Air Conditioning - Help Please, no cold air..

I hope someone here can help me, as this is driving me nuts!!
Long story, I bought this place about 8 years ago. AC worked fine for about 2 years, then the fan would blow on the outside unit, but nothing..(NOTHING) would come up though the floor vents. :mad: No cold air, or warm air either. It was pretty hot out when it first happened, so I assumed maybe it was over worked. The next day, it worked FINE. No more problem for about a week or so, then it did it again. It would work at night, but not during the day. Called the AC tech, they went under the house, (I have a double wide mobile home) did something, charged me $100 and left..and it worked fine for about two years. A couple of years later, SAME problem. :mad: They said it was my duct work. Pulled it all out, it was the coil kind, insulated, it was WET for some reason..??..not all of it, but part of it about 3 or 4 feet long. Wet enough that they thought it might have a raccoon in it. But it was just wet.
Anyway, replaced ALL my ductwork, piping, ?? What ever it is called..charged me $585.00 and it worked fine for another year. Then the same damn thing happened again!! :wall: They came out, charged me $100..and it worked fine again. I WATCH THEM work on the outside unit, and they don't do ANYTHING TO IT..just pull off the side panel, check it, and go under the house.
I turned it on last night, it was blowing nice and cold, second time I have had it on this season. NOW, it is doing the same thing all over again!! NO AIR at ALL coming out of the vents!! Not even WARM AIR!! Big fan on top of the unit is blowing like crazy..but nothing in here.
I read where people have a split unit. I don't think I do..?? I know of no other parts of it anyplace, other than the big unit outside, and the ductwork. I have a separate furnace, that was replaced approx 3 years ago. (It has went though THREE heat exchangers since then as well. So I don't have a lot of faith in the HVAC people in this area. As they have been from 3 different companies so far.)
I BELIEVE the unit to be approx 10 years old now. It may be older than that..I really don't know. I know it was never used much until I bought the place, and come summer I set it at around 72, and leave it there until it snows.
I worked in a Controlled Atmosphere department for about 2 years, (where you store fruit etc..for the winter.) But that was ammonia coolant, and the compressor's heads were over 3 feet long on each side, 3 to 5 compressors per building. But these home units I have NO CLUE about? I do build my own computers, and rebuild cars for a hobby..so I am not totally inept. (only partly.. I guess?)
The return air filter is clean, the unit its self is spotless, I vacuumed it on a regular basis, and wash as well. In the last 5 years it has had at LEAST 4 service calls..so it shouldn't feel neglected. Can anyone give me some clue as to what to look for?

I am sorry to sound so ignorant about these things, but I have never worked on one before.
Upon further inspection I found it is a Coleman Suncutter unit.(all other markings on the OUTSIDE are long faded away.) The Condensing Coil Unit is on the left side as I stand in front of the unit, the other coil is enclosed in a case on the right hand side. A 14" duct runs out the back of that side, and ports off to the different areas of the house.
One more point, I used to use just the fan in the spring time to cool the house. But after they installed the new furnace, the new stat they put on the wall has HEAT,FAN,AC on it, and ON and AUTO but it does not work when placed in the FAN/ON position like it used to. (Nothing happens at all.) When I ran it before like that, the big exhaust fan on the top of the unit would blow the whole time it was on. (I can see now that would have nothing to do with the air coming INTO the home however.) So I must assume that there is another fan in front of the air duct on the opposite side of the unit, that blows the air though the cooling coil, and into the ductwork?
There are panels all over this thing, as I recall, the one on the side did not expose that fan. So the one on the front probably wouldn't either, correct? Meaning I would have to pull off the top panel to get to the blower fan, and see if it is still working? Would that be the proper place to start? (I do have a breaker installed beside the unit so I can control the current from out there.)
Thank you for any help you can give me in this situation.

When they come out and work on it do they issue an invoice with what they have done? If you crawl under the house and inspect the ductwork what do you see? Any filters or dampers? Take a look let me know

Your not being ignorant about it , as you said you never worked on one before, hell I can't work on my on car if it breaks so I bring it to someone who knows about them.
I'm like Atribune go under the trailer and check out your ducts, maybe you can call the tech who worked on it last and ask him what was the problem the last time that he was out to your place.

Good Luck

There is a panel on the right side, toward the back of the unit you can remove to look at the circulating fan.
Mobile home ducts are terrible about collecting water especially if they lay on the ground. You can build support "bridges" or use old pallets to keep them off the ground. If the flex duct has to be replaced, make sure to use ducts approved for mobile home use. This approval rating will be marked right on the jacket of the duct.

