Drive Belt Tension Adjustment

t = Span length, inches

C = Center distance, inches

D = Larger sheave diameter, inches d = Smaller sheave diameter, inches

h = Deflection height, inches

TYPE		SHEAVE	DEFLECTION		DEFLECTION
TYPE		SHEAVE	FORCE (lbs)
		DIAMETER	FORCE (lbs)
		DIAMETER			(in)
		(in)			(in)
BELT	DRIVE	(in)	Used	New
BELT	DRIVE		Used	New


A, AX	Standard	3.0 to 4.0	4.2 ± .5	5.5 ± .5	0.313

RECOMMENDED POUNDS OF FORCE PER BELT

New V-belts will drop rapidly during the first few hours of use. Check tension frequently during the first 24 hours of opera- tion. Tension should fall between the minimum and maximum force. To determine the deflection distance from a normal position, measure the distance from sheave to sheave using a straightedge or a cord. This is your reference line. On mul- tiple belt drives, an adjacent undeflected belt can be used as a reference.

EVAPORATOR FAN ROTATION CHECK (THREE PHASE MODELS ONLY)

Check that fan rotates counter-clockwise when viewed from the drive side of unit and in accordance with rotation arrow shown on blower housing. If it does not, reverse the two in- coming power cables. In this case, repeat bearing check.

Do not attempt to change load side wiring. Internal wiring assures all motors and compressors will rotate in correct di- rection once evaporator fan motor rotation check has been made.

ELECTRICAL INPUT CHECK

Make preliminary check of evaporator fan ampere draw and verify that motor nameplate amps are not exceeded. A final check of amp draw should be made upon completion of air balancing of the duct system (see Appendix B).

REFRIGERATION SYSTEM CHECKS

Ensure the hold-down bolts on the compressor are secure and have not vibrated loose during shipment. Check that vi- bration grommets have been installed. Visually check all pip-

ing and clamps. The entire refrigeration system has been factory charged and tested, making it unnecessary to field charge. Factory charges are shown on the unit nameplate.

Install service manifold hoses. Gauges should read satura- tion pressure corresponding to ambient temperature. Charge should be checked to obtain 12° to 15° of sub-cooling per system (i.e. compressor circuits).

START-UP PROCEDURE AND CHECKLIST

Begin with power turned off at all disconnects.

1.Turn thermostat system switch to “Cool,” and fan switch to “Auto” and turn temperature setting as high as it will go.

2.Inspect all registers and set them to the normal open position.

3.Turn on the electrical supply at the disconnect.

4.Turn the fan switch to the “ON” position. The blower should operate after a 7 second delay.

5.Turn the fan switch to “Auto” position. The blower should stop after a 65 second delay.

6.Slowly lower the cooling temperature until the unit starts. The compressor, blower and fan should now be operating. Allow the unit to run 10 minutes, make sure cool air is being supplied by the unit.

7.Turn the temperature setting to the highest position, stopping the unit. The indoor blower will continue to run for 65 seconds.

8.Turn the thermostat system switch to “OFF” and disconnect all power when servicing the unit.

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.

HEAT PUMP START-UP PROCEDURE

9.Check the cooling mode for the heat pump in the same manner as above. The reversing valve is energized when the thermostat is placed in the cooling position. A clicking sound should be noticeable from the reversing valve. By lowering the temperature setting to call for cooling, the contractor is energized. The compressor, blower and fan should then be running. After the cooling mode is checked out, turn the thermostat system switch to “OFF”.

10.Turn the thermostat system switch to “HEAT” and fan switch to “AUTO”.