elco NHREX Operation and Maintenance Manual

Brand: elco

Model: NHREX

Category: Water heaters & boilers

Type: Operation and Maintenance Manual

HIGH EFFICIENCY

LOW NOX

Model : Tudor NHREX

Installation & Operating

instructions

Code : L375 01-2021

Page 2

Thank you for choosing our high efficiency, low Nox hot water heater to

ensure your domestic hot water production.

Please retain the device’s operating instructions in a

safe place for future reference.

PRODUCT CONFORMING TO EU DIRECTIVE 2012/19/EU

The crossed-out wheeled bin symbol on the appliance indicates that the

end-of-life product, to be treated separately from domestic waste, must

be returned to a waste sorting centre for electrical and electronic

equipment or returned to the dealer, on the day of purchase of a new

equivalent device.

The user must ensure that the device at the end of its life is disposed of in

an appropriate collection centre.

Selective sorting, which allows the recycling of the appliance at the end of

its life cycle, the treatment of it and the environmentally friendly disposal,

helps to avoid possible negative effects on the environment, health and

recycling of the materials that make up the product.

For more information on existing waste collection centers, contact the

local waste collection service or the store where you purchased your

appliance.

Page 3

1. RECOMMENDATIONS

a. General Recommendations

1. This manual forms an integral part of the appliance. It is to be kept safe and

accessible for consultation if necessary and must accompany the appliance in case

of transfer to another owner or user and / or transfer to another installation.

2. Carefully read the instructions and understand the advice provided. This will help ensure

the safe installation, use and maintenance of the appliance.

Failure to do so may invalidate the warranty.

3. Installation, maintenance and other work must be carried out by a competent

person in accordance with the relevant regulations and the manufacturer's

instructions.

4. This appliance is designed to produce hot water for domestic use. It should be

connected to the distribution mains supply for domestic hot water in accordance with

the performance levels of the appliance.

5. This appliance must only be used for it’s intended purpose. The manufacturer can

under no circumstances be held liable for damages resulting from improper,

incorrect or unreasonable use or from non-observance of the instructions contained

in this manual.

6. The manufacturer shall not be liable for damage to persons, animals or property

caused by improper installation.

7. Ensure that all packing materials are safely disposed of (staples, plastic bags,

expanded polystyrene, etc.), as they represent a sources of danger, especially for

children.

8. Do not touch the appliance if you have bare feet or with wet parts of the body.

9. In the event of faults and/or malfunctions, switch the appliance off and shut off the

gas valve. Do not attempt to perform any repairs yourself but contact an authorised

service technician.

10. For repairs, contact an authorised service technician and specify the use of only

original spare parts where possible. Failure to comply with the above may

compromise safety and disclaim all liability of the manufacturer.

11. The hot water temperature is controlled by thermostat which also serves as a safety

device (requiring manual reset) to prevent dangerous water temperatures. To avoid

any risk of scalding, do not exceed a maximum temperature of 50 °C at the tap

discharge via suitable mixers. To avoid the risk of legionella issues, the control

thermostat must be set to at least 60 °C.

12. Ensure that the electrical connection is as indicated in the relevant section-10

13. No flammable objects should be stored in the vicinity of the appliance.

Page 4

14. If the appliance is out of service for more than one month, close the hydraulic

circuits, connected to the water heater and drain the appliance. If the appliance is

left unused in winter for a long period in an unheated space, it is advisable to

drain it completely to avoid any risk of freezing. The manufacturer shall not be liable

for damage caused by freezing or leaking water from the installation.

15. The appliance must not be installed in damp areas ( RH ≤ 80%) and must be

protected against splashing water to avoid damage to electrical and thermal

components.

16. Do not store any type of object against the appliance.

17. For reliable and safe performance and warranty recognition, carefully follow the

information in this manual and use only the spare parts supplied by the

Manufacturer.

18. This appliance should not be operated by children and they must be attended at all

times.

b. Installer Recommendations

The appliance and its safety valve (supplied separately) must be installed in a frost-

free and properly ventilated room.

