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jay
30-10-2006, 07:03 PM
Hi,

I am facing a problem with condensation at the diffuser.

Itís a new installation Carrier ducted split unit. For ducting, have used foam sandwiched by two aluminum foil facing by SAT.
Linear diffuser is by trox.
Inlet and outlet are nearly of the same size.

Can anyone help?

Regards,
Jay

rbartlett
30-10-2006, 07:26 PM
low air velocity giving an increased drop in temperature across the coil so it falls below dew point. check the pa of the ducting against the unit rating

cheers

Richard

winfred.dela
30-10-2006, 09:58 PM
I am facing a problem with condensation at the diffuser.


Hi Jay,

Have you checked the unit performance against the system or equipment specs/design?
e.g. Airflow (cfm or cmh), static pressure (inch w.g. or mm w.g.)

Usually when the duct is longer &/or smaller sectional area you will have your actual static pressure higher than the design so the airflow is lower than the eqpt design thus lower supply air dry bulb temperature (SaTdb).
Now, you will have condensation because your SaTdb is same or lower than the Room air dew point temperature (RaTdp).

Take measurement of the following temperatures:
(1) Evaporating (Tevap)
(2) Supply air dry bulb (SaTdb) & if possible wet bulb.
(3) Room air dry bulb & wet bulb (RaTdb & RaTwb)

You may solve your problem by making the Tevap a little higher thus having a higher SaTdb.

The RaTdb & RaTwb is needed to be able to derive the RaTdp.
Make sure that the SaTdb is always higher than the RaTdp.

I hope i have stated the above correctly and would appreciate correction from others.
It's almost 2 decades that i need to solve problem like this, when i still do a/c TAB works.

Hope the above helps solve your condensation problem.

Regards
Fredy :)

jay
31-10-2006, 05:38 PM
attached is a section of diagram for the splited duct air con installed as per drawings given to me by the client. do you think there is any design fault?

jay
31-10-2006, 05:40 PM
Hi Fredy/Richard

Thanks a lot for ur response,

attached is a section of diagram for the splited duct air con installed as per drawings given to me by the client. do you think there is any design fault?

Regards,
Jay

winfred.dela
04-11-2006, 02:17 PM
The drawing indicates EF6 & EF7. Are these exhaust fans?
If these are exhaust fans & always running you may have a lot of infiltration from ambient air. This will definitely contributes to the condensation.

Again, the temperatures will be important to control so you will be able to solve your condensation problem. :)

jay
04-11-2006, 08:57 PM
I am greatful to you all, the information helped me a lot.
thanks every one,
Jay :D

Abby Normal
05-11-2006, 02:48 AM
The drawing indicates EF6 & EF7. Are these exhaust fans?
If these are exhaust fans & always running you may have a lot of infiltration from ambient air. This will definitely contributes to the condensation.

Again, the temperatures will be important to control so you will be able to solve your condensation problem. :)

Good call, could be quite humid, no fresh air intake for any positive pressure too. Verandah door right there. Leaky supply ducts in attic are problematic here, twice as bad as an exhaust fan.

jay
05-11-2006, 07:24 AM
This room is facing the sea and humidity is 75% to 90% EF6 & EF7 are exhaust fan running full time

Duct is made of singe sheet foam material and sealed totally with silicone .
I wanted to know about the design given for the duct and diffuser, they(my client) have given me same inlet and outlet sizes, could this contribute to the stated problem?
since in earlier post it was discussed that lower air intake can cause condensation.

normal spit units (wall type) installed at the same site are running without any problem.

Is there any software to design ducts? please help

thanks Jay :)

winfred.dela
05-11-2006, 07:49 AM
This room is facing the sea and humidity is 75% to 90% EF6 & EF7 are exhaust fan running full time

One of the factor that contributes to the condensation problem is the infiltration.
Why do you run the exhaust fans full time?





since in earlier post it was discussed that lower air intake can cause condensation.

This is only one of the factor




normal spit units (wall type) installed at the same site are running without any problem.

You are now comparing the units.
Have you compared the conditions each room are serving?




Is there any software to design ducts? please help

Why duct design? You need only to check the duct static pressure & air temperatures?


