Danfoss DHP-AX, Инструкция по установке и обслуживанию

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64 – Service VMBMH302
Cause Troubleshooting Remedy
7. The heat pump has stopped on
HIGH RETURN. • Check what the MAX RETURN value is set
at in the heat pump’s control computer. It
must be adjusted to the unit’s maximum
supply temperature and the system’s delta
temperature so that it does not cut at too
high a return temperature when the highest
supply temperature is transmitted.
• Check what the return line sensor shows, is
it a plausible/actual value? If not, take a resis-
tance reading from the sensors and check
against the ohm table in the Measurement
points section.
If the MAX RETURN value is not adjusted for
the system according to the troubleshooting
window, adjust it.
If the sensor is defective, replace it.
8. The compressor runs backwards.
The incoming phases have the
incorrect sequence (only applies
to 3-phase heat pumps). If the
compressor runs backwards, it will
not cope with compressing the
refrigerant and therefore does not
produce the correct power, which
leads to the control computer
requesting auxiliary heating. • If the text ERR PHASE SEQ. appears in the
display when the heat pump is powered,
(only appears in the first 10 minutes) this
means that the phases have the incorrect
sequence.
• When the compressor is running, check
the pressure pipe temperature by feeling
the pressure pipe. If the phases are correctly
sequenced it should be hot (not just warm)
even a distance from the compressor .
• When the compressor runs with the phases
incorrectly sequenced a strange noise may
be heard (loud, rattling) when the compres-
sor runs backwards.
If the phases are in the incorrect order,
switch two incoming phases at the main
terminal block and recheck according to the
troubleshooting window.
9. The compressor has been stop-
ped by the operating pressure
switch or pressure pipe sensor. Check if a square appears in the display’s
lower let corner, if so, the operating pressure
switch is open or the pressure pipe sensor
triggers an alarm for too high temperature.
• The operating pressure switch is most
easily checked by using a buzzer to see if it
is connected.
• The pressure pipe sensor value is read
off from the control computer in the HEAT
PUMP menu. Is it a plausible/actual value? If
not, take a resistance reading from the sen-
sor and check against the ohm table in the
installation instructions.
• The compressor has been stopped by the
pressure pipe sensor and you have establis-
hed that it shows the correct temperature.
This may have been caused by a leak in the
refrigerant circuit.
If the operating pressure switch has stuck in
the open position, try gently tapping on the
pressure switch head. If this does not help,
or it sticks in the open position repeatedly,
replace the pressure switch.
If the pressure pipe sensor is defective,
replace it.
If the pressure pipe temperature gets so
hot that the compressor stops, start by leak-
tracing the unit. Rectify the leak, if a leak is
found. If no leak is found, try draining and
refilling the unit and then restarting the
heat pump and seeing what the pressure
pipe temperature is. If the problem persists,
replace the compressor.
10. Expansion valve defective or
incorrectly set. Using manometer apparatus and ther-
mometer check what the overheating
reading of the unit is.
Also check that bulb and capillary tube
are undamaged and that the bulb is cor-
rectly installed.
If the overheating reading does not cor-
respond with the instructions for the
specific refrigerant, adjust the expansion
valve until the correct value is obtained.
See separate instructions for cooling
techniques.
If overheating cannot be adjusted with
the expansion valve or if the capillary
tube/bulb is damaged, replace it.
11. Lack of refrigerant, not
enough refrigerant in the system. Using manometer apparatus and ther-
mometer, check that the unit’s overhea-
ting is correct for the specific refrigerant. If there appears to be a leak in the refri-
gerant circuit, carry out leak tracing and
any necessary corrective action. If leak
tracer is not available, brush soap water
on the suspected leak and look for bubb-
les. Also check for oil as this can come
out from the refrigerant circuit.