Cruisers Forum
Main Forum => General Discussion => Topic started by: JWW on July 14, 2015, 02:05:18 pm
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Summer is here, with the heat index well above 100 and the dew point above 70 day and night here in the mid-south.
Figure its a good time to ask for opinions on weather a single 15,000 BTU A/C is sufficient (comfortable) in the 2910's & 3100.
I think their are a few folks on here who have dual units, as I followed the threads regarding the gensets not being large enough handle the load. That is manageable as they will both work fine while conected to 50 amp shore power.
I understand all of that. I am concerned about one unit comfortably cooling the larger models, assuming the insulated windows option is chosen and windshield/cab window covers are utilized.
Also , with the cargo carrying capacity being lower on the longer models, any opinions on the additional weight that accompanies a second A/C unit?
Thanks in advance for your input.
Happy Motoring
Johnny
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JWW
We ordered our 2910 with 2 AC units and are glad we did. In 2 months of ownership and only 2 weeks so far at campgrounds, we have used both units on multiple occasions. We previously had a 40' diesel with 2 AC units and there were several times we wished we had had 3 units. We are is SC so we have a good understanding of heat and humidity. We are on our third week so far this summer with highs in the high nineties and over 100 on several occasions. I was told that the 15,000 BTU would be plenty. Glad I went with my experience.
Mike
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Thank You Mike !
We are of the same mind-set as we recently sold a 43' with 3 A/C's and used them all. Nevetheless many factors go into that equation......cubic footage of air to be exchanged, efficiency of the insulation in the unit etc.....
Is your unit a D or T ? We are leaning towards the D at this time.
Plan to visit the factory before year end, as we have yet to physically see a P.C..
Want to make the right choice in down-sizing on the first pass if at all possible.
Thanks to all on the forum who take the time to share info!
Happy Motoring
Johnny
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Johnny
We have the D. We looked at lots of units after we decided to downsize. I was most impressed with the PC. The price point was right for us. So far, we are happy with our decision.
Mike
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Where do you live in MS? We live in Madison. Have a 2551
jhb
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Campmuch,
We live in Horn Lake............if the H in JHB is for Haden we have camped togather (Tenn Tom).
Happy Motoring
Johnny
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Johnny
We have the 3100 with 2 air units, love it, didn't add too much weight to unit, we have the single slide to keep the weight down. Also both units have the heaters and we were comfortable at 20 degrees in the winter, with just the heaters.
Jim & Rae Anne
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Many Thanks !
Johnny
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Johnny, I think if you are going that size MH get two A/C and 50 amps.
Hayden
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We have a 2552 with one A/C which we upgraded to a 15000 BTU Coleman unit. A non-scientific study in our PC seems to indicate that the A/C can cool the rig down up to 25 degrees on the hottest days.....if we are careful with not leaving the doors open, ensuring the shades are down, ensuring the a/c is started early in the day, etc. We have 50 amp service and if I had to do it all again I would keep the 50 amps and the Coleman unit, and add a second A/C. Mostly because we would want to do some traveling in hotter climates at times (or may find ourselves there) like Arizona in July when it's 110 in the shade. But, that's just us.
- Mike
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Thanks to all. Great input!
Johnny
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This is our fourth summer tour in our two a/c, 50 amp 2910D. We can handle hot weather pretty good now. The front windshield is the major source for heat followed by the all metal coach door.
The first thing we have done is to tint the the side and front cab windows and coach door window.
Routinely, we use an outside window "bra" for average conditions. The awning helps also to keep sun off of the coach door.
In severe heat conditions we add a aluminized "space blanket" over the windshield which is held in place with magnets. Same on the inside of the entry door.
We also have aluminized insulation cut to fit the rear window, coach door window and cab windows. These store nicely under the bed. The $2 space blankets store sandwich bags.
You evidently are aware of the weight situation with the water tank in the rear bed slideout, but I do not see how a single air conditioner could be satisfactory in hot, sunny conditions.
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We bought Magne Shades when we bought our 3100. They make a big difference in the inside temperature. An added benefit is that you can roll down the driver and passenger door windows. And they look great. Pics:
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We have the Magne Shades too, but we found that HeatShields work better. They are custom made to fit and provide nighttime privacy as well.
John and Carol
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I also have the Magna Shades. They are great for daytime privacy but they can be seen through at night when there are lights on inside the coach, so some type of interior curtain is still needed at night. For any protection from heat, they are of limited use. If parked in a nice shady campground or somewhere the temperatures are mild, they do cut glare, and act as screens if the side windows are down for ventilation.
