De Dietrich MS 24 MI – страница 5

17. ELECTRICAL CONNECTIONS

This machine is only electrically safe if it is correctly connected to an efcient earth system in compliance with current

safety regulations.

Connect the boiler to a 230V single-phase earthed power supply using the supplied three-pin cable, observing correct

LIVE-NEUTRAL polarity.

Use a double-pole switch with a contact separation of at least 3 mm. When replacing the power supply cable, t a

2

harmonised HAR H05 VV-F’ 3x0.75mm

cable with a maximum diameter of 8 mm.

…Access to the power supply terminal block

• disconnect the boiler from the mains power supply using the two-pole switch;

• remove the two screws xing the control panel to the boiler;

• rotate the control panel;

• remove the cover and access the wiring area (gure 9).

The 2A fast-blowing fuse is incorporated in the power supply terminal block (to check and/or replace the fuse, pull out

the black fuse carrier).

IMPORTANT: respect polarity L (LIVE) -N (NEUTRAL).

(L) = Live (brown)

(N) = Neutral (blue)

= Earth (yellow-green)

(1) (2) = Contact for room thermostat

CG_2008 / 1009_0301

Figure 9

18. CONNECTING THE ROOM THERMOSTAT

• Access the power supply terminal block (gure 9) as described in the previous section;

• remove the jumper on terminals (1) and (2);

• thread the two-wire cable through the grommet and connect it to these two terminals.

INSTALLATION INSTRUCTIONS

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19. GAS CONVERSION

The authorised Technical Assistance Service can convert this boiler to natural gas (G. 20) or liquid gas (G.31).

Carry out the following operations:

A) replace the nozzles of the main burner and the gas diaphragm (if tted);

B) new max. and min. calibration of the pressure regulator.

A) Replace the burner nozzles

• carefully pull the main burner off its seat;

• replace the main burner nozzles making sure to fully tighten them to prevent gas leaks. Nozzle diameters are specied

in table 2.

B) Calibrate the pressure regulator

• connect the positive pressure test point of a differential pressure gauge (possibly water-operated) to the gas valve

pressure test point (Pb) (Figure 10). Only for models with sealed chambers, connect the negative pressure test point of

the manometer to a “T” tting in order to join the boiler adjustment outlet, the gas valve adjusting outlet (Pc) and the

pressure gauge. (The same measurement can be made by connecting the pressure gauge to the pressure test point

(Pb) after removing the front panel of the sealed chamber);

Measuring burner pressure using methods other than those described could lead to incorrect results as the low pressure

created by the fan in the sealed chamber would not be taken into account.

B1) Adjustment to nominal heat output:

• open the gas tap and switch the boiler to the Winter mode;

• open a hot water tap that can provide a ow rate of at least 10 litres a minute or make sure there is maximum heat

demand;

• remove the modulator cover;

• adjust the tube brass screw (a) until the pressure values shown in table 1 are obtained;

make sure that the dynamic inlet pressure of the boiler, measured at the gas valve pressure test point (Pa) (Figure 10) is

correct (37 mbar for propane or 20 mbar for natural gas).

B2) Adjustment to reduced heat output:

• disconnect the modulator power cable and unscrew the screw (b) until a pressure value corresponding to reduced heat

output is achieved (see tab. 1);

• reconnect the cable;

• mount the modulator cover and seal.

B3) Final checks

• attach the additional plate supplied with the transformer, specifying the type of gas and the calibration performed.

gas valve

mod. SIGMA 845

a

0605_1502

CG_2273 / 1008_2602

gas diaphragm

Figure 10

b

Figure 11

ATTENTION

If the natural gas inlet pressure is too low (less than 17 mbar) remove the gas diaphragm installed over the gas valve (g.

10) and set parameter F02=00 on the electronic board (§21).

INSTALLATION INSTRUCTIONS

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19.1 GAS VALVE CALIBRATION FUNCTION

To simplify calibration of the gas valve, the calibration function may be set directly

on the boiler control panel as follows:

a) hold down the buttons and together for at least 6 seconds;

b) after about 6 seconds, the symbols ash;

c) the display shows, at intervals of one second, “100” and the flow temperature.

0805_2302 / 1002_1201

In this phase, the boiler works at the maximum heating output (100%).

d) press +/- to immediately set the power of the boiler (100% or 0%);

e) adjust the “Pmax/Pmin” screw (gure 10) to set the burner pressure value as

described in table 1.

To adjust pressure at maximum power, turn the “Pmax” screw (g. 10) clockwise

to increase or anti-clockwise to decrease pressure at the burner.

