Johnson Controls YM8M/YMLM*MP Section Ix Safety Controls, Adjustment Of Fan Control Settings

368261-UIM-A-0508

ADJUSTMENT OF FAN CONTROL SETTINGS

Cooling - The airflow delivered by the furnace during cooling operation can be adjusted to match the cooling capacity of the A/C condensing unit. This is done by moving the COOL jumper on the control board to give the desired airflow.

Do not move the motor wires to different positions on the furnace control board!

The jumper has four positions, which will deliver sufficient airflow in cooling mode for the cooling capacities shown in the table below. The CFM delivery on each jumper position is shown in Table 13.

TABLE 13: Cooling Airflow - A/C Capacity in Tons

Models		Jumper Position
	A	B	C	D
60/1200	3	2-1/2	2	1-1/2
80/1200	3	2-1/2	2	1-1/2
80/1600	4	3-1/2	3	2-1/2
100/1600	4	3-1/2	3	2-1/2
100/2000	5	4	3-1/2	3
120/2000	5	4	3-1/2	3

Continuous Fan Operation - The airflow delivered by the furnace dur- ing continuous fan operation can be adjusted as desired. This is done my moving the FAN jumper on the control board to give the desired air- flow.

Do not move the motor wires to different positions on the furnace control board!

The jumper has three positions. The "A" position delivers maximum air- flow, 100% of the blower capacity. Position "B" delivers approximately 70% of the blower capacity. And Position "C" delivers minimum airflow, approximately 40% of the blower capacity.

HUMIDIFIER	EAC	ZONING
TERMINALS	TERMINALS	JUMPER

BLACK	BLOWER		BLUE	BLOWER	YELLOW	BLOWER	RED	BLOWER
120VAC 120VAC	XFORMER	NEUTRAL NEUTRAL	XFORMER GROUND WHITE	BLOWER				HUMIDIFIER
	24VAC	MODULATE COIL	GAS VALVE
		PRIMARY		AUX				TEMP
		LIMIT		LIMIT		AIR SW		SENSOR

				ROD	VOLTAGE FLAME
NEUTRAL INDUCER	NEUTRALHOT	IGNITER	NEUTRALHOT	FLAME EACEAC	NEUTRALHOT	ZONE CONTROL		NO YES	EXT PRESSURE SENSOR
HOT
				PLUG		PUMP			A-COIL TEMP SENSOR
		COMPLO	COMPHI	ID		HEAT	YES NO	COOL	MLMH H	BUTTON
				O DHUM Y1 Y/Y2 HUMIDISTATW		R	G	C	TEST
							NO YES	FANCONTATR	L
									LMH
									+10F
									NOM
									10F-
									BUTTON RERRO

HEAT PUMP JUMPER

COOLING

SPEED

JUMPER

CONTINUOUS FAN SPEED JUMPER

TEST

BUTTON

DIAGNOSTIC

LIGHT

FIGURE 30: Furnace Control Board

LOW
VOLTAGE	HUMIDISTAT	LAST ERROR
TERMINALS	JUMPER	BUTTON

SECTION IX: SAFETY CONTROLS

CONTROL CIRCUIT FUSE

A 3-amp fuse is provided on the control circuit board to protect the 24- volt transformer from overload caused by control circuit wiring errors. This is an ATO 3, automotive type fuse and is located on the control board.

BLOWER DOOR SAFETY SWITCH

This unit is equipped with an electrical interlock switch mounted in the burner compartment. This switch interrupts all power at the unit when the panel covering the blower compartment is removed.

Electrical supply to this unit is dependent upon the panel that covers the blower compartment being in place and properly positioned.

Main power to the unit must still be interrupted at the main power disconnect switch before any service or repair work is to be done to the unit. Do not rely upon the interlock switch as a main power dis- connect.

Blower and burner must never be operated without the blower panel in place.

ROLLOUT SWITCH CONTROLS

These controls are mounted on the burner assembly. If the temperature in the burner area exceeds its set point, the ignition control and the gas valve are de-energized. The operation of this control indicates a mal- function in the combustion air blower, heat exchanger or a blocked vent pipe connection. Corrective action is required. These are manual reset controls that must be reset before operation can continue.

24 Johnson Controls Unitary Products