ANOTHER RV A/C ??????

[TOBTEK]

Looking for some advice with our Brandnew 35ft 5th wheel trailer. I had the dealer add ANOTHER A/C unit in the front bedroom in addition to the one that is std in the living room. Now the problem is that if the front a/c runs for a few hours it will freeze up and not blow much volume.....its still blows cold but set at high it blows the same as low. I ofcourse called the dealer and recieved the answer I knew I would....."bring it in and we'll take a good at her" Well the trailer is in a park at the river and the dealer is in Temecula. So I called one of those mobil Rv services that makes house call's. He didnt find anything wrong with it. I dont know what to do, I works perfect for about two hours, then hardley works untill it thaw's out .......anybody have this problem

[Frosty_pop]

My AC in my trailer does the same thing.... found the trick to be, don't turn the thermostate to the coldest setting. if it had 1 - 10, set it to 7.... still real cold and will not freeze up.

[TOBTEK]

Frosty_pop:
My AC in my trailer does the same thing.... found the trick to be, don't turn the thermostate to the coldest setting. if it had 1 - 10, set it to 7.... still real cold and will not freeze up. did that yesterday, still frickin freezing frown

[bohica]

That's the problem with all those roof air type units. My new moho has 2 one ton residential units underneath the coach. Basement a/c is the only way to go. :D

[Seadog]

Freeze up is usually low freon.

[TOBTEK]

bohica:
That's the problem with all those roof air type units. My new moho has 2 one ton residential units underneath the coach. Basement a/c is the only way to go. :D GREAT, just park next to us this weekend. I'll run a duct from your coach to ours...

[Trailer Park Casanova]

Seadog:
Freeze up is usually low freon. Yep. Your problem could be low freon.
Assuming the RV Mobil guy checked to see the controls are placed correctly inside the unit.
The mobil RV guy had no way to check the freon charge because their is no schrader valve to check the freon charge unless he soldered it on, and then you have to remove the freon charge to do this. Then rechargeing would have cured it, at least temporarily if the leak that caused it wasn't fixed.
Not unusual that the unit was either undercharged at the factory,, or has a very slow leak, usually at one of the copper line connections.
Is there a closer dealer of the same brand to where it's stored, like LHC or something?
You're best haveing the selling dealer deal with it if it's in warranty.
Try calling either Coleman if it's a Coleman or Dometic and they may refer you to a close service center.
Don't have a mobil RV guy look at it, have an A/C guy check it if you're going to pay $$$.
Could be something simple.
Use a service where the owner himself does the work,, otherwise you may get one of those guys that hangs out in front of Home Depot.
[ July 23, 2003, 08:17 PM: Message edited by: Trailer Park Casanova ]

[JetBoatRich]

Mine did the same thing this past weekend, like the others said don't put it on the coldest temp. :D

[TRG]

well i dont know that much about the whole ac.deal but i do all the paint and body for McBrides RV service and supply co. over in the city of Chino the # is 909-627-7566 give charley a call and they will take care of you!!!

[Trailer Park Casanova]

They should be able to run 100% cold, 100% of the time in any conditions, at any setting, without freeze up.
Coleman has been having labor problems,, and Dometic has intermittant quality issues.
[ July 23, 2003, 08:19 PM: Message edited by: Trailer Park Casanova ]

[Hal]

The problem is probably in the thermostat. Sounds like the stat cap tube is not sensing the return air temp and shuting the compressor off like it should. Shut the power off to the unit and pull the cover off (inside the trailer).Look at the controls, On your thermostat there should be a small thin tube attatched to it. Make sure it is in (sensing)the return air flow. Better yet just call me if you need help. Ask for Hal.

[TOBTEK]

Trailer Park Casanova:
[QUOTE]Originally posted by Seadog:
Freeze up is usually low freon. Yep. Your problem is probably low freon.
The mobil RV guy had no way to check it because their is no schrader valve to check the freon charge unless he soldered it on, and then you have to remove the freon charge to do this. Then rechargeing would have cured it, at least temporarily if the leak that caused it wasn't fixed.
Not unusual that the unit was either undercharged at the factory,, or has a very slow leak, usually at one of the copper line connections.
Is there a closer dealer of the same brand to where it's stored, like LHC or something?
You're best haveing the selling dealer deal with it if it's in warranty.
Try calling either Coleman if it's a coleman or Dometic and they may refer you to a close service center.
Don't have a mobil RV guy look at it, have an A/c guy check it if you're going to pay $$$.
Use a service where the owner himself does the work,, otherwise you may get one of those guys that hangs out in front of Home Depot.
Get it fixed because the next problem is eventually the compressor will fail because of no charge. [/QUOTE
thanks for the advice! I called dometic in the beginning, and they also said to take it in to a authorized dealer. I Can not take it without removing awnings the entire campsite.(major pain in the butt!) We are just outside of Yuma,Az which is "snowbird haven" cannt believe someone mobil can't fix this.