To adjust pressure at minimum power, turn the “Pmin” screw (g. 10) clockwise

to increase or anti-clockwise to decrease pressure at the burner.

f) press +/- to gradually set the desired power level (interval = 1%).

Press the button to leave the function.

Note:

The function is automatically deactivated after a period of 15 minutes, at the end of which the electronic board returns to

its operating status prior to the activation of the function or prior to reaching the set maximum temperature.

Table of burner nozzles

24 MI FF - 24 FF 24 - 24 MI

gas type G20 G31 G20 G31

diameter of nozzles (mm) 1,28 0,77 1,18 0,77

Burner pressure (mbar*)

2,0 5,7 2,4 5,6

REDUCED HEAT OUTPUT

Burner pressure (mbar*)

11,6 32,6 13,8 31,0

RATED HEAT OUTPUT

Diameter of gas diaphragm (mm) 4,8 — 5,5 —

N° nozzles 13

Table 1

Consumption 15°C-1013 mbar

24 MI FF - 24 FF 24 - 24 MI

G20 G31 G20 G31

3

3

Rated power

2,80 m

/h 2,00 kg/h

2,80 m

/h 2,04 kg/h

3

3

Reduced power

1,12 m

/h 0,82 kg/h

1,12 m

/h 0,82 kg/h

3

3

p.c.i.

34,02 MJ/m

46,34 MJ/kg

34,02 MJ/m

46,34 MJ/kg

Table 2

* 1 mbar = 10,197 mmH

O

2

INSTALLATION INSTRUCTIONS

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20. VISUALISATION OF PARAMETERS ON THE DISPLAY (“INFO” FUNCTION)

Press “i” for at least 5 seconds to visualise certain boiler information on the display on the front panel of the boiler.

N.B: when the “INFO” function is enabled, the message “A00”, alternating with the boiler delivery temperature,

is shown on the display (figure 12):

0605_2204 / CG_1808

Figure 12

Press buttons (+/-) to display the following information:

•

A00: current DHW temperature (°C);

A01: current external temperature (°C) (with external sensor connected);

A02: modulation current value (100% = 310 mA METHANE - 100% = 310 mA LPG);

A03: power range (%) (MAX R);

A04: heating setpoint temperature (°C) - - If the external sensor is connected, the value of the “kt” curve is displayed

(section 26);

A05: current heating delivery temperature (°C);

A06: DHW temperature setpoint (°C);

A07: — — ;

A08: value (l/minx10) of the DHW ow rate;

A09: last error that occurred in the boiler.

This function remains active for 3 minutes. It is possible to interrupt the “INFO” function in advance by pressing button

•

(i) for at least 5 seconds, or turning off the power to the boiler.

INSTALLATION INSTRUCTIONS

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21. PARAMETER SETTINGS

To set the boiler parameters, press (– ) and (– ) together and hold down for at least 6 seconds. When the function is

activate, the “F01” appears on the display alternating with the value of the parameter shown.

Edit parameters

• Press (+/– ) to scroll through the parameters;

• Press (+/– ) to edit each parameter;

• Press ( ), to save the changes. “MEM” appears on the display;

• Press (i), to exit without saving. “ESC” appears on the display.

Factory settings

Description of parameters

24 MI FF 24 FF 24 MI 24

Type of boiler

F01

10 10 20 20

10 = sealed chamber 20 = atmospheric chamber

Gas used

00 = METHANE

F02

02

01 = LPG

02 = METHANE (WITH DIAPHRAGM)

Hydraulic system

00 = instantaneous appliance

03 = appliance with external storage boiler

F03

13 04 13 04

04 = appliance for heating only

13 = preheating (24h)

14 = preheating (1h)

Setting programmable relays 1 and 2 (See SERVICE instructions)

F04/ F05

00

00 = no associated function

Maximum CH setpoint (°C)

F06

00

00 = 85°C - 01 = 45°C (function unavailable)

F07

DHW inlet priority conguration

00 01 00 01

F08

CH max. output (0-100%)

100

F09

DHW max. output (0-100%)

100

F10

Min. heating output (0-100%)

00

Delay prior to new ignition in CH mode

F11

03

(00-10 minutes) - 00=10 seconds

F12

Diagnostics (See SERVICE Instructions)

--

F13-F14-F15

Factory settings

00

Anti-legionella function (with F03=03)

F16

00 = disabled

00

55...67 = enabled (setpoint °C)

CH pressure sensor selection

F17

00 = hydraulic pressure sensor

00

01 = hydraulic differential pressure sensor

F18

Manufacture information

00

22. ADJUSTMENT AND SAFETY DEVICES

The boiler has been designed in full compliance with European reference standards and in particular is tted with the

following:

• Air pressure switch (model 24 MI FF - 24 FF)

This device only allows the burner to ignite if the exhaust ue duct is in perfect working order.

