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A Honeywell Company
DMG 973
Gas Burner Safety Control
For 2-stage forced draught and combi
oil/gas burners, facility to connect an air
damper unit
Possible flame detectors:
- Ionisation probe
- Infrared flicker detector 1020.1
- UV flame sensor UVD 971
INTRODUCTION
The burner control box DMG 973 controls and supervises
power burner for gas and dual fuel. The control box is
currently under approval according the relevant European
standards. The use on direct air heaters according DIN 4794
is also possible.
With the facility to connect an air damper unit, a 2 stage
operation with two fuel valves or a modulating operation
with one fuel valve is possible.
The microprocessor- based programming sequence ensures extremely stable timings independent of voltage variations, ambient temperature and/or switch-on cycles. The
built-in information system not only provides a continuous
monitoring of the actual state of the box (very helpful especially for monitoring the start-up phase) but also informs
about the cause of a possible lock out. The lock out cause
is stored in such a way that it can be retrieved even after a
power failure.
The control box is designed for maximum safety in case of
fluctuations in the voltage supply. If the mains voltage drops
below the permitted level, operation is interrupted and the
control box automatically prevents the start sequence from
being repeated. In this way, the safety of the system is not
put at risk by a drop in the mains voltage. This low-voltage
protection works not only during start-up but also permanently during operation.
CONSTRUCTIONAL FEATURES
Microprocessor, electronic components, output relais and
flame amplifier are placed on two printed circuit boards.
These plus the lockout- and reset circuit are well protected
inside a flame resistant, plug-in type plastic housing.
The reset switch for reset / remote lockout with its built-in
LED for displaying the information system plus the central
fixing screw are placed on top of the housing.
The wiring base S98 is equipped with spare- and
extraterminals and allows together with a variety of cable
entry points utmost flexibility of electrical wiring.
The DMG 973 is funstionally compatible to MMI 813 and
MMI 813.1
Please note: Is the DMG 973 to be used to
replace the MMI 813 or 813.1, care has to be
taken to make sure the air proving switch (LW) is
wired between terminals 4 and 7 and not like on
the MMI between 5 and 7.
Table of timings (sec.)
Model max. reaction supervised pre-ignition LK-open command LK-close post-ignition Stray light safety delay
EN1C-0131SZ20 R0305
time for air pre-purge time during pre-purge movement time monitoring time terminal 6/C
proving switch time
tlw tv1 tvz tkl tr tn tf ts tv2
01 60 44 3 36 8 2,5 5 3 6
TECHNICAL DATA
Operating voltage 220 / 240 V (-15... +10%)
50 Hz ( ±5%)
or 110 / 120 V (-15... +10%)
60 Hz ( ±5%)
Fuse rating 10 A fast, 6 A slow
Power consumption ca. 12 VA
Max. load per output
- term. 3 ignition trafo 1.5 A, cos ϕ 0.2
- term. 4 motor 2.0 A, cos ϕ 0.4
- term. 5 + 6 solenoid valves 1.0 A, cos ϕ 0.4
- term. C air damper 1.0 A, cos ϕ 0.4
- term. B alarm indicator 1.0 A, cos ϕ 0.4
total load 5.0 A, cos ϕ 0.4
max. 20 A during 0.5 sec
Direct lockout after a loss-of-flame during operation
Air proving switch 1 working contact 4 A, 230V
Sensitivity (operation) 1 µA
Min. required ion. current 1.5 µA
Sensitivity for stray light 0.4µA
Ionisation probe insulation Probe - earth
greater than 50 MΩ
stray capacity Probe - earth
less than 1000 pF
cable lenght < 3 m
Flame detectors
IRD 1020.1 side-on or end-on viewing
UVD 971 end-on viewing
Weight incl. Wiring base 190 g
Mounting position any
Protection class IP 40
Approved ambient parameter
for control and flame detector max. 95% at 30° C
- for operation -20° C... +60° C
- for storage -20° C... +80° C
Build-up of ice, penetration of
water and condensing water are inadmissible
Approvals according
to European standards EN 298 and EN 230, as
well as all other relevant
Directives and standards
Classified acc. to EN 298 FTLLXN
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APPLICATION FEATURES
1.2 Lock-out diagnoses
1. Information system
The information system is microprocessor based and reports on all aspects of burner control box operation and
flame supervision. It informs continuously about the actual
programming sequence the unit is just performing. Besides
monitoring of the programming sequence it also allows to
identify errors during start-up of operation without any
additional testing devices. The automatically performed
diagnosis is a valuable tool which facilitates service/
maintenance work and therefore saves costs. The analyses
of the error cause can be done directly on stage or if not
possible afterwards as the lock out reason is stored in a nonvolatile lock out mode memory.
