. Refer also to paragraph 1.3 Regulations and documents.

2. Fit an approved pressure-reducing valve a.

3. Fit a non-return valve e and an expansion vessel b.

4. Fit an expension valve o and connect the discharge to a drain via tundish.

You can connect a top to bottom recirculation pump to prevent stratification of the water in the water heater.

1. Fit a pipe (Ø 22 mm), a stop valve d and a top to bottom recirculation pump k.

2. Fit non-return valve e.

3. Fit stop valves i.

3.6.3 Hot water side

See b in Figure 3.3.

n Remark

Insulating long hot water pipes prevents unnecessary energy loss.

1. Optional: Fit a temperature gauge j to be able to check the temperature of the tap water.

2. Fit the T&P valve c.

3. Fit a stop valve i in the hot water outlet pipe, for use when servicing.

3.6.4 Drain valve

1. Fit the standard drain valve supplied g.

2. If a circulation pipe is to be fitted, then refer to paragraph 3.6.5. Otherwise, fit the sealing nut and gasket supplied with the drain valve. See Figure 3.4.

3.6.5 Circulation pipe

See c in Figure 3.3 and Figure 3.4.

If an immediate flow of hot water is required at draw-off points, a circulation pump can be installed. This improves comfort and reduces water wastage.

1. Fit a circulation pump f of the correct capacity for the length and resistance of the circulation system.

2. Fit a non-return valve e behind the circulation pump to guarantee the direction of circulation.

3. Fit two stop valves d for service purposes.

4. Connect the circulation pipe to the T-piece on the drain valve g. See

Figure 3.4.

IMD-0122

Figure 3.4 Drain valve

Instruction manual DR-RS 25

Page 26

3.6.6 Condensation drainage

3.7 Water connections, Vented

3.7.1 Cold water side

3.7.2 Top to bottom recirculating pump

Installation

Fit a small drainpipe with fall to the appropriate connection for condensation drainage at the rear of the water heater and connect this further to the water drainage pipe.

cNote

All piping behind the siphon must be condensation-resistant.

See a in Figure 3.3.

1. Fit an approved stop valve i on the cold water side between the water tank p and the water heater, as required by regulations. Refer also to paragraph 1.3 Regulations and documents.

You can connect a top to bottom recirculation pump to prevent stratification of the water in the water heater.

1. Fit a pipe (Ø 22 mm), a stop valve d and a top to bottom recirculation pump k.

2. Fit non-return valve e .

3. Fit stop valves i.

3.7.3 Hot water side

See b in Figure 3.3.

n Remark

Insulating long hot water pipes prevents unnecessary energy loss.

1. Fit the safety valve ca.

2. Optional: fit a temperature gauge j to be able to check the temperature of the tap water.

3. Fit a stop valve i in the hot water outlet pipe, for use when servicing.

4. If a circulation pipe is to be fitted, then refer to paragraph 3.7.4.

3.7.4 Circulation pipe

See c in Figure 3.3.

If an immediate flow of hot water is required at draw-off points, a circulation pump can be installed. This improves comfort and reduces water wastage.

1. Fit a circulation pump f of the correct capacity for the length and resistance of the circulation system.

2. Fit a non-return valve ea downstream the circulation pump to guarantee the direction of circulation.

3. Fit two stop valves d for service purposes.

4. Connect the circulation pipe to the T-piece on the drain valve g. See

Figure 3.4.

26 Instruction manual DR-RS

Page 27

3.8 Gas connection

Gas connection

Warning

Gas installation may only be carried out by an authorised installer in compliance with the general regulations imposed by the gas company. Refer also to paragraph 1.3 Regulations and documents.

cNote

Make sure that the diameter and length of the gas supply pipe are large enough to supply sufficient capacity to the water heater.

See d in Figure 3.3.

1. Fit a gas valve h in the gas supply pipe.

2. Blow the gas pipe through before use, to be sure it is clean.

3. Close the gas valve.

4. Fit the gas supply pipe to the gas control.

Warning

Check for leaks after fitting.

3.9 Air supply and flue gas discharge

3.9.1 Introduction

3.9.2 Fitting flue gas discharge and air supply for DR-RS 25, 40, 65

Warning

The installation should be carried out by an authorised installer, in compliance with the general and local regulations imposed by gas, water supply and power supply companies and the fire service. Refer also to paragraph 1.3 Regulations and documents.

The connections for the air supply and the flue gas discharge of the DR-RS 25, 40 and 65 differ from those of the DR-RS 85 and 105.

The DR-RS water heaters are approved for installation types C13 and C33.

This manual describes these installation types. If an explanation of other types of installation is required, please contact Hamworthy.

cNote

Hamworthy prescribes the use of a roof or wall-mounted concentric terminal, of a type approved for the water heater.

The following requirements must be fulfilled:

• The maximum chimney length allowed (A+B+C) is 7 metres.

• The maximum number of 45° or 90° bends allowed is 2.

• If you make use of horizontal piping, then this must slope towards the water heater with a minimum of 5 mm per metre running length!

• Make sure that the chimney discharges into an area where this is permitted for this category of water heater.

See Figure 3.5 Wall flue terminal and Figure 3.6 Roof flue terminal for example installations.

Instruction manual DR-RS 27

Page 28

Installation

3.9.2.1 Concentric wall flue terminal DR-RS 25, 40,65

Table 3.6 shows the wall flue terminal prescribed by Hamworthy (installation

type C13).

