Replaced Ceiling Air Conditioning Vents

[richfaa]

It hit a high 0f 101 degrees today in Shawnee, Oklahoma both A/C/s running full blast and we are comfortable. Thank goodness these Montana's are 50 amp service took a look at our PT 50C and we are drawing 22 amps on leg one and 17 amps on leg two. Hot water and fidge are on electric.

[richfaa]

[quote]Originally posted by richfaa

It hit a high 0f 101 degrees today in Shawnee, Oklahoma both A/C/s running full blast and we are comfortable. Thank goodness these Montana's are 50 amp service took a look at our PT 50C and we are drawing 22 amps on leg one and 17 amps on leg two. Hot water and fidge are on electric.

In reference to guru post of installing a 3rd A/C there is no doubt that we could handle it as our readings on Leg one and leg two in dicate.We could put another 13/15 amps on either leg with no problem. The only other amp sucking sources would be the micro wave, toaster, coffee maker but there are plenty of amps left. I am thinking 3rd A/C.

[richfaa]

For the record. We have been checking the temp at the A/C vents over the last few days. It is a steady 53.5 degrees from all the vents both front and rear with strong flow. The A/C in the front bedroom will freeze us out as it is cooling a much smaller area. We place a fan on the floor at the top of the steps to direct that cool air down into the much larger rear area and it helps cool the rear area.
Temps have been in the 100"s were we have been over the last couple of weeks and we are comfortable.

Our A/C system is working perfectly the problem is these RV' are ovens and heat collectors and ours is a very pretty black and gray. We still get inside temps in the 80/85 range during the hottest time of the day. These guys need 3 A/C's and I predict that Montana will be offering that in a short time as other manufacturers are. I will bet by the fall rally they will be in the new models.

[kdeiss]

[quote]Originally posted by mlh

If thesis campers are insulated the way Keystonr says they are why does it take 30,000 BTUs to cool them? I have 24,000 BTUs in my house. My AC might run 15 minutes an hour and keeps the house at 72.
Lynwood

That is the problem in the nut shell a trailer is not insulated like a home no matter how hard we try to make them into A home a trailer does not do well in extream heat or cold period!

[Rondo]

Ken--- Register and come up to the Montana Owners Club Fall Rally in Goshen, IN this September. You'll see just how the units are made and how much insulation goes into the units.

[PeteandJoan]

Took off a couple of a/c vents today just to check it out. Have always thought ours should cool better also. What size is the duct supposed to be? Mine appears to be about 6-7 inches wide X about 1-1 1/2 high. is that about right? That does not seem to be tall enough to carry much air. I don't seem to have the tall vent piece sticking up into duct like some have said they have cut off in order to open up the duct. I will have a little trouble inserting 1 1/2" pvc pipe into duct. I did not look at vents in living area but will have to check those to see if they need to be trimmed down as others have done. I do like the idea of adding 3rd a/c by removing fantastic fan in kitchen but I have two vents straddling that fan and they are very close to fan. not sure if a/c would fit there. I will replace vents with a better design for more air flow if I can find some, especially in living area. Thanks for all these great tips!

[jcurtis934]

The ac ducts are just foam and you can push up on the top of the duct with ease. Can't remember how tall mine were...but not very. I agree that dark rigs are three ac rigs and nothing except camping in alaska changes that. Love my white whale... john

[navybanker]

How do you remove the vents? I don't see any screws and don't want to damage something. Assume you either pull down and/or twist. I am very experienced in damaging something especially plastic!

[bigskyjimmy]

They just pop off,just get a finger or two under one corner and pop goes the weasel

quote:Originally posted by navybanker

How do you remove the vents? I don't see any screws and don't want to damage something. Assume you either pull down and/or twist. I am very experienced in damaging something especially plastic!

[richfaa]

Both A/C running.Set point is 73 degrees it usually will never hit that in really hot temps. Inside temp is now 74 degrees outside temp 90 degrees drawing 27 amps on LI and 18 amps on L2, 45 amps total our A/C tweeks and vent replacement helped a lot. We kept comfortable in temps over 100 degrees and very high humidity.

[washley1]

quote:Originally posted by jcurtis934

From the different posting on whisper quiet race track ducted ac being put in new units, i'd say there is a real issue there that we don't face on our older units. Hope you new rig owners figure this out in case we decide to buy a new one someday. As it stands...ain't touching a new rig at this point. John

Amen, brother! My old units work well!

[ronenz]

Would a dehumidifier make any appreciable difference to the cooling issue? I would think that dryer air would be more efficient to keep cooler and stay colder longer or does that process already take place in the roof top models?

[jameswbarton]

You are incorrect on the statement of 20 degrees F difference from outside temperature to inside temperature is the best that an AC System can do. I have had and seen many systems that can keep 70 degrees in 105 degree temperatures.

It is correct that measuring supply air temperature to return air temperature on each unit should be 18-22 degrees F on a working unit. In a ducted closed system each time the air goes through the system the supply air will be cooler than the previous temerature as long as the heating/cooling system capacity in BTU's meets or exceeds the heating/cooling load of the living space in BTU's.

Current advertisements on Montana and Montana HC's state 4 season living, tested, approved for full time living. I am shocked no one has brought a lawsuit for false advertising against them and won. They advertise the roof is R-38 in both, The floors are R-21 in both, The walls are, R-11 and R-10 in Montana and Montana High Country respectively. So if this is true the only heat/cooling issues would be doors and windows otherwise the R-Values are as good as residential construction codes for newer homes. I have 2.3 Tons or 28,500 BTU of AC on my HC roof that is far more than my stick and brick 1980's ranch home but it would only cool 9 degrees from an 85 degree temperature on its first day in a campground.