However, if you park in real heat, with sun exposure on the coach and glass, they do not reduce heat gain through the automotive glass. In fact, the black plastic mesh gets blistering hot in direct sun and transfers the heat straight into the glass which radiates right into the coach. If you need to reject heat gain from direct sun and high air temperature through the automotive glass, you need a cover on the outside that absorbs as little heat as possible, reflective or at least white, with some insulating properties. Placing insulation on the inside against the glass will help to prevent the indoor air from convecting. Unfortunately these measures block view and light completely.
As mentioned by many, awnings also help to shade side windows and coach walls. The double-pane coach windows do help reduce heat gain, but shielding them from direct sun strike improves their efficiency.
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That has not been my experience with Magne Shades. In fact, just the opposite. We stay at a resort in Florida for the month of March each year. With the AC on, there is an increase in temperature toward the cab area where I often site in a recliner to watch the campground activities. After putting on the Magne Shades, the temperature drops almost immediately. Magne Shades, fortunately, still allow you to see out. When it is cooler, we can open the cab side window for a breeze. We just close the curtain at night as usual. We love Magne Shades and consider them as one of our best purchases.
;)
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I am one that votes for my Magne shades. We are sitting on the beach in full sun in Myrtle Beach right now. We have been here all week and the sun is making my poor A/C work it's heart out. We even stopped at Walmart and bought a Lasko tower fan to help it. The cab is much cooler with the shades. Mine are just like the day time MCD shades on the side windows, we keep them down also.
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I agree with GoPhoenix in mild temperatures. Florida in March is mild temperatures. Florida in July/August is 97+. Parked in direct sun with Magna Shade the windshield glass cannot be touched on the inside because it is blistering hot. That hot surface heats the air. I love the Magna Shades in mild temperatures. Unfortunately, much of my camping is in very hot or fairly cold temperatures, so I'm either fighting the heat or the cold, and one of the first lines of defense is to prevent heat exchange through the automotive glass. Next problem is cab metal and air leaks, but that's another topic.
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Not so much one unit verses two question I have is the noise level. HOLY crap these units are noisy! I have been in a few other class C's and in not one of them was the AC unit any where near as loud as the one I have. By any chance is the noise level related directly to the brand of ac unit installed?
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Not so much one unit verses two question I have is the noise level. HOLY crap these units are noisy! I have been in a few other class C's and in not one of them was the AC unit any where near as loud as the one I have. By any chance is the noise level related directly to the brand of ac unit installed?
Yep, the low profile units on PCs are Dang LOUD. I wait patiently for ours to cool down the rig enough so I can put it into "low" mode. The same issue is with other brand rigs with the same unit and direct flow non-ducted a/c. Their higher ceilings and bigger volume probably help as well. Someone here paid more for the factory to install a Coleman. I wonder if it runs less noisy.
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Ron, I was really surprised how much quieter the ac was in a coachman leprechaun rental unit I was in last week. It was keeping their unit every bit as cool as ours with a fraction of the noise. I don't understand why they would install such noisy unit? Even with the fan on low its much louder than other units I've been in recently. Bummer if a person has to spend a pile of money to change out a noisy Ac unit.
update......I've ben reading some other forums on ac noise. It seems its luck of the draw. Some have rv's large enough to have two ac units and one will be very quiet and the other overly noisy.
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Joseph,
I have a Coleman Mach ducted unit in a 2008 Melbourne 29D and it is what I consider very noisy.
I will be picking up my new Phoenix Cruiser 2910T on 8/3/2105 and I think I may miss the ducted unit.
I like the way the cool air is spread throughout the unit when ducted. Not ever owning a direct flow unit, I am concerned about cooling the rear of the coach and after viewing this post the noise could also be a factor. (WH)
Anyone have thoughts on this!
John
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John,
As the O.P. of this topic I have learned a lot from the generous forum members who are will to share their opinions and knowledge.
In having an off forum conversation with CAMPMUCH last week, he made a statement that addressed both cooling and noise which is as follows: "use the front A/C at night to reduce the noise level in the rear of the coach, and the rear air when sitting in the front of the unit relaxing, eating etc..., and you always will have both for those occasions when cool is more desirable than quiet.
Makes a whole lotta sense to me.
And as Ron brought up in his previous post, I would like to hear more about the Coleman Unit previously ordered by a P.C. Owner.
Happy Motoring
Johnny
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When we first got our PC the A/C fan seemed very fast at first and then after awhile it would slow down. It was noisy when it would run fast and then quiet somewhat at the lower speed. I could never figure out why sometimes it would run fast and then slow down. After doing some research I found that this was normal operation when using a Dometic thermostat. In the setup menu for the thermostat there are 3 settings for fan speed: HIGH FAN, LOW FAN and AUTO FAN. By having the Fan Speed set to AUTO FAN and keeping the set temperature within 3º or 4º of the room temperature the fan runs on low most of the time and it is not as noisy.
