TXV problem

[Brutus]

I have this unit using TXV and my question is does a starving TXV can cause the evaporator to frost up or sign of undercharged?

[Sandro Baptista]

Evaporator frost it is a possibility because the suction pressure will be lower and so the firsts parts of the circuit will feeling that effect (lower evaporation temperature).

About sign of undercharged not necessary.

[Brutus]

thanks for your quick response!

my analysis was undercharged beacause it only happen during full load and i think TXV operate 100% during full loads. and other thing the unit had no liquid receiver.

[Sandro Baptista]

By the facts you presented is much possible the undercharged of the system. But if it happens at full load (much heat load) and the compressor has its capacity unchanged (so the suction pressure is higher) I don't see the reason to frost. Or the compressor have any kind of capacity control.