Actron Air ducted air conditioner

Hello everyone,
i have a Actron ducted air conditioning system in our home. it's is not heating up now a days. i set the temperature to 30 degrees but still it is blowing cold air. how can i solve this problem.
the unit which i have a large outdoor unit which have upwards air discharge arrangement. it has a a fully integrated touch button control. I have found only one sensor inside the house till now.

please give some idea about what i have to do to fix it.
Is it very expensive to get a technician to check it out.
what are the possible faults that is causing the trouble.

Call an electrician or a air con specialist. Don't go poking around any live wires.

Hi,
We also have an Actron (15? YO)
Was also not cutting in on heat, ended up being the main controller board. They tried some older boards but didn't solve the problem.
Ended up needing to install a later model which also meant some new parts $750?