Daiking ducted unit water leak

[marc5180]

weve had a problem for a couple of days now with A daikin FDY250B7VI ducted unit. The problem is water leaking out of the fan housing tray, next to the drip tray. Its made the plasterboard ceiling come through when one of the guys in the restaurant switched it off at night. Its about 5 years old and you cant alter the fan speed on the controller only on the indoor board which we found out was set to medium speed. We checked the evaporator coil and found it absoloutley filthy. dont think it has ever had a maintenace so we spent near enough all day cleaning it. Then we got a call saying it had started leaking again so we went back and spoke to daikin and they said to check the refrigerant charge. We recovered the refrigerant and the charge was fine so we recharged it again and waited with it for an hour and everything was ok although im optomistic that this would have caused the leak and im expecting a phone call that it is still leaking
Any of you guys have any input?

[frank]

If you've got water leaking out of the fan housing it can be caused by 2 things

1) A leaking drain pan
2) Water carryover in the air stream from the coil

Did you take the drain pan out during the service and test it for leaks? My first guess if you say the charge is OK

[marc5180]

Yes we checked the drain pan for leaks. We do beleive that it is Water carryover in the air stream from the coil which made us think that the fan speed was too high but now we know it is set onto medium fan speed and we dont know what to try next?

[monkey spanners]

What about the condenser fan speed controler, lower condensing pressure, will raise dehumidification i think
Have seen a sink waste piped into the air con drain by a "plumber" causing the unit to leak. The drain was fine every time we tested it, just lucky to be there when they pulled the plug, came out like a fountain
Also once had water run down between fridge pipe and amaflex from rubbish flat roof penetration, birds had pecked all the isulation off the pipe and when it rained it pooled where the pipes went through.
I think it was the fifth visit when we were there when it was raining, customer moaning "why didnt you find it the first time?" lol

Cheers Jon

[Brian_UK]

Are you sure that the condensate drainage is still clear/clean and running properly?

Is the trap still there? I've known units where someone has taken the trap out because they didn't understand its' purpose.

[marc5180]

Hi yes we haver checked the drain and the trap and it is all clean and working correctly. the water doesnt leak out of the drip tray it leaks out of the tray next to it which is the other side of the coil undeneath the fan

[Brian_UK]

SO, is there water in the drain tray proper? if there is, is it carrying over to the second tray?

If not, then the coil is producing too much condensation which is being carried over by the airflow. Follow on from that is... is there a change in the air flow since first install ? Is the coil freezing up on the downstream side ?

Is the coil clean, has filter maintenance been performed regularly?

[Andy]

Hi Marc5180

For low latent (moisture) removal normally a large evaporator is used. So that would rule out a poor pumping compressor by my way of thinking.

Sounds like the coils freezing, then the ice is melting into the airflow

Possible expansion fault.

Kind Regards Andy

[Ross]

Hi mate.

Just be aware that this model ducted is a induced draft FCU, so a trap is required unlike majority of Daikin FCU's which are forced draft & no trap required. Are you saying it did not start leaking until after the FCU was turned off? If so, why? Also in Oz it is common to fit a safety tray under the FCU to prevent water leaking from occurring. Is this the norm in the UK?

[Brian_UK]

...... Also in Oz it is common to fit a safety tray under the FCU to prevent water leaking from occurring. Is this the norm in the UK?

Don't be silly Ross, that costs money

[marc5180]

Hi Ross, a trap has been installed on the unit . When i turn off the FCU the water comes flooding out and there isnt a tray underneath, but your right there should well be

[frank]

Hi Ross, a trap has been installed on the unit . When i turn off the FCU the water comes flooding out and there isnt a tray underneath, but your right there should well be

A big clue here - if the water comes flooding out when you switch off it shows that it is not draining normally as the fan is sucking in air. Sounds like the drain pan is overflowing during normal use.

Check the drain line carefully - especially the trap and gradient

[Brian_UK]

Yep, if water isn't draining out of the trap it means that it isn't deep enough for the present fan suction pressure.

[Jase]

Is the uplift pump utilised in the unit?

Jase

[cascade tech]

Hi
I had a similar fault on a mitsibushi before .
What happpened was i blew the drain out because it was blocked and by doing that also blew the water out the p trap.
I then reset the unit and everything seemed fine because all the water drained out.

But after the third callout i was a bit irritated so i fitted a deeper p trap ( about 20cm deep and 20cm long) and filled it with water using a jug . The water in the p trap stopped the negative pressure from preventing the water reaching the drain point.

I found it best to fill up p traps when blowing out drains it saves you going back to site because of bad odours and negative pressure problems in the drain.

The units been runnning for five years im sure the fan speed is fine.

Well i hope my suggestions help.

[marc5180]

Hi guys thanks for all of your replys. Although the water doesnt leak out of the drain pan it leaks out of the fan housing next to it, on the other side of the coil. If it was a problem with the U trap then surely it would be leaking out of the drain pan?

[Brian_UK]

Hi guys thanks for all of your replys. Although the water doesnt leak out of the drain pan it leaks out of the fan housing next to it, on the other side of the coil. If it was a problem with the U trap then surely it would be leaking out of the drain pan?

If the drain doesn't work then water can be carried over into the fan tray.

[frank]

Is the uplift pump utilised in the unit?

Jase

No drain pump in this unit Jase - just a pipe connected to the drain pan

[puddleboy3]

Just a couple of points worth checking! The install manual for this unit states

1. You must not fit a trap
2. The drain outlet must not be submerged in water.

Hope this helps

[DALO]

I take it u hung the unit level!!!!!

What about the filter?? Is it the correct grade or is the fan pulling too much air through it causing carry over??
Have you checked the indoor fan motor current and compared it to specifications? Too much air and too much current.