A.O. Smith ADM - 135, ADM - 115, ADM - 80, ADM - 90, ADM - 50, ADM - 60, ADM - 40 User Manual

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2Working principle of the appliance

2.1

Introduction

Topics covered in this chapter:

 

 

General working principle of the appliance;

 

 

The appliance's heating cycle;

 

 

Protection for the appliance;

 

 

Safety of the installation.

2.2General working principle of the appliance

Legend

Only applicable numbers are mentioned.

2. hot water outlet

6. control panel

8.combustion chamber

9.anode

10.tank

11.heat exchanger

12.inspection and cleaning opening

14.cold water inlet

15.drain valve

16.gas control

20.spark igniter

21.flame probe

22.chimney pipe

24.insulation layer

33.draught diverter

34.flue gas sensor

35.radiation shield/condensation tray

36.bar burners/burner tray

37.flue gas thermostat

38.safety thermostat sensor

39.high-limitthermostat sensor

40.burner control

41.control thermostat

42.high-limitthermostat

43.safety thermostat

44.frost thermostat

45.control thermostat sensor

46.frost thermostat sensor

The figure shows a cut-awayview of the appliance.

Cut-awayview of the appliance

22

38

39

33

 

9

40

11

 

 

2

 

6

 

41

37

42

 

 

43

 

44

34

 

24

45

 

10

46

 

12

 

 

20

15

21

14

 

8

 

 

36

35

 

16

IMD-0133R2

 

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Working principle of the appliance

 

 

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2.3The appliance's heating cycle

In this appliance, the cold water enters the bottom of the tank through the cold water inlet (14). The heat of combustion is conducted to the water by the combustion chamber (8) and heat exchanger (11). The heated tap water leaves the tank through the hot water outlet (2). Once the appliance is completely filled with water, it will constantly be under mains water pressure. When hot water is drawn from the appliance, it is immediately replenished with cold water.

The gas required for combustion flows via the gas control (16) into the manifold. Orifices are mounted in the manifold. The gas is injected into the burner bars at pressure from these orifices (36). The burner bars together form the burner tray. The injection of gas into the burner bars also draws in the primary air required for combustion. The narrow opening in the orifice causes the gas flow to accelerate. This in turn causes a partial vacuum. It is this partial vacuum that draws in the air (the Venturi effect). Additional air is drawn in through the opening in the burner tray.

The hot surface igniter (20) ensures ignition of the gas/air mixture.

The flue gases released by this combustion are led through the flue tubes (part of 11). Flue baffles (part of 11) are mounted in the flue tubes. These retard the flow of the flue gases, thereby increasing the thermal efficiency of the appliance.

The flue gases are vented from the appliance via the draught diverter (33).

A radiation shield/condensation tray (35) is mounted below the burner tray. This prevents overheating of the floor area below the appliance, as well as serving as a collection tray for condensation water.

The insulation layer (24) prevents heat loss. The inside of the tank is enamelled to protect against corrosion. The anodes (9) offer extra protection.

The entire appliance is controlled by the burner control (40) and the control thermostat (41) or frost thermostat (44). The control thermostat and frost thermostat both independently measure the water temperature (Twater). The

appliance's heating cycle is activated as soon as Twater falls below the threshold value (Tset). The value of Tset depends on the selected mode of the appliance(8.2 "Operating modes"). When the appliance is in OFF mode (frost

protection), this value is determined by the frost thermostat (threshold value = 20°C). When the appliance is in ’ON mode’, the threshold value can be set via the control thermostat (±40°C - ±70°C).

As soon as Twater falls below Tset, the relevant thermostat (control or frost) will close, and the burner control will register demand. The gas control (16) is

opened, and the gas is mixed with air. This mixture is ignited by the hot surface

igniter (20) and the water is heated. As soon as Twater gets higher than Tset, the thermostat opens again. The demand will cease, and the burner control will stop

the heating cycle.

The thermostats have a certain margin both when closing and opening. We refer to this margin as the hysteresis. The hysteresis cannot be adjusted.

