Mooney M20R - Evaporator Balancing Procedure; Expansion Valve Adjustment Procedure; Special Tools

MOONEY
AIRCRAFT
CORPORATION
M20R
SERVICE
AND
MAINTENANCE
MANUAL
O.A.T.
eF)
SUCTION
DISCHARGE
PREISSURE(PSIG)
PRESSURE
(PSIG)
60-70
28
125 140
80
30
170 10
95
31
210 10
105
32
237
10
NOTE
1.
Verify
that
system
leak check and
refrigerant
charg-
Whenever
possible, the
system
should be
ch~rged
ing
has been
performed
and
system
is
operating
at
typi-
on a
hot
day (90-100’
Fl.
If
not,
’topping
off’lmay
cat values
as
outlined in Section
21-52-03,
13.
be
required
for
ambient
conditions.
2.
Remove
all
shrouds,
covers or
enclosures which
14. Allow
system
to
operate
forl0 minLAes and
then
ShlRdOlhlll.
prevent
access
to
the
evaporator
expansion
valve
adjust-
ment
knob.
CAUTION
Do
not
allow aircraft
engine
temperatures
to
3.
Verify
R-134a
manifold
gauges
and hoses
are
con-
exceed
Ilmits.
nected
to
service
ports;
manifold
gauge
set
valves
NOTE
closed.
After
shutdown both
suction and
discharde
4.
Open
both valves
on
charging
hose
quick
connect
pressures
will
~gln
to
equalize.
Pressures
s9ould
fittings.
be
equal
in
60 90
seconds.
15. Close
refrigerant
container
shutoff
valvel
(turn
5. Remove
expansion
valves’
protective
caps.
CNV).
Record the
refrigerant
container
final
weight
an
6.
Verify
that inlet
to
evapo
rater
coil
and
blower
d
ucting
calculate
system
refrigerant
charge
as
follows:
are
free
of
any
contamination
or
restrictions which could
alter air flow.
CHARGE
(Ib.)
W initial
(Ib.)
W final
(Ib.)
7. Start aircraft
engine.
16.
Turn knob
on
suction and
discharge
charginls
hose
8. Select "MAX"
on
airconditioner switch, idle
engine
at
quick
coupler
to
closed
position
and disconnect
/hoses
800--900
RPM.
Verify
Alternator is
charging.
from
service
ports.
9.
Close
cabin and
baggage
doors and allow
system
17. Remove
yellow
charging
hose
from
refrigerant
tO
Operate
for
5
minutes.
container
and
store
manifold
gauge
set.
10.
Record
compressor
suction
and
discharge
pres-
sures
and
evaporator
air inlet and outlet
temperatures.
CAUTION
Hand and
eye
protection
must
be
worn
durinQ
this
NOTE
operation
to
prevent
subcooled
refrigerant
mom
Typical
temperature
difference of
eXapomtor
inlet
burning
eyes
or
hands.
and
outlet
air
is
25+
5’
F.
2153-00
EXPANSION
VALVE
ADJUSTM~NT
11. If
suction
pressure
is above the values
outlined in
PROCEDURE
Section
21-52-03,
1
3,
the
adjustment
screw
of the
evapo-
rator
expansion
valve,
which has lowest outlet
tempera-
Even
though
the automatic
expansion
valves
areiset
at
ture,
must
be turned
CCW,
in 1/2 revolution increments.
the
factory
there
may
be
times
when
they
must
~e
ad-
justed
to
assure
proper
refrigerant
flow
at
the
d/esired
12.
Adjust
other
expansio
n
valve of
evaporatorthat
has
evaporating
temperature.
This
may
be due
to
~ciessive
higher
temperature
by turning adjustment
screw
CW,
in
pressure
drop
for
long
suction
line
runs.
Any adju~tment
1/4 revolution increments.
must not
affect
system
suction
and
compressqr
dis-
13. Wait 2--5 minutes for valves
to
stabilize
until
de-
charge
pressures
as
outlined in Section
21-52-q3,
13.
sired
pressure
is
obtained.
or
air outlet
temperature
is
Changing expansion
valve
settings
will also
change
lowest
possible.
Re-adjust
as
necessary.
evaporator
air
output
temperatures.
14.
Verify
Engine
temperatures
and alternator
output.
2163-01
SPECIAL TOOLS ANDIOR
15.
Operate
system
for
5
10 minutes after
expansion
EQUIPMENT
valve
adjustment
to
verify
setting.
Evaporator
outlet
tem-
peratures
should
be within 1--3" F of each
other.
The
following
tools
and/or
equipment
are
requi~ed
to
perform
expansion
valve
adjustment:
16.
System
contains
multiple
evaporator
modules. See
Section
21-53-03,
to
balance
evapo
rater
modules.
1.Assorted small hand
tools.
2.
Inspection
mirror,
adjustable
21-53-03
EVAPORATOR BALANCING
PROCEDURE:
3.
Thermometer,
0-1500
F
4.
Flashlight
or
service
light
Evaporator balancing
is
required
on
all
systems
with
multiple
evaporator
modules. This
process
balances
re-
5. R-134a
service manifold and
gauge
set
frigerant
flow between
evaporators
to
achieve
equal
2153-02 EXPANSION
VALVE
ADJUSTMtENI:
evapo
rater
air
o
utlet
temperatures.
See Sectio
n
21
-53-02,
1
through
10 above
prior
to
beginning
steps
below.
The
expansion
valve
adjustment
shall be
performed
in 1.Access all
evaporator
modules
and
measure/record
accordance
with,
but
not
limited
to the
following:
outlet
air
temperatures.
21-53-00
REV. 7-96
Island Enterprises