Lennox International Inc O23V2-70, O23V5-140, O23V5-154 Blower Control Board A54, YI ID12 DDZ3g f

IMPORTANT

2, Install the room thermostat and make wire connec- tions to the fan control board. Avoid installing thermo- stat on an outside wall or where it can be affected by radiant heat, Set the adjustable heat anticipator on

thermostat according to the wiring diagram sticker pro- vided on unit,

3, Install a separate fused disconnect switch near unit so power can be shut off for servicing,

4, Complete line voltage wiring from disconnect switch near unit to make-up box.

NOTE - An equipment ground screw is provided. Re- fer to unit wiring diagram and figure 18 for 023V series units. Ground unit using a suitable ground wire.

5, Any accessory rated up to 1 amp can be connected to the EAC terminal. (EAC terminal is energized when the blower is operating,)

_WARNING

Blower Control Board (A54)

O23V units are equipped with a variable speed motor which is controlled by the A54 blower control board. Blower control board settings and operation are described in this section,

O23V units equipped with a variable speed motor are ca- pable of maintaining a specified CFM throughout the exter- nal static range. A particular CFM can be obtained by posi- tioning COOL jumpers on the blower control board. The COOL jumper selections are labeled A, B, C and D; each letter corresponds with an air volume (CFM) setting. The ADJUST jumper is labeled Test, -, +, and Norm. The + and

-pin settings are used to add or subtract a percentage of the CFM selected. The Test jumper is used to operate the motor in the test mode. See figure 17.

Factory settings for the blower speed jumpers are given in the wiring diagram in figure 18. Figure 17 shows the blower control board. Use table 6 to determine the correct air vol-

ume for operation in heat and cool mode.

The CFM LED located on the blower control board flashes one time per 100 cfm to indicate selected blower speed.

For example, if the unit is operating at 1000 CFM, CFM LED will flash 10 times.

At times, the light may appear to flicker or glow. This takes place when the control is communicating with the motor between cycles. This is normal operation. Read through the jumper settings section before adjusting the jumper to obtain the appropriate blower speed.

To change jumper positions, gently pull the jumper off the pins and place it on the desired set of pins. The following section outlines the different jumper selections available and conditions associated with each one (see figure 17).

After the CFM for each application has been determined,

the jumper settings must be adjusted to reflect those given in table 6, From the table, determine which row most close-

ly matches the desired CFM Once a specific row has been chosen (% NORMal, or -), CFM volumes from other rows cannot be used, Below are descriptions of the jumper selections.

The variable speed motor slowly ramps up to and down from the selected air flow during both cooling and heating demand, This minimizes noise and eliminates the initial

blast of air when the blower is initially energized,

				Blower	Control Board		(A54)
							DIAGNOSTIC	LED
							ADJUST
						/	SELECTOR	PINS		Q3/4 120
						/	(Setting affect cooling only)			O23V-Q2/3-090
			R	(BOARD TO MOTOR)	//
ICM PIN		(_	c,<=co=>::::::::		//		HEATING SPEED		HEAT
AH4103			[. C)0,: o08			/	SELECTOR	PINS (SEE	.....	023V-Q2/3-070
						/	TABLE)		.....	023V-Q3/4-105
									HiO Oi
ARMSTRONG	PIN		D9	-E_ °JW3°'JZC]-iRr /					DI_1	O23V-Q5-140
45632-001			w,<o)o o sso ,/				COOLING SPEED

0

PCB635-1A

YI I)D12 DDZ3:g: _f'_--_

/SELECTOR PINS

_ O23V-Q5-154

jNOTE - The JW! resistor must be cut to activate the

HUM terminal.

HEAT SPEED SELECTOR

PINS (JUMPERS)

G(o)0,,0,o o	I LY_J
	Figure 17
	Page 13

O23V SERIES