2.4Protection for the appliance

2.4.1Introduction

The burner control monitors the water temperature by means of thermostats and ensures safe combustion. This takes place using:

the Water temperature protection;

the Flue gas backflow safeguard;

the Flame probe.

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2.4.2Water temperature protection

By means of the frost, high-limitand safety thermostats, the burner control monitors three temperatures that are important for safety. The table explains the working principle of the thermostats with sensors.

Temperature protection

Protection

Description

 

 

Frost thermostat

When the frost thermostat sensor (46) measures a temperature of 20°C or

 

less, the heating cycle (2.3 "The appliance's heating cycle") will start.

 

 

High-limitthermostat

When the high-limitthermostat sensor (39) measures a temperature higher

 

than 84°C, the high-limitthermostat will open. The heat demand is terminated

 

and the burner control halts the heating cycle until the high-limitthermostats

 

close once more. At that moment the burner control will reset the appliance and

 

the heating cycle will restart. The high-limitsafeguard serves to prevent

 

overheating and/or excessive formation of scale in the appliance.

 

 

Safety thermostat

When the safety thermostat sensor (38) measures a temperature higher than

 

93°C, the safety thermostat will open. The heat demand is terminated and the

 

burner control will immediately halt the heating cycle. The burner control will go

 

into a lockout error state. This must be manually reset before the appliance can

 

resume operation.

2.5Safety of the installation

2.4.3Flue gas backflow safeguard

The flue gases are discharged to the outside via the draught diverter (33) and the flue (22). To prevent the flue gases from flowing back into the boiler room, the discharge ducting is monitored by a feature called the Thermal Reflux Safeguard (TRS). This uses a flue gas thermostat (37) with a flue gas thermostat sensor (34) that are located in the draught diverter. Under normal circumstances this sensor will register the ambient temperature.

However, if the chimney is not drawing sufficiently (for example, due to a blockage in the chimney), the flue gases will 'reflux' and flow back past the flue gas thermostat sensor. The sensor will then detect an excessive temperature and the flue gas thermostat will open. The demand will cease, and the burner control will immediately stop the heating cycle. The flue gas thermostat will also lock out. It must be manually reset before the appliance can resume operation .

2.4.4Flame probe

To ensure that no gas can flow when there is no combustion, the water heater is fitted with a flame probe (21). The burner control uses the ionisation-detectingproperties of this probe for flame detection. The burner control closes the gas valve the instant it determines that there is a gas flow but no flame is present.

In addition to the appliance's standard built-insafety monitoring, the appliance must also be protected by an expansion vessel, expansion valve, pressure reducing valve,non-returnvalve and a T&P valve.

The use of an expansion vessel, expansion valve and/or pressure reducing valve depends on the type of installation: unvented or vented.

2.5.1Inlet combination and pressure-reducingvalve

In addition to the appliance's standard built-insafety monitoring, the appliance must also be protected by an expansion vessel, expansion valve, pressure reducing valve,non-returnvalve and a T&P valve.

The use of an expansion vessel, expansion valve and/or pressure reducing valve depends on the type of installation: unvented or vented.

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Working principle of the appliance

 

 

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2.5.2Unvented installation

With an unvented installation, an expansion valve valve and expansion vessel prevent the buildup of excessive pressure in the tank. This prevents damage being caused to the enamelled coating (in the appliance) or to the tank. A nonreturn valve prevents excessive pressure buildup in the water supply system. This valve also prevents water from flowing backwards from the tank into the cold water supply system. The pressure reducing valve protects the installation against an excessively high water supply pressure (> 8 bar). These components are fitted to the cold water pipe (3.6 "Water connections, Vented").

2.5.3Vented installation

With vented installation, excess pressure is taken up by the open cold water head tank. The head height of the tank determines the working pressure in the water heater, which may not exceed 8 bar. The installation must also be fitted with a vent pipe from the hot water pipe (3.6.3 "Hot water side"), which opens into the cold water tank.

2.5.4T&P valve

A T&P valve is only mandatory in an unvented installation. However, A.O. Smith also recommends the use of a T&P valve in vented installations.