It is essential that the discharge of the safety valve is connected to a tundish,

suitably connected to a drain. Specific attention to system integrity should be made

if the water heater is installed above inhabited premises ( eg.- elderly persons care

home)

To allow maintenance operations, it is imperative to provide appropriate clearances

as detailed in figure 3.

2. REGULATIONS

Gas or liquefied petroleum equipment installations must be carried out in

accordance with regulations.

This appliance may operate with a non-sealed combustion circuit of the type B11BS

Categories : II2H3P G20-20mbar - G31-37mbar

NATURE OF

GAS

COMMON DESIGNATION

NATURAL GAS PROPANE

REFERENCE GROUP H - G20

34.02MJ/m

G31

46.34 MJ/m3

Net calorific value (15° / 1013 mbar)

NORMAL SUPPLY PRESSURE 20 37

Page 5

a. European Directives and Standards

Directive 90/396/CEE as amended by 2009/142/CE Gas appliances ;

Directives 2009/125/EC (ErP) & 2010/30EU (Energy Labelling)

Directive DESP 97/23/CE Pressure equipment ;

BS EN 89 (2000) Devices for the production of hot water by storage for sanitary uses

using gaseous fuels ;

+ BS EN 89/ A3 (2006)

+ BS EN 89/ A4 (2007)

CEN/TR 1749 (2013) European scheme for the classification of gas appliances

according to the method of evacuation of the combustion products (types)

b. Installation Requirements

It is the Law that all gas appliances are installed by competent persons (Gas Safe

Registered), in accordance with the Gas Safety (Installation and Use)

Regulations 1998 (as amended). Health & Safety requirements must be taken into

account when installing any equipment. Failure to comply with the above may lead to

prosecution. It is in your own interest and that of safety, to ensure the Law is complied

with.

The installation of the appliance MUST be carried out by competent personnel and

comply with the I.E.E. Wiring Regulations, National & Local Building Regulations,

Water Bye-laws, Bye-Laws of the Local Water Undertaking, Fire Authority

Requirements any relevant requirements of the Local Authority, and Health and

Safety Executive.

Statutory Instruments

Water Supply (Water Quality England & Wales) Regulations 2016 - as amended

The Public Water Supplies (Scotland) Regulations 2014 - as amended

The Water Supply (Water Fittings) Regulation (Northern Ireland) 2009 - as amended

For gas fired equipment the installer should also refer to relevant IGEM 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 pipe work, boosters and compressors on industrial and

commercial premises.

IGE/UP/10 Installation of gas appliances in industrial and commercial premises.

Detailed recommendations are contained in the following British Standard Codes of

Practice:

BS 5440 Flueing and ventilation for gas appliances of rated input not exceeding 70kW

net

Page 6

BS 6644 Specification for the installation and maintenance of gas-fired hot water

boilers of rated inputs between 70 kW (net) and 1.8 MW (net).

BS 6880 Part 1, 2 & 3 Code of Practice for low temperature hot water heating

systems of output greater than 45kW.

BS 7074 Part 1: Application, selection and installation of expansion vessels and

ancillary equipment for sealed water systems.

Part 2: Code of Practice for low and medium temperature hot water heating systems.

BS 7671 Requirements for electrical installations. IET Wiring Regulations.

BS 8550 Guide for the auditing of water quality sampling

BS 8558 Guide to the design, installation, and maintenance of services supplying

water for domestic use within buildings. Note: this document is complimentary to BS

EN 806

BS 14743 Water conditioning equipment inside buildings. Softeners. Requirements

for performance, safety and testing

BS EN ISO 4126-1 Safety devices for protection against excessive pressure. Safety

valves.

BS EN 806 Specification for installations inside buildings conveying water for human

consumption

Note: - BS6700 - The Design, Installation, Testing and Maintenance of Services

supplying water for domestic use within buildings; is still referred to. However this

document has been superseded by BS EN 806

BS EN 1717 Protection against pollution of potable water in water installations and

general requirements of devices to prevent pollution by back-flow

Electrical Standards:- BS 3456 Part 201, EN 60335 Part 1

CP 342-2 Code of practice for centralised hot water supply. Buildings other than

individual dwellings.

The Health and Safety Commission (HSC) approved code of practice and

guidance document L8 - HSG274: Legionnaires disease. Technical Guidance.

