Carrier Infinity 24VNA6 Series User Manual

24VNA6 / 25VNA4: Service Manual
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
15
A200046
Fig. 14 – Outdoor Coil Thermistor (OCT) Attachment
(On Coil Tube Extension)
If the OCT sensor fails, defrost will occur at a fixed 60-minute interval if
operating in Auto mode, and the defrost cycle will run for the maximum
allowable time. When OCT is faulted and the equipment is running in
heating mode but defrost is not running, the reported value of OCT will
be the saturated suction temperature. In all other conditions when OCT
is faulted, the reported value of OCT will be the saturated discharge
temperature.
Outdoor Discharge Temperature (ODT) Thermistor
The ODT thermistor is used for determining discharge superheat and
protecting the compressor from over-temperature operation. It must be
secured tightly to the discharge tube and aligned parallel to the tube axis
(see Fig. 15).
NOTE: ODT must be mounted inside of the sound blanket to reduce the
influence of ambient temperature and provide accurate tube temperature.
A200047
Fig. 15 – 24VNA6Suction Thermistor (OST) and Discharge
Thermistor (ODT) Mounting Locations
If ODT sensor fails, compressor operation will be limited to 2700rpm.
When ODT is faulted, the reported value of ODT will be 47°F.
Outdoor Suction Temperature (OST) Thermistor (25VNA4 Only)
The OST thermistor is used for calculating suction super heat during
heating operation.. The OST thermistor must be secured tightly to the
suction tube and aligned longitudinally to the vertical surface of the tube
axis (see Fig. 15).
If OST sensor should fail, cooling operation will be unaffected, but
heating operation will be disabled. OST faults are displayed as critical
faults even during cooling operation so that service may be performed
before heating is required..
Pressure Sensors
The equipment contains two pressure transducers:
• Suction Pressure Transducer (SPT)
• Discharge Pressure Transducer (DPT)
The two transducers are identical parts installed on the suction inlet to
the compressor and discharge outlet of the compressor respectively. The
transducers have a sensing range of 0 to 620 psig. The connection points
to the PCM are labeled P1 and P2. These two connection points are
identical. Either pressure transducer can connected to either input. The
software in the PCM detects which transducer is connected to which
input and assigns the signals accordingly.
Signals used by control board for:
• Low pressure cut- out
• Loss of charge management,
• Compressor reliability management
• Discharge pressure cut-out
• Suction and Discharge super heat calculations
If the accuracy of either transducer is questioned, it can be checked
while attached to the PCM. Connect a gauge manifold to the appropriate
gauge port fitting and compare the gauge reading with the pressure
reported by the PCM to the Infinity Control or to the Carrier Service
Tech App. The connections at the PCM should be swapped to ensure the
discrepancy is not related to PCM translation of transducer input signal.
If suspect pressure measurement error follows transducer when
connections are switched, replace transducer. If the If the suspect
pressure measurement error changes to the other transducer when the
connections are switched, replace the PCM.
CAUTION
!
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage or
improper operation.
In order to minimize the ambient influence, make sure the discharge
thermistor curved surface hugs the pipe surface and is secured tight
using the wire tie fished through the original slot insulating polymer
body.

Carrier Infinity 24VNA6 Series Specifications

General

Brand	Carrier
Model	Infinity 24VNA6 Series
Category	Heat Pump
Language	English