Carrier 25VNA Service Manual page 17

FLASH CODE
OPERATION
(Amber LED)
System Malfunction
25VNA EVENT / FAULT (CONT.)
Heat or Cool
Mode
Cooling in Low Ambient region (55
Cool ° F and below) with "Low Ambient
Cooling Control" disabled
Outside Normal Operating Range
(e.g. improper load calculation, sys-
Cool
tem match issue, outside cooling
range etc)
Service Valve left closed (Liquid or
Cool
Vapor)
Undercharged System
Indoor Airflow too low or off
Cool
Restriction in Filter Drier plus Long
Line Application and filter drier on
Indoor Unit
Restriction due to debris
Restriction in Circuits or Tubing
Restriction in Filter Drier plus filter
83 drier on Outdoor Unit
Both
Expansion Orifice Restriction
Outside Normal Operating Range
(e.g. improper load calculation, sys-
tem match issue, outside heating
range etc)
Service Valve left closed (Liquid
Service Valve)
Outdoor Airflow too low or off
Heat
Undercharged System
Reversing Valve Bypass
Restriction due to debris
Possible Causes
Enable "Low Ambient Cooling" via user
interface
Consult Application Guidelines
Ensure Service Valves are open
Check system subcooling to determine
charge status, if low add charge using
Charging Mode (follow proper charging
procedures)
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
Clean System (refer to application
guideline) and replace filter drier
Clean System (refer to application
guideline) and replace filter drier
Check kinks and straighten or replace
circuits
Clean System (refer to application
guideline) and replace filter drier
If short lineset (less than 15 ft)
Troubleshoot TXV (see guide below); re-
place if necessary
Troubleshoot EXV (see guide below)
Consult Application Guidelines
Ensure Liquid Service Valve is open
Check Outdoor for clogging (ice or
debris) and clean or de ---ice if neces-
sary; Troubleshoot Outdoor fan motor
and make sure it is working; follow Out-
door Airflow troubleshooting instruction
Check charge in cooling (if in Cooling
Charge Mode Ambient Range), if low
add charge using Charging Mode (follow
proper charging procedures); if outside
cooling charge mode range, pull out
charge, weigh in using heating charge
mode
Reversing Valve Stuck halfway;
troubleshoot reversing valve
Clean System (refer to application
guideline) and replace filter drier
17
ACTION