Note: - due to the scope of this document, all non-domestic premises must

implement some form of water treatment.

CIBSE Publications

CIBSE Guide G Public Health Engineering

CIBSE TM13: Minimising the risk of Legionnaires’ disease.

CIBSE Guide H Building Control Systems.

CIBSE Guide Energy Efficiency in Buildings.

CIBSE Commissioning Code B: 2002.

Page 7

Department of Health

Health Technical Memorandum (HTM) 04-01: The control of Legionella,

hygiene, ‘safe’ hot water, cold water and drinking water systems.

Part A Design, installation and testing.

Part B Operational Management Department of Health (DH). Addendum

Pseudonomas aeruginosa - advice for augmented care units.

HTM 04-04 The Control of Legionella in Health Care Premises- Code of

Practice: 2006

General Requirements

All connections to the local water main shall comply with Water Supply

(Water Fittings) Regulations 1999 (as amended). Compliance with the

Regulations can be demonstrated by certification from notified body

organisations such as WRAS or KIWA.

Unvented Systems

Building Regulations - use of unvented hot water storage systems with

volumes exceeding 15 litres. G3 (England & Wales), P3 (Scotland) & P2

(Northern Ireland)

The unvented system components allows the storage vessel to be fed directly

from the mains cold water supply, or from a booster pump set, without the

need for feed and expansion tanks. The unvented system components should

be approved and comply with the Water Supply (Water Fittings) Regulations

1999 (as amended), including a suitably sized temperature or temperature

and pressure (T&P) relief valve, which locates directly into the top portion of

the storage vessel.

3. WARNINGS

Notice regarding the development and publication of this manual:

➢ It contains the most recent descriptions and characteristics of the

product.

➢ The contents of this manuals are subject to change without notice :

We reserve the right to make changes, without notice, to the features and

elements contained herein. We may not be held liable for any prejudice (including

consequential damages) caused by reliance on the material presented, including,

but not limited to, typographical errors and other publication errors.

4. CONDITIONS FOR APPLICATION OF

THE MANUFACTURER’S WARRANTY

Standard and current terms of warranty are detailed on our web site www.elco.co.uk

Page 8

5. GENERAL INFORMATION

DHW high efficiency gas low NOx hot water heater. With a very simple and flexible

operation, you can always dispose of hot water at the desired temperature and the

desired flow (within the limits of the capacity of the appliance) while respecting the

(regulatory) thermal and environmental issues.

a. ERP CLASSIFICATION

Models

NHREX

Energy efficiency class

B B B B

Load Profile

XL 2XL 2XL 2XL

Water Heating Energy Efficiency

nwh % 67 62 69 64

Daily Electricity Consumption

Qelec

kWh

0.12

0.13

0.11

Daily Fuel Consumption

kWh 31.47 39.48 35.11 38.01

Emissions of Nitrogen Oxides

mg/kWh 33 28 34 19

Annual Electricity Consumption

kWh 13 27 28 25

Annual Fuel Consumption AFC

GJ 22.6 31.2 27.8 30

Mixed water at 40°continuous

(Cold water 10°)

266

378

396

480

Acoustic Power

dB 49 49.2 49.8 50.8

b. Characteristics

Legend :

1. Draught diverter

2. Insulation

3. Overheat thermostat

4. Protech electronic

anode

5. Temperature control

thermostat

6. Enamelled tank

9. Condensate tray / drain

10. Gas valve

11. Main burner tubes

14. Flue tubes

15. Flue tube baffles

16. Hot water outlet G1”

17. Cold water inlet G1”

Page 9

Figure1 - general layout Plan view

General technical characteristics (see. Fig.-1a & 1b above):

➢ Enameled tank (Sanitary conformity according to standard BS EN 89)

allowing operation with a working temperature up to 95°C ;

➢ Durable padded vinyl jacket over dense thermal insulation material ;

➢ Draught diverter fitted with flue gas spillage device for connection to an

atmospheric chimney system B

11BS

;

➢ Model NHREX 18 fitted with thermoelectric, permanent pilot flame failure

system ;

➢ Models NHREX 26, 36 & 60 fitted with electronic full sequence intermittent

pilot ignition control

➢ Gas type G20/G31 ;

➢ Factory calibrated Model (Category by country) ;

➢ Low NOx Gas burner ;

➢ Integral Protech electronic anode protection system;

➢ Device certified to the European standard for gas storage water heaters, for

sanitary use (BS EN 89).