So the answer is in poor system design that does not meet Dometic Specifications. Doors, and Windows (improvements needed to improve heating/cooling load) using shades awnings, foil, tinting. Fixing all the holes from the interior living space to the poorly insulated leaky air basement. I personally did not want double pane windows or slide covers due to having previous negative issues with both. Are the doors insulated? Mine were not in a Fleetwood brand.

I am trying my best to get communication with both Dometic and Keystone but so far I have better luck talking to my Dogs. Dometic at least is asking me to be patient every few days as they are just too busy, I suppose they fear massive lawsuits or recalls and think they are protecting themselves. The are having record sales so I guess they figure we will put up with it. BTW the HC Quiet cool System is far from Quiet in the front Air Conditioner. The back AC is very quiet. Both units should have been return air ducted. I have to keep the TV volume high when it is hot so I can hear with the front AC almost over the Theater chairs.

[richfaa]

The cool air measured out of the ceiling vents on our 3402 measures 52 degrees that does not mean it will cool the inside of the Montana to anywhere near that .

[jameswbarton]

Richard,
I have you beat! General RV a Super large Keystone Dealers work order report states:
" Mr Barton states the AC units will not cool the coach. Mr Barton states the coach is only 9 degrees cooler than outside temperature."
" Tested both AC working fine at this time. Had temps of 37 degrees on front and 39 degrees on back."

If you coach has 57 degree supply air temperature and 75 to 77 degree return air temperature the AC unit is working correctly unless the airflow is blocked.

[richfaa]

37 and 39 degrees are pretty low you have a great A/C system. The inside temp is subject to many variables. Out side temps, temp of the outside gel coat there is a lot of heat radiated via the walls/ We have measured temps of 90 degrees on the inside walls.

It would appear that you have blocked air flow somewhere but if it is blocked how did they measure those cool temps.I can feel the cool air blowing on my body when we stand under the A/C vent in the rear of the RV.

[jameswbarton]

Hi Rich,
They (Genera RV) lied about the temps or took them when it was cold outside. When they refused to work on it I did some repair.

I have partially fixed the AC to where is now will hold 76 degrees in 92 degree outside temperature with the thermostats set on 72. The temperature measurements at this equilibrium point are: Front AC = 45 degree supply air, 75 degree return air, Rear AC 63 degree supply air, 83 degree return air. The unit is in full sun parked in the worst direction N/S with the afternoon sun hitting the drivers side, off door side wall. All the window shades are pulled and it is dark.

Obviously the front AC is running great, The rear AC not so good, and the air distribution system is below Dometic Specifications. I can see what appears to be a broken duct in the ceiling and the bathroom is always freezing possibly indicating air leakage in the ceiling. The temperature of the supply air is not a good indicator it is the difference in the supply air to return air that is a good measurement.

[richfaa]

The front A/C(bedroom area) in the 3402 cools a much smaller area and will freeze us out. We put a fan on the floor directing airflow down into the rear of the 3402 which is a much larger area to cool. We have the set point a 74 degrees and have never hit that point in extremely hot weather and by extremely hot I mean outside temps of 100 and above with high humidity and the RV mostly in the direct sunlight.

The temps on the roof and sidewalls can be extremely high and that heat is transferred to the inside walls. Temps of 90 degrees are not uncommon on the inside walls of our pretty dark colored Big Sky.
We are however comfortable in the extremely high temps the humidity is wrung out and even at a inside temp of 80 degrees it is comfortable. We also added a full window graphic on our rear window(can see out but not in) and added an awning over our main slide. The replacement A/C vents that blow straight down made a big difference.

I do not see how the ductwork can be damaged at the factory installation we will take a close look at the factory tour this fall rally.

[jameswbarton]

Rich,
Evidently the duct comes in two pieces of 20' each or maybe 16'. Both of my ducts are spliced above the kitchen. One is not quite perfect but the other is visably misaligned by 1/4 to 1/2 an inch with no tape visible. I cannot get a camera close enough as it is directly in the middle of a kitchen and bathroom vent.

Because I have a front living what is usually the smaller bedroom AC is actually cooling the living room Kitchen and Hallway. One thermostat is in the kitchen and the other in the bedroom. Since the ac's are using a common duct both are really cooling the entire coach if the bedroom door is open.

Many owners report factory damage and debris in ducts. I will also bet every 2016 high country may have ceiling vents with the collars too long blocking the airflow in the main duct.

Where did you get your door graphics. I have been looking for them, as the biggest heat radiation issue is my rear door window keeping the hall to the berdoom near 90 as there is no ceiling vent in that area.

Why in the world did Keystone make the roofs of the slides and main beige. White is far better. The same for dark body's. The main Kitchen slide in mine is the biggest heat issue. I have asked many dealers about a slide cover helping and they all tell me the cover has little effect on the roof heat of the slide. I may have to sacrifice a sheet to find out? Hope you are not headed to the SW in summer if yours can only hold 80 in Ohio where the Sun is dim.

[richfaa]

It holds 80 or less in 100 degree plus heat no matter were it is. We just returned from a road trip in the SW.

In our case we got quality graphics from a local company that specializes in marine graphics any good graphic company should be able to provide window graphics .There is nothing you can do about the sun beating on the roof or sides of the RV but the main slide awning keeps the sun out of the rear of the RV.

We may at times experience temps of 100 here in Northern Ohio but it is not common, high humidity is common. We saw temps of well over 100 degrees and high humidity on this road trip and the A/C held its own. I was impressed however in a friends new SOB with a heat pump it kept his Rv same size and comparable to ours much cooler.
We will pay attention to the duct work installation and take pictures at the factory.