A T&P (Temperature and Pressure Relief) valve monitors the pressure in the tank and the water temperature at the top of the tank. If the pressure in the tank becomes excessive (> 10 bar) or the water temperature is too high (> 97°C), the valve will open. The hot water can now flow out of the tank. Because the appliance is under water supply pressure, cold water will automatically flow into the tank. The valve remains open until the unsafe situation has been rectified. The appliance is fitted standard with a connecting point for a T&P

valve (3.7.3 "Hot water side").

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3 Installation

Warning

Installation work should be carried out by an approved installation engineer in compliance with the general and local regulations imposed by the gas, water and power supply companies and the fire service.

The appliance may only be installed in a room that complies with the requirements stated in national and local ventilation

regulations (1.3 "Regulations").

3.1

Introduction

This chapter describes the installation activities to be carried out before the

 

 

appliance may be started up (9 "Starting and running"), in particular:

 

 

Packaging;

 

 

Ambient conditions;

 

 

Technical specifications;

 

 

Water connections, Vented;

 

 

Water connections, Vented;

 

 

Gas connection;

 

 

Chimney flue;

 

 

Electrical connection;

 

 

Checking the supply pressure and burner pressure.

 

 

For a possible conversion to a different gas category, see

 

 

conversion (4 "Conversion to a different gas category").

3.2

Packaging

To avoid damaging the appliance, remove the packaging carefully.

 

 

We recommend unpacking the appliance at or near its intended location.

 

 

 

 

 

 

 

Caution

 

 

 

The appliance may only be manoeuvred in an upright position. Take care

 

 

that the appliance is not damaged after unpacking.

3.3

Ambient conditions

 

 

 

 

 

Caution

 

 

 

The appliance may not be used in rooms where chemical substances are

 

 

stored or used, due to the risk of explosion and/or corrosion of the appliance.

Some propellants, bleaching agents, degreasing agents etc. disperse vapours which are explosive and/or which cause accelerated corrosion. If the appliance is used in a room in which such substances are present, the warranty will be void.

ADM appliances are open appliances and may only be installed in an open boiler room. Their type is B11BS.

3.3.1Air humidity and ambient temperature

The boiler room must be frost-free,or be protected against frost. The table shows the environmental conditions that must be adhered to for correct functioning of the electronics present in the appliance to be guaranteed.

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Installation

 

 

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Air humidity and ambient temperature specifications

 

 

Air humidity and ambient temperature

 

 

Air humidity

max. 93% RV at +25°C

 

 

Ambient temperature

Functional: 0 < T< 60°C

 

 

 

3.3.2

Maximum floor load

 

 

 

 

 

In connection with the appliance's weight, take account of the maximum floor

 

 

loading, refer to the table.

 

 

 

 

 

 

 

 

Weight of the appliance filled with water

 

 

 

 

 

 

 

 

 

 

 

ADM 40

ADM 50

ADM 60

ADM 80

ADM 90

ADM 115

ADM 135

 

 

 

 

 

 

 

504 kg

578 kg

507 kg

573 kg

522 kg

523 kg

581 kg

 

 

 

 

 

 

 

3.3.3 Water composition

The appliance is intended for heating drinking water. The drinking water must comply with the regulations governing drinking water for human consumption. The table gives an overview of the specifications.

Water specifications

Water composition

Hardness

> 1.00 mmol/l:

(alkaline earth ions)

• German hardness> 5.6° dH

 

• French hardness > 10.0° fH

 

• English hardness > 7.0° eH

 

 

Conductivity

> 125 µS/cm

 

 

Acidity (pH value)

7.0 < pH value < 9.5

 

 

 

 

Note

If the water specifications deviate from those stated in the table, then the tank protection cannot be guaranteed (13 "Warranty (certificate)").

3.3.4Working clearances

For access to the appliance, it is recommended that the following clearances are observed (see figure):

AA: around the appliance's control column and cleaning openings: 100 cm.

BB: all sides of the appliance: 50 cm.

Above the appliance (room to replace the anodes):

-100 cm if using fixed anodes, or

-50 cm if using flexible anodes.

If the available clearance is less than 100 cm, flexible magnesium anodes may be ordered.