It is imperative to read this documentation before commissioning. At your

request, our Post sale department can organise a commissioning visit

(optional).

6. TECHNICAL CHARACTERISTICS

a. CE marking

We hereby certify that the DHW gas fired high efficiency low Nox storage water

heaters are in conformity with the requirements of Directive: EU 2016/426

b. Type

This appliance is certified for connection to an atmospheric chimney system B

11BS

accordance with CEN/TR1749 and is fitted with a flue spillage safety thermostat

Page 10

c. Technical Data

Technical Specifications Unit

NHREX 18

NHREX 26

NHREX 36

NHREX 60

DHW Capacity:

Litres 180 250 250 320

Heat Output:

kW 18.7 27.8

36.1

51.5

Heat Input:

kW 22.0

32.0

42.0 60.0

Gross Thermal Efficiency:

% 85 86.9 86 85.8

DHW Recovery Time (

△

T = 50 °C):

min 34 31 23 22

Hot Water Production (

△

T = 50 °C):

l/h 322 479 621 887

l/min 5.36 7.98 10.35 14.8

Hot Water Production (

△

T = 55 °C):

l/h 293 435 564 806

l/min 4.88 7.26 9.4 13.4

Gas Consumption (G20-20 mbar)*: m

/h 2.3 3.4 4.5 6.3

Gas Consumption (G31 – 37 mbar)*: kg/h 1.3 1.71 1.8 2.3

Flue gas temperature (maximum): °C 120 130 135 130

Flue gas flow rate:

17 22 24

g/s

Flue connection internal diameter: mm 126 140 168 180

Total Power Consumption

230 V ~ 50 Hz (IP 20) :

W 5 20 20 20

Minimum / Maximum Working

Pressure :

Bar 1/7 1/7 1/7 1/7

Maximum Working Temperature: °C 80 80 80 80

Dimensions (B x Ø x A):

1210 x

790 x

1468

1530 x

790 x

1791

1530 x

790 x

1840

1890 x

790 x

2200

Packaged Dimensions (wooden box)

(H*W*D):

1286 x

912 x

1008

1583 x

912 x

1008

1583 x

912 x

1008

1961 x

912 x

1008

Empty Weight: Kg

165 196 196

245

Full Weight: Kg

350 450 450 570

NOx Emissions:

mg/kWh

33 28 34 19

* Gas Consumption @ 1013.25 mbar, 15°C

Page 11

d. Minimum dimensions and clearances

Figure 2 - dimensions

Legend :

16. Hot water outlet G1”

17. Cold water inlet G1”

18. Flue spillage sensor (DAT)

19. Control panel

20. Instruction label

21. Inspection port

22. Nameplate

23. Warning label

26. Combustion chamber

cover

27. Gas inlet pipe

Note: Clearance above should be sufficient

to allow disconnection of flue system

and removal of flue baffles.

Figure 3 - Minimum clearances

NHREX 18 26 36 60

A 750 750 750 750

Top 500 500 500 500

B 150 150 150 150

NHREX

18 26 36 60

A 1468 1791 1840 2200

B 1210 1530 1530 1890

C 1245 1560 1560 1920

Page 12

e. Packaging / Storage / Transport / Unpacking

Each unit, after factory checks and tests, is packaged in a wooden box and stored in a

warehouse with optimum conditions for delivery.

This appliance must be stored in a covered, frost-free room with high and low ventilation.

When it is transported, it must be fixed vertically and strongly in its original packaging until

the place of installation.

In order to unpack the device for its installation on the site, here is the procedure to

follow :

Dismantling the wooden box:

- Uncouple the cap : 1

- Remove the posts : 2 et 3

- Remove the 4 screws : 4

- Remove the posts : 5 et 6

Warning!

After unpacking the unit, make sure that it is

completely intact.

Packaging elements must be sorted and collected

according to their nature for environmental

protection.