Again, please check on your temperatures:


from previous post

Take measurement of the following temperatures:
(1) Evaporating (Tevap)
(2) Supply air dry bulb (SaTdb) & if possible wet bulb.
(3) Room air dry bulb & wet bulb (RaTdb & RaTwb)

jay
05-11-2006, 12:10 PM
Hi again,

The room temperature is 25 degrees
The intake air temperature is 23 degrees
The discharge temperature is 10 degrees
The ambient temperature was measured at 32 degrees

The exhaust fans are designed to work constantly having 2 speed
1) normal speed
2) high speed (when lights are switched on)

I don't have instrument to measure duct static pressure

Jay

winfred.dela
05-11-2006, 03:46 PM
Hi again,
The room temperature is 25 degrees
The intake air temperature is 23 degrees
The discharge temperature is 10 degrees
The ambient temperature was measured at 32 degrees
I don't have instrument to measure duct static pressure


I will assume above are all dry bulb temp.

The airflow might be too low thus you have air supply (discharge?) temp at 10C wid 13C TD accross coil.

Please check:
- air flow and compare it with the eqpt specs.
- wet bulb temperature of the room & ambient.

You need to plot all your temperature readings (wet bult & dry bulb) in a psycrometric chart.
You will then have a total grasps of your condensation problem.

I suggest you get a guy who have the proper instruments & who can measure the airflow, static pressure, wet bulb temp.

Abby Normal
05-11-2006, 05:38 PM
Hi again,

The room temperature is 25 degrees
The intake air temperature is 23 degrees
The discharge temperature is 10 degrees
The ambient temperature was measured at 32 degrees

The exhaust fans are designed to work constantly having 2 speed
1) normal speed
2) high speed (when lights are switched on)

I don't have instrument to measure duct static pressure

Jay
Constant negative pressure is a disaster in a humid climate, you want a slight positive

Here is a picture that could be called "But it worked great in Arizona" a hotel design recycled from a hotel in Arizona to a hotel in the tropics, was a two speed exhaust scenario as well.

http://i32.photobucket.com/albums/d41/a_bee_normal/BedroomCondensate.jpg

Have those fans run intermittently, on either the light switch or a crank timer and your condensation will reduce and your Rh will drop down significantly

Abby Normal
05-11-2006, 05:47 PM
see figures 7.15 and 7.17 in the attached, a free chapter of a good book

http://www.masongrant.com/pdf/design_guide/ASHRAE_HCDG_C7_Mold.pdf

Even hotels with pressurized ciorridors will get in trouble with constant exhaust out of the bathrooms.

Run the fan coil fan intermittently cycling with the compressor, a small fresh air intake to the return duct work, like 100 mm with a balancing damper and a filter to catch the insects would do wonders.

Abby Normal
05-11-2006, 05:56 PM
10C supply is asking for it as well, see if a higher fan speed can get it up to about to about 13C. Make sure the filters are not plugged causing the low airflow as well.

But those exhaust fans will just be drawing in ambient humidity constantly.

winfred.dela
05-11-2006, 09:32 PM
Thanks Abby for the chapter re mold. it will be a good reference. :)

Your suggestions:



Have those fans run intermittently, on either the light switch or a crank timer and your condensation will reduce and your Rh will drop down significantly



Run the fan coil fan intermittently cycling with the compressor, a small fresh air intake to the return duct work, like 100 mm with a balancing damper and a filter to catch the insects would do wonders.




Make sure the filters are not plugged causing the low airflow as well.

But those exhaust fans will just be drawing in ambient humidity constantly.


I hope Jay will realize that he may or he may not solved his problem by asking a bunch of guys over a forum.

I hate second guessing, he should give a full detail of his problem so we will be able to give a good suggestion. e.g., Eqpt specs (nameplate): Capacity, cfm @ static pressure, Duct size, Fan capacity EF6 & EF7, Room usage and a lot more.

A TAB person with proper set instruments might be needed here.

For Jay: is the owner willing to pay a TAB guy?

Abby Normal
05-11-2006, 10:17 PM
winfred, the drawing looked like 900 mm x 250 mm duct, to a slot diffuser and return.

if that is what is installed, who knows. Saw a 192 if it is litres per second than that is not much over 400 CFM. Also saw the rated capacity looks like a little over 1.5 tons. So that is pretty low flow.

Don't know how humid it is in Tanzania, but it does not look like that big of a space to have two exhaust fans running steady or 1.5 tons of AC. How much humidity is in a steady 40 l/s of African air? That could be changing the air a couple times per hour in that little suite

Wonder if the place averages 75% RH?

