Honeywell DMG 971 Installation Instructions And Maintenance

1

A Honeywell Company

certified Qualitysystem

ISO 9001 / EN 29001

Reg. Nr. 10529

INTRODUCTION

The burner control box DMG 971 controls and supervises
power burner for gas and dual fuel. The control box is
approved and certified according the relevant European
standards. The use on direct air heaters according DIN 4794
is also 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 971 is funstionally compatible to MMI 811 and
MMI 811.1

Please note: Is the DMG 971 to be used to
replace the MMI 811 or 811.1, 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.

DMG 971

Gas Burner Safety Control

For 2-stage forced draught and combi
oil/gas burners

Possible flame detectors:

- Ionisation probe

- Infrared flicker detector 1020

- UV flame sensor UVD 971

TECHNICAL DATA

Operating voltage 220 / 240 V (-15... +10%)

50 Hz ( ±5%)

Fuse rating 10 A fast, 6 A slow
Power consumption ca. 15 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. B alarm indicator 1.0 A, cos ϕ 0.4
total load 5.0 A, cos ϕ 0.4

max. 10 A during 0.5 sec
Air proving switch 1 working contact 4 A, 230V
Stray light monitoring 5 sec
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 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

Timings (sec.)

0737.11-00-e/01/99

Model waiting time max. reaction time for supervised pre-ignition ignition time Stray light safety time delay

start air proving switch pre-purge time time total monitoring 2nd-stage

tlw tv1 tvz tz tf ts tv2

01 0 60 24 3 5 5 3 12.5

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APPLICATION FEATURES

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:

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 ❘ ❚ ❚ _

Description

❘ = short pulse
❚ = long pulse

. = short pause
_ = long pause

1.2 Lock-out diagnoses

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

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 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 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 technical
datas.

DMG 971