Page 13

7. HYDRAULIC CONNECTION & GAS

a. Hydraulic Connection

Revert to Figures 7.1 - 7.4 to visualise the schematics of some of the main features to link the

hydraulic connections. The correct installation of the tank is the responsibility of the

installer. Ensure that each unit and the associated pipe work are suitably earthed.

Legend :

1. Cold water mains

supply

2. Isolating valve

3. Strainer

4. Pressure reducing

valve

5. Expansion vessel

6. Non return valve

7. Pressure relief valve

8. Drain valve

9. NHREX water heater

10. Re-circulating pump

11. Hot water outlets

12. Temperature &

Pressure relief valve

13. De-Stratification pump

14. Buffer vessel loading

pump

15. DHW Storage

Cylinder

Figure 7.1 - NHREX Open vented system

Figure 7.2 - NHREX Unvented system - optional cold water boosted supply

Page 14

Figure 7.3 - Two NHREX in parallel unvented

Figure 7.4- NHREX with buffer vessel unvented

Page 15

Figures -7.3 & 7.4 represents the general idea on how to link 2 appliances (in parallel) in

order to double the capacity of production. Also the schematic for 2 appliances (also in

parallel) with a buffer tank allowing an increased capacity of production and ensuring a

better quality of service and the availability of the DHW.

b. Tips & Recommendations

☞ The Gas entry is via the

1/2

” for NHREX18 &

3/4

” for other models on the

bottom left of the tank:

➢ Ensure that a filter and isolating valve are accessible close to the appliance.

➢ The gas supply needs to have a union and valve close to the appliance.

➢ The gas supply must be in accordance with BS6644 and purged in accordance

with IGE/UP1

NOTE: The burner is preset to the correct flow

VERIFY THE NATURE OF DISTRIBUTED GAS BEFORE ADAPTATION OF THE

APPLIANCE

☞

The cold water inlet situated on top of the tank is a 1’’ connection

Open vented systems - refer BS EN 806 & BS 6700

➢ Ensure that the feed and expansion tank is sized to provide sufficient cold water

storage and accommodate system expansion without the risk of overflowing.

➢ Ensure that the static head created by the feed and expansion tank does not

exceed the maximum working pressure and that it provides sufficient head

pressure so that flow can be maintained at all outlets likely to be operating

concurrently. Minimum cold feed pipe size 1” (28mm)

➢ Ensure that the open vent pipe is adequately sized (minimum 11/4” - 32mm)

connecting the domestic hot water flow to the feed and expansion tank

➢ The fitting of a 3/4” (20mm) safety pressure relief valve to the tank flow is

recommended. No isolating valves should be fitted between the water heater

and the connection points for the open vent and relief valve

Unvented systems - refer BS EN 806 & BS 6700

➢ Install a stop valve on the cold water supply. The installation of the filter is

strongly recommended in order to eliminate any solid particulates or debris.

➢ Ensure that the setting of the pressure reducing valve does not exceed the

maximum working pressure of the water heater.

➢ Install a cold water inlet valve group (option supplied by Elco) incorporating non

return valve, pressure relief valve and pressure reducing valve

➢ Install a suitably sized expansion vessel acknowledging the system volume

(option supplied by Elco) in accordance with BS EN 7074

➢ The fitting of the T&P valve must be in accordance with Building Regulation G3.

(option supplied by Elco)

Page 16

☞ The hot water outlet situated

on top of

the tank is a 1’’ connection

Add an automatic air vent (AAV) on the hot water outlet and as close as possible

to the tank.

Do not increase the diameter of the hot water outlet pipe, as larger diameter pipes

increases heat losses.

It is strongly recommended that a thermostatic mixer/valve is installed close to

the appliance in order to avoid any risk of scalding.

The appliance drain pipe should incorporate a 1’’ valve. The drain water needs to

be visible either through a tundish or directly to drain.

Refer to BS 8558 for guidance on system design and materials. Pipe work

connected to the appliance should be easily assembled and disassembled.

Ensure that all pipe work is suitably earthed, as close as possible to the

appliance.

Check that the inlet water pressure does not exceed 5 bar. For pressure above

this limit, install a pressure reducing valve.

