Cooling start-up
The following sections describe the cooling start-up
procedures.
Cooling pre-start checklist
About this task:
When the installation is complete, perform the
following checks:
1. Check the electrical supply voltage. Verify that
it is the same as the voltage listed on the unit
nameplate.
2. Set the room thermostat to the off position.
3. Turn on electrical power to the unit.
4. Set the room thermostat fan switch to on.
5. Check the indoor blower rotation.
If the blower rotation is in the wrong direction,
see Phasing section.
a. Check the blower drive belt tension.
6. Check the unit supply air (CFM).
7. Measure the evaporator fan motor's amp
draw.
8. Set the room thermostat fan switch to off.
9. Turn off electrical power to the unit.
Operating the unit
1. Turn on electrical power to the unit.
2. Set the room thermostat setting lower than
the room temperature.
First stage compressors energize after the
built-in time delay of five minutes.
Additional stages of cooling will be
energized by the thermostat if needed.
Post-start checklist
1. Verify proper system pressures for both
circuits.
2. Measure the temperature drop across the
evaporator coil.
3. Measure the system amperage draw across all
legs of 3 phase power wires.
4. Measure the condenser fan amperage draw.
Installation Manual: YORK
®
Sun
™
Select YV28 to YV50
87
Johnson Controls Ducted Systems
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