Datasheet Content
503 EFD
ELECTRONIC FLAME CONTROL DEVICE
FOR INTEGRAL MOUNTING ON SIT
MULTIFUNCTIONAL GAS CONTROL
DESCRIPTION
Subject to change without notice
FEATURES
OPERATING SEQUENCE
TECHNICAL DATA
9.955.560 01
INSTALLATION
w w w . s i t g r o u p . i t
The 503 EFD is an electronic flame safety device
for controlling a gas appliance using the principles
of flame rectification.
The 503 EFD automatic device has been desi-
gned for domestic gas appliances with or without
a fan in the combustion circuit; with direct ignition
or ignition by means of an intermittent pilot in
applications which require either non-volatile or
volatile lockout. It is also possible to have two
separate electrodes for flame ignition and detec-
tion or to have these two functions incorporated in
a single electrode.
The 503 EFD family of products has been specifi-
cally designed for fixing on SIT 830, 836 and 837
TANDEM and SIT 822, 826 and 827 NOVA multi-
functional controls by means of an exclusive plastic
container which integrates itself with the valve body
and simplifies connection of the solenoid valves.
DESCRIPTION
Applications
The 503 EFD is an automatic ignition control for
applications with intermittent operation in accor-
dance with EN298 for:
- boilers with natural draught
- boilers with forced draught including dynamic
control of the air pressure switch.
Basic features include:
- Compact design
- Direct assembly on the gas control
- Incorporated igniter with reduced emission of radio
disturbances in accordance with the requirements
of the EMC directive
- Direct burner ignition (DBI) or by intermittent pilot (IP)
- Manual reset function and signalling of the
non-volatile lockout state either integrated or remote
- Multiple plug-in connectors
- Utilises well established electronic technology for
high reliability of operation
- Precise and repeatable timing
- Flame detection by ionization
- EC approval according to EN 298 standard
- Repetition of the cycle after loss off flame during
operation
- Permanent lock-out visualization, a without
thermostat input being present
- Suitable for applications at low ambient temperatures
Options available FEATURES
- Fan and air pressure switch control
- Single electrode for ignition and flame detection
- Reset button and lockout signalling integrated on
board
- Volatile lockout version for specific applications
- 230 Vac output synchronized with flame detection
(flame relay contact)
- Possibility to connect an automatic safety thermostat
in series with the solenoid valve with manual
lockout following its operation
- Protection against miswiring of the pressure switch
contacts
- Different flame current sensitivity options may be
specified
- Protection rating IP44
- Several pre-purge and safety timings can be
tailored to the application
Normal operation (natural
BOILERS WITH
NATURAL DRAUGHT draught or fan assisted)
DBI version
During the waiting or purge time,
Tw or Tp, the unit verifies that
EVMV
there is no parasitic flame signal
present, and that the internal
HV
circuitry is operating correctly. If
the unit is used on a fan-assisted
application, the air pressure
switch is verified to be in the
N.C. (normally closed) or “no
TW TW TS
flow” position.
Upon powering the fan, the unit
will not begin the operating
BOILERS WITH sequence until the N.O. (normally
NATURAL DRAUGHT open) or “flow” position is activa-
IP version ted on the air pressure switch.
After the scheduled waiting time
Tw, or purge time Tp, the built-in
igniter and the gas valve are
EV1
MV
energized. This commences the
EV2
MV safety time, Ts. The ignition
HV
spark will ignite the gas and the
flame will be sensed by the HV
electrode (single probe model)
or the detection electrode (dual
probe model).
Upon sensing the flame, the HV
TW TW TS
spark will be suppressed and the
gas valve will remain energized.
When the thermostat is satisfied,
the valve and fan are de-energi-
FAN ASSIATED BOILERS
zed and the control returns to
DBI version
the stand-by mode. The safety
OPERATING time of the 503 EFD has a
constant duration in all operating
SEQUENCE conditions and, in particular,
does not depend on the moment
EV
MV
the pressure switch is switched
HV
over.
P
TP TP TS
Behaviour under abnormal conditions
- If the air proving switch is in the N.O. (normally open) or “flow” position at
start-up, upon a request for heat, the unit will remain in a waiting mode
with the fan de-energized
- If air flow is not proven by the air-flow switch after energizing the fan, the
control will remain in the waiting mode with the fan energized until the air
flow is sensed
- Upon flame failure during normal operation, the unit will maintain the
power to the fan and start again the ignition sequence with a waiting
time (or purge time) followed by a safety time
- If no flame is sensed during any part of the safety time, the unit will
lockout
Resetting the unit
To reset the unit the reset switch is depressed. If a first reset is not
successful, wait at least 10 seconds before the next attempt.
AMBIENT WORKING TEMPERATURE
-20 to + 60 °C
HUMIDITY
95 % max. at 40 °C
SUPPLY VOLTAGE
220/240 Vac - 15 %, + 10 %, 50-60 Hz
POWER CONSUMPTION
maximum 10 VA for versions without fan
maximum 12 VA for versions with fan
ELECTRICAL RATINGS
Pilot valve or main valve: 230 Vac, 0,5 A, cosϕ≥0,4
Fan: 230 Vac, 1A, cosϕ≥0,4
Flame relay: 230 Vac, 0,5 A, cosϕ≥0,4
Alarm: 230 Vac, 1A, cosϕ=1
ELECTRICAL CONNECTIONS
High voltage probe: male fast-on connector 2,8 mm X 0,5 mm
Flame detection probe: male fast-on connector 4,8 mm X 0,5 mm
Other connections: male Molex series 2599 suitable for female Molex
series 3001 and 3002 or compatible.
PROTECTION DEGREE
Standard IP 40
IP 44 with gaskets
TIMING
Minimum waiting time Tw or purge time Tp: 1.5 ... 40 sec.
Maximum safety time Ts: 3 ... 120 sec
FLAME SENSING
Minimum flame current: 0,5... 2,5µA (standard 0,5)
Recommended flame current: > 3 times the minimum current
FUSING
Internal: 4A fast
External: 3.15A fast or less depending on the electrical loads. This fuse
protects the device in the event of overloading or short circuits and pre-
vents the intervention of the internal fuse.
IGNITION
Ignition voltage: 15 KV at 30 pF load
Repetition rate: 1Hz...25 Hz (standard 25)
Max. length of the cable: 2 m TECHNICAL
Spark gap recommended: 2-4 mm
MOUNTING DATA
Integrated on SIT 830, 836 or 837 TANDEM and SIT 822, 826, 827
NOVA multifunctional gas controls.
DIMENSIONS
TANDEM SERIES
58
97
84
121 106
34
37
92
NOVA SERIES
58 106
11
84 105
110
145 48
161
61
18 43
56
18
76
General notes
Before installing the 503 EFD read and
follow the instructions carefully. Failure to
follow the instructions could cause damage
to the ignition module or the appliance in
which it is installed. Make sure the ratings
given in the technical data match the
specifications of the appliance.
The person installing or replacing the ignition…
