Questions about semi-auto defrost refrigerator particularly Panasonic NR-BP9417Q

[Motoro]

Hi. I bought a Panasonic inverter refrigerator model number NR-BP9417Q.(https://www.panasonic.com/ph/consumer/household-appliances/refrigerators/top-freezer/nr-bp9417q.html) It comes with semi-automatic defrost feature where a button can be pressed for 3 seconds and it cuts power to the compressor. 

The only problem I have is, there's always an ice build up on the back wall of the refrigerator compartment. When the compress cycles off, the ice will melt and becomes moisture and there's a drain hole at the bottom of the back wall for water to exit. Sometimes the ice build up is thick and it needs to be defrost. But I'm not sure if the ice build up on the back wall of refrigerator compartment is normal. I know freezer will have ice build up but this is the first time I saw ice build up inside the fridge compartment. The owner's manual didn't mention this occurring. It only state that when frost reach 10mm thickness defrosting is necessary and showed an image of a loaded freezer but no mentioned about the refrigerator compartment.

Actually, I had the unit replaced a week after purchasing it because Panasonic customer service said ice build up is not normal. However, the replacement is also experiencing the same thing. I called customer service and was told again that the ice build up isn't normal so they sent in a technician from an authorized repair shop. The technician explained that the ice build up is actually normal and told me that the customer service might not be aware that the model number I gave is for a manual defrost refrigerator. He said that the refrigerator compartment gets cold from the cooling element directly behind the ribbed back wall thus ice will form when it gets cold. He further adds that single door and non-frost refrigerator do not have this problem since the former get its cold from the freezer and the latter gets cold via fan blowing cold air from the freezer. 

However, the ice build up still bothers me because I kept thinking about the customer service insisting that it isn't normal and the owner's manual didn't mention it either. So, is it normal to have ice build up on the back wall of a semi-automatic (technically manual defrost) refrigerator compartment?

Thanks for any info.

[16345Ed]

So you have to manually defrost...

Id read defrosting section of owners manual it appears you aren’t defrosting long enough or often enough. 

[evaappliance]

The more humid your area is the more and faster it will build up . 

2 hours ago, 16345Ed said:

it appears you aren’t defrosting long enough or often enough

 

[Motoro]

Thanks for the quick response. So you guys are saying that it is totally normal for the refrigerator compartment to have ice build up just like the freezer compartment, only that it happens only on the back wall?

[Budget Appliance Repair]

That style, YES.  That is is the refrigerator section evaporator plate which is a cycle defrost - refrig should be between 33-38 degrees so when t-stat is satisfied it turns off off and this ice build up on the evaporator plate will melt and run off into the drain tray.

If the the bottom picture is the worst you ever see it that is completely normal.

[Motoro]

On 8/2/2018 at 9:58 PM, Budget Appliance Repair said:

That style, YES.  That is is the refrigerator section evaporator plate which is a cycle defrost - refrig should be between 33-38 degrees so when t-stat is satisfied it turns off off and this ice build up on the evaporator plate will melt and run off into the drain tray.

If the the bottom picture is the worst you ever see it that is completely normal.

Now I know. Thank you, Sir.