Goodman Mfg CPG SERIES Input Rating, AIR Flow Adjustments, Motor Sheave Adjustments

Open Thermal Protection Device

If the primary limit switch opens, the gas valve is immediately deenergized, the induced draft and air circulating blowers are energized. The induced draft and air circulator blowers remain energized until the limit switch recloses. The diag- nostic fault code for an open limit is four (4) flashes.

A primary limit will open due to excessive supply air tempera- tures. This can be caused by a dirty filter, excessive duct static, insufficient air flow, or a faulty limit. Check filters, total external duct static, blower motor, blower motor speed tap (see wiring diagram), and limit. This limit will automatically reset once the temperature falls below a preset level.

Flame Detected with Gas Valve Closed

If flame is detected with the gas valve deenergized, the com- bustion and air circulator blowers are energized. The diag- nostic fault code is five (5) flashes for this condition. The control can be reset by removing the power supply to the unit or it will automatically reset after one hour. Miswiring is the probable cause for this fault.

ABNORMAL OPERATION - COOLING

Short Cycle Compressor Delay

The automatic ignition control has a built-in feature that pre- vents damage to the compressor in short cycling situations. In the event of intermittent power losses or intermittent ther- mostat operation, the ignition control will delay output to the compressor contactor for three minutes from the time power is restored. (Compressor is off a total of three minutes). The diagnostic LED will flash six (6) times to indicate the com- pressor contactor output is being delayed.

NOTE: Some electronic thermostats also have a built-in compressor short cycle timer that may be longer than the three minute delay given above. If you are using an electronic thermostat and the compressor has not started after three minutes, wait an additional five minutes to allow the thermostat to complete its short cycle delay time.

INPUT RATING

It is the responsibility of the contractor to adjust the gas input to the unit. The input rate can be calculated by using the formula:

INPUT Btu/Hr =	3600 x HV
	T

WHERE:

HV = Heating value of fuel = Btu/ft3 of gas

T = Time in seconds per ft3 of gas flow as read from gas meter

Adjust input rate by varying the adjustment of the gas pres- sure regulator on the gas valve. All adjustments must be made with furnace operating at high fire and at normal operating temperature. Clockwise (P) rotation of the pressure regula- tor screw increases pressure and gas flow rate. Turn screw counterclockwise (Q) to decrease pressure and gas flow rate.

After adjustment the furnace temperature rise must be within the range specified on the unit data plate. NOTE: Thermal efficiency of the furnace is a product efficiency rating deter- mined under continuous operating conditions independent of any installed system.

Regulator Cover Screws

(Reg. Adj. Beneath these screws)

	High Fire
	Adjust
	Low Fire
	Adjust
INLET	OUTLET

Gas Valve

On/Off Switch

WHITE-RODGERS 36H54 PRESSURE ADJUSTMENTS

CAUTION

TO PREVENT UNRELIABLE OPERATION OR EQUIPMENT DAMAGE, THE GAS MANIFOLD PRESSURE MUST BE AS SPECIFIED ON THE UNIT RATING PLATE. ONLY MINOR ADJUSTMENTS SHOULD BE MADE BY ADJUSTING THE GAS VALVE PRESSURE REGULATOR.

AIR FLOW ADJUSTMENTS

The drive on the supply fan is typically set in the middle of the RPM range. The drive motor sheave pitch diameter is field adjustable for the required airflow. Refer to “Drive Adjustments” section below.

When the final adjustments are complete, the current draw of the motor should be checked and compared to the full load current rating of the motor. The amperage must not ex- ceed the service factor stamped on the motor nameplate. The total airflow must not be less than that required for op- eration of the electric heaters or the furnace.

If an economizer is installed, check the unit operating bal- ance with the economizer at full outside air and at minimum outside air. Upon completion of the air flow balancing, we recommend replacing the variable pitched motor sheave with a properly-sized fixed sheave. A matching fixed sheave will provide longer belt and bearing life and vibration free opera- tion. Initially, it is best to have a variable pitched motor sheave for the purpose of airflow balancing, but once the balance has been achieved, fixed sheaves maintain alignment and minimize vibration more effectively. For direct drive units, move green wire for fan.

MOTOR SHEAVE ADJUSTMENTS

VL, VM & 2VP VARIABLE PITCH KEY TYPE MOTOR SHEAVES

The driving and driven motor sheaves should be in align- ment with each other and the shafts parallel.

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