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Sbrav77
Premium
join:2004-03-02
Bourbonnais, IL

Mobile Home Central Air

Currently, we live in a 1987 Skyline double wide mobile home. It's about 1630 square feet. We have a Coleman furnace with the area beneath to install an a coil for central air. However, we have a Miller self contained unit outside. It's got all the air conditioning stuff inside the unit. We just had the unit serviced, was about 1 1/2 lbs. low on freon. There is one cold air intake located in the laundry room, in the floor. It has the insulated coil tubbing running about 10 feet or so to the air conditioning unit. Then on the other side, it has the coil tubbing running to a type of air splitter. It takes the main air feed and splits it into two seperate runs. One run goes to each side of the trailer. There is one vent system on each side. The air output seems to be pretty good Measured the temp coming from the vents and it's about 63. However, the unit never seems to be able to get the inside temp below 81 or 82 on the thermostat. I have tried partially closing off some of the vents and leaving them all open. It seems to be a bit better with them all open. But my question, would it be beneficial to add another cold air return up higher maybe in the center of the trailer? Right now the unit is having to run nonstop until the evening when the sun goes down to keep it fairly cool. This is really killing me in the electric bill dept.
Any other suggestions or ideas would be welcome. I really can't afford to replace the air unit with a more efficient model right now. Just looking for ideas.


davidg
Good Bye My Friend
Premium,MVM
join:2002-06-15
none

1 recommendation

if it was low, you have a freon leak. no other means for it to be low. did they find and fix it?

do you change your filters REGULARLY? dirty filters restrict airflow and lead to poor performance. torn/bowed filters allow dirt past them and can cause the coils to get clogged and again reduce airflow.

you need to measure temps on either side of the coil. air coming in from teh room minus temp of air going back out to teh room should be around 20 degrees difference. it may be as low as 15 degrees during really hot and humid days.

have you been under the house to check the insulation? my wife lived in a late 80's double wide when we first met. she had similar issues and upon inspection we found most of the insulation was hanging down. resecured it and that solved her problems.

adding a return to a system should only be necessary if it was not moving air from one end to another and you were getting pressure build up or in the case of too small a return duct. if that were the case you would get cold in one area with major airflow, and inthe other area it would barely blow. if the duct were too small then the unit would be sucking air hard and whistling.

did this unit EVER keep the house cold as desired under similar temps as you currently have?
--
Lack of Preparation on YOUR Part does NOT Constitute an Emergency on Mine!

Sbrav77
Premium
join:2004-03-02
Bourbonnais, IL
No. The unit really hasn't ever kept the place as cold as I would have liked. We have been here 9 years and had the freon recharged 3 times. They didn't check for any leaks. I'm sure it's not a very big leak. The ac tech that worked on it last did give me a tip that has helped some. He found that since our furnace has the space below for an ac unit, the ducts were there. When the air was running, it was blowing a bunch of cold air up through the duct into the bottom of the furnace. He recommended I get a piece of sheet metal and close off the duct during the summer when the furnace isn't in use. This has helped some. But not to the point where I would like it.


davidg
Good Bye My Friend
Premium,MVM
join:2002-06-15
none
reply to Sbrav77
you say it has never kept it as cold as YOU would liek, but give us a hard number example.

check the things i listed and see if any of them are happening.

also, if you had the same company refill it 3x and they never checked for a leak, you need to find a new HVAC company! the coolant is in a sealed system. if it is low, it is leaking. let it run dry and you can ruin it.
--
Lack of Preparation on YOUR Part does NOT Constitute an Emergency on Mine!