The information system communicates with the outside
world using a LED (the used Flash-Code is similar to the
Morse-Code). The messages are optically transmitted by a
appropriately flashing LED. Using an additional terminal
(optional), the messages can be recorded and displayed in
easy readable form.
1.1 Programming sequence display
The built-in microprocessor controls not only the programming sequence but the information system too. The
individual phases of the programming sequence are
displayed as Flash-Code.
The following messages can be distinguished:
In case of a failure the LED is permanently illuminated. Every
10 seconds the illumination is interrupted by a flash code,
which indicates the cause of the error. Therefore the following
sequence is performed which is repeated as long as the unit
is not reset.
Sequence:
illuminated phase dark phase Flash-Code dark phase
❘ ❚ ❚ ❚ ❚
for 10 sec for 0.6 sec for 1.2 sec
Error diagnosis
Error message Flash-Code Possible fault
lock out ❘ ❚ ❚ ❚ ❚ within lock out safety time
safety time no flame establishment
stray light ❘ ❘ ❚ ❚ ❚ stray light
during monitored phase,
detector may be faulty
air proving switch ❚ ❚ ❘ ❘ ❘ air proving switch
in closed position contact welded
air proving switch ❘ ❘ ❘ ❚ ❚ air proving switch does not
time-out close within specified time
air proving switch ❘ ❘ ❘ ❘ ❚ air proving switch opens
opened during start or operation
loss of flame ❚ ❚ ❚ ❚ ❘ loss of flame during
operation
Message Flash-Code
waiting for ❘ ❘ .
air proving switch
pre-purge ❘ ❘ ❘ .
tv1
pre-ignition ❘ ❘ ❘ ❘ .
tvz
safety time ❚ ❘ .
ts
delay 2nd stage ❚ ❘ ❘ .
tv2
running ❘ _
low mains voltage ❘ ❚ ❚ _
Internal fuse defect ❘ ❚ _
> control box defect
Description
❘ = short pulse
❚ = long pulse
. = short pause
_ = long pause
Flash-Code for manual lock out
anual/external ❘ ❘ ❚ ❚ ❚ ❚ ❚ ❚ ❚ ❚
lock out
(see also 3. lock out and reset)
2. Flame detection
The following types of flame detectors are suitable:
– Ionisation probe, temperature resistant material, well
insulated (material and insulation same as for ignition
electrode).
– Infrared-flicker detector type IRD 1020.1 with mounting
flange M 93 or the UV solid state flame sensor UVD 971.
Flame detection using an ionisation probe is only possible
in conjunction with mains supplies which provides a neutral earth connection.
Connecting the IRD 1020.1 or UVD 971 the correct wiring
has to be observed.
2.1 Stray light monitoring
The stray light check is performed at the end of the prepurge time for thr duration as mentioned in the table of
timings.
DMG 973
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3. Lock out and reset
7. Mounting and electrical wiring
The unit can be reset or brought into lock out mode in two
different ways:
Internal
In the lock out case the unit can be reset by pushing the builtin button meaning a new start-up cycle is performed.
External
Instead of using the built-in lock out button the same
function can be achieved by using an external button which
connects terminal 9 with A (see also circuit and block
diagram).
If the pushputton (internal or external) is pressed during
normal operation or during the start sequence for more then
3 sec. and afterwards released, the control box will perform
a shutdown.