In the event of one or more of the following faults:

• ue terminal obstructed

• venturi tubes obstructed

• fan blocked

• venturi tube connection - pressure switch tripped

the boiler remains on standby and error code E03 is displayed (see table in section 10).

• Fumes thermostat (model 24 MI - 24)

This device has a sensor positioned on the left section of the fumes hood and shuts off the gas ow to the main burner

if the ue is obstructed and/or if there is no draught.

In these conditions the boiler shuts down and displays error code E03 (section 10).

After eliminating the problem, press button ( ), for at least 2 seconds to re-ignite immediately.

It is forbidden to disable this safety device

INSTALLATION INSTRUCTIONS

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• Safety thermostat

Thanks to a sensor placed on the CH ow line, this thermostat interrupts the ow of gas to the burner if the water in

the primary circuit overheats. In these conditions, the boiler is blocked and only after the fault has been eliminated can

it be ignited again by pressing ( ), for at least 2 seconds.

It is forbidden to disenable this safety device

• Flame ionization detector

The ame sensing electrode, located on the right-hand side of the burner, guarantees safety of operation in case of gas

failure or incomplete ignition of the burner.

In these conditions, the boiler is blocked after 3 ignition attempts.

Press ( ), for at least 2 seconds to re-establish normal operating conditions.

• Hydraulic pressure switch

This device allows the main burner to be ignited only if system pressure is higher than 0.5 bars.

• Pump overrun for heating circuit

The electronically-controlled pump post-circulation function lasts 180 seconds and is enabled, in the heating mode, if

the ambient thermostat causes the burner to go out.

• Pump overrun for DHW circuit

The electronically-controlled pump post-circulation function lasts 30 seconds and is enabled, in the DHW mode, if the

probe causes the burner to go out.

• Frost protection device (CH and DHW systems)

The electronic boiler management system includes a “frost protection” function for the heating system which, when

delivery temperature falls below 5°C, operates the burner until a delivery temperature of 30°C is reached.

This function is enabled when the boiler is switched on, the gas supply is open and the system is correctly pressurised.

• Water not circulating in primary circuit (pump probably blocked)

If there is insufcient or no water circulating in the primary circuit, the boiler blocks and the error code E25 is shown on

the display (section 10).

• Anti-block pump function

If no heat demand is received for 24 consecutive hours, in the heating mode, the pump will automatically start and

operate for 10 seconds. This function is operative when the boiler is powered.

• Three-way valve anti-blockage function

If no heat demand is received for a period of 24 hours, the three-way valve performs a complete switching cycle. This

function is operative when the boiler is powered.

• Hydraulic safety valve (heating circuit)

This device is set to 3 bar and is used for the heating circuit

.

Connect the safety valve to a drain trap. Do not use it to drain the heating circuit.

N.B.: domestic hot water is guaranteed even if the NTC sensor develops a fault. In this case, temperature is controlled

by the delivery sensor.

23. POSITIONING THE IGNITION AND FLAME-SENSING ELECTRODE

9912070100

Figure 13

INSTALLATION INSTRUCTIONS

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24. CHECKING COMBUSTION PARAMETERS

To measure combustion efciency and the toxicity of the products of combustion, the boiler is tted with two dedicated

test points.

One connection point is connected to the exhaust duct and is used to measure combustion efciency and the toxicity of

the products of combustion.

The other is connected to the air intake circuit and is used to check for the presence of any products of combustion

circu¬lating in installations with co-axial ues.

The following parameters can be measured using the test point connected to the exhaust duct:

• temperature of the products of combustion;

• concentration of oxygen (O

) or, alternatively, carbon dioxide (CO

);

2

2

• concentration of carbon monoxide (CO).

The temperature of the comburent air must be measured on the test point located on the air intake ue by inserting the

measurement sensor by about 3 cm.

N.B.: to regulate the rated power, see chapter 19 (B1)

For natural draught boiler models, a hole must be made in the exhaust ue at a distance from the boiler equal to twice

the internal diameter of the ue.

The following parameters can be measured through this hole:

• temperature of the products of combustion;

• concentration of oxygen (O

) or, alternatively, carbon dioxide (CO

);

2

2

• concentration of carbon monoxide (CO).

