My Unit Seems To Be Struggling And Is Freezing Up? - Samsung RC090MHXEA Service Manual

My unit seems to be struggling and is freezing up?

In cold weather we get reports that units are freezing up excessively or the unit is not
achieving high enough radiator and floor temperatures:
This can be caused by the unit having a fault or it not being big
enough for the job.
Firstly, we will test if the unit is working ok:
First draw off 30 liters of water from the cylinder, run a couple of
taps for 5 mins to achieve this.
The heat pump should be able to achieve a 48C flow temperature
without using the immersion heater if it's working ok.
If it's struggling to reach the 48C it might be a refrigerant or a flow
problem
Note it takes the tank much longer to heat up than normal, especially when the tank
temperature is high. And it takes a lot more power to do this.
If the unit can meet the tank temperature the heat pump is ok. Now we have to make some
more tests.
If its struggling to heat the house firstly take field setting 2091 and 2092 out of the system set
them to 0. Now running the unit at a constant temperature test the unit at a 50C flow
temperature. If it can't make 50 C against the heat pump is probably not big enough.
To prove this if you close of half of the heating circuit you will see the flow temperature can be
met. If this happens you need to get out your heat loss calculation and check it's been done
correctly.
The next thing to check is the flow rate. If the flow rate is low the unit will not achieve its
maximum potential. Size 16 units need 30l/min, size 9 units need 20l/min.
If the unit can't make 48C flow you need to do a performance
test, this is done using the service partner tool excel.
Call our office 02380 274833 with the following info:
Unit model and serial number
The flow and return temperatures
The flow rate
Using outdoor unit function (press k4) see page 2
No 2 compressor speed and no 5 compressor outlet temperature.
www.freedomhp.co.uk ©G Hendra Nov 18 7