Figure 3.5 Wall flue terminal

Table 3. 6 Concentric wall flue terminal specifications

Item Description

Wall flue terminal

Tube material Construction Concentric

Tube diameters Flue gas discharge DR-RS 25:Ø80 mm

1. No other wall flue terminal is permitted. The wall flue terminal set can be ordered using this article number from Hamworthy, the manufacturer or from a trade supplier

(1)

Part No. DR-RS 25: 562702039

DR-RS 40: 562702040 DR-RS 65: 562702041

Construction Concentric

Flue gas discharge Thick-walled aluminium with lipped sealing ring

Air supply Thin-walled galvanised sheet steel

DR-RS 40: Ø100 mm DR-RS 65: Ø130 mm

Air supply DR-RS 25: Ø125 mm

DR-RS 40: Ø150 mm DR-RS 65: Ø200 mm

IMD-0060

28 Instruction manual DR-RS

Page 29

Air supply and flue gas discharge

3.9.2.2 Concentric roof flue terminal for DR-RS 25, 40, 65

Hamworthy heating limited prescribes the roof flue terminal (installation type C33) as specified in Tab l e 3. 7 .

Figure 3.6 Roof flue terminal

Tab le 3.7 Concentric roof flue terminal specifications

Item Description

Roof flue terminal

Tube material Construction Concentric

Tube diameters Flue gas discharge DR-RS 25:Ø80 mm

1. No other roof flue terminal is permitted. The roof flue terminal set can be ordered using this article number from Hamworthy, the manufacturer or from a trade supplier

(1)

Part No. DR-RS 25: 562702043

DR-RS 40: 562702044 DR-RS 65: 562702045

Construction Concentric

Flue gas discharge Thick-walled aluminium with lipped sealing ring

Air supply Thin-walled galvanised sheet steel

DR-RS 40: Ø100 mm DR-RS 65: Ø130 mm

Air supply DR-RS 25: Ø125 mm

DR-RS 40: Ø150 mm DR-RS 65: Ø200 mm

IMD-0061

Instruction manual DR-RS 29

Page 30

a air supply

b flue gas discharge

Installation

3.9.3 Fitting flue gas discharge and air supply for DR-RS 85 and 105

The air supply duct a and flue gas discharge duct b of the DR-RS 85 and 105 emerge separately from the top box, as shown in Figure 3.7. They must be connected to the concentric wall flue terminal (see Figure 3.8) or roof flue terminal (see Figure 3.9) via a transition piece.

Figure 3.7 Parallel connections on DR-RS 85 and 105

n Remark

Hamworthy prescribes the use of a roof or wall-mounted concentric terminal, of a type approved for the water heater. See paragraphs 3.9.3.1 Concentric

wall flue terminal for DR-RS 85 and 105 and 3.9.3.2 Concentric roof flue terminal for DR-RS 85 and 105. Use of an incorrect roof or wall-mounted

terminal can cause the installation to malfunction.

The following requirements must also be fulfilled:

• The maximum chimney length allowed (A+B+C) is 7 metres.

• The maximum number of 45° or 90° bends allowed is 2.

• If you make use of horizontal piping, then this must slope towards the water heater with a minimum of 5 mm per metre running length!

• The transition piece, to convert the air supply and flue gas discharge from parallel to concentric, must be placed immediately before the roof or wall flue terminal.

• The duct length of the air supply must be approximately the same as that of the flue gas discharge chimney.

• Make sure that the chimney discharges into an area where this is permitted for this category of water heater.

See Figure 3.8 Wall flue terminal and Figure 3.9 Roof flue terminal for example installations.

IMD-0252

30 Instruction manual DR-RS

Page 31

Air supply and flue gas discharge

3.9.3.1 Concentric wall flue terminal for DR-RS 85 and 105

Ta bl e 3 .8 shows the wall flue terminal prescribed by Hamworthy (installation

type C13).

IMD-0226

Figure 3.8 Wall flue terminal

Tab le 3.8 Specifications for transition piece and concentric wall flue terminal

Item Description

Wall flue terminal and transition

(1)

piece

Tube material Construction Parallel

Tube diameters Flue gas discharge Ø130 mm

1. No other wall flue terminal is permitted. The wall flue terminal set can be ordered using this article number from Hamworthy, the manufacturer or from a trade supplier

Part No. 562702042

Construction: Concentric

Flue gas discharge Thick-walled aluminium with lipped sealing ring

Air supply Thick-walled aluminium with lipped sealing ring

Air supply Ø130 mm

Instruction manual DR-RS 31

Page 32

Installation

3.9.3.2 Concentric roof flue terminal for DR-RS 85 and 105

Hamworthy heating limited prescribes the roof flue terminal (installation type C33) as specified in Table 3.9.

IMD-0239

Figure 3.9 Roof flue terminal

Table 3. 9 Specifications for transition piece and concentric roof flue terminal

Item Description

Roof flue terminal and transition piece

Tube material Construction Parallel

Tube diameters Flue gas discharge Ø130 mm

1. No other roof flue terminal is permitted. The roof flue terminal set can be ordered using this article number from Hamworthy, the manufacturer or from a trade supplier

32 Instruction manual DR-RS

(1)

Part No. 562702046

Construction Concentric

Flue gas discharge Thick-walled aluminium with lipped sealing ring

Air supply Thick-walled aluminium with lipped sealing ring

Air supply Ø130 mm

Page 33

3.10 Electrical connections

3.10.1 Introduction

3.10.2 Preparation

Electrical connections

Warning

The installation should be carried out by an approved installer in compliance with the general and local regulations imposed by the gas, water and power supply companies and the fire service. Refer also to paragraph 1.3 Regulations and documents.