[TOBTEK]

Trailer Park Casanova:
They should be able to run 100% cold, 100% of the time in any conditions, at any setting, without freeze up.
Chances are you guys got a short charge at the factory when the units were built.
They're "Capillary tube" metered freon so their is no way to adjust them for frost other than a correct charge.
Coleman has been having labor problems,, and Dometic has intermittant quality issues. I AGREE! why have a A/C unit if it wount work :confused:

[TOBTEK]

Hal:
The problem is probably in the thermostat. Sounds like the stat cap tube is not sensing the return air temp and shuting the compressor off like it should. Shut the power off to the unit and pull the cover off (inside the trailer).Look at the controls, On your thermostat there should be a small thin tube attatched to it. Make sure it is in (sensing)the return air flow. Better yet just call me if you need help. Ask for Hal. HAL....I'd love to pick your brain, where can I call you?....toby

[Havasu Sun]

Hal,
Your right, Our Stat wire/tube was hanging in the open space of the air intake. No matter what temp we were setting it at if froze up even blowing chunks of ice out the vents. I removed the cover on the inside of our unit and inserted the small stat wire/tube into the fins of the coil, now it seems to be working perfect. No need to remove the A/C cover on the outside of your unit.
HS

[TOBTEK]

Havasu Sun:
Hal,
Your right, Our Stat wire/tube was hanging in the open space of the air intake. No matter what temp we were setting it at if froze up even blowing chunks of ice out the vents. I removed the cover on the inside of our unit and inserted the small stat wire/tube into the fins of the coil, now it seems to be working perfect. No need to remove the A/C cover on the outside of your unit.
HS So, when I remove the cover inside the coach. Where do I find this stat wire/tube, where is it located??????

[Hal]

Call me at 909-737-1792.... Hal

[TOBTEK]

Hal:
Call me at 909-737-1792.... Hal HAL.....THANKS A MILLION. Hope your coaching work's. With wifey argue at me at the river because itS hot in the trailer REALLY sucks! HAVE A MARTINI HONEY! wink

[TOBTEK]

well, found the "stat line" I think. It is the one thick solid coming out above the thurmistate dail and was cliped to the housing in the return air track.. right?
Well, I took this wire and bent it up into the air track, right in front of the thing that looks like a raditor. Make a long story short, ITS STILL FREEZING UP :( I tried med air pressure and turning the temp WAY down as well.....still froze. At one point it was 1/4 inch thick over the entire raditor surface. The only funny thing about it was when it shot a bunch of ice out the vent and blasted a friend of ours with the snow cone material all over his upper body....was pretty funny!
Now what? Thinking maybe the actual thurmistate is bad?

[TOBTEK]

anyone?

[spectratoad]

I would check the for freon charge fitting so that you can have the freon level checked. Then I would look at the thermostat. I am not an HVAC guy so that is about the extent of my knowledge, sorry.

[Outnumbered]

Mach22,
Mine does the same thing, but seems to be only when the humidity is high like it is now. I thought it was just something they did. Mine is an older Dometic unit. Kicks ass unless its humid. What I usually do is turn the heat on for about a minute to melt the ice then turn it back on and it works good for several more hours. Never have had it freeze so bad ice or water shoots out though. If mine were new I would probably not go thru this BS but its old so I just deal with it. Keep us posted if you figure it out. I would be curious to know what causes it. Thanks and good luck.
OL

[TOBTEK]

im about ready to take it off and throw it into the river! :mad: :mad: I have spent hours on the phone with the dealer and manufacture....without any resolve. Sure glad I stepped up to a new unit :rolleyes: I'll keep ya posted, and charge a dollar to anyone who wants THE FIX :D

[TOBTEK]