Note

When installing the appliance, be aware that any leakage from the tank and/or connections can cause damage to the immediate environment or floors below the level of the boiler room. If this is the case, the appliance 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 5cm deep with a length and width at least 5cm greater than the diameter of the appliance.

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Working clearances

B

B

 

3.4Technical specifications

AA

 

A

 

A

A

A

 

IMD-0262R2

The appliance is supplied without accessories. Check the

dimensions (3.4.1 "Dimensions of the appliance"), gas data (3.4.3 "Gas data") and other specifications (3.4.2 "General and electrical specifications") of any accessories you plan to use.

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Installation

 

 

3.4.1Dimensions of the appliance

Plan and elevation of the appliance

is

Legend

F

See the table.

10º

E

37º

45º

G

H

D

2

5

A

B

6

6

4

1

 

3

P

R

M

K

J

S

N

IMD-0135R2

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Dimensions (all measurements in mm unless otherwise indicated)

Dime

Description

ADM

ADM

ADM

ADM

ADM

ADM

ADM

nsion

 

40

50

60

80

90

115

135

 

 

 

 

 

 

 

 

 

A

Total height

1900

2100

1900

2100

2000

2085

2085

 

 

 

 

 

 

 

 

 

B

Height of top of appliance

1760

1960

1760

1960

1795

1870

1870

 

 

 

 

 

 

 

 

 

D

Appliance diameter

710

710

710

710

710

710

710

 

 

 

 

 

 

 

 

 

E

Depth

800

800

800

800

800

800

800

 

 

 

 

 

 

 

 

 

F

Width

1100

1100

1100

1100

1105

1105

1105

 

 

 

 

 

 

 

 

 

G

Diameter of chimney flue

150

150

180

180

225

225

225

 

 

 

 

 

 

 

 

 

H

Heart appliance / Heart chimney

660

660

660

660

675

675

675

 

flue

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

J

Height of chimney flue

1840

2040

1840

2040

1935

2010

2010

 

 

 

 

 

 

 

 

 

K

Height of gas connection

400

400

400

400

400

400

205

 

 

 

 

 

 

 

 

 

M

Height of cold water supply

565

565

565

565

575

650

650

 

 

 

 

 

 

 

 

 

N

Height of hot water outlet

1605

1810

1605

1810

1640

1715

1715

 

 

 

 

 

 

 

 

 

P

Height of cleaning opening

730

730

730

730

740

825

855

 

 

 

 

 

 

 

 

 

R

Height of drain valve connection

500

515

500

515

525

600

595

 

 

 

 

 

 

 

 

 

S

Height of T&P valve connection

1550

1760

1550

1760

1595

1660

1660

 

 

 

 

 

 

 

 

 

1

Cold water supply connection

R11/2

R11/2

R11/2

R11/2

R11/2

R11/2

R11/2

 

(male)

 

 

 

 

 

 

 

2

Hot water outlet connection

Rp11/2

Rp11/2

Rp11/2

Rp11/2

Rp11/2

Rp11/2

Rp11/2

 

(female)

 

 

 

 

 

 

 

3

Gas control connection (female)

Rp3/4

Rp3/4

Rp3/4

Rp3/4

Rp3/4

Rp3/4

Rp1

4

Drain valve connection (female)

Rp11/2

Rp11/2

Rp11/2

Rp11/2

Rp11/2

Rp11/2

Rp11/2

5

T&P valve connection (female)

1 - 11.5

1 - 11.5

1 - 11.5

1 - 11.5

Rp11/2

Rp11/2

Rp11/2

 

 

NPT

NPT

NPT

NPT

 

 

 

6

Cleaning/inspection opening

Ø 100

Ø 100

Ø 100

Ø 100

Ø 100

Ø 100

Ø 100

 

 

 

 

 

 

 

 

 

3.4.2General and electrical specifications

General and electrical specifications

DESCRIPTION

Unit

ADM

ADM

ADM

ADM

ADM

ADM

ADM

 

 

40

50

60

80

90

115

135

 

 

 

 

 

 

 

 

 

Capacity

litres

309

357

298

335

278

253

252

 

 

 

 

 

 

 

 

 

