16
MEP100P
The MEP100P programmers provides a fixed 15 second post purge period upon detection of the
operating Control (1-7) or Air Flow switch (7-6) opening.
MEP100 as FLAME SWITCH (refer to Figure 11)
For systems that require flame switch operation, that is, relay KF will toggle on with flame signal and
off without flame signal, the MicroM provides this function when equipped with an MEP100 pro-
grammer. To operate as a flame switch, Terminals 1 and 6 MUST be powered with 120 VAC while
Terminal 7 MUST be left unpowered. Terminals 3, 4, and 5 will provide an isolated (KL relay not
energized) set of contacts with Terminal 3 being the common input, Terminal 4 will be normally
closed and Terminal 5 will be normally open. If Terminal 7 is powered or if Terminal 6 is non-
powered and a flame signal is present, the MicroM will lockout after 1 minute and Terminals 4
and 5 will no longer switch with flame signal. Refer to Figure 11 for configuration wiring. Air
Flow LED will blink while flame is detected.
TIMING CHART
Terminal #5 is energized 3 seconds after flame is detected.
Re-ignited PTFI on flame fail after Terminal 5 energized.
Recycle on loss of interlock (air flow) after flame proven.
MEP101
Same as MEP100 but will tolerate flame signal during “Off” cycle.
MEP102
PTFI time limited to 5 seconds, lockout on flame fail.
MEP104
PTFI time limited to 10 seconds, lockout on flame fail.
MEP200 SERIES
The MEP200 Series programmers come equipped with a bank of dipswitches that allow user select-
able prepurge timing, selectable PTFI timing, selectable post purge, selectable air flow proven open
at start, and selectable recycle/non-recycle operation. Refer to PROGRAMMER DIPSWITCH SET-
TINGS for detailed information.
Recycle operation refers to flame failure during the main (AUTO) firing period. In the event of a
main flame failure, power is removed from Terminal 3 and Terminal 5. If selected by the dipswitch,
the control will enter a post purge period for 15 seconds and revert back to the Idle state where the
pre-purge period begins.
If non-recycle operation is selected, in the event of a main flame failure, power is removed from Ter-
minal 3 and Terminal 5. The control will enter a forced post purge period of 15 seconds, after which
the Alarm LED is illuminated and the alarm relay is energized putting power on Terminal A.
TYPE MEP100
PROGRAMMING SEQUENCE
L1/7
ON
INTERLOCK
AIR FLOW
PROVEN
FIRING
PERIOD
L1/7
OFF
PTFI
10 SEC
SAFE
START
CHECK
PERIOD
8
T
E
R
M
I
N
A
L
S
3
4
5
