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25VNA4: Installation Instructions
Troubleshooting
Systems Communication Failure
If communication with the Infinity control is lost with the User Interface
(UI), the control will flash the appropriate fault code (see
Check the wiring to the User Interface and the indoor and outdoor units
and power.
Model Plug
Each control board contains a model plug. The correct model plug must
be installed for the system to operate properly (see
Table 4 – Model Plug Information
MODEL
MODEL PLUG
NUMBER
NUMBER
25VNA424
HK70EZ003
25VNA436
HK70EZ015
25VNA448
HK70EZ027
25VNA460
HK70EZ039
The model plug is used to identify the type and size of unit to the control.
On new units, the model and serial numbers are input into the board's
memory at the factory. If a model plug is lost or missing at initial
installation, the unit will operate according to the information input at
the factory and the appropriate error code will flash temporarily. An RC
replacement board contains no model and serial information. If the
factory control board fails, the model plug must be transferred from the
original board to the replacement board for the unit to operate.
CAUTION
!
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage and/or
improper operation.
Do not attempt to install an incorrect model plug as this could cause
some units to operate incorrectly and fail prematurely.
NOTE: The model plug takes priority over factory model information
input at the factory. If the model plug is removed after initial power up,
the unit will operate according to the last valid model plug installed, and
flash the appropriate fault code temporarily.
Pressure Switch Protection
The outdoor unit is equipped with high pressure switch. If this switch
opens the VFD will lose line power and the compressor and fan motor
will not operate. The high pressure switch opens at 670 +/- 10 psig and
closes at 470 +/- 25 psig. If this occurs the PCM will set a diagnostic
code per table 7. The outdoor pressure transducer installed at the
discharge of the compressor is monitored by the PCM and the PCM will
take action to avoid the high pressure switch from opening.
Compressor Protection
The Primary Control Module continuously monitors the operation of the
compressor and takes action when it is nearing the edge of the
boundaries of reliable operation.
transducers to maximize the reliability and minimize the off time of the
system due to operation outside of the compressor boundaries. The
PCM takes different actions for each edge of the boundary, but each
culminates in a reduction of compressor speed to the minimum
allowable and, in the worst case, will power off the compressor to avoid
excursions outside the boundaries. If a shutdown does occur then the
PCM will set a diagnostic code per
Line Voltage Diagnostics
The primary control module monitors the line voltage for low and high
voltage events. If a low voltage or high voltage event occurs and another
fault occurs simultaneously the PCM will set a fault that indicates this
was due to the system conditions and not the components. If this occurs
several times in a row the PCM will set a malfunction and lock out
operation for 1-4 hours, depending on the condition. Refer to
the list of fault codes and
Table 9
lockout times for each one.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Table
Table
4).
PIN RESISTANCE
(K-ohms)
Pins 1-4
Pins 2-3
5.1K
24K
5.1K
360K
11K
150K
18K
62K
The PCM utilizes the pressure
Table
8.
Table 8
for the list of malfunctions and the
Forced Defrost Pins (J9)
The forced defrost pins have several functions. When shorting the pins
using a clip wire the below functions can be executed:
"If the pins are shorted for more than 5 seconds and the unit is in heating
8).
mode then the unit will enter into a defrost.
"If the pins are shorted more than 1 seconds and less than 5 seconds
when the system has just turned off and an active call for cooling or
heating is present the 5 minute initial on-time will be defeated.
"If the unit is in the OFF mode and the pins are shorted at power on the
unit will enter into Status Code Recall Mode.
Temperature Thermistors
Thermistors are electronic devices which sense temperature. As the
temperature increases, the resistance decreases. Thermistors are used to
sense outdoor air (OAT), coil temperature (OCT), the suction line
thermistor (OST) between the reversing valve and the accumulator, and
the outdoor discharge thermistor (ODT) at the outlet from the
compressor.
Refer to
Table 5
and
Table 6
the OAT, OCT, and OST.
Table 5 – Resistance Values versus Temperature
TEMPERATURE
25.0°C (77.0°F)
0.0°C (32.0°F)
-17.8°C (0 °F)
Table 6 – ODT Resistance Values versus Temperatures
TEMPERATURE (°C)
25
75
125
If the outdoor air or coil thermistor should fail, the control will flash the
appropriate fault code (see
IMPORTANT: The outdoor air thermistor, coil thermistor and suction
thermistor should be factory mounted in the final locations. Check to
ensure thermistors are mounted properly (See
Fig.
31).
Outdoor Air Thermistor
The outdoor air thermistor is a 10Kohm resistor used for multiple system
operations.
It provides the outdoor air temperature to the primary
control module and user interface. It is essential for controlling the
system and is used in almost all modes of operation. The sensor is
mounted in the control box per
Fig. 29 – Outdoor Air Thermistor Mounting Location
for
16
for resistance values versus temperature for
RESISTANCE (ohms)
10.0 + / - 2.3%
32.6 + / - 3.2%
85.5 + / - 3.4%
RESISTANCE (K OHMS)
50.15 + / - 5.0%
7.565 + / - 3.0%
1.7 + / - 1.4%
Table
8.)
Fig.
29,
Fig.
29.
Fig. 30
and
A200045
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