Installation Operating Instructions
53
can be readily found. After the cause of
the pilot failure has been corrected, resume
normal operation by following the Lighting
Instructions.
(3) SHUTDOWN INSTRUCTIONS
(a) Close manual shut-off valves and pilot
valves.
(b) Turn off main electric switch.
8. EP CONTROL SYSTEM – 5015B thru 5026B (see Fig.
45)
The 5015B thru 5026B boilers utilize two EP control
systems that are interconnected electrically thru all
operating and safety controls. Should any of the
aforementioned controls break the power supply circuit,
both EP control systems would be de-energized. The
succeeding paragraphs describe the function and
operation of each EP Control System. Should a pilot
failure on one EP Control System occur, the other EP
Control System would not be affected. Thus main
burners on the unaffected side would ignite on a “call
for heat” and would continue to operate until the
SECTION IV - OPERATION (continued)
operating control was satised.
The EP Control System utilizes and RM7890A Relay
Module and a Q179C Rectication Pilot, which in
addition to a pilot burner and rectifying ame rod ame
detector to prove pilot, includes an ignition electrode
for spark ignition of the pilot. A Webster 612-6A7
Transformer supplies the high voltage spark potential.
Once pilot ame is proven, ignition stops but pilot
ame continues as long as there is a “call for heat”
(intermittent electrically ignited pilot).
The RM7890A Primary Control is a non-programming
amplifying relay which when used with the Q179C
Pilot provides solid state electronic Flame Safeguard
Protection that will not allow the main gas valve to
open on “call for heat” or that will shut down main
burners within 0.8 second if pilot ame is not “proved”.
Relay Module will lock out on safety shutdown within
15 seconds if there is a pilot ame failure on start or, if
during the “run” cycle, pilot ame is not re-established.
Since #8 terminal in the Relay Module is de-energized
at end of safety switch timing, a solenoid valve in the
pilot line will close and thus 100% shut-off is achieved.