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08-15-2017, 11:47 AM
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#1
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Member
Join Date: Jul 2017
Posts: 47
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Shocking A/C air handling
The A/C in my Rockwood Signature Ultralight has always had problems cooling the unit to the point where I thought that the A/C was broken or defective in some way. The air coming out of the ceiling registers was never more than barely cool, and the air flow very weak. I thought I needed a second A/C unit so made a modification to the electrical system to allow the addition of a heat pump.
The A/C unit has also dripped water out of from the inside cover and I thought it was some kind of condensation (wrong). I saw a post where someone added a marine observation port to allow dumping of the cold air directly into the rig, and also saw mention of sealing the duct work to prevent leaks, so I decided to remove the cover and see what I could do to implement some of these fixes. I was also perplexed as to why the A/C was dripping while it was turned off on a foggy night.
I was shocked to see that one bolt was backed out nearly 2 inches, and all were loose - this is why water was dripping. It was probably my bad not checking the bolts, but this dripping was occurring from day one so it could have been poor assembly.
Next, I looked for ducts, but found none. I ran my hand into two slit-like spaces leading into the roof space and concluded that this must be the "ducting" to the air outlets, and was correct. Evidently there are no ducts in my ceiling - the A/C air simply dumps right into the space between the roof and the ceiling (this explains why I felt air coming out of the light fixtures when the A/C is running). Sure there is 3/8 inch styrofoam on the interior of the ceiling and another layer on the inside of the roof, but really? ... using the entire roof as the air ducting system? No wonder the air flow was weak, and temperature was barely cool.
I read another post where someone measured the temperature of their roof to be 191 degrees on a sunny day. I cannot believe that a 3/8 inch layer of styrofoam will do much of anything to keep the ceiling space from becoming really hot and storing that energy in everything in the ceiling, like the light fixtures, structural supports, etc. In effect, the A/C had to cool all structural elements down before it much of anything to cool the rig.
It looks like this A/C unit was designed for a TT because there is a large grid where air is supposed to come out. Rockwood had covered this with a sheet metal plate which deflected the cold air into the slits leading to the ceiling space (see pics). They could then punch a hole anywhere in the ceiling to tap into the "duct" because essentially the entire ceiling is one big duct (talk about a waste of energy).
Because the ceiling air outlets are essentially only eye candy with little to no function, I took off the sheet metal in the A/C cover and was amazed at the difference. A huge volume of icy cold air now comes out of the unit, and in a test yesterday I was able to get the rig down to 65 degrees before the A/C automatically shut off. I've never been able to get the rig that cold under these weather conditions. Sure, I have lost air distribution through the ceiling, but I have gained more than enough cold air to make the rig comfortable.
The take home lesson - if you are having problems with your rig cooling, take off the A/C cover and see what surprises the manufacturer has in store for you. I've learned that my rig looks beautiful on the inside, but those looks come at the expense of function.
The yellow arrow points to one of the slit-like opening into the ceiling space
This is how I discovered that there are no ducts - I fed a tape measure into the slit and worked it back toward an air outlet - no obstructions of any kind and I could move the tape in all directions.
This shows the interior A/C cover where the air was supposed to come out in the original A/C design, and you can see black foam through the grid
This is the interior of the cover - you can see the sheet metal plate which I took off. The A/C unit now blows huge quantities of icy cold air - a gigantic contrast to the barely cool air that has always come out of the unit. I was more than willing to give up poor air distribution for cold air.
__________________
PZ
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2011 Rockwood 8288SS
2012 Ram 3500 6.7L Cummins
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08-15-2017, 12:46 PM
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#2
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Senior Member
Join Date: Jun 2012
Posts: 10,907
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I see you have ceiling registers, so I'm pretty sure you have ducts in the ceiling. The ducts run the length of the foam in the ceiling. However, the builders have to cut in ducts from the AC unit to the ceiling ducts at whatever location your AC is at. Your problem may be that they didn't cut out that duct from the AC unit in the center of the ceiling out to the ducts that run the length of the ceiling. There are a lot instances where they cut this duct, but they don't cut it very well, and it becomes a major restriction for air flow from the AC unit to the ceiling registers.
In the pic below, the first pic is shot down my ceiling duct. You can see light on the right hand side from the duct over to the AC unit (I had the AC unit cover removed at the time).
In this pic, I've cut out additional foam to make the duct from the AC unit to the ceiling duct larger. You can see there's a bit more light coming in and you can see the foam I cut out laying on the bottom of the duct.
It sounds like they failed to cut the ducts from your AC unit to the ceiling ducts.
See attached sketch.