Sbrav77
Premium
join:2004-03-02
Bourbonnais, IL
It has been 3 different people that have serviced it. Never the same person. The second person was very reasonable in his prices as he worked out of his house. But, he must have left the area as his number is disconnected. I"m thinking about calling the last person back out to see what they would recommend. Most of the things you mentioned, I have already checked. I'll have to get a temp reading from both aides of the coil. This might be a silly question. But, do you mean a temp reading from the cold air return then the temp from the vents blowing into the rooms?


davidg
Good Bye My Friend
Premium,MVM
join:2002-06-15
none

1 edit
no, from as close to the coil as possible, INSIDE the duct. drill a small hole, stick in a thermometer, get your temps, then seal the holes back up. one hole should be on one side of the coil, one on the other. just don't hit the coils themselves!!
--
Lack of Preparation on YOUR Part does NOT Constitute an Emergency on Mine!


mityfowl
Premium
join:2000-11-06
Dallas, TX

2 edits
reply to Sbrav77
I'm from Kankakee and it's been a while but the 2 best people in town were Glady's, and Home Appliance and Heating. Glady's were my friends and they always respected Home Appliance. I used to run around with 1 of the the Home appliance boys but he didn't know anything! You're ok though because he lives in Dallas now.

Here's the thing: before you can even think about air return or anything else. You got to nail that leak!

I've had home a/c that didn't need a charge for 12 years. When it was shorter I usually found the high pressure nut getting loose.

For what it's worth.

Good Luck!


Splitpair
Premium
join:2000-07-29
Cow Towne
kudos:3
reply to Sbrav77
said by Sbrav77:

However, we have a Miller self contained unit outside.
That is a package A/C and do you know what is the BTU or ton rating of it is?

BTW your coiled duct is called flexduct.

Now normally by “code” a mobile home A/C unit will be ducted with “HUD” flexduct this is a black PVC wrapped flex duct that is “allowed” to be placed in “direct” contact with earth.

The problem with that while the duct meets “code” no one has told the various creatures who live in the ground they cannot chew thru outer lining allowing the fiberglass insulation to be compromised by water.

IMO the first thing you need to do and this is a nasty job is to crawl underneath the home as best as you can and inspect the ductwork.

Can the flexducts be picked up easily or do they feel heavy? If there are heavy sorry your ducts are wet and need to be replaced.

Now if they pass the lift test then turn on the blower and bare handed check the return flexduct from where it connects to the home all the way to where it connects to the A/C unit. Are there any cracks in the outer jacket and if you find any is the inner duct damaged? Do you hear any air leaking into the return duct any leak no matter how minor is a problem and needs to be cleared.

Then do the same from where the A/C unit feeds to the Y and then from the Y into the home. You should not be able to feel any air leaking out of any of the ducts and they should be dry and about ambient temperature not cool or moist. There should be zero leaks and remember with a package unlike a split where the evporator is inside any leaks from the feed or into the return air duct will have a great affect on the living space as air lost outside of the living space will be made up with warm and moist air pulled into the living space converesly if outside air is pulled into the return duct your cool air will be pushed out of the living space.

Also with a package your evaporator is always operating in a vacuum as such the trap on the condensate drain must have its drain opening a minimum of 1.5 inches below the centerline of the A/C's drainpipe. If the trap is not deep enough when the unit is running the vacuum will pull air back thru trap causing the water in the drain pan to splash soaking the air box’s insulation and preventing the pain from draining while the unit is running. A lack of a trap is even worse. This condition will result in high humidity in the living space.

I would also recommend if you know how to do it kill the power to the unit and remove the access cover for the evaporator side of the unit. Is the evaporator nice and pretty and clean if not get some A/C coil cleaner and make it pretty. A gunked up evaporator kills efficiency. Then check the weatherstrip on the access cover I’ll bet it’s dried out. That stuff is inexpensive and don’t forget what I said about packages if it’s leaking you are going to have a warm moist home.

Wayne
--
If you cannot fix it with a buttset and some beanies you ain't a technician.


Splitpair
Premium
join:2000-07-29
Cow Towne
kudos:3
reply to Sbrav77
said by Sbrav77:

This is really killing me in the electric bill dept. Any other suggestions or ideas would be welcome.
Also consider tinting the windows on the sunny side of the home.