The condensate discharge must comply with the Building Regulations and Water

Bye-laws. Appliance discharge must not be blocked or modified.

c. Principle of Operation (see Figure -1)

The appliance is equipped with a low Nox burner. The gas passes though the injector

into the burner. The gas valve guarantees the gas flow through the injector by the

setting pressure. The gas flow through the injector entrains secondary air into the

burner tube.

Combusted gases pass from the burner into the combustion chamber and through the

heat exchanger immersed in the stored water. The flue gases pass through the heat

exchanger tubes loosing temperature as they rise through the flue way baffles into the

draught diverter and flue system.

Note: During initial cold firing or sustained high demand hot water draw off, the flue

gases may condense in the flue tubes and drip into the condense tray. The condensate

is discharged to drain from the condense tray.

The thermostat sensor monitors the water temperature in the tank. As soon as the

temperature drops to the set-point value, the controller starts the ignition cycle, and the

burner starts. Once the flame is detected, the burner ignites and the water temperature

rises. Once the correct temperature is reached, the burner switches off. If the overheat

thermostat sensor detects too high a temperature, the burner switches off and the

controls require manual reset.

8. QUALITY OF WATER

The system is intended for the storage and the production of hot water (DHW).

Under no circumstances should this equipment be fired before the cold water supply

to the equipment has been checked and treated, where required. All installations of

hot and cold water supplies shall be thoroughly flushed and cleaned

Page 17

before being filled and used. If an installation is not flushed and/or if the water is not

of the right quality, it may invalidate the manufacturer’s warranty.

Refer to ICOM document Water Quality Consideration of Domestic Hot Water

Systems for Commercial Applications.

The water must comply with the regulations for drinking water for human consumption.

Note - If the water specifications differ from the specifications in the table, the tank

protection cannot be guaranteed.

9. FLUE SYSTEMS & VENTILATION

Atmospheric flues B

11BS

in accordance with CEN TR 1749

The draught diverter supplied separately with the appliance must be installed

carefully following the instructions supplied in the carton with the specific draught

diverter. The flue spillage detection safety device must also be correctly installed

following the instructions supplied with the draught diverter.

Flue spillage detection safety device (DAT) - is a thermal device that shuts down

the pilot burner when incorrect flue gas flow is detected in the draught diverter.

It is a resettable thermal device placed in series with the flame safety circuit of the

thermocouple (NHREX 18) or of the electronic board (NHREX 26-60) in addition to

the overheat safety thermostat.

The DAT thermostat causes the burner to stop completely if faults occur due to

improper draft in the flue.

To restart the device, you must:

Isolate the electrical supply before accessing the reset button in the control

panel

Reset the thermostat (DAT) (ref 6 figure 11.2) located inside the control

panel

IMPORTANT - This device must never be taken out of service. Any

intervention on this device is strongly discouraged as serious risks to

personal safety may occur.

Should the device operate frequently, call the installer or after-sales service

approved by the manufacturer.

The flue pipe and fittings used must be of appropriate corrosion resistant material.

The diameter of the flue used must not be smaller than the flue connection on the

Page 18

appliance draught diverter and must be installed in accordance with the requirements

of BS 5440:

Part 1, BS 6644 or IGE/UP/10 as appropriate. The complete flue system must

be designed so as to safely evacuate the products of combustion from the appliance.

The flue pipe should rise for at least 500mm vertically from the draught diverter connection

before any change in direction. Any horizontal runs should include a rise of 60mm per

1000mm run.

A method of disconnection should be included in the flue immediately above the draught

diverter allowing removal for servicing purposes. The flue must be adequately supported and

the draught diverter must not be used to support the flue.

If the flue pipe is run through a cold, unheated area, or outside, it should be of twin wall

construction providing insulation to prevent condensation forming.

IMPORTANT Flue terminal locations must be in accordance with BS5440 part 1, BS6644

and IGE/UP/10, or subject to manufacturer’s guidance.

b. Ventilation

It is important to ensure that an adequate supply of fresh air for combustion and

general plant room ventilation is provided in accordance with BS5440 part 2, BS6644

& IGE/UP/10. The following requirements for natural ventilation direct to outside must

be met:

Alternatively, the ventilation requirement may be met by the provision of mechanically

supplied and mechanically extracted air (interlocked to the appliance to prevent

appliance operation in the event of mechanical system failure) or mechanically

supplied air (interlocked) and natural extract at the rate of: Supply air at 2.8m

/h per

kW of net appliance input and a difference between inlet & extract (inlet minus

extract) air at 2m

/h per kW of net heat input.

