A21 Coolant Level Error - Panasonic 2WAY Multi Technical & Service Manual

A21 Coolant Level Error

Error detection method
• A fl ag will be set if the possibility of air entering the coolant circuit is detected during air-mix confi rmation
operations prior to starting the engine (complete combustion.) (The engine will continue to operate.)
An error will be triggered if this possibility is detected three consecutive times.
* However, there are also cases in which the error will be triggered after only one detected when operating
after the [Automatic Air Purge Mode] ([S Air]) or when the engine is fi rst started after an A21 error has been
reset.
Troubleshooting
1
Coolant level 1-1 Is the prescribed amount of coolant in the reserve tank?
check
2
Are there any external signs of coolant leaks? Check
2-1
Coolant leakage
visually.
check
2-2 Can any coolant be confi rmed in the oil pan?
Remove the drain hose from the exhaust gas heat
2-3 exchanger and operate the pump. Is any coolant emitted
from the outlet?
3
3-1 Can any air be confi rmed in the coolant circuit?
Air-mix check
Does air continue to be emitted no matter how many times
3-2
the air purging process is performed?
Does air continue to be emitted even after the engine has
3-3
been shut down?
4
Are there any severed wires, defective contacts or short
Coolant pump
4-1
circuits on the coolant pump's lock?
check
5
Coolant electric
three-way valve
check
5-1 Is the coolant electric three-way valve operating normally?
● For work procedure for replacing outdoor main board, see "5. Reference Document".
● For board and Electrical Wiring Diagram, see Chapter 6.
• Outdoor main board: page VI-2
• Outdoor power board: page VI-3
• Converter board: VI-4
• Indoor control board for DC motor models: page VI-5
• Outdoor Unit Electrical Wiring Diagram: page VI-6
IV–21
Yes 3-1
No 2-1
Yes Repair
No 2-2
Replace the engine
Yes
head or packing
No 2-3
Replace the exhaust gas
Yes
heat exchanger
No 3-1
Yes 3-2
No 4-1
Yes 3-3
No End after air purge
Check for leaks on the
Yes plate heat exchanger
and repair if necessary.
Replace the engine
No
head or packing
Replace the coolant
Yes
pump
No 5-1
If the problem reoccurs,
replace the outdoor unit'
Yes s power board or main
board and keep an eye
on the situation.
Replace the three-way
No
coolant valve.