__________________
1988 Coleman Sequoia - popup (1987-2009) - outlasted 3 Dodge Grand Caravans!
2012 Roo19 - hybrid (2012-2015)
2016 Mini Lite 2503S - tt (2015 - ???)
2011 Traverse LT, 3.6L, FWD
2009 Silverado 1500 Ext Cab, 5.3L, 4x4, 3.73
2016 Silverado 2500HD Dbl Cab, 6.0L 4x4, 4.10
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08-15-2017, 02:08 PM
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#3
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Member
Join Date: Jul 2017
Posts: 47
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Thanks for the information rockfordoo! The pdf of the ducting system was particularly helpful. How tall and wide are the ducts in your pictures? I can get my tape measure 10 inches toward either side of the A/C unit. You're probably right about how they failed to cut things properly because I have such weak flow through the registers, even when I close all but one - even with all closed but one I do not get hardly much increase in flow. Also, the air intake was about half obstructed with excess foam so air intake was also being restricted on the input end.
Also, I think I might have air leaks in the system because I'm getting cool air through the light fixtures that are not in the path of the ceiling registers - a leak maybe/probably which would explain how little air flow increase I get when closing all registers except one? If this is the case, I do not see an easy fix to be able to use the ceiling registers.
__________________
PZ
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2011 Rockwood 8288SS
2012 Ram 3500 6.7L Cummins
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08-15-2017, 08:20 PM
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#4
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Senior Member
Join Date: Jun 2012
Posts: 10,907
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Quote:
Originally Posted by owgpz
Thanks for the information rockfordoo! The pdf of the ducting system was particularly helpful. How tall and wide are the ducts in your pictures? I can get my tape measure 10 inches toward either side of the A/C unit. You're probably right about how they failed to cut things properly because I have such weak flow through the registers, even when I close all but one - even with all closed but one I do not get hardly much increase in flow. Also, the air intake was about half obstructed with excess foam so air intake was also being restricted on the input end.
Also, I think I might have air leaks in the system because I'm getting cool air through the light fixtures that are not in the path of the ceiling registers - a leak maybe/probably which would explain how little air flow increase I get when closing all registers except one? If this is the case, I do not see an easy fix to be able to use the ceiling registers.
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The ducts a little wider than the round registers, so probably 6"-7" wide and maybe 1-1/2" to 2" inches high. Here's a pic with my little light switch light inside.
Here's what the light looks like, a little larger than a home light switch face plate:
Lots of folks have also reported that they don't seal off the ends of the channels (although my diagram shows them stopping). So the air goes out to who knows where. Some folks have pulled the last register in the run and inserted some foam on the downstream side and sealed it with caulking so the air can't go past the register. I've updated the diagram to show this.
__________________
1988 Coleman Sequoia - popup (1987-2009) - outlasted 3 Dodge Grand Caravans!
2012 Roo19 - hybrid (2012-2015)
2016 Mini Lite 2503S - tt (2015 - ???)
2011 Traverse LT, 3.6L, FWD
2009 Silverado 1500 Ext Cab, 5.3L, 4x4, 3.73
2016 Silverado 2500HD Dbl Cab, 6.0L 4x4, 4.10
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08-15-2017, 09:10 PM
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#5
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Member
Join Date: Jul 2017
Posts: 47
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Thanks for all the information - very helpful!
__________________
PZ
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2011 Rockwood 8288SS
2012 Ram 3500 6.7L Cummins
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08-16-2017, 02:58 PM
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#6
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Senior Member
Join Date: Jun 2015
Location: Valencia Pa
Posts: 602
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My 2012 rockwood 8288ws signature ultralight ac unit works well. It struggles when it gets into the mid 90s i can only maintain 73 or 74.
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08-16-2017, 03:52 PM
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#7
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Member
Join Date: Mar 2017
Posts: 49
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We also have the SIG UL and had the same issues with little to no cooling. We had put the aluminum window reflectors on our windows (and there are a lot of them!!), and had to use a clothespin to keep the louvers on the vents open. Still hot as H in there in summer.
We read on one of the blogs about a guy who found that the foam used to seal off the main opening into the ductwork was covering half the hole! He recommended going in and trimming it off. We did not do that since not that handy, but had thought of asking our tech to check it out.
However, before we could do that we had a mice issue: when we cut the AC on this spring, little bits of foam came spewing out! Long story short, we had ServiceMaster come out and thoroughly clean the ducts. And yes, they could see the styrofoam "ducts."
Here is where things get peculiar: this summer when we turned the AC on, it cooled great! Duh! Unsure what happened up there, whether it was the mice or ServiceMaster who fixed the problem but obviously something changed!
