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Brian HVAC Guy
Brian HVAC Guy, HVAC Technician
Category: HVAC
Satisfied Customers: 800
Experience:  I have been an HVAC/R mechanic/technician for 30+ years.
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I have an interthrm unit in a mobile home. The evaporator

Customer Question

I have an interthrm unit in a mobile home. The evaporator coil sits atop the fan which blows down into the ductwork. Im having an issue where there is several inches of water collecting at the bottom right corner under the fan. I can see some condensation collecting under the pan. There isnt much water in the actual pan itself. I need to get this fixed, it has already ruined sub floor.
Submitted: 1 year ago.
Category: HVAC
Customer: replied 1 year ago.
Adding photos
Expert:  airheatman replied 1 year ago.
Hello. My name is ***** ***** I'll do my best to help. Let's get started and see what we can do.If water is not in pan but water below, we need to see where water is getting down there from (Crack in pan , dripping from coil and not running down coil fins into pan or whatever).
Customer: replied 1 year ago.
Some water is in pan but i see it collecting underneath the pan too.
Expert:  airheatman replied 1 year ago.
Have you blown out drain line good and is blower wheel clean? Often a dirty blower wheel can cause water to blow out of pan and drip down. See below:
http://i.imgur.com/0SMKehU.jpg
Customer: replied 1 year ago.
Ill look tomorrow on blower. How could that cause water to blow? Pipe is clean btw.
Expert:  airheatman replied 1 year ago.
The unit is designed to move a certain amount of air across the coil.Too much or too little air going across coil changes the static pressure and creates a turbulance in the air handler causing water to be blown or drawn from pan.
Customer: replied 1 year ago.
Fan was not dirty at all.
Expert:  airheatman replied 1 year ago.
I will open to other experts to see if they may have ideas.If pan is not rusted or cracked,coil is clean,drain line is clean and blower is clean, not sure what else could be causing the water underneath.
I have opted out of the question to see if perhaps other experts may have more information and can assist.Please do not rate or reply as that will send question back to my desk.Please stand by to see if another expert can assist further.
Customer: replied 1 year ago.
Couple more photos.
Expert:  Brian HVAC Guy replied 1 year ago.

Hi I'm Brian and I'm here to help!

Water problems like this can be a bear to find! The obvious thought is the water is coming down into the blower section from above in the coil section but in your pictures, I don't see much (if any) evidence of that. Localizing where the water is coming from in the blower section will help to narrow in on its source. Feel the cabinet insulation to see if you can narrow down the location. On occasion, I have used a clear piece of plexiglass in place of the blower panel door to watch what's happening and that sometimes gives a clue.

I can't tell for sure but it almost looks like the copper line with black insulation around it is wet. The insulation on the cabinet behind the copper lines appears to be wet too. There appears also to be a large gap around the copper lines where the go from the coil section into the blower section, this could be an issue. The air going by that large gap will not have gone through the cooling coil so it's water vapor content (air humidity) will be higher. When that air contacts the colder conditioned air in the blower section that's already gone through the cooling coil, the air will condense its moisture out on any surface below the dew point. I would seal up that hole where the copper lines go through the two sections. Also seal it up where it goes through the bottom of the air handler at the floor, if it's not already.

These are my best suggestions based on your pictures. It's a tough thing to diagnose without being on site but I would check those things out.

Please reply if you have further questions about this. Otherwise, please remember to rate positively (3 stars or better) before you leave! Bonuses are welcome and very appreciated!

Thank you,
Brian

Customer: replied 1 year ago.
Actually the unit has been off for over a month. This camera makes the photos look wet sometimes. Ive been away a few days so ill investigate further tonight.
Expert:  Brian HVAC Guy replied 1 year ago.

Very good then, let me know if I can help.

-Brian

Customer: replied 1 year ago.
Sorry for the long delay, been a busy week. Attaching new photos. I got everything sealed that i could put my hands on. Taped down in the ductwork as well. I managed to take a photo of the water since the system hasnt been on in a while. Any ideas on what to try now?
Expert:  Brian HVAC Guy replied 1 year ago.

I'm sorry to say that I really can't tell where the water is coming from. I will say that if it's been off for all this time, I would start looking at other sources of water intrusion. If the air has been off for over a month, it's not coming from the ac unit!. I wish I could be of more help.

Best regards,

Brian

Customer: replied 1 year ago.
Brian, fhe unit was powered on last night in order to test your hypothesis. In less than 10 minutes water had begun to accumulate at the bottom.
Expert:  Brian HVAC Guy replied 1 year ago.

Ok, that certainly seems to point toward the unit itself as the source of the water. The one thing that struck me, and it's kind of hard to see in the pictures, but is the air duct (trunkline) under your mobile home sealed really well to the air handling unit? If there are gaps there it could be a cause a lot of condensation.

