Goodman Mfg VC8 Operational Checks & Safety Circuit Description, Normal Sequence Of Operation

OPERATIONAL CHECKS & SAFETY CIRCUIT DESCRIPTION

LED	LED	Indication	Possible Causes	Corrective Action(s)	Notes & Cautions
	Status
	Off	ξ Normal condition	ξ None	ξ None	ξ None
	1 Flash	ξ Communications	ξ Communications	ξ Depress Learn Button	ξ Depress once
		Failure	Failure	ξ Verify that bus BIAS	quickly for a power-
Red				and TERM	up reset
				dipswitches are in the	ξ Depress and hold
Communications
				ON position.	for 2 seconds for
LED
					an out-of-box reset
	2 Flashes	ξ Out-of-box reset	ξ Control power up	ξ None	ξ None
			ξ Learn button
			depressed
	Off	ξ No power	ξ No power to furnace	ξ Check fuses and	ξ Turn power OFF
		ξ Communications	ξ Open fuse	circuit breakers;	prior to repair
		error	ξ Communications error	replace/reset
				ξ Replace blown fuse
				ξ Check for shorts in
				low voltage wiring in
				furnace/system
				ξ Reset network by
				depressing learn
				button
				ξ Check data 1/ data 2
				voltages
	1 Steady	ξ No network found	ξ Broken/ disconnected	ξ Check	ξ Turn power OFF
	Flash		data wire(s)	communications	prior to repair
			ξ Furnace is installed as	wiring (data 1/ data 2	ξ Verify wires at
			a legacy/ traditional	wires)	terminal blocks are
			system	ξ Check wire	securely twisted
Green Receive				connections at	together prior to
				terminal block	inserting into
LED				ξ Verify furnace	terminal block
				installation type	ξ Verify data1 and
				(legacy/ traditional or	data voltages as
				communicating)	described above
				ξ Check data 1/ data 2
				voltages
	Rapid	ξ Normal network	ξ Control is “talking” on	ξ None	ξ None
	Flashing	traffic	network as expected
	On Solid	ξ Data 1/ Data 2	ξ Data 1 and data 2	ξ Check	ξ Turn power OFF
		miss-wire	wires reversed at	communications	prior to repair
			furnace, thermostat,	wiring (data 1/ data 2	ξ Verify wires at
			or CT™ compatible	wires)	terminal blocks are
			outdoor AC/HP	ξ Check wire	securely twisted
			ξ Short between data 1	connections at	together prior to
			and data 2 wires	terminal block	inserting into
			ξ Short between data 1	ξ Check data 1/ data 2	terminal block
			or data 2 wires and R	voltages	ξ Verify data1 and
			(24VAC) or C (24VAC		data voltages as
			common)		described above

NORMAL SEQUENCE OF OPERATION

POWER UP

The normal power up sequence is as follows:

•115 VAC power applied to furnace.

•Integrated control module performs internal checks.

•Integrated control module displays 88 on dual 7-segment display LED’s.

•Integrated control module monitors safety circuits continuously.

•Furnace awaits call from thermostat. Dual 7-segment LED’s display 0 P while awaiting call from thermostat.

HEATING MODE

The normal operational sequence in heating mode is as fol- lows:

•R and W1 (or R and W1/W2) thermostat contacts close, initiating a call for heat.

•Integrated control module performs safety circuit checks.

•Induced draft blower is energized on high speed for a 15- second prepurge. Humidifier terminal is energized with induced draft blower.

•Induced draft blower steps to low speed following prepurge. Low stage pressure switch contacts are closed.

•Igniter warm up begins upon step to low speed and presence of closed low stage pressure switch contacts.

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