Danfoss DHP-AX Installation And Service Instructions Manual page 65

Cause
12. Overfilled refrigerant circuit.
13. Short active collector, e.g.
short or dry bore hole, short sur-
face 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 com-
puter is not set/adjusted to the
customer's requirements/wishes.
2. Lack of refrigerant, not enough
refrigerant in the system.
3. Short active collector, e.g.
short or dry bore hole, short sur-
face soil collector.
4. Collector too long, pressure
drop too great.
Troubleshooting
Using manometer apparatus and ther-
mometer, check that the unit's overhea-
ting is correct for the specific refrigerant.
• Check the length of the collector that
is being used and compare with the col-
lector length in the dimensioning docu-
mentation.
• In addition, check that the collector is
not suspended "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 tem-
perature.
• 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 ther-
mometer, check that the unit's overhea-
ting is correct for the specific refrigerant.
• Check the length of the collector that
is being used and compare with the col-
lector length in the dimensioning docu-
mentation.
• In addition, check that the collector is
not suspended "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 connected in series) if more
than 1 coil is being used.
VMBMH302
Remedy
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 ener-
gy 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 hig-
her output or supplement it with a hig-
her 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 com-
pressor.
INTEGRAL A2 = Start value (calculated
from A1) for the auxiliary heater.
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.
If the active collector is too short, the
heat pump cannot receive enough ener-
gy from the heat source , which results
in it requiring an addition to cover the
energy requirement.
If a longer collector is being used than
recommended for the specific heat
pump, it must be divided on several
parallel connected coils.
Service – 65