FULTON PHW 1000, Installation, Operation And Maintenance Manual, Page: 59 / 94

Fulton Heating Solutions, Inc. -- PHW Manual -- 2010-0713
Page 59
c) The INITIATE sequence will be initiated if the operating control input is
de-energized during PREPURGE.
d) STANDBY: The RM7865 is ready to start an operating sequence when the operating
control input determines a call for heat. The burner switch, limits, operating control, inter-
locks, critical loads and all microcomputer monitored circuits must be in the correct state
for the RM7865 to continue into the PREPURGE sequence.
e) NORMAL START-UP PREPURGE : The RM7865 provides a PREPURGE timing of 35
seconds with power applied and the RM7865 operating control indicating a call for heat.
1. Combustion pressure switch, purge fan switch ILK, burner switch, limits, operating
control and all microcomputer monitored circuits must be in the correct operating
state.
2. The fan motor output, terminal 5, is powered to start the PREPURGE sequence.
3. The purge fan switch ILK input must close within three seconds to start the 35
second PRE-PURGE; otherwise, lockout occurs.
f) IGNITION TRIALS
(without Flame Rod Option)
1. Combustion Pressure Establishing Period (CPEP):
a) The ignition transformer, terminal 10, is energized two seconds prior to
opening of the main fuel valve.
b) The main fuel valve, terminal 8. is energized for four seconds. Combustion
pressure must be proven by the end of the six seconds of CPEP to allow the
sequence to continue to the Combustion Pressure Stabilization. Period
(CPSP). If combustion pressure is not proven by the end of CPEP, the
RM7865 will recycle to PREPURGE.
2. Combustion Pressure Stabilization Period (CPSP):
a) If the combustion pressure switch is energized at the end of CPEP, the
RM7865 enters an eight second Combustion Pressure Stabilization Period. If
the combustion pressure switch ILK opens, the RM7865 will recycle to
PREPURGE only if the selected number of retry attempts is not exceeded.
After the eight seconds, the RM7865 will enter the RUN period.