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Chaffoteaux & Maury
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MX2 30 FF

Chaffoteaux & Maury MX2 24 FF, MX2 30 FF Maintenance & Serice Manual

Supplied By www.heating spares.co Tel. 0161 620 6677
MAINTENANCE AND
c
Heating and Instantaneous Domestic Hot Water
Dimensions
SERVICE GUIDE
Fanned Flue Combination Boiler
All dimensions in mm
I Safety valve outlet
The boiler is suitable for the flue types:
• type C 12
• type C 32
• type C 52
Outer case dimensions :
Fig. 1
- Height : 720
- Width : 390 (minimum space required 400)
- Depth : 296
J Heating flow K D.H.W. flow L Gas supply M Cold water inlet N Heating return
Technical data
Nominal gas flow rate at 15°C and 1013 mbar MX2 24 MX2 30
Maximum Minimum Maximum Minimum
power 24 kW power 10 kW power 30 kW power 10 kW
- Natural gas ( G 20) at 20 mbar 2.76 m
- Butane gas ( G 30) at 28 mbar 2.06 kg/h 0.94 kg/h 2.50 kg/h 0.94 kg/h
- Propane gas ( G 31) at 37 mbar 2.02 kg/h 0.93 kg/h 2.47 kg/h 0.93 kg/h Injectors and gas valves seat diameter MX2 24 MX2 30
Natural gas Butane or Propane Natural gas Butane or Propane
3
DHW flow rate at 30°C MX2 24 : 11,4 l/min
MX2 30 : 14,3 l/min
DHW flow rate at 35°C MX2 24 : 9,85 l/min
MX2 30 : 12,25 l/min Minimum DHW operating flow rate : 2 l/min Minimum DHW working pressure : 0.1 bar Maximum DHW working pressure : 10 bar Gas category : II 2H 3+
/h 1.27 m3/h 3.41 m3/h 1.27 m3/h
- Manifold injectors (11 for 24 kW) 1.35 mm 0.80 mm 1,30 mm 0,80 mm (14 for 30 kW)
These Instructions Must Be Left With The Appliance.
Supplied By www.heating spares.co Tel. 0161 620 6677
Pump and expanssion vessel characteristics
PUMP HEAD AVAILABLE
Minimum flow rate (with all heating thermostatic valves closed)
mCE
Head available / flow
1. Pressure relief valve
2. Heating Flow isolating valve
3. DHW outlet
4. Gas service tap
System capacity chart
Central heating initial pressure when cold (in bar)
C liters
Note : The system initial pressure should be over the following value :
System static height (in metre) + 0.7 = Initial pressure (in bar)
10
Components location
5.Water service tap
7. CH Return isolating valve
1 2 3 4 5 7
Fig. 2
8. Steel chassis
9. Flow control thermistor
10. Return control thermistor
11. Over heat security
12. Expansion vessel (not visible)
13. Gas valve
14. Electrical box
15. ON/OFF push button and power on indicator light
16. Domestic hot water temperature
adjustment
17. Heating flow temperature adjustment
18. CH pressure gauge
19. Heating temperature indicator
20. Reset button and Red indicator
21. Orange indicator - Burner ON
22. Three way valve
23. 3 way valve motor
24. Multigas burner comprising:
-25. 11 or 14 burner heads
-26. Manifold
-27. Ionization electrode
-28. Ignition electrode
29. Main heat exchanger
30. Water/water heat exchanger
31. DHW flow sensor
32. Combustion chamber made of aluminium coated steel with 4 ceramic fibre panels to insure heat insulation
- Lock out / flame failure
2
33. Right hydraulic assy
34. Left hydraulic assy
35. Single speed pump
36. Automatic air separator and automatic vent
37 Automatic by-pass
38. Flue hood with fan
39. Air Pressure switch
40. Flue sampling point
Supplied By www.heating spares.co Tel. 0161 620 6677
FUNCTIONING
38
39
11
25 28
27
26 30 34
13
40
9
Switching on
1) Check that the gas service tap is opened at the gasmeter and main power is on.
2) Check that pressure in central heating system is above 0.8
12
8
29
32 10 24
36 33
35
bar and below 1.5 bar with the pressure gauge 18.
3) Open the gas tap 3.
4) The boiler is now ready to use.
5) Push on the knob 15 . The knob 15 "power on" will light.
Hot Water
1) Turn the DHW thermostat clockwise 16.
2) Turn on a hot water tap, the orange "burner on" indicator will light 21 and the water will become hot.
Control panel
21
19
14
Fig. 3 Fig. 4
22
MX2 FUNCTIONAL DIAGRAM
15 20171618
Fig. 6
Heating mode Hot water mode
Fig. 5
3
Supplied By www.heating spares.co Tel. 0161 620 6677
Heating
1)Turn the CH thermostat clockwise 17.
2) If the room thermostat (if fitted), the boiler temperature control and the clock (if fitted) are all calling for heat, the orange "burner on" indicator 21 will light and the heating will be on. When there is a need for hot water while the heating is on, it is only necessary to turn on a hot tap. The heating will be interrupted momentarily while the hot water is being delivered. The boiler will switch back automatically to heating when the tap is turned off.
Note: if the boiler has been push off for some time the first attempt to light it may result in a lockout press the reset button 20 and the boiler will light.
To put Boiler Off Completely
1) Push the on/off button 15 and the light is off.
2) Turn the gas tap 4 Fig. 2 OFF.
Domestic Hot Water Mode
In order to supply hot water, the main switch
15 Fig. 4 must be in ON position I This will be confirmed by the green light 15 Fig. 4. Turn the selector switch 16 clock .
