Changed Point - Mitsubishi Electric PUHZ-RP3VHA Technical & Service Manual

1-2. Changed point

• Precautions when reusing existing R22 refrigerant pipes
(1) Flowchart
The existing pipe thickness meets speci-
fications and the pipes are not damaged.
Check if existing air conditioner can operate.
Existing air conditioner can
operate.
Perform cooling operation
for about 30 minutes and
then do a pump down work.
Disconnect existing air con-
ditioner from piping.
Existing pipes can be reused.
In case the unit is RP3
which utilizes AB oil.
Connect a new air conditioner.
Connecting a new air conditioner
1Flaring work should be done so that flare meets the dimension for R410A.
Use flare nut provided with indoor and outdoor unit.
2When using gas piping of [19.05mm for RP4, 5 and 6.
Make sure that DIP SW8-1 on outdoor unit controller board is set to ON.
WThis is to keep the pressure on pipes within permissible range.
Use different diameter joint or adjust the piping size by brazing.
3When using pipes larger than specified size for RP3.
Make sure that DIP SW8-1 on outdoor unit controller board is set to ON.
WThis is to prevent oil flow ratio from lowering due to the decrease in flowing refrigerant.
Use different diameter joint or adjust the piping size by brazing.
4When existing pipes are specified size.
The pipes can be reused referring to table 1 on page 18.
Use different diameter joint or adjust the piping size by brazing.
When using existing pipes for RP4, 5 and 6.
Make sure that DIP SW8-2 on outdoor unit controller board is set to ON and perform
replacement operation.
wChemical compounds containing chlorine left in existing pipes are collected by rep-
lace filter.
The air conditioner automatically performs cooling operation through replace filter
for about 2 hours.
Measure the existing pipe thickness and check for damage.
Existing air conditioner
cannot operate.
Use a refrigerant recovery
equipment to collect the re-
frigerant.
Check the oil condition
when collecting the refrige-
rant.
Oil is clean.
In case the unit is RP4, 5
or 6 which utilize ester oil.
Connect a new air conditioner.
Perform replacement operation.
·When performing replacement operation, make sure that DIP SW8-2 on outdoor unit controller board is
set to ON.
wChemical compounds containing chlorine left in existing pipes are collected by replace filter.
The air conditioner automatically performs cooling operation through replace filter for about 2 hours.
The existing pipe thickness does not meet
specifications or the pipes are damaged.
Oil is dirty.
When the compressor bearings
are glazed, rotation scratches
are present, or the compressor
breaks down, iron particles or
oil deterioration will blacken the
oil.
Disconnect existing air conditioner
from pipes and clean pipes using
cleaning device.
Attach a filter drier.
5
Existing pipes cannot be
reused. Use new pipes.