Unit Cooler Ice Up

[hongyunref]

Hi, Everyone. I faced some problems of my project.
I installed a set of Compressor and Condenser c/w 2 units of different model of unit coolers for 2 units of coldroom. Below show the model of items that installed:

Compressor: Bitzer 4EC-6.2Y-BJ Semi Hermetic Compressor
Eden EFGP 0343.51 RB G4 Condenser 34.3Kw
Eden FEME 0450 G4 Unit Cooler 4.50Kw @ 6KTD c/w 3x300mm fan set (Temperature Require -2'c)
Eden FEM 0492 G4 Unit Cooler 4.92 Kw @ 8KTD c/w 1x300mm fan set (Temperature Require 3'c)

The problems that i faced are when the Coldroom A reached -2'c, Coldroom B's unit cooler will ice up.
May I know what's wrong of the unit cooler happened? Can any one could help and assist to solve this situation.

Thanks and Best Regards.

[frank]

To reach your target set points of -2C and +3C, both units will need to evaporate below freezing, therefore, it is normal for the indoor units to ice up. You should install a defrost system to both units.

How are you controlling the temperature in the +3C space? do you have an EPR or LLSV fitted?

[hongyunref]

Hi, Thanks for your reply.
The both systems installed defrost system, it work normal 12 months previous and this problem occur this month.
In the pass 12 months, defrost every 6 hours but now have to defrost every 2 hours.

[mbc]

is it 2 separate systems?
do you have ice on suction side of comp.( check expansion valve).
what is the definitional temp. on both units.?
check evaporates air flows.
are your doors sealed ?

[PaulZ]

Hi hong
I would be checking the door seals. Sounds like there is a lot of outside air getting in and this would be fairly humid I would expect given where you are.
A bit more information about the system components would also be helpful (see Franks post).
Have you checked the charge, are the LL driers blocked, is the condenser blocked.
Paul

[sedgy]

hi , can I take it you have liquid solenoids on both systems ? if you have, then you could have liquid line no1 going to cond, unit no 2 so you would end up with one unit trying to pump down both systems into one unit?= sedgy