Also, we have the round vent style in our ceilings, and when I looked through the little louvers in the bedroom vent, there could not have been more than a 1-2" space to the top of the duct (or ceiling -- whatever is up there!) Not much room for air to flow, is it?
Hope you figure out how to fix yours without having to get the mice to help!
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08-16-2017, 04:36 PM
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#8
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Member
Join Date: Jul 2017
Posts: 47
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Just to experiment a bit, I stuffed cloth into the openings leading into the ceiling cutting off the "ducts", took off the sheet metal cover from the shroud so air would dump directly down into the unit, and called my wife to the rig to show her a "modification"
I had her stand right under the A/C and turned it on - she squealed in delight when she felt the blast of cold air coming down. After living in the rig since 2011 with barely cool weak air, she told me to leave it just the way it is. Sure, no ducts, but our fiver is only 28 feet and now the entire lower living area is cool. The bedroom has an automatic thermostat controlled Fantastic vent, so when we want to cool that area we simply dial in a temperature and the vent draws up cool air. I was relieved - a happy wife means a happy life.
I wish I would have checked this before I did a modification to bring in two 30A power sources.
__________________
PZ
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2011 Rockwood 8288SS
2012 Ram 3500 6.7L Cummins
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08-18-2017, 10:25 PM
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#9
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Senior Member
Join Date: Jul 2015
Location: Somewhere in the Ozarks...
Posts: 1,133
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We have very seldom used the AC duct system. There is so much more cold air when we use the bottom dump on both ACs that I don't even care if anything comes out of the ducts. When we did use the ducting, it just didn't seem like enough air coming out.
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2015 Forest River Rockwood Signature Series Ultra Lite 8289WS w/Diamond pkg.
2014 RAM CTD 6.7 Tradesman 4WD Auto Crew Cab Long Bed
Honda eu2200i generators
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08-30-2017, 02:53 PM
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#10
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Member
Join Date: Jul 2017
Posts: 47
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Just to spruce up the temperature control a bit more, I replaced the original analog thermostat with a residential Honeywell digital unit. It was basically plug and play once you get the wiring right - the whole project tool all of about 30 minutes.
The original Coleman Mach compared to the New digital on the right. The digital uses two AA batteries as the power source.
After removing the Coleman, these are the original six wires. The new digital does not have a hi/lo fan speed setting, so I did not use all the wires - only four, and capped off the gray and blue.
Here the wires are in place, and the rest tucked back into the wall. Red is the original 12V, yellow is the A/C, white is the furnace, and green is the high fan speed.
The finished install - works perfectly, keeps the temperature way better, and best of all, I need not futz around with those tiny micro control switches any more!
__________________
PZ
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2011 Rockwood 8288SS
2012 Ram 3500 6.7L Cummins
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08-30-2017, 04:38 PM
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#11
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Member
Join Date: Jun 2017
Location: Collinsville, Oklahoma
Posts: 81
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Just an FYI, that looks like the same thermostat I have in my shop, learned the other day if the batteries are dead it would not work.
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2017 F-150 XLT EcoBoost 3.5 Crew Cab 4x4
2018 Rockwood #8328BS
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08-30-2017, 08:02 PM
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#12
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Pickin', Campin', Mason
Join Date: Aug 2015
Location: South Western PA
Posts: 19,051
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Just wondering why you didn't install the digital version of the Coleman stat? Wire to wire swap and it would have allowed you to keep both fan speeds.
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2022 Cedar Creek 345IK 5th Wheel•Solar & Inverter•2017 Ford F-Series SCREW 4x4•Factory Puck•B&W Companion•TST Tire Monitor w/Repeater•Sinemate 3500w Gen.
F&AM Lodge 358 Somerset, PA - JAFFA Shrine - Altoona, PA
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08-31-2017, 04:42 AM
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#13
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Senior Member
Join Date: Jul 2015
Location: Somewhere in the Ozarks...
Posts: 1,133
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Quote:
Originally Posted by 5picker
Just wondering why you didn't install the digital version of the Coleman stat? Wire to wire swap and it would have allowed you to keep both fan speeds.
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I was wondering the same thing myself. Probably cheaper than the after-market one, too. Just installed mine last week. Exact replacement for the analog one in the picture.
__________________
2015 Forest River Rockwood Signature Series Ultra Lite 8289WS w/Diamond pkg.
2014 RAM CTD 6.7 Tradesman 4WD Auto Crew Cab Long Bed
Honda eu2200i generators
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08-31-2017, 05:50 AM
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#14
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Senior Member
Join Date: May 2017
Posts: 5,712
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The pic that showed the "Blocked Outlet w/blk foam" ? That's not an outlet of the original design.....that's the filter for the air "INTAKE" .