Abby Normal
05-11-2006, 10:24 PM
Yes full information is always best, just have a gut feeling on this, the steady exhaust is a disaster here. One thing, with that low of a fan speed the carrier is pulling out as much moisture as it can.

winfred.dela
11-11-2006, 03:51 PM
Hi Abby,

The low airflow you mentioned is maybe due to a higher actual duct static pressure than what the fan coil can deliver.

I hope the evaporator can still handle all the liquid/gas, Jay might find the compressor damaged due to liquid slugging.

Of course these are all guess work, we maybe wrong. :)
We cannot really understand this one, Jay is still very secretive with some of his information. :)

Regards
Winfredy

Abby Normal
11-11-2006, 07:33 PM
We can all guess and be experts winnie, never makes up for being there and actually seeing the problem.

High static could be causing low airflow and hence a possibilty.

I will slow the fan speed down to get more dehumidification at times.

But the ducts looked fairly gewnerous for the air flow I was assuming to be litres per second on the drawing. It just looks like an air flow for a 1 ton system but using a 1.5 ton system.

The ducts looked pretty short, Maybe the linear supply/return grilles are the restriction, who knows. The occupants would be complaining that they were whistling perhaps if that was the case.

Constant exhaust and the negative pressure that accompanies it is just asking for trouble in my anything but humble opinion :)

jay
11-11-2006, 08:36 PM
Dear Friends

Believe me I am trying my best to be most informative as asked
and what you have told me is helping me to understand better.

Tanzania is usually 75%to 100% depending upon weather
now adays its 100% during early morning dropping to 85% in mid day
I was advised to install units as per their specification.
PLEASE HELP ME to understand what is wrong in their design if so.
what else should i provide for you all to understand I shall try to be not secretive
you all are giving me your valuable advise and I am grateful for that

this ef 6 /7 are exhaust fans from nuair UK having two motors one running on slow speed all time and second come to action when light is switched on

i have infra temp and one normal service thermometer
thanks Jayesh

winfred.dela
11-11-2006, 10:54 PM
Believe me I am trying my best to be most informative as asked
and what you have told me is helping me to understand better.
. . .
I was advised to install units as per their specification.


Let's again start then. . . . I hope you answer each item.

(1) What are their specification? Please list the conditions/design parameters they are requiring.

(2) What is the usage of this room?
- Just a regular bedroom?
- why use 2 fans?

(3) Have questions below that have never been answered and also some comments.



Why do you run the exhaust fans full time?




Have you compared the conditions each room are serving?




I suggest you get a guy who have the proper instruments & who can measure the airflow, static pressure, wet bulb temp.




A TAB person with proper set instruments might be needed here.


Jay, please bear with us. We are trying to help but you are the key person here, the front liner.
We may be able to solve your problem & close this thread in few days or in few months or years or may not . . :D

Please answer the above point by point. :)

jay
12-11-2006, 08:09 PM
hi Winfred

Q1) 1) What are their specification? Please list the conditions/design parameters they are requiring
A1) this installation layout was given to me to install units as per their specification.
now since it has developed this condensation problem they want me to do repair or to say solve this problem at my cost if i cannot prove that it is design fault

Q2) What is the usage of this room?
- Just a regular bedroom?
- why use 2 fans?
A2) The layout I had attached was of master bedroom
two fans are installed as per their requirement
one in open wardrobe and one in bathroom

Q3) Why do you run the exhaust fans full time?
A3) It has been in design that way i was not allowed to change any thing

Q4) Have you compared the conditions each room are serving
A4) yes all ducted spits are behaving in similar manner
they are 8 of them except normal wall units which
are again 8 of them

Q5) I suggest you get a guy who have the proper instruments & who can measure the airflow, static pressure, wet bulb
A5) no one here has these kind of gadgets .
I have just bought infra temp thermo and one
normal industrial
this is designed by most reputed company in America and for their most VIP person residence .

I can give you details of room sizes and layout of units plus I shall look for this gadgets to give readings
once again I am holding no information as I know one cannot help without proper diagnose .
thanks Jayesh

winfred.dela
12-11-2006, 08:59 PM
Dear Jayesh,

Please see below my comments.

Q1) 1) What are their specification? Please list the conditions/design parameters they are requiring
A1) this installation layout was given to me to install units as per their specification.
now since it has developed this condensation problem they want me to do repair or to say solve this problem at my cost if i cannot prove that it is design fault.