When a tap or shower is turned on, the flow of mains water, above 2 litres per min., will activate the 3 way valve 22 Fig. 5 to move to the DHW position.
. If this happens
The pump will now circulate primary water heated by the main heat exchanger through the secondary heat exchanger.
The gas valve 13 Fig. 5 open to allow gas to the burner. The ignition sequence begins and a continuous high speed spark ignites the gas. As soon as a flame is detected the orange indicator bulb 21 Fig. 4 will light and the modulating solenoid opens to allow the full gas rate. If a flame is not detected, after 8 seconds, the security solenoids close and shut off the gas. The red lockout indicator bulb 20 Fig. 4 will show. The domestic hot water temperature is controlled by the flow and return control thermistor 9- 10 Fig.5. This system anticipates the changes of temperature in the secondary heat exchanger and ensures accurate temperature regulation.
When the tap is closed the burner is extinguished and the pump stops.
Priority will be given to a demand for hot water. This will interrupt the central heating for the duration of hot water delivery.
Central Heating Mode
To be able to supply heating, the main button 15 Fig. 4 must be in I position. This will be confirmed by the green light.
Turn the selector switch 17 clock. When there is a demand for heating
(either from the room thermostat or the
clock) and the boiler temperature control is calling for heat. The pump starts allowing the ignition sequence to begin.
The gas valve 13 Fig. 5 open to allow gas to the burner. The ignition sequence begins and a continuous high speed spark ignites the gas. As soon as a flame is detected the orange indicator bulb 21 Fig. 4 will light. After 45 seconds the modulating solenoid opens to allow the full gas rate. If a flame is not detected, after 8 seconds, the security solenoids close and shut off the gas. The red lockout indicator bulb 20 Fig. 4 will show.
The central heating flow temperature is controlled by the central heating control thermistor 9 Fig. 5. The boiler has been designed to minimise cycling and will not attempt to relight for 3 minutes after the boiler thermostat has been satisfied (it is possible to reduce the time to 30 s if necessary). When the room thermostat is satisfied the burner will switch off and the pump will remain running for a further 3 minutes before it stops.
NB : it is possible to override the 3 minute delay by putting off and on the central heating selector switch 17.
WIRING
DIAGRAM
4
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ADJUSTMENTS ON CONTROL PCB
Adjustment on the PCB :
- P1 : Potentiometer to adjust the CH power
- P2 : Potentiometer to adjust the lighting power
- P3 : Not use
P1
Célectic Domestic flowmeter time 1.5 sec Domestic flowmeter time 0 sec.
AON operation Modulating operation Maximum heating setting 40 °C Maximum heating setting 85 °C Low-speed pump High-speed pump Anti-cycle 30 secs Anti-cycle 3 min
Detail
After completling adjustments replace rubber cover and refit outer casing
REGULATION
Temperature regulation for C/H and DHW circuits are controlled by 2 thermistors. The C/H knob allows the adjustment of temperature between 35 and 85°C. The DHW knob allows the adjustement of the DHW temperature between 40 and 60°C. The 2 thermistors are identical and interchangeable.
Resistance value are
- 10000 Ω at 25 °C
- 5828 Ω at 40 °C
- 1669 Ω at 80 °C
- 973 Ω at 100 °C
AIR PRESSURE SWITCH
The air flow rate is detected by a pressure differential created by a venturi located in the flue duct.
ON threshold ∆P > 137 Pa OFF threshold ∆P < 117 Pa
COMBUSTION TESTING
Nox Values
MX2 Natural Gas G20
MX2 24 MX2 30
CO Values ( mg/kWh )
Natural Gas G20 max power
MX2 24 44 MX2 30 58
ROUTINE SERVICING
To ensure continued efficient operation of the appliance, it is recommended that it is checked and serviced as necessary at regular intervals. The frequency of servicing will depend upon the particular installation condition and usage, but in general, once a year should be adequate.
It is the law that any service work must be carried out by a competent person such as your local Chaffoteaux Service Centre, British Gas or other CORGI registered personnel in accordance with the current Gas Safety (Installation and Use) Regulations.
The service schedule should include the following operations:
- Check the pressure in the system.
- Check the correct operation of the appliance.
- Check the correct operation of the gas controls.
- Check the functions of the safety controls.
- Check combustion chamber insulation panels for damage.
- Clean the burner.
- Clean the heat exchanger.
- Check the burner manifold injectors.
- Clean gas and water filters.
- Check expansion vessel charge pressure.
- Clean and check operation of safety valve.
Additional Procedures that may be necessary:
- Check that the fan blades are clean.
- Check, clean and replace components as necessary.
- Carry out combustion test utilising the test points in the flue turret.
SUGGESTED SEQUENCE for SERVICING
Before disconnecting or removing any parts, isolate the gas and electricity supplies. Ensure that the appliance is cool.
(for detail please see section on Parts Removal and Replacement)
Preliminary Checks
- Remove outer case
- Check the system pressure is at least
0.8 bar cold
- Check operation of solenoids.
- Check that the burner is extinguished fully when solenoids are closed in both DHW and C/H modes.
- Test ionisation functions and check that lockout occurs by turning off gas tap.
CLEANING THE BOILER
Any cleaning work must only be done when the boiler is switched off. Under normal circumstances dusting should be enough. An occasional wipe over with a damp cloth will remove any marks from the casing. On no account use an abrasive cleaning powder or liquid.
- Check burner pressure and gas flow rates.
5
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