Community Forums

bruceisla · 07-23-2017, 05:23 PM

Quote:

Originally Posted by rinker5959

I don't have one return filter. Each return vent (9 of them) all have a round filter in them. I've taken those all out and cleaned them and also run without for a minute to no avail. I'll take the unit out this week and investigate. Thank you everyone for the help.

Your setup sounds like a Newmar setup ... equal number of returns and cold outlets staggered front to back and each is offset from a centerline by about 5 inches. All the cold on one side and all the warm on the other side. If that's the case, when you remove the top unit you will probably be looking down into the ducts.

flywithcoop · 07-24-2017, 06:55 AM

Call and/or email the Tiffin service center and ask for Help. They are pretty good at troubleshooting problems. Also check the Tiffin RV network. It is only for Tiffin owners and has a ton of info.

John Boy · 07-24-2017, 07:21 PM

Quote:

Originally Posted by rinker5959

I have an 07 Allegro 32ba FRED.

The AC has cold air coming out but it surely isn't blowing out nearly enough. Some vents can barely be felt working. On the return side vent 2 of them will suck up and hold a piece of paper to them but the rest of them will not even hold up a Kleenex. Anyone know where my problem is? It seems as though the fan on the unit ip top is working fine. I was in 94 degree heat the other day and RV was at 90 with AC running 5 hours at campground on shore power.

Thank you
Tim

I have an LA, same year, etc. Don't have a specific answer but you should ignore most of the advice on here.
The intake vents are ALL connected. Front to back and back to front. If you take the whole vent cover off (4 screws) you have a lot more access and options. I would put a bright light in one end and use a mirror at the other end to check for blockage. Move from vent to vent to locate the blockage if there is one. A flexible hose or "snake" or shop vac hose can be used to push the blockage if you have one.
I have pushed a damp cloth from one vent to the next to remove dust.
We are in NC and it's hot but manageable. Can run both units but usually don't. Right now, 9pm, 79 degrees in and 59 degrees out. We do run small portable fans for additional air movement.
I hope you can fix it without taking the unit off the roof.
John

John Boy · 07-24-2017, 07:25 PM

The output vents are ALL connected (to each other) as well. Check that channel as well.

chuckftboy · 07-24-2017, 07:58 PM

rinker, you stated that you only have 1 unit and it was 94 degrees out. That's a lot of coach to try to cool on a 94 degree day with only 1 unit. My coach is a few feet longer and if it is in the mid to high 90's I struggle with 2 units. Thinking I need 3 sometimes.

John Boy · 07-26-2017, 03:47 PM

Hope "no news is good news"!

curtsr · 07-26-2017, 04:50 PM

As Darwin mentioned, it sounds like the evaporator coil is freezing up. If its a heatpump, switch it to heat a while and see if the flow increases. If its not a heatpump, leave the compressor off and just run the fan on high. If flow gradually increases, chances are you have a freezing evaporator coil.

RedRocket · 07-26-2017, 05:22 PM

Since your rig is a bit older, give these short videos a view and consider trying to seal up the main AC unit better than it probably is right now. I know it made a significant difference for my single AC unit. Besides, it's only a bit of your time and really cheap to buy a roll of aluminum ducting tape.

Videos do not have to be specific to a brand as most all roof mounted AC units could have the same issue.

https://www.youtube.com/watch?v=E_GNjfFpTGU

https://www.youtube.com/watch?v=AzdQoDublzs

Rkesselus · 07-26-2017, 10:26 PM

Quote:

Originally Posted by rinker5959

I don't have one return filter. Each return vent (9 of them) all have a round filter in them. I've taken those all out and cleaned them and also run without for a minute to no avail. I'll take the unit out this week and investigate. Thank you everyone for the help.

