Air Conditioner Types and How much is too much - Montana Owners Club

zzuroweste1 · 04-20-2005, 04:07 AM

I am purchasing the new 3400rl and it has one 15000 btu ac. Is this enough for florida and texas summers or should I go for the second one. how big should I get it and what is the type that comes on the montana originally.. I appreciate your help.

Montana_2779 · 04-20-2005, 06:42 AM

We are in the Houston area. There is no such thing as too much A/C! We are in the 297RKS (exterior length: 33ft). Our single A/C seems to be doing fine. However, we do keep our night shades down all the time in the bedroom, and all other shades are closed during the day to reduce some sun (while we're at work). As well, when we were originally looking at a 37' 5er from another manufacturer, we insisted on a second A/C. Personally, if the cost is not a factor, I'd recommend as many A/C units as you can get. This should cover you in all types of hot weather (120 degrees in Arizona to 95 degrees and 90% humidity on the Gulf Coast). We found Florida (especially the interior and central coastal portions) to have very similar weather to Southeast Texas. If Texas and Florida are your primary destinations, you'll be glad to have the extra cooling power.

All of that being said, be sure to check the specs on the 3400RL to be sure that the extra A/C's will not over extend your electrical capacity. In some cases, owners may have to use one A/C or the other while using other electrical items. If you'll be getting a 50amp system, this is usually not a problem.

Montana Sky · 04-20-2005, 12:28 PM

I have the 3400RL and will be having another a/c installed in the bedroom here next month. I have the 15,000btu a/c in the living room, but when the temps rise over 85 degrees it seems that a/c runs most the late morning and all afternoon. I am having another 15,000btu put in the bedroom. The cost difference was something like 70bucks. I will agree with Pete, you can never have too much a/c. The other reason I am going with the bigger one is this way I do not have to run the living room one all the time. Cool the back half off and leave the front one going all afternoon. Place a fan in the hallway to pull air into the rear of the coach and all will be well. Can get loud in the rear with the tv and a/c going and people trying to talk.

Montana_2753 · 04-21-2005, 03:14 PM

I just had a second 15,000BTU unit put in the bedroom area (already pre-wired for it). Cost difference was $100.00 more than a 13,500BTU and was recommended by installer, which, BTW, was RV Lifestyles in QUARTZSITE, AZ. I agree with both previous posts, in this case it's better to have TOO MUCH AC than wishing you had more. I would also think the efficiency would be better, especially in the hotter climes. I had the Fantastic Fan moved to the vent opening by the shower. The installer was able to "fish" the power wires to the new location so the automatic functions will still work. What was also recommended was to have a 12V fan placed behind the refrigerator to help it run more efficiently. There is an "On/OFF" switch as well as a thermostat that turns the fan on when temperature reaches around 105F in the compartment. These were all done because I will be spending summers in Quartzsite and other hot climates.

cs413 · 05-19-2005, 04:15 PM

I'm glad you brought up the a/c issue. I have a 2 month old 3650RK. I have only pulled it 2 miles from the dealership to home, so I am opening it up from time to time making sure everything works. I'm sure it has the 15000 btu unit (can't find the manual) in it because this beauty is 37' long.
It's getting pretty warm and muggy here in Panama City, Florida so I've been testing out the air. It seems to do pretty good, but naturally the bedroom is the warmest being the farthest away from the unit. My question or statement is - why in the world wouldn't Keystone put in ceiling vents that were adjustable and would close??!! All of them are one solid piece of plastic. They turn 360 degrees but they won't close! All you would have to do is close the kitchen vents and that would send more air to the front for more cold air at night or when you need it in the bedroom. For the price of this trailer, I can't believe they couldn't give you adjustable vents. Anyway - I am now looking for retrofit vents for a 2 month old trailer. Called Keystone - NO HELP THERE - blew me off and told me to call my dealership. Did that - not the right size vents. These are 7" overall and they carry 5" overall. I have been doing an internet search and any time I search for vents, a/c vents, ceiling vents, I usually get ZERO products found for your search. Has anyone else looked for these vents? I can't believe they would be that hard to find. Camping World was also a zero product search. Any help would be nice. Thank you.

DHenry · 05-19-2005, 04:58 PM

cs413, try a local heating company for the vent registers. I am sure that they can order them for you. It may take a few weeks to get them but if you are not going to be in the area you can have them shipped to an address that you can be at easily.

stiles watson · 05-19-2005, 06:59 PM

My 3670 has two A/C units. I have been in it during hot. You may not need the second A/C until bed time, but, in my opinion it is needed in the Southern climes. Especially if the electricity is included in the rate, I am gonna make sure I am cool. My second unit doen't use the duct system. It is like a window unit mounted on top and venting into the bedroom is directly off the unit.

