Operational Problem - Miscellaneous - Danfoss DHP-AL Installation And Service Instructions Manual

Problem – irregular indoor temperature
Cause
1. The heat pump's control computer
is not set/adjusted to the customer's
requirements/wishes.
2. Incorrectly positioned/installed sen-
sors.
14.8 Operational problem – Miscellaneous
Problem – The heat pump runs and runs but never stops
Cause
1. Air in the heating system.
2. Lack of refrigerant, not enough refrig-
erant in the system.
3. Changed conditions. Have you
increased your heating and/or hot water
demand?
54
Troubleshooting
Check the ROOM and CURVE, MIN, MAX
CURVE5, CURVE0, CURVE-5 and HEATSTOP
settings.
Check that outdoor sensors and any room
sensors are installed according to the
instructions and that they are calibrated.
Troubleshooting
Listen for air in the heat pump and heating
system.
Using manometer apparatus and thermom-
eter, check that the unit's overheating is
correct for the specific refrigerant.
Then check in the same way that the unit's
cooling is correct. See separate instructions
for cooling techniques.
• If the heat pump has been dimensioned
for a certain demand and this demand is
increased, the heat pump might not be able
to maintain the desired room temperature.
• If hot water consumption increases, a
larger proportion of time is used to produce
hot water, which means less time for heat
production.
VMBME102
Remedy
Adjust incorrect values in the heat pump's
control computer.
ROOM = Desired indoor temperature
CURVE = Should be set so that the desired
indoor temperature (ROOM) is maintained
regardless of the outdoor temperature.
MIN = Lowest set-point value on the supply
pipe regardless of the outdoor temperature (on
the condition that heat stop does not apply).
MAX = Highest set-point value on the supply
pipe regardless of the outdoor temperature.
CURVE5,0,-5 = The supply temperature can be
adjusted up or down 5°C at these outdoor tem-
peratures.
HEATSTOP = Stops all production of heat when
the outdoor temperature is the same as or
greater than the set value. To exit heat stop the
outdoor temperature must drop to 3°C below
the set value.
• Check that the room sensor is positioned in
a suitable place that is representative of the
building and calibrate it if necessary. Avoid
placing near external doors, windows and heat
sources.
• Install the outdoor sensor according to the
instructions and calibrate it, if necessary.
Remedy
Bleed the heating system circuit according to
the installation instructions.
If cooling is not at the correct level compared
with the specific refrigerant and is too low,
there is insufficient refrigerant in the unit.
Follow the correct procedure (depending on
type of refrigerant) to add the correct amount
of refrigerant.
If there appears to be a leak in the refrigerant
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 bubbles. Also check for oil as this can
come out from the refrigerant circuit.
If the heat pump cannot cope with the
demand, replace it with one with a higher
output or supplement it with a higher output
auxiliary heater.