I can not imagine that you have 9 return vents. I would think on a ducked system the multiple vents are all output vents and the return vent is located in the bottom of the AC itself. So if air is going into the vent the squirrel cage fan is mounted backwards. I could be wrong but that is how a Dometic system works.

bruceisla · 07-27-2017, 04:20 AM

Quote:

Originally Posted by Rkesselus

I can not imagine that you have 9 return vents. I would think on a ducked system the multiple vents are all output vents and the return vent is located in the bottom of the AC itself. So if air is going into the vent the squirrel cage fan is mounted backwards. I could be wrong but that is how a Dometic system works.

Not necessarily .... the coach manufacturer designs and installs the ductwork. For instance, on my Newmar 45ft with 3 top units, there are 10 inlets and 11 outlets. They are all 5 1/2 inch vents. There are no accessible central airboxes under the top units.

HGC · 07-27-2017, 08:29 AM

If you have done the "kleenex" test and there is no flow or little then there is a blockage. Take a Shopvac or whatever brand and tape off the hose to the furthest input vent and turn it on. It could be that some foam insulation is loose and clogging your vent system. With any luck you can dislodge it. This is how they clean ductwork in homes. If you can get extended hoses it would help. We have a Tiffin 36LA and have had the ceiling filters off and can see how the pressed foam can clog a unit. and sometimes they use additional heat tape to seal ducts. Good luck and let us know what worked!
In addition, you can rent a plumbing camera from Home Depot and actually see the problem.

rinker5959 · 07-27-2017, 12:11 PM

Thank you everyone for all the suggestions and advice. I have not had access to the coach for a week or so but I will be doing some of these suggestions this weekend. I know 94 is hot outside but to only change the coach temp by 3 degrees when the air coming out of the vents is between 15-20 below ambient??

I don't believe it's a freezing issue. The final, coils filters are all completely clean and as I said the air coming out is 15-20 degrees below ambient.

I may look into adding a rear unit as well because most of our travelling will be in summer months. My wife and I are on 42 so we can only envy those of you that have more time to travel 😝😝

bruceisla · 07-27-2017, 01:12 PM

Quote:

Originally Posted by rinker5959

Thank you everyone for all the suggestions and advice. I have not had access to the coach for a week or so but I will be doing some of these suggestions this weekend. I know 94 is hot outside but to only change the coach temp by 3 degrees when the air coming out of the vents is between 15-20 below ambient??

I don't believe it's a freezing issue. The final, coils filters are all completely clean and as I said the air coming out is 15-20 degrees below ambient.

I may look into adding a rear unit as well because most of our travelling will be in summer months. My wife and I are on 42 so we can only envy those of you that have more time to travel 😝😝

Good luck and please let us know what you find. FWIW, I had an older 37' Endeavor with two 13500 Dometic A/C units. Although it took awhile, one unit could get the coach down to below 80 when the outside air was 95. Two units were much faster to cool but could easily hold low 70's if I wanted to. However, it did require Reflectix on the windshield. I am currently sitting in our 45' Newmar with three 15000 Dometic units ... I'm in Florida and the outside temp is 91 with some occasional clouds. The three units are running in "Auto" and only two of the units are cycling .... the other is not running (it's idle because the bedroom is not calling for cooling). I could turn two of the units off and the 3rd would still hold the temp at 76 but it would probably run continuously. The net of all this is that, once cooled, I can keep a 45' (lot's of interior volume) comfortable with 2 units and probably 1 if it's cloudy. I'm pretty sure yours should do the same ....

ALinMaine · 07-29-2017, 06:58 AM

Our new 32SA front AC was just not keeping up on an 80 degree day; significant icing out side on unit. Poor air flow only getting worse the longer it ran. I used my cell phone camera to look in the ducts. I found the duct tape seam between the return air and plenum loose and pinching off the return air into my front unit. In addition there was a substantial amount of wood chips, screws and other junk never removed during build throughout the ducts. Used my shop vac with some 1/2" PVC pipe to suck out the crap. Used some foil tape and a paint stick to extended my reach to get a tight joint. Works like its supposed to now. Tiffin build quality is great compared to most, but still sloppy on some items.