Owner`s manual

58
SET(U)-F / ITT(U)-F Manual
IM091221
RD: FEB 2014
RL: 8B
CHANNEL MICRO 50N IGNITION CONTROL - SPECS
The MICRO 50N is a microprocessor-based DSI (Direct Spark Ignition) control which continu-
ously monitors the entire system to ensure safe operation under all conditions.
Features of the MICRO 50N DSI Control include 30 second purge and 20 second ignition trial,
with three ignition attempts, a diagnostic alarm output, automatic recycle on lockout (soft lock-
out).
SPECIFICATIONS
Operating Voltage: 24 VAC, 50/60Hz
Power Consumption: 200mA maximum, exclusive of valve/alarm loads
High Voltage: 15kV minimum with 50 pF load
Spark Gap: 3/16” [4.8 mm]; 0.150 inches +/- 0.050 inches [3.8 mm +/- 1.2 mm]
Spark Rate: 60 sparks per second
Gas Valve Output: 2A maximum
Alarm Output: 2A maximum, dependent on optional alarm type
Operating Temperature: -40°F to +185°F (-40°C to +85°C)
Environmental Protection: Polyurethane encapsulated units pass 500 hour salt spray test to
ASTM 117
Mating Connectors: 6 Pin: MOLEX 08-50-8063 or equivalent
NORMAL OPERATING SEQUENCE
Power up / Pre-purge
When powered up, the unit performs a series of diagnostic checks to determine if the system is
in working order.
Trial for Ignition
After a pre-purge, the unit will power the valve solenoid and begin a trial for ignition. The spark
will be enabled for the first 80% of the trial period and then suppressed for the last 20% of the
trial period to allow the unit to sense weak flame signals.
Run
When a flame is sensed, the unit suppresses the spark and keeps the valve powered. Power is
removed from the unit when the thermostat is satisfied.
ABNORMAL CONDITION OPERATING SEQUENCE
No Flame Established - Soft Lockout Mode
If a flame is not established during the trial for ignition, the unit will perform an inter-purge and
retrial for ignition. This protocol is followed for the number of tries specified. If a flame is not es-
tablished during the final ignition attempt, the unit will enter the soft lockout mode, which in-
cludes a reset delay before another normal trial for ignition series begins.
Loss of Flame - Spark Restoration Retrial
If there is a loss of flame during the run mode, the unit will energize the spark within 0.8 seconds
and perform a spark restoration trial for ignition. In this mode, the ignition means is restored with-
out the gas valve being closed. If a flame is not established during the restoration trial, the unit
will perform as in “No Flame Established” fault operation above.
Leaking Valve - Hard Lockout Mode
If a flame is present when the gas valve is not energized, the unit will enter the hard lockout
mode.
Internal Fault - Hard Lockout Mode
If an internal fault is detected within the unit, the unit will enter the hard lockout mode.
System or External Fault - Hard Lockout Mode
If the unit detects a system fault or an external fault, the unit enters the hard lockout mode.