Operational Problem - Hot Water - Danfoss DHP-AL Installation And Service Instructions Manual

Problem – Shrieking whistling noise
Cause
1. Whistling expansion valve.
2. Noise from the soft-starter.
3. The compressor's IPR valve opens.
Problem – Noise – miscellaneous
Cause
1. Vibrating protective sleeves on the pres-
sure switches.
2. Vibration noise from the electrical instal-
lation.
3. The heat pump is not level.
14.6 Operational problem – Hot water
Problem – Temperature and/or quantity
Cause
1. Defective 3-way valve motor.
2. Jammed 3-way valve insert.
The valve is not secure and releases hot
water to the radiators during hot water
production.
3. Air in TWS coil or water outer jacket.
50
Troubleshooting
1. Take overheating readings, adjust to the
recommended value.
2. Open and close the valve fully in and out.
3. Adjust the expansion valve to recom-
mended overheating value again.
Measurement check the input and output
phases for the soft-starter as well as the
control signals from the control computer,
see wiring diagram.
The compressor has an integrated IPR valve
that opens at 28 ±3 bar.
When the valve opens, pressure equalizes
between the compressor's high and low
pressure side and a milling/whistling sound
is heard.
To establish whether the valve opens at the
correct pressure, connect a manometer on
the high and low pressure side.
When the valve opens, this is indicated by
the pressure on the low pressure side rising
and reaching the pressure on the high pres-
sure side.
Check at what pressure the valve starts to
open.
Troubleshooting
Establish where the vibration noise is com-
ing from.
Check for electrical steps or similar devices
screwed to the heat pump and wall. These
can cause vibrations and noise.
Check that the heat pump is level by using
a spirit level.
Check that the heat pump is supported by
all four feet
Troubleshooting
Check the function of the 3-way valve, that
it runs between the end positions by run-
ning a manual test.
Detach the motor and test closing and
opening of the valve by pressing the con-
trol arm
During hot water production:
• Listen for air.
• Check the temperature difference
between supply and return pipe.
VMBME102
Remedy
Check if the noise has stopped, if not, con-
tinue with point 2.
Continue with point 3.
If the problem persists, replace the expan-
sion valve.
If the soft-starter is defective, replace it.
If it opens at a too low pressure, replace the
compressor.
Remedy
Prevent the protection sleeve vibrating by
using insulation tape for example.
Carry out according to the installation
instructions.
If the heat pump is not level, adjust using
the feet.
Remedy
If the motor is defective, replace it.
If the insert jams, remove and clean it, or
replace it.
Bleed the system.
A Large temperature difference can indicate
air in the system.