AIR Flow Adjustments, PSC Motor, Maintenance

To connect manometer to gas valve:

1.Back outlet pressure test screw (inlet/outlet pressure boss) out one turn (counterclockwise, not more than one turn).

2.Attach a hose and manometer to the outlet pressure boss of the valve.

To remove manometer from gas valve:

1.Remove manometer hose from outlet pressure boss.

2.Turn outlet pressure test screw in to seal pressure port (clockwise, 7 in-lb. minimum).

3.Turn on electrical power and gas supply to the system.

4.Turn on system power and energize valve.

5.Using a leak detection solution or soap suds, check for leaks at pressure boss screw. Bubbles forming indicate a leak. SHUT OFF GAS AND FIX ALL LEAKS IMMEDIATELY.

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 fan speed wire.

NOTE: Never run CFM below 350 CFM per ton, evaporator freezing or poor unit performance is possible.

PSC MOTOR

Adjust the CFM for the unit by changing the speed tap of the indoor blower motor at the heat or cool tap on the control board connection with the one of the speed taps on “M1” or “M2” (Black-High Speed, Blue-Medium Speed, Red-Low Speed).

EEM Motor

Adjust the CFM for the unit by changing the position of the low voltage leads on the motor terminal block. Green is for Fan Only. Yellow is for Cooling and Heat Pump Heating. Re- fer to Appendix A for blower performance at each speed tap. NOTE: If more than one lead is energized simultaneously, the motor will run at the higher speed.

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.

VL & VM SHEAVES ADJUSTMENT

1.Loosen set screw “B” using a 5/32" Allen key.

2.Making half or full turns from closed position, adjust sheave pitch diameter for desired speed. DO NOT OPEN MORE THAN FIVE FULL TURNS.

3.Tighten set screw “B” securely over flat.

4.Carefully put on belts and adjust belt tension. DO NOT FORCE BELTS OVER GROOVES.

5.Ensure all keys are in place and the set screws tight before starting drive. Recheck set screws and belt tension after 24 hours service.

NOTE: Future adjustments should be made by loosening the belt tension and increasing or decreasing the pitch diameter of the sheave by half or full turns as required. Readjust belt tension before starting drive.

VL & VM

Sheave

NOTE: Do NOT operate sheave with flange projecting beyond the hub end.

MAINTENANCE

WARNING

HIGH VOLTAGE!

DISCONNECT ALL POWER BEFORE SERVICING OR INSTALLING THIS UNIT. MULTIPLE POWER SOURCES MAY BE PRESENT. FAILURE TO DO SO MAY CAUSE PROPERTY DAMAGE, PERSONAL INJURY OR DEATH.