What has to be figured out is whether the water is coming from the coil condensation because it's either not making into the pan or coming out of the pan when it shouldn't. OR, if the water is from condensation within the lower fan section because there is too much humidity in there for one reason or another. That's why I recommended above to get a piece of plexiglass to tape on to the air handler in place of the blower panel. That way you can shine a flashlight through the clear panel while the unit is running and this should really help locate the source. Then you can treat the problem. At this point it's really just a guessing game and we don't seem to be winning it.

Thanks,

Brian

Customer: replied 1 year ago.
Where to get plexiglass from? Someone told me the unit is sweating. It appears that water is coming from the pan under the coil not the exterior side.
Expert:  Brian HVAC Guy replied 1 year ago.

My local Home Depot carries THIS PLEXIGLASS sheet in stock. I would think it should be large enough for a standard air handler fan blower panel. Yeah, sweating is what I was talking about as a possible issue, we have to determine whether something inside the unit is sweating when it shouldn't be and why OR if it's just the unit not draining properly OR perhaps water is dripping off (or being sucked off) the cooling coil. Once that is figured out, we can plan the attack to fix it. The problem for me is pictures don't really show water droplets very well so the pictures are very hard for me to interpret. I have to count on your observation skills and ability to relay them to me.

Thanks,

Brian

Expert:  Brian HVAC Guy replied 1 year ago.

THIS SHEET may be even better, it's thinner and the width and length is more likely a better fit.

Expert:  Brian HVAC Guy replied 1 year ago.

You will have to cut them to size to match up to the air handler panel opening so it can be taped in without air leaks so yeah, unless you have a table saw, the thinner sheet will be much easier to do that.

Expert:  Brian HVAC Guy replied 1 year ago.

Just a suggestion, but if you decide to try the plexiglass route, the folks at the Home Depot should be able to cut it to size for you. Plexiglass can be tough to cut without cracking it all up! *speaks from experience* Just make sure you measure right before you go pick it up!

-Brian

Customer: replied 1 year ago.
Hi there, i hope youll accept my apology for the lacl of response. Working a lot of odd shifts and hours lately.I have installed the plexiglass panel. Once the unit started cooling, i could see water flying off the coil. Some water was making it to the pan while a majority went flying.
Expert:  Brian HVAC Guy replied 1 year ago.

No worries, I'm still here!

Ok, that is not an uncommon issue. There are several things or a combination of them that you can try to stop this.

First, it's important that you ensure the coil is clean. A dirty coil on the blower side of the coil can cause the condensate not to follow the aluminum fins down into the pan.

If the coil is clean, sometimes it's as easy as the coil just having to little surface tension to flow the water down the aluminum fins. In that case, if you mix a mixture of Dawn dishwashing soap and water in a spray bottle in a 10/1 ratio (10 parts water), then spray it on the coil on the side closes to the blower, that will help the water flow down into the pan.

It can also help to lower the blower speed one or two speeds if you have a multi-speed motor.

In rare circumstances I've had to add sheet metal vanes into the entering air side of the coil to help diffuse the airflow better through the coil to prevent this issue.

I would think one or more (or maybe even all) of these solutions should solve your problem.

Please reply if you have further questions about this. Otherwise, please remember to rate positively (3 stars or better)

before you leave! Bonuses are welcome and very appreciated!

Thank you,
Brian

Customer: replied 1 year ago.
I managed to get some triple d cleaner and it was sprayed at 10 to 1 onto coil. After sitting several minutes i turned the unit on and still water flows. Ive attached a few more photos of the unit with blower and model of unit. I cant find anything to see what speed this needs to be on.
Expert:  Brian HVAC Guy replied 1 year ago.

Depending on what Triple-D cleaner it was, it may make matters worse. I've had plenty of coils behave that way after coil cleaning with an actual coil cleaner solution. If it was a 'leave-on' or 'no-rinse' coil cleaner, those type normally help but the high alkaline or foaming cleaners can exacerbate the issue. I've found diluted Dawn brand dishsoap works best.

As for the blower speed, that is chosen based on what size outdoor unit you have installed. That is what the table is referring; the size in btuh/1000 (024-048) of your outdoor unit and the corresponding blower speed to choose. I disagree with their recommendations though. AC units should have 400 cfm of air per 12,000 btuh of cooling +/- 10%. So if you have a 2.5 ton outdoor unit (30,000 btuh), you should set the blower to provide 1000 cfm of airflow. The table shows the estimated cfm output for each speed tap of the blower at the bot***** *****ne in the tables. That is also dependent on how restrictive (or not) your duct system is. If you can tell me the size in tons or btuh of the outdoor unit, I will make my recommendation on what cooling speed your air handler should be set at.

-Brian

Customer: replied 1 year ago.
Here is the photo of the outside unit.
Customer: replied 1 year ago.
Diversitech Triple D Universal Coil Cleaner is what I used to spray on the coil.