- There are no specifications provided to you. You only install, so you have no liability whatsoever.


Q2) What is the usage of this room?
- Just a regular bedroom?
- why use 2 fans?
A2) The layout I had attached was of master bedroom
two fans are installed as per their requirement
one in open wardrobe and one in bathroom

- Get the capacity of the fans (nameplate data) or if non, just the diameter & make (propeller? centrifugal? no. of blades?).

Q3) Why do you run the exhaust fans full time?
A3) It has been in design that way i was not allowed to change any thing

- You have to insists on this one, fans should be intermittent. You need to install manual switches to these fans. Better: a door switch for the wardrobe & for bathroom: fan should only run when light is on.
- Advise the customer that they will save energy & money by having switches for the fans and not running it continuously.

Q4) Have you compared the conditions each room are serving
A4) yes all ducted spits are behaving in similar manner
they are 8 of them except normal wall units which
are again 8 of them

- There you are. You may have a low air flow with the ducted splits.
- Another question: does units without ducts have also fans in the rooms they served?

Q5) I suggest you get a guy who have the proper instruments & who can measure the airflow, static pressure, wet bulb
A5) no one here has these kind of gadgets .
I have just bought infra temp thermo and one
normal industrial
this is designed by most reputed company in America and for their most VIP person residence .

- If there are no TAB persons around, then you have to add at least a Psychrometer in your gadgets. A digital psychrometer with hourly log would be nice. If you cannot find, just have a Sling Psychrometer and it would be just fine.
- You need to record the dry bulb & wet bulb of the ambient air & room air.


Hope you can solve this one soon Jayesh. . . :)

Regards
Winfredy

jay
12-11-2006, 10:04 PM
There are no specifications provided to you. You only install, so you have no liability whatsoever
ans) they want me to prove they are wrong or else I shall have to repair for them

Get the capacity of the fans (nameplate data) or if non, just the diameter & make (propeller? centrifugal? no. of blades?).
ans)Exceptionally quiet operation, imperceptible to a maximum of 43dBA @ 3m.
1 OPUS30-2MAS 1 Twin Duct mounted watts26, voltage230,dba free air27l/s (97m3/hr), @3m26

You have to insists on this one, fans should be intermittent. You need to install manual switches to these fans. Better: a door switch for the wardrobe & for bathroom: fan should only run when light is on.
ans) fan units has two motor one is running full time in slow mode and once light is switched on it goes to twin fan mode with high speed on humidity sensor

Another question: does units without ducts have also fans in the rooms they served
ans)no

but two wall units are with ducted split to cool large living room and ducted units show sign of condensation on diffuser only, ducts are dry

should i scan more layout details for you

thanks Jayesh

Abby Normal
12-11-2006, 10:46 PM
Steady exhaust fans are causing humid air to infiltrate in constantly. Change the fans to run only when the lights are on. This will eliminate the constant infiltration of humid air.

Make sure the filters are not plugged restircting your air flow. 10C will cause condensation even in fairly dry air, so increase fan speed tap to ge supply temp up to 13C.

The fan coil fan should only run when the compressor runs, otherwise you will be re-evaporating moisture.

Constant exhaust in a humid climate is a disaster. It would appear the duct work is in the attic as well. Leaky ducts up there further depressurize the space.

Shutting the exhaust fans off and increasing fan coil speed should be quick to do and an easy experiment.Should have noticeable results over night.

winfred.dela
13-11-2006, 09:25 PM
Change the fans to run only when the lights are on.




Make sure the filters are not plugged restircting your air flow.




increase fan speed tap to ge supply temp up to 13C.




The fan coil fan should only run when the compressor runs.



Hi Jayesh, above advises from Abby should be done first & see if the result will be enough (& acceptable) for your customer . . . :)

Thanks Abby & Regards :)

Samarjit Sen
14-11-2006, 08:11 AM
Fredy,

I feel that the problem lies in low air velocity, inadequate air discharge and infiltration. As Jay says that humidity is very high. Check on infiltration too.

Please correct me if I am wrong.

Abby Normal
14-11-2006, 01:29 PM
A5) no one here has these kind of gadgets .
I have just bought infra temp thermo and one normal industrial this is designed by most reputed company in America and for their most VIP person residence .



