Burnham K50 manual Proceed to Paragraph 15- Minimum Input

to a Q309 Thermocouple. The RA890F Protectorelay		(7) The Q179D pilots continue to burn.
Primary Control is a non-programming, amplifying		c. SAFETY SHUTDOWN
relay which when used with the Q179D Pilot provides
		(1) SAFETY SWITCH CIRCUIT
solid state electronic Flame Safeguard Protection
		If limit control, low water cut-off or any
during a “call for heat” pilot failure. Main burners
		other electrical safety switch opens, power
will shut down within 0.8 second and the Protectorelay
		to	terminal #6 and all other terminals on both
will lock out on safety shutdown within 15 seconds.
		RA890F relays is interrupted. Main gas valves
Should a pilot failure occur during the “off” cycle, the
		are thus de-energized and main gas burners
thermocouple will cool and within 45 to 90 seconds,
		are immediately extinguished. Standing pilot
will cause the L62GB-3C Pilot Safety Switch to which
		flames in the Q179D pilots will continue to
it is connected, to break the electrical circuit to the main
		burn.
gas valves as well as shut off the flow of gas to the
		(2) PILOT FAILURE
pilot. Thus 100% shut-off is achieved.
a. LIGHTING INSTRUCTIONS		(a)	Flame rod supervision of the Q179D pilots
			occurs only during the operating cycle (call
(1)	Make sure all Manual Main Shut-off Valves and
			for heat) since it is during this period that
	all Pilot Valves have been off for at least five		the control is energizing the RA890F relays.
(2)	minutes.		If pilot failure occurs during this period
	Set Operating and Limit Controls to desired		on one of the Q179D pilots, the main gas
	settings.		valves controlled by that particular RA890F
(3)	Turn on Main Electric Switch and Service		will close in 0.8 second. The RA890F will
	Switch.		lock-out on safety within 15 seconds. The
(4)	Open pilot valve on one side of boiler. Depress		burners controlled by the other RA890F will
	button on L62GB-3C Pilot Safety Switch to		continue to burn.
	which it is connected and light pilot with match.	(b)	If pilot failure occurs on one of the Q179D
	Continue to hold button in for one minute		pilots during the “off” cycle of the operating
	or until pilot remains lighted after button is		control, there will be no electronic flame rod
	released. Light pilot on opposite side of boiler		supervision since neither RA890F relay is
	using same procedure.		energized during the off cycle. This is due
(5)	Press reset button on each RA890F relay.		to the utilization of a thermocouple in each
(6)	Open Manual Main Shut-off Valves – main		Q179D modified pilot which controls its
			own pilot safety switch. This thermocouple
	burners will light.
			will cool in 45 to 90 seconds de-energizing
Proceed to Paragraph 15- Minimum Input
			the pilot safety switch which interrupts the
Adjustments (for diaphragm “Lo-Hi-Lo” or			circuit between terminal #5 and the gas
motorized type gas valves)
			valves and also shuts off the flow of gas to
SEQUENCE OF OPERATION EO – See Fig. 47			the pilot. Thus 100% shut-off is achieved.
b. NORMAL OPERATION – 5015B thru 5026B			If the operating control calls for heat
			during this period the RA890F relay will
(1)	When the operating control calls for heat,
			immediately sense “no flame” on the pilot
	terminal #6 of each RA890F Protectorelay is
			and the relay will lock out on safety within
	energized.
			15 seconds.
(2) A component check circuit in each RA890
			Assuming the pilot on the opposite side is
	Protectorelay is activated which checks the
			burning, the gas valves on that side will
	electronic network of the relay.
			open and main flame will be ignited on that
(3)	Flame rod circuit between each Q179D pilot and
			side only.
	terminal “F” on its respective RA890F proves
		7. EE CONTROL SYSTEM – 5006B thru 5014B
	presence of flame electronically at its Q179D
		The EE Control System utilizes an RA890F
	pilot.
(4)	Terminal #6 on each RA890F is energized	Protectorelay and a Q179C Rectification Pilot, which
		in addition to a pilot burner and rectifying flame rod
	supplying power to its respective main gas
		flame detector to prove pilot, includes an ignition
	valves.
		electrode for spark ignition of the pilot. A Webster
(5)	Main gas valves open and main burners are
		612-6A7 Transformer supplies the high voltage spark
	ignited by the pilot flames.
		potential. Once pilot flame is proven, ignition stops but
(6)	When operating control is satisfied, terminals #6
		pilot flame continues as long as there is a “call for heat”

and #5 on the RA890F relays are de-energized,	(intermittent electrically ignited pilot).
main gas valves close and main burners are
	The RA890F Protectorelay Primary Control is a non-
extinguished.
	programming amplifying relay which when used with

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