Hello. I have a problem with a room with two evaporators (air defrost) using R-404A, the room is supposed to be at 2°C, but I can't get to lower it more than 8°C because there has been ice building up just in a horizontal strip (all long of the back of the evaporator), the distributor and the pulp tubes are also frozen, but at the suction side only the 3 tubes of the circuits on the strip where there's ice are frozen.

Suction pressure: 56psi
Suction temp: 0°C
Superheat: 6°C

This room is part of a system supplied from a Parallel Compresors Rack, there are another 4 rooms working fine.

Any help is appreciated!