The problem could be the 'most reputed company in America' is from the Northern Part of the USA. The correct way of doing things depends on your local environment. The placement of vapour barriers, the effects of humidity etc are the complete opposite in the Northern United States compared to the Southern United States.

http://www.buildingscience.com/topten/south.htm

Go read "The Number 1 dumb thing to do" and then the "Number 9 dumb thing to do"

There is a lot of good information on www.buildingscience.com (http://www.buildingscience.com)

Try this link as well, look under "Practices that will Minimize Mold Growth" as they are mainly practises that will lower humidity.

http://www.fsec.ucf.edu/bldg/science/mold/index.htm

Abby Normal
14-11-2006, 02:18 PM
Some reputed American Rocket Scientists also crashed a few hundred million dollars worth of space probes into Mars because of a problem with the metric system, so do not be intimidated.

That drawing you posted was called Bedroom 2 and it showed two exhaust fans EF-6 & 7. Well what about the other bedrooms?

What about EF-1 through 5 and 8 through 12? They will all depressurize the house if they run steady, and humid air will infiltrate in via the path of least resistance, could be bedroom 2. Running a bunch of exhaust fans steady in a humid climate is a MAJOR DESIGN FLAW. Stop the fans to reduce the humidity and get the supply air temperature up above a normal dewpoint temperature of room air. Air at 24C and 50% will have a dewpoint around 12.8C. Your supply temp of 10C would require 40% RH to not cause condensation. So either fix the restriction and or increase the fan speed. 190 l/s is too low for the cooling capacity you are indicating, unless it was treating some outside air mixed in with the return air. 190 l/s is a nominal air flow for 1 ton of cooling you have 1.5 tons (18,000 Btu/hr and then some). So I see no indication of outside air being ducted to the return, so for 1.5 tons of cooling 190 l/s is also a DESIGN FLAW . Maybe it was supposed to be only a 1 ton system.

I see some high end condos here and they market them with a separate AC system for the master bedroom suite. It is a problem finding AC systems small enough for this without going to the ductless splits. But with poor construction in a humid environment, 1.5 tons of cooling should handle at least 50 square meters. I don't think the space in bedroom 2 is anywhere near that.

At a 70 percent sensible heat ratio if they are maintaining 25 C and you supply 13 C, you would need around 18,000 x 0.7 ( 1.08 x (25-13)x1.8)= 540 CFM = 255 l/s.

Again here is a reputed American Design that was not suitable for a humid climate

http://i32.photobucket.com/albums/d41/a_bee_normal/BedroomCondensate.jpg

The owners told me, "The design worked great in Arizona". It was a constant exhaust with two speed fans. The problem was a ceiling void was a turned into a big negative pressure plenum and the plenum had exterior walls with multiple cracks, unsealed penetrations that allowed humid outdoor air in. The plenum also sucked air out of the rooms below and caused humid air to infiltrate into the rooms. They shut the AC off in some unoccupied units on the ground floor while occupied upper floor units had the AC running. You are seeing condensation on the underside of a floor deck. The deck temperature was about 76F, ambient dewpoint 81F at the time. I cut some 30cmx30cm holes in the ceiling to get those pictures. Every time an outside door was open to the suite the air rushing up through the hole in the ceiling was 'cooling me off', I put a flow hood on the opening and with an outside door open, air was flowing into the hole at 1.5 m/s.

You need to look at each fan on an individual basis, but they really should only be running when someone is having a 'bowel movement', taking a shower, or perhaps cooking. If they want constant ventilation they need to do it by pressurizing with dry air.

You need to have something that can measure temperature and humidity such as a sling psychromter or a thermal hygromoeter. We have them here on Gilligan's Island so there is no reason you can't get them in Africa.

You could also tell reputed Americans to add a dedicated dehumidification system for the next VIP they design for.

jay
15-11-2006, 08:07 PM
I think I need some practical course on this duct aircons .
You all are great I have no doubt I am too near to solution I shall attach more drawings for you all.

winfred.dela
15-11-2006, 09:29 PM
Again here is a reputed American Design that was not suitable for a humid climate




You could also tell reputed Americans to add a dedicated dehumidification system for the next VIP they design for.