Please note
The unit can only be brought to lockout mode or
be reseted if power is applied to the unit.
4. Low-voltage protection
at 220 / 240V (110 / 120V) nominal voltage
The mains voltage has to be more than 187 V
order to allow the unit to perform a start-up.
(94 V
eff
) in
eff
The mains voltage is not only monitored in the start-up
phase but also permanently during operation. If the voltage
drops below < 160 V
control box proceed to safety shut-down and goes into a
(80 V
eff
) during start-up or run time the
eff
waiting status. If the voltage rises again, the control box
performs automatically a start-up as soon as the mains
voltage is > 187 V
(94 V
eff
).
eff
Wiring base:
– 3 earth terminals with additional terminal for burner
earthing
– 3 neutral terminals with internal permanent connection to
neutral terminal 8
– 2 independant spare terminals (S1 and S2)
– extra terminals A, B and C are standard (wiring base S98
12-pin)
– 2 slide-in plates and 2 easy knock out holes plus 2 knock
out holes in the base bottom faciliate the base wiring
Please note
To assist trouble-free operation the main neutral
connection terminal 8 in the wiring base must be
fully tightened. The terminal screws are already in
the undone position. To connect a wire to the
terminal, the screw only needs to be fastened.
General: The control box and detector probes should not be
subjected to excessive vibration.
5. Safety
The design and control sequence of the DMG 970 controls
will comply with the currently applicable standards and
regulations (see also TECHNICAL DATA).
6. Burner with an air damper motor
The position of the air damper during pre-purge
has to be assured by suitable actions
(EN 676, 4.4.1.2).
DMG 973
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INSTALLATION INSTRUCTIONS AND MAINTENANCE
3. Fault finding
1. Important notes
– The controls must be installed by qualified personnel
only. The relevant national regulations have to be
observed.
– On commissioning the wiring has to be carefully check-
ed according the appropriate diagram, Incorrect wiring
can damage the unit and endanger the installation.
– The fuse rating has to ensure that the limits specified in
TECHNICAL DATA will not be exceeded. If these precautions are not observed, the effect of a short circuit can
cause severe damage to the control and installation.
– For safety reasons a minimum of one control shutdown
per 24 hours has to be observed.
– Disconnect the mains before the control box is plugged
in or out.
– The control box is a safety device and must not be
opened!
2. Function control
For safety reasons the flame detection system should be
tested on commissioning the installation as well as after a
service or longer shut-down.
a) Start-up with closed gas valve
– After lock out safety time is over the unit has to go into
lock out mode!
b) Normal start-up, when burner is running, close gas valve
– After loss of flame, the control box has to go into
lockout mode
c) Normal start-up, during pre-purge or operation, interrupt
the air proving switch
– The control box has to perform a lockout immediatly
d) Bridged air proving switch before start
– the fan motor switches on for approx. 2 - 3 secs,
followed by a lockout. After 10 secs., this quick
lockout is resetted by the control box and a second
start attempt follows (fan motor switches on for approx.
2 - 3 secs.). A standard lockout appears if the air
proving switch (LW) contact is still in it’s closed
position (e.g. welded contacts). Has the air proving
switch (LW) changed to it’s open position in the
meantime (e.g. by a run down motor), a normal start
sequence follows.
The built-in information system facilitates the trouble shooting in the case of problems occurring during start-up or
during operation.
A list of possible lock out messages can be found in
APPLICATION FEATURES chapter 1.2.
Please note:
The control box is locked in lock out mode
and the reasen for the lock out is displayed
until the control box is reset, either by an
internal or external reset (see also subject “3.
Lock out and reset").
Removing the control box from its wiring base or by
interrupting the supply line may not reset a lock out. Therefore, by applying power, the fan motor switches on for 2-3
secs. before the control box goes to lock out again and the
cause of the last lock out.