NHREX 18 26 36 60

High level

(free area cm

)

44 64 84 120

Low level

(free area cm

)

88 128 168 240

Figure 9.1 - Ventilation requirements

c. Tips & Recommendations

➢

The appliance must be connected to the flue system using certified pipes that

resist combustion products, condensates and temperature of at least 135°C.

➢

The flue system should be installed in accordance with regulations and the

manufacturer’s instructions. It must be adequately supported with the ability to

dismantle or remove sections if necessary. This duct diameter must not be

smaller than the appliance connection.

➢

This flue system must be protected from any mechanical shock.

Page 19

10. ELECTRICAL CONNECTION

Wiring external to the appliance must be in accordance with the I.E.E. Wiring

Regulations and any Local Regulations which apply. Wiring must be completed in

heat resistant cable of 1.0mm

cross sectional area.

The heater is supplied for connection to a 230volt, 50 Hz, A.C. Single phase. Fuse

rating is a 3 amp.

The method of connection to the mains electricity supply must facilitate complete

electrical isolation to the heater preferably a 3 amp fused double-pole switch with

neon, having a 3mm contact separation in both poles and serving only the heater.

The point of connection to the mains should be readily accessible and adjacent to the

heater.

The appliance is phase-sensitive. It is absolutely essential to connect the mains live

(L) to the live of the appliance, and the mains neutral (N) to the neutral of the

appliance.

Refer to wiring diagram - Figure 10

Note: The manufacturer cannot be held responsible for any damage caused by the lack,

or inadequacy, of the connection of the appliance to an effective grounding system.

Overheat safety

thermostat

Thermostat of

régulation

Electrode

ionization

Electrode

ignition

Reset button

Flame

indicator

Flue spillage security

Brown

Blue

Black

Neutre

Ground

Phase

Neutre

Ground

Phase

Black

Electronic blo ck

ProTech

Protech

Anode

Ramp safety thermostat

Qte de 1 à 3

Gas valve coil

Thermocouple

Ramp Safety

thermostat

NHREX 26-36-60

NHREX 18

Overheat safety

thermostat

Flue spillage security

Electronic b lo ck

ProTech

Figure 10 – Wiring Diagram

Note - the NHREX 18 has self energising controls and only requires an electrical supply to

support the integral Protech electronic anode system.

A permanent electrical supply is required to ensure that the Protech system is energised and

protecting the tank.

11. INSTALLATION

Before commissioning ensure that the installation is correct:

➢Correct Hydraulic connection

➢Tank under pressure and filled

➢Electrical supply polarity correct

➢Gas soundness

➢Correct installation of flue system

➢Correct installation of condensate tray drain

➢Controls correctly set

a. Initial commissioning

✓ Ensure that the tank is filled with water (very important). Let the air out of the

vent tube (7) and collect the equivalent of a glass of water. Close the vent tube.

Never start the appliance without water in the tank!

✓ Purge any air from the water tank and gas supply.

✓ Electrically power the unit

✓ Open the gas stop valve

WARNING : CHECK THE POLARITY OF THE POWER SUPPLY

During a first commissioning or after prolonged period of shutdown, the purging

of the gas circuit is carried out by several start-up tests.

Legend :

1. Gas valve adjustment

2. Piezo igniter

LIGHT THE PILOT

Open the main gas shut-off valve. (At the first commissioning

or after a prolonged stoppage period, purge the pilot flame

circuits during the ignition sequence to avoid unintentional

ignition)

Figure 11.1 NHREX 18 controls

Page 21

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elco NHREX Operation and Maintenance Manual

Brand: elco

Model: NHREX

Category: Water heaters & boilers

Type: Operation and Maintenance Manual

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elco NHREX Operation and Maintenance Manual

elco NHREX Operation and Maintenance Manual

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