Rheem A17 Series, Руководство по установке

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Components
6.1 Cooling Mode
When the EcoNet
TM
Control Center or 2-stage
conventional 24VAC thermostat calls for the 1st stage
of cooling, the outdoor fan motor is energized and the
1st stage of the compressor and indoor blower mo -
tor are energized. The system then provides cooling
and dehumidification for the conditioned space. If the
Control Center or thermostat calls for the 2nd stage
of cooling, the compressor shifts to the 2nd stage of
capacity and the indoor blower motor speeds up to the
2nd stage of air-flow. The system will cycle between
the 1st and 2nd stages as directed by the Control Cen -
ter or thermostat. When the call for cooling has ended
or the thermostat is switched to the OFF position, the
compressor and outdoor fan motor are de-energized,
but the indoor blower motor continues to operate for 30
– 45 seconds to extract the residual cooling capacity in
the cold indoor coil before it stops.
6.0 SEQUENCE OF OPERATION
Operation
6.2 On-Demand Cooling
Dehumidification
The EcoNet
TM
Control Center can be configured for
On-Demand Dehumidification for applications with an
EcoNet
TM
enabled air-handler or gas furnace with a
variable speed ECM motor. The On-Demand Dehumid -
ification feature is not available on the (-)H2T air-han -
dlers. On-Demand Dehumidification allows the system
to automatically increase the level of dehumidification
in the cooling mode by decreasing the indoor air-flow
by 15% when the indoor relative humidity measured
at the EcoNetTM Control Center rises above the set-
point. Once the relative humidity drop to the set-point,
the indoor air-flow level returns to normal.
7.0 COMPONENTS & CONTROLS
7.1 Compressor
Copeland Ultratech 2-stage scroll compressors are
used in all (-)A17 condensing units. The 2nd capacity
stage is activated by a DC signal that energizes an
internal solenoid which shifts the compressor to full
capacity. The 24VAC Y2 signal from the thermostat is
rectified to DC current by the 2-Stage Outdoor Control
(TSODC), providing the DC output to the low voltage
terminals on the compressor.
7.2 Compressor/Fan
Motor Capacitor
3 ton models utilize a dual capacitor for the com -
pressor and PSC outdoor fan motor. 2, 4, and 5 ton
models utilize a single capacitor since they have ECM
outdoor fan motors that do not require a capacitor.
7.3 Compressor
Contactor
All models utilize a single-pole contactor to control the
compressor.
• When a low ambient control is used for system
operation below 55 o F.
All heaters are located on the lower half of the com -
pressor shell. Its purpose is to drive refrigerant from
the compressor shell during long off cucles, thus pre -
ventig damage to the compressor during start-up.
At initial start-up or after extended shutdown periods,
make sure the heater is energized for at least 12 hours
before the compressor is started.
(Disconnect sweitch is on and wall thermostat is off.)
Model
Number
Compressor
Model Number
Charge Limit
Without Crankcase
Heat
(-)A1724AJ* ZPS20K5E-PFV-130 9.6 lbs.
(-)A1736AJ* ZPS30K5E-PFV-130 9.6 lbs.*
(-)A1748AJ* ZPS40K5E-PFV-130 12 lbs.*
(-)A1760AJ* ZPS49K5E-PFV-130 12 lbs.*
7.4 Compressor Crackcase
Heat (CCH)
NOTE:
A crankcase heater should be installed if:
• They system charges exceeds the values listed in
the adjacent tables,
They system is subject to low voltage variations or
While scroll compressor usually do not require crank -
case heaters, there are instances when a heater
should be added. Refrigerant migration during the off
cycle can result in a noisy start up.
Add a crankcase heater to minimize any start up noise
or bearing “wash out”
*Crankcase Heater Factory Installed