Hi Jayesh,

Usually, we in countries that are considered 3rd world are very impressed with the A/C & R design from guys located in very rich countries countries. In addition, our customers insists that it should be followed strictly. . .no ifs & buts . . . :(

You should never be, especially when you are already experiencing problems that are BIG TIME. You should not take any blame nor lost any money for your time, effort & work. :o

Please take Abby Normal's comments to your customer and insist that the designer be contacted and make revisions to his previous design. :)

I have seen a lot of these errors while working in Subic Naval Base & its one of the reason i left that high paying job (compared to local companies) in mid 80s.
Again, in my small city down here south of the Phils., I have done a lot of these insistings & revisions. One of my customer have even filed a court case in the US to prove that the American company had made an error in their design.
This month, one American company even left a project that is almost finish and we (me, american personnel & local company) have to finish it without the blessing of the so called American Designer. I may even find myself in another court case. :rolleyes:

I hope you solve this problem soon. We are rooting for you. . . :)

Regards
Winfredy :)

Abby Normal
15-11-2006, 09:49 PM
Jayesh

I was able to read the bedroom2.doc where you scanned a drawing and pasted it into Word, but I can't read the additional schedules and drawings, they are too small.


Maybe get a free photobucket account and upload there and provide us a link to them. Or maybe try the Word approach again.

Dan
16-11-2006, 04:08 AM
Go read "The Number 1 dumb thing to do" and then the "Number 9 dumb thing to do"

Good stuff Abby!

jay
17-11-2006, 08:03 PM
I am extremely obliged to genius like you all, believe me, after I presented details given by you all they politely asked, If I can help to solve this problem.

Their engineer (COWI) flew from U S had pointed to only one fault, that my diffusers are not insulated, rest all is ok

However, when I presented our Refrigeration Engineer forum reports, they were shocked to know that, there are too many mistakes in the design and were overlooked.

I am quite happy today and from bottom of my heart, I say thanks for your valuable time and priceless expertise shared with me.

Today, I was given a chance to prove my point right and have done one small duct modification.
Soon, shall give you the result/report.

Thanks Jayesh

winfred.dela
17-11-2006, 08:15 PM
Today, I was given a chance to prove my point right and have done one small duct modification.
Soon, shall give you the result/report.


Hi Jayesh,

Nice to hear you finally convinced the customer, which i usually experienced as the easier part . .:)

Next, the problem solving stage. . . and in my experience WILL NOT be as easy. . . :)

But still, this calls for a celebration. Also, congratulations! :)

Regards
Winfredy :)

Abby Normal
18-11-2006, 03:33 AM
Well glad you are not in trouble, but it sounds like we were just pointing out what could have went wrong.


Congratulations

Abby Normal
18-11-2006, 01:26 PM
Jayesh, I think you mentioned that some kind of humidity sensor was switching those exhaust fans to high speed.

You could have high humidity in there as it is from the constant low speed exhaust and then this could trigger the high speed.


Like 'putting out fire with gasoline'

Abby Normal
18-11-2006, 03:47 PM
that Florida Solar Engergy Center link on "Practises that Minimize Mold Growth" has moved to http://www.fsec.ucf.edu/en/consumer/buildings/basics/moldgrowth.htm

COWI sems to be a Danish company with an affiliate in Tanzania. They hire an American firm to do the air conditioning design?

Abby Normal
20-11-2006, 08:39 PM
There are many ways to ventilate Richard, the correct way depends on your environment. You need to go research psychrometrics

If it is humid like the tropics you have to cool it off and dry it out first, if it is frigid like Canada maybe you have to heat it up first then humidify it. If it is 20C and 40% RH, you would not do anything to the fresh air but filter it.

The best way to ventialte is to add air neutral in temperature with the right amount of humidity that does not add any heating or cooling load to the space. A lot of times a furnace or an air conditioner just draws in some fresh air and conditions it with the room air.

alfredobertiz
08-10-2007, 09:52 AM
jay

try to take the measurement of the RH inside the room and check the SAT and face velocity of diffuser.


Hi,

I am facing a problem with condensation at the diffuser.

Itís a new installation Carrier ducted split unit. For ducting, have used foam sandwiched by two aluminum foil facing by SAT.
Linear diffuser is by trox.
Inlet and outlet are nearly of the same size.

Can anyone help?

Regards,
Jay

alfredobertiz
30-10-2007, 09:52 AM
hi jay

try to check outlet velocity,

alfredobertiz
08-11-2007, 01:31 AM
hi jay

I have encounter same problem where condensation occur at the face of diffuser. The system was installed with 2 unit single package working together. When on of the unit was shut down for repair works condensation was observed on the face of the outlet. The diffuser was located near the kitchen.
Try to check the outlet velocity and as much as possible try to eliminate vapor inside the room