Topics covered in this paragraph:

• 3.10.2 Preparation;

• 3.10.3 Mains;

Figure 3.10 shows a front view of the electrical connection block. Ta bl e 3. 1 0

shows the associated connections.

Tab le 3.10 Electrical connection block DR-RS

Mains power Volt Free contact

Lock out

123456789

Close Control

Thermostat

NO P NC NO P NC

Corex Anode

power

Time clock

Volt Free contact

power

Normal run

Time clock

connection

A LNLNLNLL

13 14 15 16 17 18 19 20 21

Instruction manual DR-RS 33

Page 34

Installation

Figure 3.10 Connection block (connections 1 through 10 explained in

Table 3.10)

In preparation, first remove the protective cover from the control column:

• Undo the 4 screws 1 and remove the protective cover 2 from the electrical section. The connection block 3 is now visible.

IMD-0362

n Remark

Refer to A Electrical diagram DR-RS for the connection of electrical components.

3.10.3 Mains

The water heater is supplied without a power cable and isolator.

n Remark

In order to receive electrical power, the water heater has to be connected to the mains by means of a permanent electrical connection. A double pole isolator with contacts gaps of at least 3 mm must be fitted local to the water heater. The power cable must have cores of at least 3 x 1.0 mm2.

1. Feed the power cable through the metric strain relief on the top of the control column.

2. Connect earth ( terminals 1 through 3 of the connection block as indicated in Table 3.10.

3. Tighten the strain relief so that the cable is clamped.

4. If you do not need to make any more connections, then fit the protective cover back on the control column.

A), phase (L

) and neutral (N) of the power cable to

34 Instruction manual DR-RS

Page 35

3.11 Checking the supply pressure and burner pressure

Checking the supply pressure and burner pressure

5. Connect the power cable to the isolator.

Warning

Leave the water heater disconnected until you are ready to start it up.

cNote

Before you start up the water heater and/or begin to check the supply pressure and burner pressure, you must first fill the water heater. Please refer to paragraph 4.2 Filling the water heater for filling instructions.

cNote

Before starting up for the first time and following conversion, you must always check the supply pressure and burner pressure. If necessary, adjust these to be certain of optimum performance of the water heater.

cNote

The easiest way to check the gas pressures is by using two pressure gauges. This procedure assumes that these two gauges are available.

Legend:

a burner pressure regulator

b burner pressure control cap

c burner pressure control

adjusting screw

d blank plate

e supply pressure test nipple

f gas control

g burner pressure test nipple

If the water heater must operate on a gas category other than that for which the water heater has been set up at the factory (see rating plate), the water heater will first have to be converted. See paragraph 3.12 Conversion to a different gas

category.

Gas control valve for DR-RS 25, 40, 65 and 85

IMD-0256

Figure 3.11 Gas control valve

Instruction manual DR-RS 35

Page 36

Installation

Gas control valve for DR-RS 105

Figure 3.11 Gas control valve(Continued)

To check the supply pressure and burner pressure, proceed as follows:

1. Disconnect the water heater from the power supply. See paragraph

7.3.2 Isolate the water heater from the power supply.

2. There are two test nipples on the gas control (Figure 3.11):

- supply pressure test nipple e;

- burner pressure test nipple g.

Sealing screws are located inside the test nipples. Loosen both sealing screws by a few turns. Do not loosen them completely; this makes them difficult to tighten again.

3. Connect a pressure gauge to burner pressure test nipple g.

IMD-0257

n Remark

All gas pipes should be vented and free of leakage.

4. Open the gas supply.

5. Connect a pressure gauge to test nipple e.

6. Switch on the power to the water heater using the isolator on the water heater.

7. Set the control thermostat to the highest position and start the water heater running by putting the On/Off switch to position I.

8. The heating cycle will start and the burner tray will ignite after a short time.

9. After the burner tray has ignited, wait for approximately 1 minute before you start reading the dynamic pressures.

10. Use the pressure gauge to read the supply pressure at the test nipple e. Refer to Table 3.5.

n Remark

Consult the mains gas supply company if the supply pressure is not correct.

36 Instruction manual DR-RS

Page 37

Checking the supply pressure and burner pressure

11. Use the pressure gauge to read the burner pressure at test nipple g. Refer to Ta bl e 3 .5 .

n Remark

If the burner pressure is not correct and the water heater is fitted with a blank plate, you will not be able to adjust the pressure. In this case, consult your installer or supplier. If the water heater is fitted with a burner pressure regulator, then the pressure can be adjusted by following steps 12 through 16.

12. DR-RS 25, 40, 65 or 85: Adjust the burner pressure by turning burner pressure control adjusting screw c, depending on the correction required:

- Adjusting screw anticlockwise: burner pressure decreases.

- Adjusting screw clockwise: burner pressure increases.

13. DR-RS 105 Adjust the burner pressure by turning burner pressure control adjusting screw c (Pg) using the supplied Allen key, depending on the correction required:

- Adjusting screw anticlockwise: burner pressure increases.

- Adjusting screw clockwise: burner pressure decreases.

Warning

Adjusting screw Ps regulates the starting pressure. This need never AND may never be adjusted!

14. Check the burner pressure against the value given in the table.

15. If the pressure setting is incorrect, then:

- For DR-RS 25, 40, 65 or 85 repeat steps 12 and 14 until the correct

pressure is achieved.

- For DR-RS 105 repeat steps 13 and 14 until the correct pressure is

achieved.

