York MILLENNIUM Y22, Installation Manual

Page: 70 / 140

102777-YIM-E-0206
70 Unitary Products Group
Example: By actual measurement, it takes 7 seconds for the
hand on the one cubic foot dial to make a revolution with just
a 570,000 Btuh furnace running. Read across to the column
in Table 24, headed 1 Cubic Foot where you will determine
that 525 cubic feet of gas per hour are consumed by the fur-
nace at that rate. Multiply 525 x 1050 (the Btu rating of the
gas obtained from the local gas company). The result of
551,000 Btuh is within 5% of the 570,000 Btuh rating of the
furnace.
ELECTRIC HEATING
The electric furnace is operational as shipped from the fac-
tory and does not receive any field adjustments.
COOLING OPERATING INSTRUCTIONS
COMPRESSOR
Compressors are factory mounted ready for operation (See
page 63 Compressor Rotation).
OIL LEVEL - All compressors are factory charged with oil.
Each compressor is equipped with an oil level sight glass.
Check for proper oil level which is approximately to the center
of the sight glass. Recheck oil level at startup.
INTERNAL WIRING
Check all electrical connections in the unit control box;
tighten as required.
CONDENSER FANS
Check for proper condenser fan rotation; clockwise facing the
air discharge. If condenser fans are rotating backwards, line
voltage to unit single point power connection is misphased
(See page 63 Compressor Rotation).
MILLENNIUM SEQUENCE OF OPERATION
OVERVIEW
The Millennium Simplicity control has comprehensive rule
sets to respond to heat and cool calls, provide anti-shortcycle
and other safeties, date / time clock, and other features mak-
ing the programmable thermostat unnecessary. The Millen-
nium Simplicity extends on the rules of the Synthesys digital
control.
With an attached (optional) Room Sensor, the control pro-
vides calls for heating and cooling and occupied override.
The control determines when to start morning warm-up,
mechanical cooling, or heat based on parameter settings in
the Millennium Simplicity control, its internal time clock,
Occupied and holiday schedules, the deviation from the set-
points, and the rate of temperature change.
A separate thermostat cannot determine if an output function
is available. For example, if the belts on the supply fan were
to break, the thermostat would still call for the fan to operate
and, if space conditions require, call for heating or cooling.
Logic in the control prevents undesired operation of heating
and cooling stages, with interlocks and minimum run times.
Moreover, the control can report faults on its digital display or
on a network to a monitoring system.
Control logic is designed such that airflow must be proven
before any heating or cooling stage can operate. Mechanical
cooling is locked out below 40°F outdoor ambient for all units
without head pressure control. The control provides voltage
to energize the contactors for the supply fan, cooling stages,
heating stages, and options such as the economizer and
power exhaust. The thermostat makes calls for cooling and
heating; the Simplicity control is responsible for executing the
rules putting these calls into action and protecting the unit
through appropriate safety devices. If the Millennium Simplic-
ity senses low voltage, it will hold any call that energizes a
contactor until the voltage is adequate. It will not alarm for low
voltage, but will provide a flash code.
The control also energizes the supply fan and cooling stages
based on external inputs from the thermostat:
• G - Supply Fan
• Y1-1st Stage Cooling
• Y2-2nd Stage Cooling
• Y3-3rd Stage Cooling
• Y4-4th Stage Cooling
FIGURE 28 - TYPICAL FLAME APPEARANCE
G A S
S U P P L Y
P I P E
B U R N E R
B U R N E R B R A C K E T
I G N I T O R
B U R N E R F L A M E
( B L U E O N L Y )
H E A T E X C H A N G E R T U B E