Fan coil unit condensing badly at piping entrance to unit

[Ant]

The fan coil unit (split unit) in my kid room is condensing very badly. It is at the area where the piping enter the fan coils. Model of fancoil is Mitsubishi MSYGE10VAR1. The thickness of insulations is 3/4 inch and running on 410a. The installation contractors gave so many reason for the excessive condensation till I don't know what to believe him - I think he doing alot of guessing work. The insulation piping are encased in 6 x 4 inch PVC trucking and gaps are sealed with silicon. The only time I know there is excessive water in truncking is when water droplet start dripping from tiny holes in the silicon sealing the PVC trucking. So many attempts and reinsulation has be done and re-done but condensation kept coming back. I am staying a in a humid and hot country in Singapore. This is frustrating. Now the 2nd bed room FCU cannot cool the room down. When I try lowering the temperature, the kid room condensation problem become worse. Not sure the 2 problem are related as they are served by the same condensing unit. Anyone can help? This is Mitsubishi latest Star Mex VRF system for residential . Thanks.

[The Viking]

Is this unit ON, with the fan blowing, when this occurs?
High humidity you say... Any idea of how high?
If you take the filters out of the indoor unit and look at the aluminium fins behind it, is there any ice?
Is there any ice on the outside of the lagging?
If you turn the unit OFF, remove the filter and pour/spray water on to the aluminium fins behind, will this water leak out in to the lagging or disappear without creating leaks?

Questions, questions questions...


:cool:

.

[Ant]

Is this unit ON, with the fan blowing, when this occurs?
High humidity you say... Any idea of how high?
If you take the filters out of the indoor unit and look at the aluminium fins behind it, is there any ice?
Is there any ice on the outside of the lagging?
If you turn the unit OFF, remove the filter and pour/spray water on to the aluminium fins behind, will this water leak out in to the lagging or disappear without creating leaks?

Questions, questions questions...


:cool:

.

Hi,

Thanks for the questions. There is no icing in any area that I can see. The humidity is above 80-90% all the time in Singapore.

Please note that the condensing is not at the coil not at typically air discharge vents area but at the insulated pipping (3 - 4 ft section) just before the fan coils. These insulated pipping are further encased in PVC casing for aesthetics reason. The insulation must have total soak through to cause so bad condensation.

Please advise what else can I do to resolve this once for all? Thanks for dropping by and appreciate your kind suggestion.

[khongminhhason]

hi ant,
i think condensation occurs when a cold surface in contact with hot and humid air
if you isolate this cold surface hot and humid air from the condensation will not occur again.
may be your insulation for gas pipe is not sealed you should check it if it is seal or not

[monkey spanners]

Make sure the drain is working ok, have seen where the flexible pipe has a hole or not fitted propperly.

Also have seen condensation or even rain water from outside run down between copper pipe and insulation till it finds a join or hole then dripps out.

Can you run it with the lid off safely the trunking to see where and how the water collects?