16. Shut down the water heater by putting the On/Off -switch to position 0.

17. Shut off the gas supply.

18. Disconnect the two pressure gauges and re-tighten the sealing screws in the test nipples.

Instruction manual DR-RS 37

Page 38

Installation

38 Instruction manual DR-RS

Page 39

3.12 Conversion to a different gas category

Conversion to a different gas category

3.12.1 Introduction

If the water heater must operate on a family of gas (LP gas or natural gas) or other gas category than that for which the water heater has been set up at the factory, the water heater will have to be adapted using a special conversion kit.

Warning

The conversion may only by carried out by an authorised installer.

Warning

After conversion, check the supply pressure and the burner pressure.

3.12.2 Conversion

1. Disconnect the water heater from the mains. See paragraph 7.3.2 Isolate

the water heater from the power supply.

2. Shut off the gas supply.

3. Referring to Ta b le 3 . 5, compare the present gas category with the target gas category and ascertain whether the diameter of the pilot flame orifice is different. If this is the case, then the pilot flame orifice must be replaced. See paragraph ’3.11.3 Replace orifice’.

4. Referring to Ta b le 3 . 5, compare the present gas category with the target gas category and ascertain whether the diameter of the main orifice is different. If this is the case, then the main orifices must be replaced. See paragraph

3.12.3 Replacing orifices.

5. Referring to Ta b le 3 . 5, compare the present gas category with the target gas category and ascertain whether there is a different use of a flat plate or burner pressure regulator. If this is the case, then these must be exchanged. See paragraph 3.12.4 Replacing burner pressure regulator or flat plate

(DR-RS 25-40-65-85).

6. Referring to Ta b le 3 . 5, compare the present gas category with the target gas category and make the appropriate adjustments. See paragraph

3.11 Checking the supply pressure and burner pressure.

n Remark

The present gas category is stated on the rating plate.

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3.12.3 Replacing orifices

Legend:

a strain relief

b lead for spark electrode

c lead for flame probe

d burner control

e gas control connector(s)

f gas control

g gas coupling

h burner tray

IMD-0254

Figure 3.12 Disassembled gas control

1. Detach the protective cap van the control column:

2. Remove the strain relief a and detach the leads of the spark electrode (b =

3. Unscrew the connector(s) e of the gas control f.

4. Detach the gas coupling g before the gas control.

5. Remove the ten screws holding the burner tray h in place.

6. Withdraw the burner tray from the water heater.

n Remark

Loosen the 4 screws and remove the protective cap by lifting it upwards. The electrical section will now be visible.

red) and the flame probe (c = black) from the burner control d.

When exchanging the pilot flame orifice and/of orifices: Lay the burner tray on its side and approach it from the underside.

40 Instruction manual DR-RS

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Legend:

spark electrode

b flame probe

c pilot flame orifice socket

d pilot flame orifice

e main orifice

Conversion to a different gas category

Figure 3.13 Gas control

IMD-0255

7. If Ta bl e 3 . 5 Ga s d a ta indicates that the pilot flame orifice must be replaced:

a. Detach the spark electrode a from the retaining clip. This will give

clearance to disassemble the pilot flame orifice.

b. Turn the flame probe b to loosen it from the bracket and give more room.

c. Detach the pilot flame orifice socket c.

d. Replace the pilot flame orifice d with the pilot flame orifice of the correct

diameter from the conversion kit.

e. Fit the bracket, the flame probe and the spark electrode.

8. If Table 3.5 Gas data indicates that the main orifices of the burners must be replaced:

a. Remove the main orifices e.

b. Fit the main orifices from the conversion kit. You can check the required

orifice diameter based on Tab le 3 . 5 Ga s da t a . The orifice diameter is shown on the orifice by means of stamped figures.

9. If required, you must now also replace the burner pressure regulator or flat plate. See paragraph 3.12.4 Replacing burner pressure regulator or flat

plate (DR-RS 25-40-65-85).

10. Return the burner tray to its place, tightening all the screws.

11. Re-fit the gas coupling before the gas control and screw the gas control connector(s) back in place.

12. Connect the leads of the spark electrode and the flame probe to the burner control and fit them in the strain relief.

13. Connect the gas.

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14. Refit the protective cover.

n Remark

Refer to A Electrical diagram DR-RS for the connection of electrical components.

3.12.4 Replacing burner pressure regulator or flat plate (DR-RS 25-40-65-85)

Referring to Tab l e 3. 5 G as d at a , ascertain whether the gas control needs to be fitted with a burner pressure regulator or blank plate. If necessary replace them:

1. Complete steps 7 through 9 of paragraph 3.12.3 Replacing orifices.

2. Detach the burner pressure regulator a or flat plate d. See Figure 3.11 Gas

control valve.

3. Fit the burner pressure regulator of flat plate from the conversion kit.

4. Complete steps 10 through 14 of paragraph 3.12.3 Replacing orifices.

5. Add a sticker to the Data Label.

n Remark

When you have completed replacing the necessary components, you must adjust the supply pressure and burner pressure to match the target gas category. See paragraph 3.11 Checking the supply pressure and burner

pressure.

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4 Filling and draining

4.1 Introduction Topics covered in this chapter:

• Filling the water heater.

• Draining the water heater.

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Legend

a pressure-reducing valve

(mandatory if the mains water pressure exceeds 8 bar)

b expansion vessel (mandatory)

c T&P valve (mandatory)

ca) safety valve

d stop valve (recommended)

e non-return valve (mandatory)

ea) non-return valve

f circulation pump (optional)

g drain valve

h gas valve (mandatory)

i stop valve (mandatory)

j temperature gauge

(recommended)

k top to bottom recirculation

pump (optional)

l top box

m hot water draw-off points

n condensation drainage

o expension valve (mandatory)

p water tank

q float valve

r 3-way venting valve (optional)

s overflow pipe

a cold water supply

b hot water outlet

c circulation pipe

d gas supply

e flue gas discharge

Filling and draining

gis

The components referred to in these paragraphs are illustrated in Figure 4.1.