The temperature of the combustion air must be measured close to the point where the air enters the boiler. The hole,

which must be made by the person in charge of the system during commissioning, must be sealed so as to ensure that

the exhaust duct is airtight during normal operation

.

25. PUMP CAPACITY/ HEAD

A high static head pump (GRUN-

DFOS UPSO 15-50), suitable for

installation on any type of single- or

1009_24011009_2402

double-pipe heating system, is used.

The automatic air valve incorporated

in the pump allows quick venting of

the heating system.

O

2

HEAD mH

FLOW l/h

O

2

HEAD mH

Graph 1

FLOW l/h

INSTALLATION INSTRUCTIONS

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26. CONNECTING THE EXTERNAL SENSOR

The wiring harness leaving the control board includes two RED wires tted with faston covers. Connect the external sensor

to these two wires.

With the external sensor connected, the “kt” curve (Graph 2) can be changed by pressing +/- .

N.B.: In case of installation in an average living unit (good perimeter insulation and radiator systems), set the “kt” climate

curve to “25”.

“kt” curves

TM

1012_0501

TM = Flow temperature range

Te

Te = External temperature

Graph 2

27. CONNECTING AN EXTERNAL STORAGE BOILER

Model 24 - 24FF

The DHW priority sensor NTC is supplied as an accessory.

CONNECTING THE STORAGE BOILER SENSOR

The boiler can be connected to an external storage boiler. Hydraulically connect the storage boiler as shown in g. 14.

Connect the DHW priority sensor NTC to terminals 5-6 on terminal block M2. The sensitive element of the NTC sensor must

be inserted in the special well located on the storage boiler. Adjust DHW temperature (35 °C...60 °C) by pressing +/– .

KEY:

UB STORAGE BOILER

UR HEATER

V3V EXTERNAL THREE-WAY VALVE

M2 CONNECTING TERMINAL

BLOCK

SB DHW PRIORITY STORAGE

CG_2085 / 1101_1701

BOILER SENSOR

MR HEATING FLOW

MB STORAGE BOILER FLOW

RR HEATING / STORAGE BOILER

RETURN

Figure 14

IMPORTANT : Make sure that parameter F03 = 03 (section 21).

INSTALLATION INSTRUCTIONS

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28. ANNUAL SERVICING

To optimise boiler efciency, carry out the following annual controls:

• check the appearance and air-tightness of the gaskets of the gas and combustion circuits;

• check the state and correct position of the ignition and ame-sensing electrodes;

• check the state of the burner and make sure it is rmly xed;

• check for any impurities inside the combustion chamber.

Use a vacuum cleaner to do this;

• check the gas valve is correctly calibrated;

• check the pressure of the heating system;

• check the pressure of the expansion vessel;

• check the fan works correctly;

• make sure the ue and air ducts are unobstructed.

WARNINGS

Before commencing any maintenance operations, make sure the boiler is disconnected from the power supply.

Afterwards, move the knobs and/or operating parameters of the boiler to their original positions.

29. DRAINING THE BOILER CIRCUIT

Drain the boiler by opening the drain tap.

In boilers MS 24 MI and MS 24 MI FF the drain tap is located at the bottom while for boilers MS 24 and MS 24 FF it is

next to the pump (1 – g. 15).

To drain the boiler using the drain tap located at the bottom, proceed as follows (g. 15):

- close the boiler on/off valves;

- open the drain tap using an 8 mm hex wrench;

- drain the boiler;

- close the drain tap using the 8 mm hex wrench.

CG_2284 / 1009_2405

Figure 15

INSTALLATION INSTRUCTIONS

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34. WIRING DIAGRAM

24 MI FF

DETECTION/IGNITION

ELECTRODE

CG_2075 / 1001_1806

THERMOSTAT

THREE-WAY VALVE

PUMP

GAS

VALVE

FAN

DOMESTIC WATER

PRIORITY SENSOR

DHW NTC SENSOR.

EXTERNAL

SENSOR

HYDRAULIC PRESSURE

SWITCH

SAFETY

THERMOSTAT

AIR PRESSURE SWITCH

CH NTC SENSOR

PROGRAMMING

Cable colours

C = Light blue

M = Brown

N = Black

R = Red

G/V = Yellow/Green

B = White

V = Green

INSTALLATION INSTRUCTIONS

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24 MI

DETECTION/IGNITION

ELECTRODE

CG_2076 / 1001_1807

THERMOSTAT

THREE-WAY VALVE

PUMP

GAS

VALVE

DOMESTIC WATER

PRIORITY SENSOR

DHW NTC SENSOR.

