airflow spec for AC vents

[terawatt]

Scott or Coley,

I know that this subject has been covered extensively in this forum, but my trailer is currently at the dealer and we are having a disagreement about what is acceptable airflow through the AC vents. Without getting into particulars that would probably bore the masses, does an airflow spec exist? It is becoming obvious to me that "adequate" means different things to different people, so I am looking for some quantitive way to measure.

Thanks,

terawatt

 

[Scott]

Dometics quantitive way to measure the performance of an Air Conditioning unit is to have it put out air that is between 16 degrees and 22 degrees cooler than the air it is taking in. That is measureable, and will give you a good idea at to how the A/C is performing.
Now - beyond that, see if the air is cold when it blows straight down - and then compare it to how the air is coming out of the vents when the down vent on the unit is closed. There may be an issue in the vents, or the way the unit is sealed in its opening and to the ducting that needs to be addressed.

ST

 

[terawatt]

Thanks for the reply, Scott. I appreciate the response, but my AC is definitely blowing cool enough, my problem is that one of the vents in the living area has very little air coming out of it an the other has almost none. It makes no difference if I have the quick cool vent open or closed......the airflow remains about the same. I know that a few people have discussed this problem before in this forum and I am totally convinced that I have a leak or a pinched vent somewhere. The problem is that my dealer believes it is normal to have very little air coming out of the two rear vents. If the dealer doesn't believe there is a problem, then they certainly won't try to fix it. I am looking for some airflow number to tell them that might convince them that there is a problem.....something that can actually be measured.

 

[Scott]

I am going to tell you to tell the dealer that you want them to double check the seal around the unit itself (sometimes the plastic shroud that telescopes up into the opening is not attached properly and comes down some - allowing air to escape into the roof - and not into the ducting) - as well as the duct runs themselves. If they say they don't know how to do this - tell them to get on the phone with Heartland's Dealer Services dept. and they will talk them through it.
You can also purchase the new style A/C air vents which became available to us recently that have larger openings/slots - so air flow is increased.

One thing to note. The air vents in your coach, if the older style, are designed to shoot the cold air at more of a "sideways" direction, not straight down. This system is said to cool the room better, because it causes the flow to circulate in the room better. Don't know if I believe that or not - but I have felt those vents and the blow a lot harder to the side thans they do straight down.
FYI

ST

 

[terawatt]

I informed the dealer of what you told me. They said they will check it out today. I'll keep you posted.

Thanks

 

[ChopperBill]

I did the mod that TimK mentioned in the air conditioning section. WHAT A DIFFERENCE! I was tickled pick when saw dust blew out into the living room all over the Euro chairs. (Wife is going to be like a cat in heat!) More came out of the bed room vents but not as great a difference as the living room vents. There is more air coming out of the vents with the grill open as it did with it closed before!

 

[terawatt]

Hey thanks ChopperBill,

I hadn't seen TimK's post before you pointed it out to me. I'll definitely try it.

terawatt

 

[jimtoo]

Although the dealer told me he made the mod of the tent after I told him about it, the other day the unit started freezing up and I removed the cover to check it out and found the thermostat that is mounted on the evaporator coils had fallen off and the dealer had not made the modification, but had blocked off about 1/2 of the curb side duct to force more air to the other side. Not being at home, I made a tent modification, as suggested on this forum, from some cardboard and duct tape, for temporary use and to try it, and put cover back on. The difference is like day and night. The unit blew out a bunch of saw dust and shavings and now the unit will keep the 5er pretty cool.

You would think that the company, Heartland, would at least add a couple of more vents and do a recall or ask all the people to bring their units back for for the modification that appears to solve the problem.

Heartland is getting a lot of bad press about this issue. I have had several rv'ers ask about the a/c problem. Evidently a lot of people are reading the forum.

 

[ChopperBill]

$2 dollars worth of material and 5 minutes work would make a bunch more happy customers! I'm just glad that TimK came up with the simple fix so we can all be cool this summer! Thanks again Tim!
on a p.s. I made sure the lip of the lower side of the tent was up into the vent on the off door side and not just placed at the bottom of the housing and it made it even better.

 

[jimtoo]

Your correct about $2.00 in materials. When we get back home I will make a neat and clean installation out of metal like TimK suggested. Maybe the factory will reimburse Timk for his engineering and the rest of us for making the modification. I also think that if we had a couple more outlets in the living room and kitchen area we would see even better results.

 

[Ken Washington]

Has enyone taken a picture of this tent fix and if not, please post it for us to see. I would be interested in trying it even though I have two A/C's.

 

[jimtoo]

You can see modification drawing here. Just scroll down to see pictures and drawing. //heartlandowners.org/showthread.php?t=1069 These were posted by timk and they work. Now if the factory will just step up to the plate and make some changes.

 

[ct0218]

I made an inverted V diverter out of sheet metal, slightly wider than the opening because the width increases above the opening. I had a somewhat difficult time getting it in because of that. I also noticed that the air flow from the blower was not was not even across the opening but appeared stronger towards the door side of the opening. I was able to offset the diverter towards the door a little to even up the flow. The 2 ends were notched and bent down so that they would hang down outside the actual duct while the center section continued along the same plane and was inserted into the duct (resting on the flat bottom part of the duct). That creates less turbulence also, and helps lock it in so that it doesn't move. It definitely improves the air flow.