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08-31-2017, 06:09 AM
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#15
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Senior Member
Join Date: Feb 2016
Location: W-S NC
Posts: 441
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Quote:
Originally Posted by TheWolfPaq82
The pic that showed the "Blocked Outlet w/blk foam" ? That's not an outlet of the original design.....that's the filter for the air "INTAKE" .
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That's what it looks like to me as well.
If that is the case, it explains the water dripping and the lack of cooling.
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08-31-2017, 06:43 AM
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#16
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Senior Member
Join Date: Mar 2015
Location: N. Illinois
Posts: 2,371
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Ran into similar with little to no air flow in bath and bedroom. I was able to verify the clear path in the ducts using a Depstech camera(borescope) and android phone( cheap to acquire and comes in handy for blind areas). I think the biggest fault was flow characteristics of styrofoam, duct size and right angle bend runs to the AC. I have used the aluminum coated duct wrap and foil to isolate the hot from cold side of the AC, digital Coleman-Mach tstat, foam blocks in the ceiling vents, frosted skylight and circulating fans. It does a reasonable job cycling with the 13.5K Btu AC up to mid 90s. That's probably as good as I'm going to get without swapping AC units or adding one more. After that I rethink how bad I wanna camp
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2016 Flagstaff 27VRL Emerald
14K Equalizer
2020 Silverado 2500HD CC 4X4 6.6L gas 3.73
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08-31-2017, 06:44 AM
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#17
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Senior Member
Join Date: Dec 2012
Posts: 7,640
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Quote:
Originally Posted by TheWolfPaq82
The pic that showed the "Blocked Outlet w/blk foam" ? That's not an outlet of the original design.....that's the filter for the air "INTAKE" .
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I believe that is the original design for a non ducted AC unit (notice the adjustable louvers around the blocked grate). Appears the unit was modified (blocking off the output) to try and make it a ducted unit.
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08-31-2017, 07:23 AM
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#18
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Senior Member
Join Date: Dec 2015
Posts: 253
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Our a/c unit is very similar to original poster's. The blocked outlet on his is indeed the outlet. The inlet filter would be on the left side in the picture but has been removed.
Fortunately for us the outlet was not blocked by the factory and we can dump cold air into the interior by opening the slide on the grill. Otherwise the cold air is forced into the "ducts" and the interior is cooled much less.
By looking into the ducts with a light I can see that the "ducts" are merely openings in the foam insulation in the ceiling. The top of the "duct" appears to be the bottom side of the roof fiberglass.
I purchased a usb probe camera with a 15' cable last year to examine a sewer line. I will stick it into the duct work today and see what I can find out.
BTW, if interested I paid less than 20 bucks for this thing on ebay and it works with my Android cell phone mini usb. It is waterproof and has a variable LED light on the probe head. I have used it for many things after checking out the sewer line. The app that comes with it allows video and picture capture.
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N. Brevard County, Florida
2010 Lexington 255 GTS
2000 Jeep Cherokee Toad
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08-31-2017, 09:46 AM
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#19
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Member
Join Date: Jul 2017
Posts: 47
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Quote:
Originally Posted by tdst51
I was wondering the same thing myself. Probably cheaper than the after-market one, too. Just installed mine last week. Exact replacement for the analog one in the picture.
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I looked at the Coleman digital but it was a little over $69 while I paid $41 for the Honeywell. However, the biggest problem I had with the Coleman was the small display (I need glasses) and even more importantly for me was the small slider switches to change from heat to cool, fan speed, etc. My clumsy fingers would often switch it to the wrong position without my glasses. One of the nicest features of the Honeywell is that I can set the upper and lower temperature settings and it will automatically change from A/C to furnace and back - the Coleman cannot do that.
__________________
PZ
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2011 Rockwood 8288SS
2012 Ram 3500 6.7L Cummins
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08-31-2017, 09:52 AM
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#20
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Senior Member
Join Date: Dec 2015
Posts: 253
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I was wrong about the ducts. Removing the louver from the ceiling I could see that the dimpled top of the duct is foam and not the similar looking roof fiberglass. I have attached a picture taken with my probe camera. The brown surface is the ceiling under the duct. The stalagmites are glue. So my ducts are actually 3-sided cutouts in the ceiling foam.
So I assume the reason my a/c can't keep up in hot weather is because the ducts are small and rough. Fortunately we learned to open the "dump valve" and let it flow directly into the living area. It's very loud but it cools.
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N. Brevard County, Florida
2010 Lexington 255 GTS
2000 Jeep Cherokee Toad
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