Datasheet Content
MMI 962.1
Gas burner automatic
safety control
For power gas burners
Terminals for air damper motor
Built-in remote reset for lock-outs
Possible flame detectors:
- Ionization probe
- Infrared flicker detector
INTRODUCTION
The gas burner automatic safety control MMI 962.1 controls
and monitors blown gas- and combined burners of any
nominal thermal load (tested and certified according to
EN 298).
If an air damper unit is connected, a 2-stage operation with
two fuel valves or a modulating operation with one fuel valve
is possible.
TECHNICAL DATA
Various types and model designations differentiate the
automatic safety controls with respect to the programme Operating voltage 220 / 240 V (-15... +10%)
times, as well as with regard to differing national standards. 50 Hz
The control box type MMI 962.1 Mod. 23 can be used Differing frequency Results in a proportional
deviation of the time
instead of the types MMI 812 Mod. 23 or MMI 812.1
Rating fuse max. 10 A rapid, 6 A slow
Mod. 23. Power consumption 10 VA
Max. load per output:
- term. 3 2A, cos ϕ 0.2
- term. 4, B 2A, cos ϕ 0.4
CONSTRUCTIONAL FEATURES - term. 5, 6, C 1A, cos ϕ 0.4
total load 5A, cos ϕ 0.4
The automatic control is housed in a non-inflammable, Amplifier sensitivity 1 µA
transparent, plug-in type plastic case and contains: Minimum required
– Synchronous motor with speed reducer gears as the Ionization current 5 µA
drive for the switching cam Flame detector cable max. 20 m cable length
Air pressure monitor working contact 4 A, 230 V
– Switching cam with informative programme display in Waiting time for
colour malfunction remedy None
– 12 times cam assembly for controlling the programme Flame detector
sequence - Ionization probe
– Plug-in type circuit boards with the electronic components - Infrared flicker detector IRD 1020
Weight, incl. base 350 g
Mounting position any
The following important indicating - and operating elements Insulation standard IP 44
are located on the front panel of the automatic control: Admissible ambient
– Illuminated pushbutton for indication of malfunctions temperature for controller
and reset and flame detector -20° C… +60° C
– Programme display in colour Classified acc. to EN 298 BTLLXN
– Screw for central mounting
program timings (sec.) MMI 962.1
Model 23
Waiting time at start-up tw 8
Max. reaction time for air
proving switch tlw 15
0708.20-01-e/04/99
Pre-purge time tv1 30
LK open signal tlk 38
Pre-ignition time tvz 3
Total ignition time tz 6.6
Safety time ts 3
Time delay term.6 / term.C tv2 8
1
APPLICATION TECHNOLOGY FEATURES COMMISSIONING AND SERVICE/MAINTENANCE
1. Flame Monitoring 1. Important Remarks
– Before commissioning, the wiring has to be accurately
The flame monitoring can be effected with the following checked. Faulty wiring can damage the unit and endanger
flame detectors: the safety of the installation.
– With ionization electrodes in power grids with earthed – The mains fuse has to be selected so that the limit values
neutral conductor, utilizable with gas burners (interference indicated under "Technical Specifications" are under no
effects of the ignition spark cannot influence the formation circumstances exceeded. Non-compliance with this
of the flame signal). regulation can have very serious consequences for the
– With infrared flicker detector type IRD 1020 for all types control unit and for the installation in the case of a short-
of burners. (siehe Dok. 746) circuit.
– For safety reasons, at least one control shut-down per
24 hours must be assured.
2. Burner Control – The control unit must be plugged-in or -out only when the
mains supply has been disconnected.
– The burner controls MMI 962.1 features a low-voltage – Automatic burner safety controls are safety devices and
protection. If the supply voltage dropps below 160 V must not be opened.
during operation, the burner switches-off. When the
supply voltage raises above 180 V, the burner performs 2. Functional Check
a restart independently. During commissioning and after an overhaul of the burner,
– The automatic burner controls MMI only operates when the following checks have to be carried out:
a) Starting test with closed manual valve and bridged gas
a load is connected to terminal 5. If the fuel valve is
monitor contact:
interrupted by an external contact during the pre-purging
– The device must go into a fault condition after the
phase, a resistance of max. 22 kW, 4 Watt has to be
safety period has elapsed.
applied bet-ween the terminals 5 and 8.
b) Close the manual valve in operating position with the gas
– Functional test of the air pressure monitor before the
monitor contact bridged.
startup and monitoring of the air pressure during the pre-
– The device must go into a fault condition after a flame
purging time, as well as in the operating condition of the
failure.
burner. For normal applications a working contact with a
c) Air pressure monitor contact interrupted:
power rating of 4 A / 230 V is sufficient.
– Device goes into a fault condition.
– In the case of the automatic control MMI 962.1, contacts d) Bridge air pressure monitor contact before starting:
can be installed between the terminals 1 and 9 (e.g., valve – Device must not start.
limit position contacts). These are checked for their
correct closing position when the unit is started up. The 3. Trouble Shooting
connection 1-9 has to be closed during the starting Burner does not go into operation, programme indication
phase of the auto-matic control. remains:
– No fuel valve must be connected to terminal 6. – Electrical connection defective.
– Thermostat or gas monitor "OFF".
3. Safety Burner does not go into operation, programme indication
rotates continuously:
With respect to design and programme sequence, the gas – Air pressure monitor defective, respectively, not in starting
burner automatic safety controls of the MMI 962 type range position. (Working contact must be open).
comply with the currently applicable European standards – Connection term. 1 - term. 9 interrupted
and regulations. – mains voltage < 180V
The automatic control switches to fault…
