Lochinvar 399 operation manual Sequence of operation, BLR Ignition

					Installation & Operation Manual
11 Operating information
Sequence of operation
			OPERATION		DISPLAY
1. Upon a call for heat, the control turns on the appropriate pumps				BLR: Standby
	(system and boiler pumps for space heating call; DHW pump
	for DHW call).			OUT: 123.8F(129)
2. The control			connects 120 VAC to the blower. The blower
	does not run at this time.			BLR: Standby
	• The manual reset high limit must be closed and reset.
				OUT: 123.8F(129)
	• Once the pumps are turned on, the flow switch must close.
• If the unit is equipped with gas pressure switches, they must
	close.
	• If an auxiliary limit is connected to the unit, it must close.
	• The air pressure switch must be closed.
3. The control then starts a 15 second prepurge cycle.				BLR: PREPURGE
				OUT: 123.9F(129)
4. Once the prepurge cycle is complete, and the blocked drain				BLR: IGNITION
	switch is closed, the control starts the 4 second trial for ignition
	by sending spark voltage to the spark electrode and opening			OUT: 123.9F(129)
	the gas valve.
5. If the control does not detect flame before the trial for ignition
	ends, the control will perform a 10 second postpurge. The 399			BLR: POSTPURGE, PREPURGE
	model will start another prepurge and trial for ignition. If the
	burner does not light after 4 trials on the 399 model, the control			OUT: 123.9F(129)
	will lock out for one hour and then try again.
	If the burner does not light after 1 retry on Models 500 - 800 the
	control will lock out.
6. If the control detects a flame before the trial for ignition ends, it				BLR: SH 20% RATE
	begins to modulate the burner in order to maintain the set point.
	If the boiler lights due to a space heating call for heat, and the			OUT: 124.8F(129)
	ramp delay		function is active (default is off), the modulation
	will be held to a series of increasing limits afterthe burner has lit.
7. If the		space heating call for heat is active, and the DHW
	thermostat or sensor starts a DHW call for heat, the control will			BLR: DHW 85% RATE
	turn on the DHW pump, wait 2 seconds, and then turn off the
	boiler pump.		This will divert the hot water away from the	OUT: 177.8(180)
	heating zone(s) and send it to the DHW tank instead. The
	control will then modulate to maintain the outlet temperature to
	the DHW boiler set point.
8. If the boiler is not part of a cascade, and the DHW call for heat
	remains active for more than 30 minutes, and the space heating
	call for heat is also active, then the control will turn on the boiler			BLR: SH 41% RATE
	pump, turn off the DHW pump after 2 seconds, and resume
	modulating based on the space heating set point. As long as			OUT: 123.0F(129)
	both the space heating and DHW calls for heat remain active,
	the control will switch back and forth between the two modes
	until one of them is satisfied.
9. Once both calls for heat are satisfied, the control will turn off the				BLR: POSTPURGE
	burner.	The blower will remain on for the 10 second postpurge
	cycle.	Any pumps that are running will continue to run for their		OUT: 127.4F(129)
	respective pump delay times, then turn off.
10.	Boiler pump off, system pump continues its delay if longer.			BLR: Standby
				OUT: 124.7F(129)
11.	System pump off.			BLR: Standby
				OUT: 122.9F(129)

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