UNVENTED

d f e d

VENTED

d k e d

eia

IMD-0066

dfed

IMD-0065

Figure 4.1 Installation diagrams

4.2 Filling the water heater

4.2.1 Filling unvented installations

To fill the water heater, proceed as follows.

1. Open the stop valve i in the hot water pipe and, if present, the stop valves d for the circulation pump.

2. Shut drain valve g.

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Draining the water heater

3. Open the nearest hot water draw-off point m.

4. Open the supply valve i on the cold water side a so that cold water flows into the water heater.

5. Completely fill the water heater (when cold water flows at normal pressure from the nearest hot water draw-off point, the water heater is full).

6. Vent the entire installation of air, for example by opening all hot water drawoff points.

7. The water heater is now under water supply pressure. There should be no water coming out of the expansion valve o nor the T&P valve c. If this does happen, the cause might be:

- The water supply pressure is greater than the specified 3.5bar.

Rectify this by fitting a pressure-reducing valve a.

- The expansion valve in the protected cold supply setup is defective or

incorrectly fitted.

4.2.2 Filling vented installations

To fill the water heater, proceed as follows.

1. Open the stop valve i in the hot water pipe and, if present, the stop valves d for the circulation pump.

2. Shut drain valve g.

3. Open the nearest hot water draw-off point m.

4. Open the supply valve i on the cold water side a so that cold water flows into the water heater.

5. Completely fill the water heater (when cold water flows at normal pressure from the nearest hot water draw-off point, the water heater is full).

6. Vent the entire installation of air, for example by opening all hot water drawoff points.

7. The water heater is now under water supply pressure. There should be no water coming out of the T&P valve c. If this does happen, the T&P valve might be defective or incorrectly fitted.

4.3 Draining the water heater

4.3.1 Draining unvented installations

4.3.2 Draining vented installations

Some service activities require the water heater to be drained. The procedure is as follows:

1. Shut the water heater down by putting the On/Off switch to position 0.

2. Disconnect the water heater by putting switching the mains isolator off.

3. Shut off the gas supply h.

4. Close the stop valve i in the hot water pipe.

5. Close the supply valve in the cold water supply a.

6. Open the drain valve g.

7. Vent the water heater (or installation) so that it drains completely.

Some service activities require the water heater to be drained. The procedure is as follows:

1. Shut the water heater down by putting the On/Off switch to position 0.

2. Switch the mains isolation off.

3. Shut off the gas supply h.

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Filling and draining

gis

4. Close the stop valve i in the hot water pipe.

5. Close the stop valve between the water tank and the cold water inlet.

6. Open the drain valve g.

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5 Controls

5.1 Introduction Topics covered in this chapter:

• 5.2 Control panel;

• 5.3 Explanation of the symbols;

• 5.4 ON/OFF switch;

• 5.5 Control thermostat;

• 5.6 Burner control reset button;

5.2 Control panel Figure 5.1 shows the control panel The panel consists of:

• an ON/OFF switch;

• a reset button;

• a control thermostat with rotary knob;.

IMD-0363

Figure 5.1 The control panel

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Controls

gis

5.3 Explanation of the symbols

5.4 ON/OFF switch The ON/OFF switch is used to put the water heater in the ON mode or OFF

Table 5.1 shows the meanings of the symbols on the control panel.

Table 5. 1 Icons and their meaning

Symbol Name Explanation

ON/OFF switch ’ON mode’ / ’OFF mode’

Reset button with error indicator

Temperature control To set water temperature (T

mode. The water heater remains live, even when in the OFF mode. This ensures the frost protection remains activated.

Reset burner control

set

)

n Remark

To electrically disconnect the water heater, you must use the isolator between the water heater and the mains power supply.

5.5 Control thermostat Use the rotary knob on the control thermostat to set the desired water

temperature to between 40°C and 70°C. The rotary knob is continuous, over a scale of 1 to 4. Table 5.2 shows the temperatures corresponding to each position.

Table 5. 2 Temperature setting

5.6 Burner control reset button

PositionTemperature

2 ≈ 50°C

3 ≈ 60°C

4 ≈ 70°C

An error can cause the burner control to lock out. When this happens, the red lamp in the reset button will light up. After eliminating the cause of the error, you can reset the water heater using the reset button.

≈ 40°C

n Remark

Before resetting, always eliminate the cause of the error.

To identify the various errors, refer to chapter 6 Status of the water heater. Chapter 8 Troubleshooting describes how to troubleshoot errors and problems.

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6 Status of the water

heater

6.1 Introduction Topics covered in this chapter:

• 6.2 Operating modes;

• 6.3 Error conditions;

6.2 Operating modes When running, the water heater has three basic operating modes, namely:

• DISCONNECTED

In this mode the water heater is off and all components are electrically dead. The isolator (switch between the water heater and the power supply) is turned off. On the control panel, the ON/OFF switch is at position 0.

• OFF

In this mode, the frost protection is activated. The isolator is set to position I. On the control panel, the ON/OFF switch is at position 0.

• ON

In this mode the water heater continuously fulfils the demand for heat. On the control panel:

- the ON/OFF switch is at position I;

- The water temperature can be set by turning the rotary knob on the control thermostat, see paragraph 5.5 Control thermostat.

6.3 Error conditions If the water heater has an error the heater will not operate. The frost protection

will also be out of operation.