According to the Dometic thermostat manual "When AUTO FAN is selected the fan speed will vary depending on the difference between the temperature set-point and the room temperature. In AUTO FAN the compressor and fan cycle On and Off with the thermostat.
When the difference is: >5º The fan operates on HIGH
When the difference is: <4º The fan operates on LOW"
I now try to keep a temperature in the RV so that it is always less than 4º. It keeps the fan running on low speed and thus a quieter operation.
Barry
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We are the culprits who had the Coleman Mach 8 unit installed at the factory. There are four varieties available: 13,500 BTU A/C, 13,500 BTU Heat Pump, 15,000 BTU A/C and 15,000 BTU Heat Pump. We chose the 15,000 BTU A/C. The standard units installed in a PC are 13,500 BTU units.
Noise is a very relative thing, obviously, and comparing the Coleman Mach 8 to a standard unit I would say that they are comparably noisy on high speed and the Coleman is quieter on low speed.
We also have wood floors which probably contributes to any noise being amplified a bit more than carpet or other materials.
Other benefits of the Coleman:
- Lowest low profile unit made
- Lightest low profile unit made
- Has the largest BTU resistance heater of any RV air conditioner
- Built in Kansas
These units are built by Airxcel and bear the Coleman name.
The chart on their website shows interesting info like fan speeds, amperage and such for comparison:
http://www.rvcomfort.com/rvp/products/rooftop/mach8.php
- Mike
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Oh.....and I'm not sure if the standard PC A/C units have any way to adjust the direction of airflow, but the Coleman has adjustable fins on the forward and rear ends which allow for directing the air a bit.
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Mike,
Yes, the standard PC AC has the front and rear fins that can be adjusted left/right and up/down. The fins are separated in half on both the front and rear so you can adjust the left/right sides of the coach separately. Or you can close off a section if you so desire.
Sue
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I wonder if it is possible to reduce the Dometic roof a/c noise by placing a breathable sound deadening blanket covering the large louvered intake at the bottom of the unit. It would likely do next to nothing for noise and restrict air flow a bit, but experimentation is always intriguing.
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PC should thicken the roof and duct the AC, would be much nicer MH. We can't hear the TV at 100 volume when AC running.
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PC should thicken the roof and duct the AC, would be much nicer MH. We can't hear the TV at 100 volume when AC running.
If Phoenix had a ducted a/c unit, we would not be owners of a PC because the over-all height would exceed our garage door opening. But we are the rare few impacted with the extra height. I would think that ducted a/c would be quiet by comparison.
We have the 5 speaker +subwoofer sound system which plays over the a/c noise, but it's not comfortable. Running the a/c at the lower setting helps a lot for watching TV.
An alternative is to run the Ford engine for dash a/c. That works quite well with our 2350. Run both a/c systems for a fast cool-down, then go with the low roof alone thereafter.
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Randall, that is exactly the way our is and with the surrounds sound you have to turn it up so far the entire camp ground hears it. There has to be an alternative to this, just need to find it.
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Randall, that is exactly the way our is and with the surrounds sound you have to turn it up so far the entire camp ground hears it. There has to be an alternative to this, just need to find it.
For the most part...it's strictly an airflow issue. X amount of air flowing through Y sized air plenum. There's friction between the air and the plenum and the outlets.
I have had 2 motorhome from 2 different manufacturers that were ducted....still had airflow noise. Just as much as the PC when it runs on high fan. The big difference on those motorhomes is the theromostat allowed either high or low fan speed with auto fan. I kept them on low speed and the fan only came on when needed.
The newer Dometic units allow only always on high, always on low or Auto where the unit decides if high or low but does turn off.
Until Dometic gives us the option of AutoHi, AutoLo, AlwaysHi and AlwaysLow...we're stuck.
But in any event...air conditioners in "small rooms" will always be somewhat noisy.
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Somewhat noisy is a long way from the difference I experienced from one unit to ours. I wish I had looked into the brand. I'd estimate it was at least 30% quieter than mine if not more. Of course it could be mine is just louder than most.
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Don
Thanks for a simple and accurate explanation of the A/C noise issue. There is a work around for the Dometic thermostat AUTOFAN issue. In AUTOFAN mode the fan will cycle on and off and when it is on it will remain on low speed if the set temperature is within 4º of the room temperature.
Barry
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PC should thicken the roof and duct the AC, would be much nicer MH. We can't hear the TV at 100 volume when AC running.
We oped out of an AC as we do mostly Dry Camping anyway. (Two Fantastic fans in coach, usually does it for us!) But wonder if AC was mounted over Bedroom vent area, if that would still provide proper cooling with lower DB noise level at the front of the coach to make it acceptable?
Denny and Barb
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We have the dual air in our 3100, we run the rear air most the time in less it over 90 degrees. Noise is a lot less and watching TV is not bad. Most the time if we run the front, it's on air at low speed.
Jim