Danfoss Heat Pump, Troubleshooting Manual

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22 VMIFB202
Defective 3-way valve motor
Action:
Check that the motor can be run to the limit positions in a manual test.
If it is still, measure at the molex switch to see if there is current to it. Measure between 2 and 3 where there should always be 230V and
between 2 and 6 where there should be 230V in switching mode
If there is voltage replace the motor.
Jammed 3-way valve insert (applies to Honeywell inserts)
Action:
The valve does not seal and releases heat to the radiators during hot water production.
Pull off the motor and press down the spring loaded shaft on the valve
If it jams, clean or replace the insert. (It can be screwed out with a wrench intended for these 3-way valves)
Air in TWS coil or water outer jacket
Action:
During hot water production listen for air
Check the difference between supply and return line. A large difference can indicate air in the system.
If necessary, bleed the system
Start temperature set too high for hot water production
Action:
Check set start value for HW production. (should be 40-44°C)
If the start value is too high it results in short running times, set the value down to factory setting
If the system has a high (>+8°C) brine temperature, you may have to reduce the start value further for a longer running time.
Sensor error, hot water sensor.
Action:
Check that the hot water sensor (the start sensor) shows the correct value?
On newer models the peak sensor is also included and determines the start for hot water start (weighted value). Measure the resistance
of the sensors, check against the ohm table in the installation manual.
Start sensor is on terminal block 311-312 and peak sensor is on 325-326 (remove the sensor from the block before measuring)
If the sensor is defective, replace it
Large drain flow (>12 l/min)
Action:
Carry out a drain test using a stopwatch and a bucket. Set it so that you lose 12 l/min/40°C hot water.
One should drain approx 190-220 litres hot water at 40°C
If the drain water flow is greater than 12 l/min, stratification in the water heater is affected, which reduces the hot water capacity.
Install the pressure reduction valve on the incoming cold water, replace with a mixer with a lower flow, adapt the drain flow on the
existing mixer do not open the tap fully.
Mix and drain always to the temperature that it should be from the beginning.
Troubleshooting Guide Temperature or the quantity of hot water