Error Possible fault
Burner not working - Thermostat circuit open
- Faulty electrical wiring
- Mains voltage < 187 V (< 80 V)
- Terminal A continuously on
power (e.g. terminal A is used as
a support terminal)
Fan motor starts for a short - Control box has not been reset
period of time, control box - Air proving switch not in open
goes to lock out position
Control box locks out - Air proving switch has not
during pre-purge closed within 60 secs.
- Air proving switch has re-opened
Control box locks out - Air proving switch open
at the end of pre-purge - Flame signal (stray light)
Burner starts, - No ignition or no fuel
flame not established
after safety time,
lock out
Burner starts, - No or too low flame signal (flame
flame established, does not stick, bad insulation of
after safety time, the ionisation probe, bad conneclock out tion to frame ground)
- Insufficient light on IRD
- Sensitivity adjustment
too low on IRD
DMG 973
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CIRCUIT AND TIMING DIAGRAM DMG 973
WITH AIR DAMPER MOTOR
Ph
max. 10A fast
HS
ST GW RT
6A low
5
4
1
3
2
IS
M
Z
6
V1
N
WITHOUT AIR DAMPER MOTOR
Ph
max. 10A fast
HS
ST GW RT
6A low
5
4
1
3
2
6
EV
HS Mains switch
GW Gas proving switch
ST Limit thermostat
RT Control thermostat
EV External reset and lock out button
B
C
9
7
A
8
LW
L
SA
EV
B
C
9
7
A
8
IS Ionisation probe
(IRD 1020.1, UVD 970 see separate
diagram)
Z Ignition
M Burner motor
V1 Solenoid valve, 1st-stage
V2 Solenoid valve, 2nd-stage
LW Air proving switch
SA External lock out signal
L Air damper motor
tlw max. reaction time for air proving
switch
tv1 Supervised pre-purge time
tlk LK-open command during
pre-purge
tr LK-close movement
tf Stray light monitoring
tvz Pre-ignition time
tn Post-ignition time
ts Safety time
tv2 Delay terminal 6/C
LW
IS
M
Z
N
IRD- OR UVD CONNECTION
IRD 1020.1
UVD 971
BLOCK DIAGRAM DMG 973
Oscillator
µC
Watchdog
Reset
Flame
amplifier
V1
V2
EEPROM
µC
blue
black
brown
SA
tlw
Fault display
Information
system
tv1
tlk
term. 8
term. 2
term. 9
Reset and
lock out
Mains
monitoring
Power
supply
monitoring
ts
tvz
tf
tr
tv2
tn
DMG 973
Power
supply
rlk
RV1 RV2 RS
RZ
rv1
RLK
rs
rz
rv2
2C657 43B 89A
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DMG 973 AND SOCKET
4,5
HOLDER M 93 FOR IRD
35
3
62,5
86
24
Reset button
30
44
Earth
30
M4
16
30
57-60
UVD 971 IRD 1020.1
29
29
38,5
24
Slide-in plate
35
25
Underside cable
entry ø16 mm
50
60
UVD = 29
IRD = 44
14
15.1
48
4
17
ø20.5
HOLDER M 74 FOR UVD
35
ø 14
ø20
48
26
4.5
3
4,5
4
26
7
21,8
21,8
ø13,5
UVD = 89
IRD = 104
VARIATION IRD
right
axial
left
ORDERING INFORMATION
ITEM DESIGNATION ITEM NO.
Control box DMG 973 Mod. 01 0353001
Socket Wiring base S98 12-pin 75310
Insert plate PG-Plate 70502
optional Cable entry plate 70503
Flame detector IRD 1020.1 end-on 16532
Flame detector IRD 1020.1 left 16533
Flame detector IRD 1020.1 right 16531
optional UVD 971 16722
Support for IRD Holder M93 for IRD 1020 59093
Support for UVD Holder M74 for UVD 59074
Connection cable Plug type, 3 core cable, 0.6 m with tag wire ends 7236001
The above ordering information refers to the standard version.
Special versions are also included in our product range. Specifications subject to change without notice
DMG 973
A Honeywell Company
6
Satronic AG
Honeywell-Platz 1
Postfach 324
CH-8157 Dielsdorf
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