If the water heater should go into an "error" state, you will be unable to continuosly draw hot water. These error conditions are divided into three groups:

• Lock out error in the burner control When this happens, the red error lamp in the reset button will light up on the control panel. The burner control is locked out. After removing the cause, the reset button must be pressed to re-start the water heater.

• The water heater cycles continuously When this happens, the water heater continues to attempt to start-up, but an error is causing the heating cycle to fail. See paragraph 7.4 The water heater’s heating cycle. After removing the cause, the water heater will start-up again by itself.

• Blocking errors You can recognise this condition by the fact that the water heater makes no attempt to start operation, despite the water temperature being lower than the control thermostat setting (see 5.5 Control thermostat). These errors disappear automatically once the cause of the error has been removed, after which the water heater resumes by itself.

The cause of the error cannot be seen on the control panel. For a detailed overview of error conditions, please refer to chapter 8 Troubleshooting.

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Status of the water heater

gis

If, as end-user, you find the water heater in an error condition, you may attempt to re-start the water heater by pressing the reset button once. However, should the error return or become persistent, you should contact your service and maintenance engineer.

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7 Starting up and

shutting down

7.1 Introduction Topics covered in this chapter:

• Starting up;

• Shutting down;

• The water heater’s heating cycle.

7.2 Starting up Start-up the water heater as follows:

1. Fill the water heater. See chapter 4 Filling and draining.

2. Open the manual gas valve (see Figure 4.1 Installation diagrams).

3. Switch on the power to the water heater using the isolator between the water heater and the power supply.

4. Set the water heater in ’ON mode’ by switching the ON/OFF switch on the control panel to position I.

5. Set the desired water temperature using the control thermostat. See paragraph 5.5 Control thermostat

If there is a heat demand, the water heater will run through a heating cycle. See paragraph 7.4 The water heater’s heating cycle.

7.3 Shutting down You can:

• Shut the water heater down for a brief period (’OFF mode’).

• Isolate the water heater from the power supply.

• Shut the water heater down for a longer period.

7.3.1 Shut the water heater down for a brief period (’OFF mode’)

To shut the water heater down for a brief period, you must activate the frost protection. Refer also to paragraph 2.3 The water heater’s heating cycle.

You can use the frost protection to prevent water freezing in the water heater. Activate the frost protection by switching the ON/OFF switch on the control panel to position 0.

7.3.2 Isolate the water heater from the power supply

The water heater should only be isolated from mains power in the correct way. The correct procedure is as follows:

1. Shut the water heater down by switching the ON/OFF switch to position 0.

2. Isolate the water heater by switching the isolator between the water heater and the mains power supply to position 0.

7.3.3 Shut the water heater down for a longer period

Drain the water heater, if you are shutting it down for a longer period of time. Proceed as described in paragraph 4.3 Draining the water heater.

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Starting up and shutting down

gis

7.4 The water heater’s heating cycle

The water heater’s heating cycle is activated as soon as the measured water temperature (T depends on the currently selected water heater operating mode. For example, if the water heater is in the ’OFF mode’ (frost protection), then this value is 20°C. If the water heater is in the ’ON mode’, then this threshold value is selectable, for example, position 3 (60°C).

The heating cycle runs in turn through the following states:

1. Heat demand;

2. Zero state control by pressure switch;

3. Start fan;

4. Pressure difference in air supply;

5. Ignition of pilot flame;

6. Ignition of burner tray;

7. Running.

The complete cycle is explained in the example set out below.

) falls below the threshold value (T

water

). This threshold value

set

n Remark

The water heater runs through an identical cycle when frost protection is activated.

1. The control thermostat sensor measures the water temperature. The water temperature falls below the set temperature, e.g. 60°C, causing the control thermostat to close. The burner control now detects a heat demand and starts the heating cycle.

2. Once the heat demand is registered, the burner control runs a zero state control on the pressure switch and the fan begins drawing air.

3. Once the air supply is guaranteed to be sufficient, the pilot flame is ignited.

4. Following ignition, once the pilot flame is verified by ionisation detection, the burner tray is ignited: the water heater is now running. This means that actual heating has started.

5. When the water is up to temperature, the heat demand cuts out. The gas control closes and the pilot flame and the burner tray are extinguished.

With any subsequent heat demand, the heating cycle will resume from step 1.

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8 Troubleshooting

8.1 Introduction This chapter covers the following errors:

• Gas smell.

• Water leakage.

• Explosive ignition.

• Poor flame profile.

• No hot water

• Insufficient hot water.

If the water heater has gone into an error condition, then the heat demand will be (temporarily) ignored and no hot water will be supplied. The frost protection will also be out of operation. The error conditions are divided into three groups:

• Blocking errors You can recognise this condition by the fact that the water heater makes no attempt to start operation, despite the water temperature being lower than you have set with the control thermostat (see 5.5 Control thermostat). These errors disappear automatically once the cause of the error has been removed, after which the water heater resumes by itself.

n Remark

Footnotes referred to from within any table are shown at the bottom of the last page of that table.

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Immediately contact your installer or local gas company.

n Remark

Warning

Immediately close the main gas valve.

Warning

Maintenance may only be performed by a qualified service and maintenance engineer.

8.2 Troubleshooting table for general errors

Table 8. 1 General errors (Sheet 1 of 2)

Gas smell Gas leak

Symptom Cause Solution Remark

Warning

Do not operate any switches.

Warning

No naked flames.

Warning

Ventilate the boiler room.

Tighten the threaded connection. If the leak persists, consult your installer.

Water leakage Leakage from one of

Trace the leak.

Leakage from another

(threaded).

nearby water water

the water connections

heater or pipe

segment.

Consult the supplier and/or manufacturer.

