Honeywell DMG 973 User Manual

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

1

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

2