Hi Chaps

I wonder if any one can help.

I have an install with 2 VRVIII outdoor condensing units (REYQ12's) running 3 x 10 kw indoor ducted units each.

Although all up and running i have noticed what i feel to be excessive frosting outside on the condensor fins. First one side, then the other, swapping from one side of the unit to the other whilst one side defrosts, but this is happening at around 10 - 15 minute intervals. Is this correct?

I charged one unit using the automatic charge method which after working out the charge manually i feel is about 2 kg short. I also am a bit concerned as following the install guide to working out the additional refrigerant charge makes no reference to the ammount already pre charged. Which on the footplate states 10.5kg.

I also feel the air off temps inside are not high enough.

Any information or tips on charging and commissioning these units would be greatfully recieved.

Kind regards
Gareth