Montana_3696 · 05-20-2005, 12:32 AM

I agree with those who've stated that in the deep south one can't have too much A/C ... we were in Vegas last summer and it was 114 and 119 degrees the two days we were there ... our single 15,000 btu unit was able to keep our camper comfortable but ran almost nonstop in doing so ... not a single drop of condensation hit the ground during the entire time

... on concern that you may need to check out is to make sure your camper is wired in a manner that can accomodate two units, by this I mean 30 amp service running 2 15,000 btu units may well be very limited in what else you can run

Jim

Montana_1925 · 05-20-2005, 01:57 AM

Have you checked to see if there is a vent for A/C in the toilet area ? We read in Trailer Life about someone being very upset because there was no vent in the toilet area and he spends most of his time in Florida and Texas. I know our toilet area has no vent for A/C or heat. Just something else to think about. He wanted a vent and Montana told him that if he installed one, his warranty would be void. After contacting Trailer Life and having them support him, Montana decided to let him keep the warranty while he had a vent installed in the toilet area. We wintered in Texas and it was really hot, I can't imagine the heat during other times of the year.

Montana_2779 · 05-20-2005, 07:38 AM

Red is right...the water closet can get pretty darned hot, and there is usually not an A/C drop in there. However, we've found that the stock electric fan vent in the roof does a nice job of drafting cool air in (we've seen no need to go to a Fantastic Fan or A/C drop in our case). When we get home from work, we'll open the WC door and roof vent and turn on the fan. Within a couple of minutes, the WC temp equalizes with the rest of the bedroom.

Unlike Jim, our A/C spits out PLENTY of runoff condensation. That's what you get when the humidity averages 80% (Stiles can tell you all about our bad hair days down here). Jim is also quite right in recommending a thorough check of the electrical situation. As noted above, A 30amp system probably won't handle 2 A/C's running at once. However, cutting off the main A/C and turning on the bedroom A/C at night should work fine.

cs413 · 05-20-2005, 03:54 PM

My 3650 is prewired for the second unit with 50 amp service. That's not a problem. I was trying the cheaper route first. My wife and I are not retired (and doesn't look like we will be soon either) so we are not able to spend much time in the trailer. I brought it home on 3/12/05 and haven't had it out yet, I haven't even dewinterized it yet. I called Keystone today and they were a little more helpful. They told me the manufacturer of the vents and the supplier they get them from. I thought I was home free. When I called "Partner Supply", they had no idea what I was talking about or who Keystone RV was. Oh well, they tried. They also said the reason the vents are stationary is so people can't close them and damage the unit. But closing only a couple shouldn't hurt anything. They're oversized vents anyway. I guess I'll stop worrying about it and call it a day. It's just me. I'm kind of a perfectionist and little things like that tend to frustrate me. But I'm starting to mellow out in my old age. If it does get too warm inside, I'll just bite the bullet and put the second unit in. They obviously expect you to or it wouldn't be prewired for it. Thanks for your all your input.This is a great site and I am learning a lot about problems to look out for, their solutions, and preventive maintenance. I traded in a 32RCS Holiday Rambler TT and had virtually 10 trouble free years. I hope I get that lucky with my Monty.

cs413 · 05-23-2005, 07:31 PM

Well, I don't think they make a 7" ceiling vent that closes. I threw in the white flag and made an appointment for 6/1 at the dealership to have the second a/c unit installed. But he told me he could order the 15k unit, but a 13.5k unit would do the job and keep the amps down. Since that unit will pretty much only be cooling the bedroom I tend to agree. Even though I'm wired for 50 amps, Running 2 units and the microwave at the same time will be close to full load. I couldn't run my a/c and microwave at the same time in me TT, it would trip the outside breaker. I want to be cool but I don't need to freeze. Of course most parks still don't have 50 amp service, runing both units at the same time is a moot point anyway. But at least we will be cool at night while sleeping.

T and J · 05-23-2005, 08:37 PM

Another thing that will help, is leaving the bedroom ceiling vent open. Yeah I know sounds crazy leaving a vent open when trying to cool the coach in 90 degree heat, but heat rises and if you let it out you may be able to get away with out a second ac (retrofit is probably prohibitively expensive)! This will also ease the strain on the ac unit. If you don't have a plug in volt meter now is the time to get one, ours is plugged into a receptacle right inside the door, low voltage kills many ac units every year and it seems 75% of RV parks have low voltage. Also, don't just check voltage before you set up! Check under load, and frequently during your stay. As other campers come and go, and temperature rises and falls voltage can rise and fall dramatically!
Stay Cool! Terry

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