Thanks for the advice Coleman, I did build the little ramps for it to sit on when I had it replaced last time. (I wasn't going to pay them to do it twice..not while I owned it anyway.) Seems to still be dry. I have it elevated above the unit's base now..which I think was the moisture problem before. It sat almost UNDER IT, it was so low..so it had no place to go really, but into the duct.
I checked the invoices for each time they came out..They just charged for labor, no parts, except for the duct work. Each time it just says "labor, 1 HR..or 1.5 hours..etc". Not what they actually DID.
As for calling and asking him for help with it. When he replaced all that ductwork claiming that was the cause "all along"..(refering to the other service calls BEFORE that)..and then it did the same damn thing the following year?? Well..lets just say I already made my call then, and I doubt he would come running to help ME out very soon.
I don't ask for a "deal" I just want what I pay for is all. If a man tells me its dead, fine..replace it. I don't have a problem with that. But I am tired of getting screwed!! (Now I know how people feel when they take their car to get it fixed!! It is all about TRUST.) I am sorry to say, SO FAR, I have not been able to find anyone I can trust in this line of work in THIS AREA.
I am SURE YOU are ALL honest people, and you work hard for what you EARN. or you would not be on here helping others for nothing. So please don't take me wrong..I know it is like any other business, there is good and bad in EVERYTHING. I just need to find a GOOD one is all.
Atribune, I can not find any dampers, but I am leaning that way myself. I found a diagram of how it was SUPPOSE to be installed on this place. It shows TWO dampers, that are suppose to be put in IF the AC unit does not use the furnace fan to help circulate the air. (According to the install manual for it anyway.) I don't know where they put them, or IT, as I suspect it to be only one, as the whole place goes dead, not just half of the house, as it SHOULD be with two dampers. I will crawl around under there tomorrow, and see what more I find.(Other than SPIDERS!! I HATE SPIDERS!!) :eek:
I can FEEL the fan spinning though the housing when I touch it. And the air coming out IS COLD, but there is almost no FLOW at all, inside the house over the ducts, and almost no suction for the return vent. (Usually that will grab the filter and just slam it down into the holder it has so much suction.) So something seems to be blocking it. Damper makes sense to me. It SEEMS like I thought that last time though, and was never able to find it. But I will continue the search. Thanks for all your advice, you are all very helpful indeed.:) To bad you don't live in this area..I would GLADLY do brake jobs in return for AC work!! :D

I turned it on last night, it was blowing nice and cold, second time I have had it on this season. NOW, it is doing the same thing all over again!! NO AIR at ALL coming out of the vents!! Not even WARM AIR!! Big fan on top of the unit is blowing like crazy..but nothing in here.

If it's blowing cold at 1st then the air eventually stops yet the indoor blower is running, it sounds frozen up. Usually due to ...

1. Bad airflow.
a.dirty filter
b.dirty indoor coil
c.blocked or closed vents
d.indoor blower not coming on

2.Low refrigerant charge due to a leak.

3. Mechanical malfunction.

On #1 you should be able to handle checking all those. To clean the indoor coil you will need to gain access to it via the airhandler.

The dampers should be as follows:
(1)The supply side damper should be where the flex connects to the trailer ductwork. The flex should connect to a device which looks like a box cut on the diagonal. This connector has a "flapper" in it that opens via air pressure in the flex duct.
(2)The return damper should be under the furnace. This damper is also normally closed & is opened by the furnace fan. It's purpose is to reduce the amount of cold air being blown up thru the furnace when the A/C is on.

To gain access to the evaporator coil, you have to remove the entire top of the unit (much, much easier with another set of hands).
A relatively easy test to see if the flex duct is the problem is to disconnect it from the unit, turn on the A/C, & check the air flow inside. Good air flow means the duct is the problem. Don't run the unit without the duct except for a few minutes.

Mattison,
Thanks for your reply, however..as I stated before the filters are clean, (new in fact, as I change them each spring before I start the unit.)
Also there is no "inside unit" or "indoor blower" or "indoor coil" it is a one piece unit that sits outside. The vents are all open and working fine as well.
The way I understand it is, if it is low on coolant, it would ice up on me, but it is not doing so. So unless it is a thermal trip problem, I don't think the cause is with the unit its self. As it seems to function properly. I pulled the top off the unit yesterday, and the blower fan is working fine, and the cold coil seemed to be pretty clean as well. Just a little dust on it was about all. I shot it with some 409, and rinsed it off, and it looks as good as new really. The pipes were, as I have read in other areas on here. Big one cold and slightly damp, the other one cool..no ice or frost on them.
Air flow seems to be the weak spot in the system however. And I believe it to be a damper that is not opening when it needs to. As I turned it on yesterday morning around 11am, and it worked FINE again all day long, and last night as well. I did however notice a DRASTIC difference in the air flow to part of the vents as opposed to the others. I know there is suppose to be two ducts that break off for the two sides of the house, so I believe one of them is staying CLOSED, and the second one is sticking, causing me this grief, sporadically off and on.
Grady, thanks for the description as to what to look for. I will check it out today, (if it ever stops raining.) I was aware of the duct under the furnace, but that only opens when the furnace kicks on to draw in fresh air. As the fan does not come on the furnace with the AC, it does not open. (I checked it to be sure it is opening and closing ok, and it is working fine, only coming on when the furnace does, and closes when its blower shuts off.)
I DO have a RETURN vent approx 2 feet X 1.5 feet in the living room however. I don't know if that would have a damper installed in it as well or not? I will try to find out when I check the others today. If I find the cause to be the dampers, which it probably is, (as it works most of the time, and just does this to try to give me a stroke.) Is there a way to wire them open? For the summer for example, then just close them back up come fall? Or would that damage the unit? As many times as they have been under there, and from what I guess, have opened them..without replacing them, then perhaps it is a lube problem?? :confused:
Thank you all so very much for your help on this. I will let you know what I find out with the dampers.
Thanks again. :)
Gary~*

There should be no damper at the return duct connection. The supply damper might be sticking due to orietation of the damper box. The flat side needs to be very close to vertical. Once I saw a guy who didn't mind crawling under the trailer twice a year. He drilled a hole in the damper box & inserted a rod to prop the damper open in the summer. Each fall he would remove the rod. The man would not spend the money to replace the damper box with one that worked right. To each his own, I guess.

I have NO problem with replacing it, if that is the problem, and I can find a replacement for it someplace.
I just assumed they replaced those with the ductwork, and it died again so fast that I didn't see the point was all.
I will locate them, and see if I can find replacements for both of them. I would rather have something work the way it is DESIGNED to, than to screw with it, if I don't have to.
But it is good to know I can rig it to stay open, and not cause any damage to the unit its self if I have to. :)
Thanks!!!
Gary~*