Johnson Controls RHP143 Series User Manual

System start-up
Energize crankcase heater (where
applicable)
About this task:
In order to energize the crankcase heater, set the indoor
cooling thermostat to the OFF position. Close the line
power disconnect to the unit. The outdoor unit (where
applicable) has a CCH thermostat that opens at 45°F and
closes at 35°F outdoor ambient temperature.
NOTICE
An attempt to start the compressor without at least
8 h of crankcase heat may damage the compressor.
Installation of an accessory crankcase heater is
required if not factory installed for installations over
the maximum allowable line length.
With power to unit and thermostat in cooling position:
1. In the cooling cycle, discharge gas is pumped to
the outdoor coil which is the condenser. The indoor
coil is the evaporator.
2. If the fan switch is in ON position, a circuit is made
through the blower relay to provide continuous
blower operation.
3. With fan switch in AUTO position, a circuit is made
from thermostat cooling contact through blower
relay to provide blower operation.
4. The system will cycle with thermostat demand to
provide cooling as needed.
System operation
Anti short-cycle delay
The control includes a 5 min anti-short-cycle delay (ASCD)
timer to prevent the compressor from short-cycling after
a power or thermostat signal interruption. The ASCD
timer is applied when the control is first powered from
the indoor unit thermostat and immediately following the
completion of a compressor run cycle. The compressor
and the outdoor fan will not operate during the 5 min that
the timer is active.
The ASCD timer can be bypassed by shorting the TEST
terminals for 3 s while the thermostat is calling for
compressor operation (Y input signal energized).
Low voltage detection
The control monitors the transformer secondary (24
VAC) voltage and provides low voltage protection for
the heat pump and its components. In particular, the
control prevents contactor chatter during low voltage
conditions. If the voltage drops below approximately
19 VAC, the control will continue to energize any relays
that are already energized but will not energize any
additional relays until the voltage level increases. If the
voltage drops below approximately 16 VAC, the control
will immediately de-energize the relay outputs and will
not energize any relays until the voltage level increases.
Test input
The control includes a TEST input connector that can be
used for various testing functions during installation and
service. The TEST input connector is shown in Figure 22.
Table 45 summarizes the behavior of the control when the
two TEST pins are connected. More detailed descriptions
of the various functions are included in other sections of
this document.
Table 45: TEST input functionality with Y
Duration of connection (s) Control behavior with thermostat signals present
< 2 No response
Bypass ASCD (Reduce timer to zero immediately). If Y1 is
present and high-pressure switch is closed, contactor is
energized. If Y2 is also present, second stage output (M2)
will also be energized.
2 to 5
Clear pressure switch lockout and reset the 6 h PS timer.
> 5
Initiate defrost cycle ignoring the COIL temp and record
that defrost cycle was initiated by TEST short.
Energize Wout and begin defrost cycle immediately upon
expiration of timer.
Test pin short removed Terminate defrost as normal.
Test pin short not removed Continue defrost cycle until TEST connection removed.
R-410A Outdoor Split-System Heat Pump Installation Manual - YH2E / THE2 / RHP143 Series 33
Johnson Controls Ducted Systems

Johnson Controls RHP143 Series Specifications

General

Brand	Johnson Controls
Model	RHP143 Series
Category	Heat Pump
Language	English