Danfoss DHP-AL Installation And Service Instructions Manual page 58

Cause
11. Lack of refrigerant, not
enough refrigerant in the sys-
tem.
12. Overfilled refrigerant cir-
cuit.
13. Short active collector, e.g.
short or dry bore hole, short
surface soil collector.
14. Changed conditions. Have
you increased your heating
and/or hot water demand?
Problem – Auxiliary heater cuts in too soon
Cause
1. The heat pump's control
computer is not set/adjusted to
the customer's requirements/
wishes.
2. Lack of refrigerant, not
enough refrigerant in the sys-
tem.
3. Short active collector, e.g.
short or dry bore hole, short
surface soil collector.
4. Collector too long, pressure
drop too great.
58
Troubleshooting
Using manometer apparatus and thermometer,
check that the unit's overheating is correct for the
specific refrigerant.
Then check in the same way that the unit's cool-
ing is correct. See separate instructions for cooling
techniques.
Using manometer apparatus and thermometer,
check that the unit's overheating is correct for the
specific refrigerant.
Then check in the same way that the unit's cool-
ing is correct. See separate instructions for cooling
techniques.
• Check the length of the collector that is being
used and compare with the collector length in the
dimensioning documentation.
• In addition, check that the collector is not sus-
pended "in free air" if boreholes are used.
• 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 (only
applies to VL-systems).
Troubleshooting
Check the ROOM, CURVE, INTEGRAL A1 and
INTEGRAL A2 settings
Using manometer apparatus and thermometer,
check that the unit's overheating is correct for the
specific refrigerant.
Then check in the same way that the unit's cool-
ing is correct. See separate instructions for cool-
ing techniques.
• Check the length of the collector that is being
used and compare with the collector length in
the dimensioning documentation.
• In addition, check that the collector is not sus-
pended "in free air" if boreholes are used.
Check the length of the collector that is being
used and that it is connected in parallel (not con-
nected in series) if more than 1 coil is being used.
Remedy
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 cor-
rect procedure (depending on type of refrigerant)
to add the correct amount of refrigerant.
If there appears to be a leak in the refrigerant cir-
cuit, carry out leak tracing and any necessary cor-
rective 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 cooling is not at the correct level compared with
the specific refrigerant and is too high, there is too
much refrigerant in the unit. Follow the correct
procedure (depending on type of refrigerant) to
add the correct amount of refrigerant.
If the active collector is too short, the heat pump
cannot receive enough energy from the heat
source , which results in it requiring an addition to
cover the energy requirement.
If the heat pump cannot cope with the demand,
replace it with one with a higher output or sup-
plement it with a higher output auxiliary heater.
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.
INTEGRAL A1 = Start value for the compressor.
INTEGRAL A2 = Start value (calculated from A1) for
the auxiliary heater.
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 cor-
rect 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 active collector is too short, the heat pump
cannot receive enough energy from the heat
source , which results in it requiring an addition to
cover the energy requirement.
If a longer collector is being used than recom-
mended for the specific heat pump, it must be
divided on several parallel connected coils.
VMBME102