20
Pilot stabilization timing begins as soon as flame is proven.
Lockout on loss of air flow (interlock circuit) after flame is proven.
Lockout on flame fail.
MEP300 SERIES
This programmer type must be used with the MEC320 or MEC480 type chassis. Refer to typical
wiring arrangement illustrated on page 41.
The MEP300 Series Programmers provide additional relays used to control Terminal 3 and 4
separately. This allows the implementation of early spark termination, pilot proving period and
interrupted pilot operation. The MEP397 programmer contains a “run-check” switch to assist in test-
ing size, position and stabilization of pilot in conjunction with the flame detector.
TIMING CHARTS
0 Second post purge on operating control open.
15 Second post purge on flame fail during PTFI, Proving and MTFI.
Lockout on flame fail during PTFI, Proving and MTFI.
Relight operation on main flame fail.
Recycle operation on air flow failure.
Reset from lockout from pushbutton on line voltage.
TYPE MEP562
PROGRAMMING SEQUENCE
L1/7
ON
PURGE
COMPLETE
FIRING
PERIOD
L1/7
OFF
PTFI
5 OR10 SEC
SELECTABLE
PURGE
8
T
E
R
M
I
N
A
L
S
3
4
5
SELECTABLE
POST PURGE
MTFI
10 SEC
STABLIZATION
8 SEC
PERIOD
INTERLOCK
AIR FLOW
PROVEN
TYPE MEP300
PROGRAMMING SEQUENCE
L1/7
ON
PURGE
COMPLETE
FIRING
PERIOD
L1/7
OFF
10 SEC
PTFI
5 SECOND
PURGE
8
T
E
R
M
I
N
A
L
S
3
4
5
POST PURGE
(SEE NOTE)
INTERLOCK
AIR FLOW
PROVEN
5 SEC
PILOT
PROVING
5SEC
MTFI
INTERMITTENT
PILOT