Havasu Sun:
Hal,
Your right, Our Stat wire/tube was hanging in the open space of the air intake. No matter what temp we were setting it at if froze up even blowing chunks of ice out the vents. I removed the cover on the inside of our unit and inserted the small stat wire/tube into the fins of the coil, now it seems to be working perfect. No need to remove the A/C cover on the outside of your unit.
HS I re-positioned the stat wire up into the flow of air but NOT directly INTO the coils them selves. Would make sense that the wire would pick up the low temp and turn off with ICE/SNOWCONE all over it. IS IT OK TO INSERT THIS WIRE INTO THE COILS? Have been on the phone all morning with the dealer, coachnet, & dometic trying to get some answers....no luck yet. real neet :mad:

[Seadog]

I firmly believe that you will find the problem to be low freon. You may have a pinhole leak. The only solution is to have a qualified technician with a freon handling license test it. These units are two pieces bolted down. Depending on the setup, you have the power cord and on newer units, the remote thermostat. If need be, you can pull the unit if you are mechanically inclined, but the dealer should do it under warranty. They probably don't want to because Coleman only allows them one hour labor to replace units and they like to charge the customers two. A skilled person can usually swap one out in about 45 minutes.
As for having to take the unit to them, they are kind of designed for that purpose and its not unreasonable for them to expect it.

[rrrr]

The main two reasons an evaporator coil can freeze is because the suction pressure is too low or there is insufficient airflow. If you look on a manifold gauge set you can see the approximate temperature conversion scale for different pressures.
Generally speaking a unit using R-22 refrigerant should operate at around 75 psi suction pressure with the outdoor temperature in the high 90's. This translates to a coil temp of around 45 degrees. If the pressure is below 60 psi, then the coil temp is gonna be below freezing, and the moisture that is condensed on the coil will turn to ice.
As I said, lack of airflow could do it too, but that is usually caused by a very dirty filter or clogged coil surface, by something like long cat hair or whatever. Since the unit is new, this seems unlikely.
One way to check the charge... when the unit is running but not frozen, if you can put a probe type thermometer on the suction line (insulated larger line between the coil and the compressor inlet) the temperature should be around 55 to 61 degrees if the unit is properly charged. Pierce the insulation with the probe and put it right on the tubing. If it's outside that range then a system pressure check is necessary.
[ July 29, 2003, 04:45 PM: Message edited by: rrrr ]

[rrrr]

OBTW, I forgot to say why the suction pressure is low..... needs more freon. Seadog is prolly correct on this one.

[VillainDave]

bohica:
That's the problem with all those roof air type units. My new moho has 2 one ton residential units underneath the coach. Basement a/c is the only way to go. :D Hey Bo if this is a See Ya motor coach I would like to talk with you more about it! I'm in the maket for one!

[Seadog]

Tobtek, while I feel for your fustration, the logical diagnosis of your problem requires that the system be opened or the unit replaced. If the system is opened, it requires a license per EPA regs.
The way a Ac unit works is that freon is moved in a constant loop through two heat exchangers. The compressor forces the freon under pressure to the outside exchanger. By being under pressure, it holds a lot of heat which is then released to the outside.
After the freon is cooled down , a suction is pulled on it to reduce the temperature to near freezing. As it goes through the second heat exchanger, it absorbs the heat from inside the RV or house. This heat is then off to the compressor for another trip.
Once you understand the loop, it is easy to see that there are three primary areas that can fail. The compressor can fail, the heat exchangers can fail to function or the freon can be lost (actually overcharging can also reduce efficiency, but that is another story) There are numerous relays and capacitors and other gizmos, but they are functions of the primary equipment.
If the compressor goes, you have nothing. The heat exchangers can have problems if the fins are clogged or the fan fails. Usually this happens on the outside coils and the unit burns up because it cannot release the heat.
Now that the theory is over, I need to find someone to help me take a thirty year old 100+ lb unit off my motorhome and hoist a 84 lb new unit up there.

[Havasu Sun]

TOBTEK,
I put the stat wire/tube into the fins of the lower part of the coil. I don't know if it is ok, but it works for us. I am not an a/c mechanic. It's not freezing up now, might just be a bandaid.
HS

[JetBoatRich]

Seadog:
Now that the theory is over, I need to find someone to help me take a thirty year old 100+ lb unit off my motorhome and hoist a 84 lb new unit up there. Swing it by and we will give you a hand eek!