Carrier 25VNA Service Manual page 20

FLASH CODE
OPERATION
(Amber LED)
System Malfunction 96
System Malfunction 97
Event 98
System Malfunction 99
25VNA EVENT / FAULT (CONT.)
Heat or Cool
Possible Causes
Mode
Low supply line voltage (< 180 VAC)
Stormy weather causing intermittent
Both
voltage dropouts
Loose wire in control box area
Inverter internal damage
High supply line voltage (> 257 VAC)
Both Stormy weather causing intermittent
voltage spikes
Inverter internal damage
Both High Torque or Flank Loading Event
Outside Normal Operating Range (e.g.
improper load calculation, system
match issue, outside cooling range,
outside heating range etc)
Restriction due to debris leading to
Overcharge when charging in Cooling
Both
mode
Restriction in EXV plus Long Line Ap-
plication leading to Overcharge when
charging in Cooling mode
None condensibles leading to high
load
Service Valve left closed (Liquid or Va-
por)
Overcharged System
Outdoor Airflow too low or off
Cool
Restriction in Filter Drier plus Long
Line Application and filter drier on Out-
door Unit
Restriction in EXV plus Overcharge
Restriction in Circuits or Tubing
Electric Heater plus Heat pump applic-
ation: Electric Heater stuck on
Furnace plus Heat pump application:
Furnace stuck on
Restriction in Filter Drier plus Long
Line Application and filter drier on In-
door Unit
Expansion Orifice Restriction
Service Valve left closed (Vapor Ser-
vice Valve)
Heat
Indoor Airflow too low or off
Overcharged System
Reversing Valve Stuck in Cooling
Restriction due to debris
20
ACTION
Check supply voltage to ODU; if low con-
tact utility provider
When adverse weather subsides unit
should self ---recover; cycle ODU power if
necessary
Loose wire: check for loose wire in ODU
Replace Inverter
Check supply voltage to ODU; if high con-
tact utility provider
When adverse weather subsides unit
should self ---recover; cycle ODU power if
necessary
Replace Inverter
System will try to self ---mitigate, persistent
conditions will lead to lockout (refer to Er-
ror Code 99)
Consult Application Guidelines
Clean System (refer to application
guideline) and replace filter drier
If long line, troubleshoot EXV
Clean System (refer to application
guideline) and replace filter drier
Ensure Service Valves are open
Check system charge using Cooling Char-
ging Mode (follow proper charging proced-
ures)
Check Outdoor Coil for clogging (ice or
debris) and clean or de ---ice if necessary;
Troubleshoot Outdoor fan motor and make
sure it is working; follow Outdoor Airflow
troubleshooting instruction
Clean System (refer to application
guideline) and replace filter drier
troubleshoot EXV
Check kinks and straighten or replace cir-
cuits
If User Interface is not requesting Electric
Heat check for heater relays, if on
troubleshoot Electric Heater
If not in Defrost and Furnace is running
same time as heat pump, troubleshoot Fur-
nace
Clean System (refer to application
guideline) and replace filter drier
Troubleshoot TXV (see guide below)
Troubleshoot EXV (see guide below)
Ensure Vapor Service Valve is open
Check Indoor for clogging (ice or debris)
and clean or de ---ice if necessary;
Troubleshoot Indoor fan motor and make
sure it is working; follow Indoor Airflow
troubleshooting instruction
Check charge in cooling (if in Cooling
Charge Mode Ambient Range), if low add
charge using Charging Mode (follow prop-
er charging procedures); if out side cool-
ing charge mode range, pull out charge,
weigh in using heating charge mode
troubleshoot reversing valve
Clean System (refer to application
guideline) and replace filter drier