Maximum operating pressure

bar

8

8

8

8

8

8

8

 

 

 

 

 

 

 

 

 

Empty weight

kg

195

221

209

238

244

270

329

 

 

 

 

 

 

 

 

 

Heating-uptime ∆T = 45oC

minutes

30

26

19

17

12

8

7

Number of anodes

-

2

2

2

3

3

4

4

 

 

 

 

 

 

 

 

 

Number of bar

-

3

4

5

7

7

9

6

burners/orifices

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Number of flue tubes/flue

-

5

6

7

9

12

16

17

baffles

 

 

 

 

 

 

 

 

Electrical power consumption

W

30

30

30

30

30

30

60

 

 

 

 

 

 

 

 

 

Supply voltage

volts

230

230

230

230

230

230

230

(-15%+10% VAC)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Mains frequency

Hz (± 1Hz)

50

50

50

50

50

50

50

 

 

 

 

 

 

 

 

 

IP class

-

30

30

30

30

30

30

30

 

 

 

 

 

 

 

 

 

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Installation

 

 

3.4.3Gas data

Gas data

is

Description II2H3+

Unit

ADM

ADM

ADM

ADM

ADM

ADM

ADM

 

 

40

50

60

80

90

115

135

 

 

 

 

 

 

 

 

 

Gas category 2H: General

 

 

 

 

 

 

 

 

Orifice diameter

mm

3.20

3.20

3.10

2.95

3.20

3.20

3.90

 

 

 

 

 

 

 

 

 

(1) = Blank plate

1, 2 or 3

2

2

2

2

2

2

2

(2) = Burner pressure regulator

 

 

 

 

 

 

 

 

(3) = High/low regulator

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Gas category G20 - 20 mbar

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Nominal load (gross calorific value)

kW

42.2

56.5

66.4

82.5

98.3

126.6

143.4

 

 

 

 

 

 

 

 

 

Nominal output

kW

32.3

42.8

50.2

62.4

74.3

95.8

109.8

 

 

 

 

 

 

 

 

 

Supply pressure

mbar

20

20

20

20

20

20

20

 

 

 

 

 

 

 

 

 

Burner pressure

mbar

8.5

8.5

8.5

8.5

8.5

8.5

11.3

 

 

 

 

 

 

 

 

 

Gas consumption (*)

m3/h

4.0

5.4

6.3

7.9

9.4

12.1

13.7

Gas category 3+: General

 

 

 

 

 

 

 

 

Orifice diameter

mm

1.70

1.70

1.70

1.50

1.70

1.70

2.25

 

 

 

 

 

 

 

 

 

(1) = Blank plate

1, 2 or 3

1

1

1

1

1

1

3

(2) = Burner pressure regulator

 

 

 

 

 

 

 

 

(3) = High-lowcontrol

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Gas category G30 - 30 mbar

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Nominal load (gross calorific value)

kW

41.6

55.3

68.2

80.7

96.1

123.5

138.4

 

 

 

 

 

 

 

 

 

Nominal output

kW

32.6

42.8

52.8

62.6

74.5

95.8

108.5

 

 

 

 

 

 

 

 

 

Supply pressure

mbar

30

30

30

30

30

30

30

 

 

 

 

 

 

 

 

 

Burner pressure (†)

mbar

-

-

-

-

-

-

-

Gas consumption (*)

kg/h

3.0

4.0

5.0

5.9

7.0

9.0

10.1

Gas category G31 - 37 mbar

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Nominal load (gross calorific value)

kW

38.4

51.1

63.3

77.7

89.6

113.0

130.1

 

 

 

 

 

 

 

 

 

Nominal output

kW

30.0

39.5

48.9

60.1

69.2

87.4

101.7

 

 

 

 

 

 

 

 

 

Supply pressure

mbar

37

37

37

37

37

37

37

 

 

 

 

 

 

 

 

 

Burner pressure (†)

mbar

-

-

-

-

-

-

-

Gas consumption (*)

kg/h

2.7

3.7

4.5

5.6

6.4

8.1

9.3

(*) Based on 1013.25 mbar and 15 °C.

(†) 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.

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