Mitsubishi Electric CITY MULTI PQRY-P200YMF-B Service Handbook page 117

Checking code Meaning, detecting method
1505 Suction Judging that the state when the
pressure suction pressure reaches 0kg/
2
abnormality cm G (0MPa) during compressor
operation indicates high pressure
by the discharge temperature and
low pressure saturation tempera-
ture, the back-up control by gas
bypassing will be conducted.
2000 Interlock In modes other than the stop
operation mode, the pump interlock circuit
performs an abnormal stop when
it has been open continuously for
10 minutes, and at that time,
displays "2000." However, This is
displayed when DIP SW 2-8 on
the heat source unit MAIN board
is OFF.
2134 Abnormal 1. If the inlet water temperature
water is detected to be below 5°C or
temperature over 50°C during operation
(the first time it is detected),
the heat source unit is
stopped temporarily, the
system enters the 3-minute
restart prevention mode, then
restarts the heat source unit
after 3 minutes.
2. If the inlet water temperature
is detected to be below 5°C or
over 50°C again within 30
minutes after the heat source
unit stops following the
operation in 1 above, (the
second time it is detected), an
abnormal stop is performed,
and at that time, "2134" is
displayed.
3. If the inlet water temperature
is detected to be below 5°C or
over 50°C again longer than
30 minutes after the heat
source unit stops following the
operation in 1 above, it is
treated as having been
detected the first time and
operation is the same as in 1
above.
Cause
• Operation while neglecting to open
ball valve. Especially for the ball
valve at low pressure side.
At cooling : Gas side ball valve
At heating : Liquid side ball valve
• When plural systems are existing,
the low pressure abruptly drop at
indoor stopping by the erroneous
wiring of transmission line (differ-
ent connection of transmission line
and refrigerant piping).
• Temporary vacuum condition due
to refrigerant distribution unbalance
(insufficient refrigerant of low pres-
sure line) immediately after charg-
ing refrigerant.
1) Failure of the heat source water
circulating pump to operate.
2) Disconnection
3) Connector pulled out, faulty
contact.
4) Faulty interlock input circuit on
the relay board.
5) Faulty interlock input circuit on
the control board.
1) Failure of the heat source water
circulating pump to operate.
2) Cooling tower or heating
equipment out of order.
3) Clogged or dirty water heat
exchanger.
4) Faulty thermistor. (TH6)
5) Faulty thermistor input circuit on
the control board.
6) Faulty thermistor installation.
(TH6)
–114–
Checking method & Countermeasure
Once vacuum operation protection is
commenced, do not attempt to
restart until taking the measures
below.
<Checking method>
• Check ball valve for neglecting to
open.
• Check extended piping for
clogging when ball valve is
opened.
• Check transmission line for errone-
ous wiring. (Confirm the correct wir-
ing and piping connection between
indoor and heat source units by op-
erating indoor unit one by one.)
<Countermeasure>
• After checking with the above
method, make error reset by
power source reset.
• Then operate for 10~15-minutes
under the operation mode reverse
to that when the vacuum opera-
tion protection occurred (Heating
if error occurred in cooling, while
cooling if it occurred in heating),
and then enter into the ordinary
operation state.
Check the thermistor's resistance.
Check the temperature picked up by
the sensor by the LED monitor.