Possible causes of Condensor coils freezing

[asmaircon]

Hi,

I was wondering why sometimes on outdoor condensor coils do they ice up with thick white frost, iv seen this once in heat mode, is there simple causes for this to happen, on splits im talking about.

Thanks :)

[stufus]

In heating the condenser coil act's as the evaporator ,low pressure/low temperature meets humid air=frost
Cheers
Stu

[The Viking]

OK,
First, let's be a bit picky about definitions.
The condensor is the part of the refrigeration cycle where heat is rejected.
The evaporator is the part of the refrigeration cycle where heat is absorbed (or where things get cold).

Now, when the system is in heating mode and the heat is rejected from the indoor unit...
What is the outdoor unit's coil operating as?

Remember that in a reversible system, like a heat pump split or a VRV/VRF system, the function of the coils changes depending on which mode the system is in.

:cool:

So, back to your question.
Have you got it figured out?
If not,
In heating mode the outdoor coil is the evaporator and just like the evaporator in an old fashioned fridge/freezer frost and ice will form on it. This is especially true when it is taking heat from cold moist outside winter air.

If it is an excessive amount of frost/ice and/or the system not manages to get rid of it by means of defrost cycles then there might be a problem. Likely faults include lack of refrigerant, lack of airflow and control issues.

:)