Burnham K50 manual Operating and safety controls. Should any

the Q179C Pilot provides solid state electronic Flame			burners and pilot burners are immediately
Safeguard Protection that will not allow the main gas			extinguished. Normal operation can be resumed
valves to open on “call for heat” for that will shut			when the cause of safety switch malfunction
down main burners within 0.8 second if pilot flame			is corrected. Make sure all manual resets are
is not “proved”. Protectorelay will lockout on safety			activated where involved.
shutdown within 15 seconds if there is a pilot flame		(2)	PILOT FAILURE
failure on start or, if during the “run” cycle, pilot			(a) Pilot failure can occur during the start of
flame is not re-established. Since #3 terminal in the
			operating cycle of the boiler. Any pilot
Protectorelay is de-energized at end of safety switch
			failure, on the Q179C electronic pilot, after
timing, a solenoid valve in the pilot line will close and
			ignition of pilot flame will close the main
thus 100% shut-off is achieved.
			gas valves in 0.8 second.
a. OPERATING INSTRUCTIONS
			(b) For 15 seconds after failure of the Q179
(1)	Make sure Manual Main Shut-off Valve and		pilot, the relay through terminals #3 and #4
	all Pilot Valve have been off for at least five		will try to re-establish pilot flame. If not
	minutes.		pilot flame can be sensed by the flame rod
(2)	Set Operating and Limit Controls to desired		circuit, terminal #3 and #4 are de-energized,
			and the relay will lock out on safety.
	settings.
			(c) Pilot failure is caused by the following:
(3)	Turn Manual Main Shut-off Valve and Pilot
			(1)	Complete loss of gas supply.
	Valve to Open Position.
(4)	Turn on Main Electric Switch and Service		(2)	Poor ignition spark caused by low
	Switch – Pilot will automatically light main			voltage, poor ground connection, faulty
	burners.			wiring, and possibly a defective ignition
SEQUENCE OF OPERATION EE - See Fig. 48				transformer.
			(3)	Low gas pressure will prevent flame rod
b. NORMAL OPERATION - 5006B thru 5014B
				circuit from sensing pilot flame properly.
(1)	When the operating control calls for heat,
			(4)	Unusually strong secondary air drafts
	terminal #6 of RA890 Relay is energized.			can blow the pilot flame away from the
(2) A component check circuit in the RA890 Relay				flame rod momentarily causing nuisance
	is activated which checks the electronic network			shutdown.
	in the relay.		(5) A pilot line solenoid valve will not open
(3)	Terminals #3 and #4 of the relay are energized.			because of faulty wiring, low voltage, or
	Terminal #3 opens pilot line solenoid valve			possibly the valve is defective.
	supplying gas to pilot. Terminal #4 energizes		(6) A defective RA890 may be the cause
	ignition transformer creating electric spark			but items (1) thru (5) should be followed
	ignition at pilot.			first. Refer also to RA890 relay literature
(4)	Flame rod circuit between Q179C pilot			furnished with the control.
	and RA890 proves presence of pilot flame		(d) By referring to the Sequence of Operations
	electronically.
			step by step operation of the system can
(5)	Terminal #4 to ignition transformer is de-
			be controlled and the cause of pilot failure
	energized.		can be readily found. After the cause of
(6)	Terminal #5 is energized and supplies power to		the pilot failure has been corrected, resume
	the main gas valves.		normal operation by following the Lighting
(7)	Main gas valves open and main burners are		Instructions.
	lighted by pilot.	d. SHUTDOWN INSTRUCTIONS
(8)	When operating control is satisfied, terminals
		(1)	Close manual shut-off valves and pilot valves.
	#6 and #5 are de-energized. Main Gas Valves
		(2)	Turn off main electric switch.
	and pilot line solenoid valve are all de-energized
		8. EE CONTROL SYSTEM – 5015B thru 5026B
	and main burner and pilot burner flames are
	extinguished.	The 5015B thru 5026B boilers utilize two EE control
c. SAFETY SHUTDOWN		systems that are interconnected electrically thru all
(1) SAFETY SWITCH CIRCUIT		operating and safety controls. Should any of the

If limit control, low water cut-off or any other	aforementioned controls break the power supply circuit,
	both EE control systems would be de-energized. The
electrical safety switch opens, power to terminal
	succeeding paragraphs describe the function and
#6 in relay is interrupted thus de-energized
	operation of each EE Control System. Should a pilot
terminal #5 and #3 in relay which de-energizes
	failure on one EE Control System occur, the other EE
main gas valves and pilot valves. Main gas
	Control System would not be affected. Thus main

56