EXTERNAL

SENSOR

HYDRAULIC PRESSURE

SWITCH

SAFETY

THERMOSTAT

FUMES THERMOSTAT

CH NTC SENSOR.

PROGRAMMING

Cable colours

C = Light blue

M = Brown

N = Black

R = Red

G/V = Yellow/Green

B = White

V = Green

INSTALLATION INSTRUCTIONS

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24 FF

DETECTION/IGNITION

ELECTRODE

CG_2271 / 1006_1603

THERMOSTAT

THREE-WAY VALVE

PUMP

GAS

VALVE

FAN

TERMINAL BLOCK M2

EXTERNAL

HYDRAULIC PRESSURE

SENSOR

SWITCH

SAFETY

THERMOSTAT

AIR PRESSURE SWITCH

CH NTC SENSOR.

PROGRAMMING

Cable colours

C = Light blue

M = Brown

N = Black

R = Red

G/V = Yellow/Green

B = White

V = Green

INSTALLATION INSTRUCTIONS

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24

DETECTION/IGNITION

ELECTRODE

CG_2272 / 1010_2101

THERMOSTAT

THREE-WAY VALVE

PUMP

GAS

VALVE

TERMINAL BLOCK M2

EXTERNAL

SENSOR

HYDRAULIC PRESSURE

SWITCH

SAFETY

THERMOSTAT

FUMES THERMOSTAT

CH NTC SENSOR.

PROGRAMMING

Cable colours

C = Light blue

M = Brown

N = Black

R = Red

G/V = Yellow/Green

B = White

V = Green

INSTALLATION INSTRUCTIONS

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35. TECHNICAL SPECIFICATIONS

Model MS 24 MI FF 24 FF 24 MI 24

Category II2H3P

II2H3P

II2H3P II2H3P

Rated heat input

kW 25,8 25,8 26,3 26,3

Reduced heat input

kW 10,6 10,6 10,6 10,6

Rated heat output

kW 24 24 24 24

kcal/h 20.600 20.600 20.600 20.600

Reduced heat output

kW 9,3 9,3 9,3 9,3

kcal/h 8.000 8.000 8.000 8.000

Useful efciency according to directive 92/42/EEC

— ★★★ ★★★ ★★ ★★

Max. water pressure in CH system

bar 3 3 3 3

Expansion vessel capacity

l 6 6 6 6

Expansion vessel pressure

bar 1 1 1 1

DHW max. water pressure

bar 8 — 8 —

DHW min. dynamic water pressure

bar 0,15 — 0,15 —

Minimum DHW ow

l/min 2,0 — 2,0 —

DHW output at ∆T=25 °C

l/min 13,7 — 13,7 —

DHW output at ∆T=35 °C

l/min 9,8 — 9,8 —

Specic output (*)

l/min 12 — 12 —

Temperature range in heating system

°C 30/85 30/85 30/85 30/85

Temperature range in DHW system

°C 35/60 35/60*** 35/60 35/60***

Type

— C12-C32-C42-C52-C82-B22

B

B

11BS

11BS

Coaxial ue duct diameter

mm 60 60 - -

Coaxial air duct diameter

mm 100 100 - -

2-pipe ue duct diameter

mm 80 80 - -

2-pipe air duct diameter

mm 80 80 - -

Flue duct diameter

mm - - 125 125

Max. ue mass ow rate

kg/s 0,014 0,014 0,020 0,020

Min. ue mass ow rate

kg/s 0,014 0,014 0,018 0,018

Max. exhaust temperature

°C 146 146 110 110

Min. exhaust temperature

°C 116 116 85 85

NOx Class

— 3 3 3 3

Type of gas

— G20 G20 G20 G20

— G31 G31 G31 G31

Natural gas supply pressure

mbar 20 20 20 20

Propane gas supply pressure

mbar 37 37 37 37

Power supply voltage

V 230 230 230 230

Power supply frequency

Hz 50 50 50 50

Rated power supply

W 130 130 80 80

Net weight

kg 33 32 29 28

Dimensions Height mm 730 730 730 730

Width mm 400 400 400 400

Depth mm 299 299 299 299

Protection against humidity and water (**) IP X5D IP X5D IP X5D IP X5D

(*) according to EN 625

(**) according to EN 60529

(***) with external storage boiler

As DE DIETRICH constantly strives to improve its products, it reserves the right to modify the information contained in this document at

any time and without prior notice. This document is issued purely for the sake of information and should not be considered as a contract

with third parties.

INSTALLATION INSTRUCTIONS

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