When I bought the home I am in now I would notice the A/C would kick on about 3 in the afternoon and run until the sun set and only then it would go back to cycling. We had a tint guy come out here and install the foil he arrived around 1 or so and left about 4 and the A/C was cycling by the time he departed. The tint made a major difference in the amount of heat entering the home and was of some of the best money I have ever spent.

Wayne
--
If you cannot fix it with a buttset and some beanies you ain't a technician.

Sbrav77
Premium
join:2004-03-02
Bourbonnais, IL
Thanks for the tips. I think we do have the newer flex duct type of material you described. I crawled underneath several years ago and replaced it all. As the old stuff was soaked with water and not allowing very much air through. I'll have to see if I can find the size of the air conditioner outside on the unit. I'll check the rest of the tips you gave me also. Thanks for the advice.


08034016
Hallo lisa Aus Amerika
Premium
join:2001-08-31
Byron, GA
reply to Sbrav77
Pictures?


pro7070
BJ "The Prodigy" Penn
Premium
join:2002-06-28
Inman, SC
kudos:1

1 edit
reply to Sbrav77
said by Sbrav77:

Currently, we live in a 1987 Skyline double wide mobile home. It's about 1630 square feet. We have a Coleman furnace with the area beneath to install an a coil for central air. However, we have a Miller self contained unit outside. It's got all the air conditioning stuff inside the unit. We just had the unit serviced, was about 1 1/2 lbs. low on freon. There is one cold air intake located in the laundry room, in the floor. It has the insulated coil tubbing running about 10 feet or so to the air conditioning unit. Then on the other side, it has the coil tubbing running to a type of air splitter. It takes the main air feed and splits it into two seperate runs. One run goes to each side of the trailer. There is one vent system on each side. The air output seems to be pretty good Measured the temp coming from the vents and it's about 63. However, the unit never seems to be able to get the inside temp below 81 or 82 on the thermostat. I have tried partially closing off some of the vents and leaving them all open. It seems to be a bit better with them all open. But my question, would it be beneficial to add another cold air return up higher maybe in the center of the trailer? Right now the unit is having to run nonstop until the evening when the sun goes down to keep it fairly cool. This is really killing me in the electric bill dept.
Any other suggestions or ideas would be welcome. I really can't afford to replace the air unit with a more efficient model right now. Just looking for ideas.
I have the same problem in a mobile home I use as an office. I added a couple window units which didn't raise or lower my power bill, but it did take the load off the Central air which just couldn't keep up. At least the central air will cut off during the day and not run constantly. Older mobile homes are just terrible at insulating.

Sbrav77
Premium
join:2004-03-02
Bourbonnais, IL
reply to 08034016
I worked a double shift today and didn't get home til 7:30 this evening. I'll try to get some pictures posted tomorrow if I have time. We do have a small window unit in our master bedroom. Which is located in the rear of the trailer. That's the room that doesn't seem to really get that cool with the air running. The other bedrooms stay comfortable. However, they are quite a bit smaller also. Of course, the air conditioner in the rear doesn't really help any for the central air. One thing I have noticed though, we have a thermometer in the computer room, which is right when you walk in the front door. The temp in that room reads usually about 3 degrees cooler than the thermostat temp. It's a hunter digital thermostat that I put in about 2 or 3 years ago. The thermostat is no more than 10-12 feet from the computer room with no walls or obstructions in the way. Not sure what to make of the temp difference.


davidg
Good Bye My Friend
Premium,MVM
join:2002-06-15
none
uneven air flow or one is located close to/on an exterior wall.

at our office we have a tstat that is mounted to a cinderblock wall. the temp on it is always 5+/- different from holding it just 6 inches off the wall.

also, you can take 5 identical tstats and place them side by side in a room and possibly get 5 different readings. that is why decent tstats have a calibration setting so the installer can calibrate them to true for the area they are in.
--
Lack of Preparation on YOUR Part does NOT Constitute an Emergency on Mine!