Leakage from the

water heater’s hot

the heater has reached the set temperature.

water tank.

Condensation Before drawing off (too much) hot tap water, wait until the water in

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If the error has not been rectified and no other cause can be found,

isolate the water heater from the power supply, shut off the gas

If ignition is not improved, consult your installer.

valve and alert your installer.

heater enough time to heat up the water.

thermostat is cutting in/out. If so, check that the circulation-

and/or top to bottom recirculation pump are working properly.

1. Reduce the rate of hot water consumption. Allow the water

Contaminated orifice. Clean the orifice. See 9.4.3 Cleaning the orifices

Improve the air supply.

Contaminated air

supply

8.3 Troubleshooting table ’insufficient hot water’

If the water heater fails to supply any hot water, there are several possible causes.

Refer to Table 8.2 Insufficient hot water

Table 8. 2 Insufficient hot water

Set the correct supply pressure and/or burner pressure, see

3.11 Checking the supply pressure and burner pressure.

Incorrect supply

pressure and/or burner

pressure.

Contaminated burner Clean the burner. See 9.4.2 Cleaning the burners

Warning

Maintenance may only be performed by a qualified service and maintenance engineer.

Symptom Cause Solution Remark

Explosive ignition

Table 8. 1 General errors (Sheet 2 of 2)

Poor flame profile

Symptom Cause Solution Remark

Set the control thermostat to a higher setting. See paragraph

5.5 Control thermostat.

) is too low

set

setting (T

Insufficient hot water The water temperature

Hot water supply used

up.

2. If this error occurs regularly, check whether the high-limit

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See appendix A Electrical diagram DR-RS. If you cannot resolve

the error, contact your installer.

If the error has been corrected, the water heater will automatically

If the error cannot be resolved or is persistent, contact your

resume running when there is a heat demand.

If the error cannot be resolved or is persistent, contact your

installer.

thermostats.

compliance with the directions. See paragraph 3.9 Air supply

1. Check that the chimney installation has been constructed in

Too much resistance in

the flue gas discharge

(the air pressure

Repeated starting of

the heating cycle

(cycling of water

and flue gas discharge.

switch opens during

heating).

heater)

Instruction manual DR-RS 56

• Trace the blockage.

• Remove the blockage.

• Check the wiring of the air pressure switch.

• Check that the air pressure switch is working properly.

1. Check that the isolator is ON.

2. Check the voltage across the isolator.

3. Check the voltage on the electrical connector block.

4. Check the voltage on the burner control.

5. Check the fuse in the burner control.

The measured voltage must be 230 VAC +15% -10%.

1. Blockage in the flue gas discharge or air supply:

No voltage from power

If the water heater fails to supply any hot water, there are several possible causes.

Refer to table Table 8.3 No hot water.

Warning

Maintenance may only be performed by a qualified service and maintenance engineer.

8.4 Troubleshooting table ’no hot water’

Table 8. 3 No hot water (Sheet 1 of 2)

supply.

Symptom Cause Solution Remark

No attempt to start

the heating cycle

The air pressure

No attempt to start

switch does not close.

the heating cycle

(blocking error)

2. Defective air pressure switch

1. Check that the control thermostat is switched (closed).

Break in the

thermostat circuits.

2. Check the leads and sensors of the control and high-limit

Page 57

See paragraph 7.4 The water heater’s heating cycle

If the error cannot be resolved or is persistent, contact your

installer.

If the error cannot be resolved or is persistent, contact your

installer.

1. Check whether the control thermostat is working.

2. Check whether the high-limit thermostat is working.

1. Check whether the thermostat is defective.

2. Check whether the thermostat sensor is defective.

3. Check the wiring of the thermostat.

No gas:

1. Check that the gas valve is open.

2. Check that gas control opens (clicking of the gas control).

3. Check the gas control wiring.

No ignition:

1. Check whether the spark igniter sparks in the pilot flame cap.

2. Check the wiring of the hot surface igniter.

3. Check that the spark igniter is correctly fitted in the bracket.

No flame detection:

1. Check that the flame probe is not defective.

2. Check that the wiring to the flame probe is correctly connected.

There are 3 possible causes for this error: (a), (b) or (c). To determine the cause, you need

to make the error recur while checking which phase of the heating cycle this happens in.

1. Reset the water heater by pressing the reset button 1x;

2. Cause (a) occurs between steps 4 and 5 of the heating cycle;

3. Cause (b) occurs in step 5 or 6;

4. Cause (c) occurs in step 7.

(a) Constant

interruption in the

safety circuit

(b) Failed attempt to

start

Warning

Maintenance may only be performed by a qualified service and maintenance engineer.

Reset button

illuminated (lock out

Table 8. 3 No hot water (Sheet 2 of 2)

error in burner

control)

3. Check that the circulation pump (if present) is working.

safety circuit during

heating (the safety

thermostat has cut out)

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Warning

Maintenance may only be performed by a qualified service and maintenance engineer.

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9 Maintenance

9.1 Introduction

cNote

Maintenance may only by carried out by an approved service and maintenance engineer.

At each service, the water heater undergoes maintenance both on the water side and on the gas side. The maintenance should be carried out in the following order.

1. Preparing for maintenance;

2. Water-side maintenance;

3. Gas-side maintenance;

4. Finalising maintenance.

9.2 Preparing for maintenance

n Remark

Before ordering spare parts, take a moment to write down the water heater type and model and the full serial number of the water heater. Only by ordering with this information can you be sure to receive the correct spare parts. These details can be found on the rating plate.

