Datasheet Content
MicroGasTM P25 Series
A Family of Full Sequence Controls
Certified to EN 298 : 2003
technology factfile
Microcontroller technology lies at the heart
of this microgas™ range of full sequence
controls, offering a large number of control
and timing options not normally available
from simpler units.
This compact family of control units offer
safe start-up and supervision of a wide
range of gas burning appliances, for
domestic, commercial and industrial
applications. An equally wide range of
control sequences and timing options are
available, all based on an integral spark
ignition system.
By a combination of hardware and
software selection, customers can be
offered forced or atmospheric sequences,
volatile or non-volatile lockout, a range of
spark rates and many timing and logic
functions, including multiple ignition
attempts and post purge.
This 4270 series is CE Certified and fully
complies with the requirements of the GAD
via EN 298 : 2003.
Typical applications
• Combination Boilers
• Condensing Boilers
• Heating Boilers
• Water Heaters
• Warm Air Heaters
• Radiant Tube Heaters
key features
• Programmable logic and timings
• Atmospheric or fanned application
• Integral spark and flame detection
• Multiple ignition attempts
• Volatile or non-volatile lockout
• Dual or single probe for ignition and flame detection
• Post purge
• Compact size
• Optional ‘floating supply’ capability for flame detector
• Dual, self-checking safety system
• CE Certification to EN 298 : 2003
system operation sequence
To keep abreast of current developments, controls may be subject
to change without notice. Such changes may affect the accuracy
of information contained in this data-sheet, and the manufacturers
advice should be sought if any problems arise.
Pactrol Controls Limited Unit 3, Three Sisters Enterprise Park, Antler Court, Ashton-in-Makerfield, Wigan WN4 8DU, UK
Technical specification
Electrical Supply
Voltage 230 V + 10% - 15%
Frequency 50 - 60Hz (+/- 3Hz)
Power Consumption 15VA
Supply Phase Relationship Sensitive to Live and Neutral phase reversal
Internal fuse 2A HPC (20mm)
Contact Ratings
All relay drives where used 1A Inductive 0.6pf @230V ac
Total maximum load current: 2A
Ignition
Open circuit voltage 15kV Minimum (30pf loading)
Spark energy > 4mJ (W.H.I.T.B.)
Spark gap tolerance 2.5mm to 4.5mm
Spark rate as specified in description of function
Flame Detection
Principle Rectification
Electrode configuration Dual or single probe ignition & detection
Flame detector response Flame on = 1 second max
Flame off = as specified in description of function
Minimum flame current required 1uA @230Vac supply Hardware Options
Environmental Conditions The P25 series of controls is available with
Ambient temperature range -10oC to 70oC several factory selectable options. These
Humidity 90% RH Maximum are shown in the adjacent diagram.
“L” Lockout indication with reset (indication
and reset are connected
to CON5).
operation “F” Fanned with optional 2-wire
APS (CON4).
Connections details
“1” Single stage direct burner ignition
(valves connected to CON1).
“2” Pilot + main burner (all valves
connected to CON1).
“1+1” Pilot + main burner (pilot valve
connected to CON1, main valve
to CON3).
“X” External isolating transformer for flame
detector (connected to CON3). This option
can only be selected in conjunction with
option “1” or “2”.
If this option is not specified then a jumper
link must be connected to CON3 in place
of the transformer.
(See below.)
Electrical Supply Options
The control can be specified
with either:
• A fixed phase-earth relationship
(the earth is bonded to one of the
phases in the property electrical
installation). In this case the flame
detector circuit is phase sensitive.
• An external 230V:230V 2VA
transformer with earthed
secondary. In this case the flame
detector circuit is completely
isolated from the mains supply
and is non-phase sensitive. (This is
for applications where the
phase-earth relationship is floating
or fixed at mid-rail).
• An external link which creates a
phase-earth relationship (fitted
instead of the external transformer).
Timing and Control Options
Pre-purge time: 1.5 - 50 seconds Lockout type volatile or non-volatile
Wait or pre-purge time for atmospheric burners, is the time from
the start signal, to energisation of the ignition device. Appliance type fanned or atmospheric
Pre-purge time for fanned appliances, is the time from the air
pressure switch closing (signaling sufficient airflow) to energisation APS type 2 or 3 terminal or not present
of the ignition device.
Number of ignition attempts: 1 - 5
Pre-ignition time: 1.0 - 50 seconds A number of ignition attempts can be programmed into the control
Pre-ignition time is the time following the pre-purge period when to allow it to try again if the burner does not light on the first
the ignition device, alone, is energised. attempt.
Ignition time: 1.0 - 50 seconds Minimum ignition required
Ignition time is the time that the ignition device is energised for Tells the control to remove the means of ignition immediately a
during ignition, whilst the flame detector signals an absence of flame is detected (or to leave it energised until the end of the
flame. ignition period).
Safety time: 1.0 - 50 seconds Ignition type: 3/5/12/25/50 Hz
Safety time is the time that GV1 is energised for during ignition,
whilst the flame detector signals an absence
of flame. On flame loss the following events can be programmed to occur:
Lock-out
Safety GV1 time: 0.3 - 3.0 seconds If the control is programmed to have lock-out on flame loss, then it
Safety GV1 time is the time that GV1 remains energised for, after will immediately go to lock-out…
