Daikin EUWY 24KBZW1 Series, Service Manual

Page: 193 / 210

ESIE11-02 Pre-Test Run Checks
Part 4 – Commissioning and Test Run 4–27
3
4
5
1
The valve does not
shift from heating to
cooling Check the operation conditions in the table below to find the cause of the malfunction.
The procedure to solve the problem is described in the last column.
See the illustration to situate the numbers in the table heading.
1 2 3 4 5 6 Cause Procedure
Hot Cool Hot as in
column
1 Cool as
in
column
1 Temper-
ature of
valve
body Temper-
ature of
valve
body The pressure
differential is too
high. 1. Raise the head pressure.
The valve will reverse
during the pressure equal-
ization period.
2. Recheck the system.
The pilot tubes
are clogged. 1. Raise the head pressure.
2. Operate the solenoid to
free the dirt.
3. If there is still no shift,
replace the valve.
Hot Cool Hot as in
column
1 Cool as
in
column
1 Hot Temper-
ature of
valve
body There is dirt in
one bleed hole. 1. Raise the head pressure.
2. Operate the solenoid.
3. If the procedure was
unsuccessful:
■
Remove the valve and
clean it.
■
Check for air before
reinstalling.
■
If there is still no
movement: replace the
valve, add a new strainer
to the discharge tube and
mount the valve
horizontally.
Hot Cool Hot as in
column
1 Cool as
in
column
1 Hot Temper-
ature of
valve
body The piston cup
head leaks. 1. Stop the unit.
2. After pressure equaliza-
tion, restart with
de-energized solenoid.
3. If the valve shifts,
retry with the
compressor on.
If there is no reversal,
replace the valve.
Hot Cool Hot as in
column
1 Cool as
in
column
1 Hot Hot The pilot is
defective. Replace the pilot valve.
Warm Cool Warm as
in
column
1 Cool as
in
column
1 Warm Temper-
ature of
valve
body The compressor is defective.