To test whether all components are still working properly, you should complete the following steps:

1. Put the ON/OFF switch on the control panel to position 0.

2. Set the control thermostat (note the original setting) to the highest position and put the ON/OFF switch back to position I.

3. If there is no heat demand, draw some hot water off to initiate a heat demand.

4. Check whether the heating cycle runs correctly. See paragraph 7.4 The

water heater’s heating cycle.

5. Set the control thermostat back to the original setting and put the ON/OFF switch back to position I.

6. Check the supply and burner pressures and adjust these, where necessary. See paragraph 3.11 Checking the supply pressure and burner pressure.

7. Check that all components of the flue gas system are properly attached.

8. Test the operation of the expansion valve of the cold supply setup. The water should spurt out.

9. Test the overflow operation of the T&P valve. The water should spurt out.

10. Check the drain pipes from the discahrge points of any valve and remove any lime buildup that may be present.

11. Drain the water heater. See paragraph 4.3 Draining the water heater.

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9.3 Water-side maintenance

9.3.1 Introduction

9.3.2 Checking the anodes

Maintenance

The following steps should be carried out on the water side:

1. Checking the anodes.

2. Descaling and cleaning the heater.

Timely replacement of the anodes extends the service life of the water heater. The water heater’s anodes must be replaced as soon as they are 60% or more used up (take this into consideration when determining the maintenance frequency).

1. Remove the chimney attachments from the top box.

2. Detach the lid of the top box.

3. Detach the fan leads and remover the lead from the strain relief.

4. Undo the screws of the top box.

5. Remove the top box from the water heater.

6. Undo the screws of the cover on the top of the water heater.

7. Remove the cover from the water heater.

8. Remove the sealing ring from the hot water tank.

9. Loosen the anodes using suitable tools (27 mm A/F).

10. Check the anodes and if necessary, replace them.

11. Now also check the flue baffles. Replace them, if necessary. See paragraph

9.4.4 Checking the flue baffles.

12. Fit a new sealing ring around the edge of the hot water tank and replace the cover.

13. Replace the top box.

14. Feed the fan lead through the strain relief and connect the lead to the fan. See appendix A Electrical diagram DR-RS.

15. Fit the lid back on the top box.

9.3.3 Descaling and cleaning the heater

Scale and lime buildup prevent effective conduction of the heat to the water. Periodic cleaning and descaling prevents buildup of these deposits. This increases the service life of the appliance, and also improves the heating process.

Take the rate of scale formation into account when deciding on maintenance frequency. Scale formation depends on the local water composition, the water consumption and the water temperature setting. A water temperature setting of maximum 60

To guarantee a good, watertight seal around the cleaning opening, the gasket , O-ring g, spring washers, bolts and if necessary, the lid c should be replaced with new parts before reassembly. See Figure 9.1. A special set is obtainable from Hamworthy for this purpose.

60 Instruction manual DR-RS

c is recommended for prevention of excessive scale buildup.

Page 61

Gas-side maintenance

To simplify descaling and cleaning of the tank, the appliance is equipped with two cleaning openings.

Figure 9.1 Cleaning opening

1. Remove the cover plate a on the outer jacket. See Figure 9.1.

2. Carefully remove the insulation b and set it to one side. This will be needed

3. Undo the bolts.

4. Remove the lid, the gasket and the O-ring.

5. Inspect the tank and remove the loose scale deposits and contamination.

6. If the scale cannot be removed by hand, then the appliance will need to be

7. Close the cleaning opening. To avoid damage to the tank, the bolts that

again later.

descaled using a suitable cleaner.

fasten the lid should be tightened with a torque no greater than 50 Nm. Use suitable tools for this. To properly seal the cleaning opening, we recommend tightening the bolts in the sequence shown in Figure 9.2.

Figure 9.2 Bolt tightening sequence

9.4 Gas-side maintenance

Take care

The burners may be hot.

9.4.1 Introduction

The following steps should be carried out on the gas side:

1. Cleaning the burners.

2. Cleaning the orifices.

3. Checking the flue baffles.

9.4.2 Cleaning the burners

1. Detach the burners.

2. Carefully remove any contamination present on the burners.

3. Re-attach the burners.

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9.4.3 Cleaning the orifices

9.4.4 Checking the flue baffles

Take care

The flue baffles may be hot.

Maintenance

1. Remove the orifices.

2. Remove any contamination present in the orifices.

3. Re-attach the orifices.

1. Complete steps 1 through 8 of paragraph 9.3.2 Checking the anodes.

2. Remove the flue baffles from the water heater.

3. Check the flue baffles for rust and remove any which is present.

4. Check the flue baffles for wear and replace any worn flue baffles.

5. Complete steps 12 through 15 of paragraph 9.3.2 Checking the anodes.

9.5 Finalising maintenance

To finalise the maintenance carry out the following steps:

1. Fill the water heater. See paragraph 4.2 Filling the water heater.

2. Re-start the water heater. See 7.2 Starting up.

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A Electrical diagram

DR-RS

Instruction manual DR-RS 63

Page 64

Legend

A Jacket

Brown

B Isolating transformer

Blue

Yellow / Green

C APDS (Air pressure differential switch)

Black

D Filter

E Reset button

White

Red

F Frost thermostat

G Control thermostat

H ON/ OFF switch

K Safety thermostat

L High-limit thermostat

M Burner control

N Connector clip strip

P Earthing strip

R Relay (Max. 250V, 10A)

OPTIONAL COMPONENTS:

S Clock

T Potentiostat

White / Orange

White / Purple

Black / Green

Black / Red

Black / White

Figure A.1 Electrical diagram DR-RS

Instruction manual DR-RS 0307248 _R1.3 64