AC Questions

[MontanaMike]

Does anybody know if the AC ducts in the Carbon line (357) are in a racetrack pattern like some of the other Keystone RVs? I'm having a cooling issue (single 15k AC) and I was thinking about blocking the duct work on one side of the racetrack assuming my RV is equipped as such. This would be a temporary fix until we can get around to adding the 2nd AC.

Here's a picture (stock Keystone one) showing the 2 vents in the living area. Im guessing that the the 2 vents shown are on each side of the racktrack since the one in the bathroom is directly in line with the left vent and the one in the loft bed is directly in line with right vent. The bathroom is the only place that cools down quite nice.

http://www.keystonerv.com/media/1736538/357carbon_4.jpg
and this one:
http://www.keystonerv.com/media/1736533/357carbon_1.jpg
here is the bedroom:
http://www.keystonerv.com/media/1778640/carbon-357-bedroom.jpg

There is one in the bathroom which is just aft and left of the bedroom and I think 2 in the bedroom. Ours is prepped for the 2nd AC in the bedroom but with just a crank up roof vent. I'm also wondering if maybe that 2nd AC prep is somehow letting all the cool air the roof vent.

It's been unusually warm up here and my wife is none too happy with our choice of RV. Our old RV was only 30 feet long and was cooled pretty well by a single 13.5k AC. Any help would be much appreciated.

[dcg9381]

When I bought the Carbon 327, I was told that it had "racetrack" ducting. For whatever that's worth.

Can you tell me what it means?

[MontanaMike]

picture is from another Keystone brand of RV:

https://lh3.googleusercontent.com/-ruAgWpg9fOg/Va_7ovAU1GI/AAAAAAAAqVs/d1y9vU2hwcQ/s800-Ic42/Capture.JPG

[skydiverchuck]

It sounds like you know what your doing but I just thought I'd ask. Did you open all the vents on the ducting and did you close the slider vents on the unit? The first time I took mine out it felt like it took forever to cool off. It's hot here, we're in the central valley of California. After I posted a similar post someone advised me to close the vents on the unit... It works better.

The other thing I did this trip was about an hour before we got to the campground I pulled over and started the generator and turned the AC on high, it wasn't cold in the unit but it was comfortable enough to be inside and cold by hour 2... YMMV

[dcg9381]

Cant imagine one AC unit cooling that thing.. Unless you're in Alaska.

I dunno if this helps, Mike, but the 327 is provisioned for a washer and dryer. If you're using the garage, you could get an AC unit from Home Depot - I think they have them to 8k BTU, exhaust it out the dryer vent...

This is what we plan to do long term for cooling the garage in hot states (and we've already got 2 AC units)

[Face Down]

There are two vents in the bedroom, IDK for sure but it seems like the 357 is set up with a race track design as it makes sense from the vent layout. I can tell you that with a 2nd AC in the bedroom it stays cooler up there than the rest of the RV. Wife keeps it as an icebox and I shiver in the heat of summer. :eek:

[1jeep]

so heres a silly question, why would they have a separate thermostat to control each ac unit if they both feed the same vents?

My 327 has 2 units, one in the bedroom and I can control the temp separately than the unit in the main cabin.
Looking at the info you guys have posted I could shut off the one in the bedroom and just run the main unit and in theory it should also cool the bedroom.

[Face Down]

so heres a silly question, why would they have a separate thermostat to control each ac unit if they both feed the same vents?

My 327 has 2 units, one in the bedroom and I can control the temp separately than the unit in the main cabin.
Looking at the info you guys have posted I could shut off the one in the bedroom and just run the main unit and in theory it should also cool the bedroom.

Good point...I am camping this weekend (it has been 3 weeks and a miss my Carbon!) and I will investigate more.

[firekat96]

We got our 357 in April and after one trip we took it back because it wasn't cooling to what I figured it would even with the 1 AC. Come to find out the dealer found a lot of holes in the ductwork and a section that had pulled loose at the return. Before having this fixed I could only get the inside temp 12 degrees cooler than outside. When we went to pick it up they had it running and it was down to 66* inside and 90* outside. Flow was much better throughout all the vents. We're still adding the 2nd ac but it does keep it tolerable now.

And for some reason the garage stats much cooler than our bedroom. We leave the sliding vents closed on the unit and just use the ducts.

We have the duel zone thermostat and we also found that the temperature reading on it is 12* off. It reads 12* hotter than a regular thermometer I have setting on top of it.

[chuckster57]

Dual zone thermostats should have a remote temp sensor. If it does then that would explain the different readings.

[Pull Toy]

Our Alpine has a dual A/C Racetrack. Both A/C units normally feed the ductwork. The dual zone thermostat only works for "2" zones when the Bedroom A/C is set to cool the bedroom only (see pic's of toggle in Bedroom ceiling faceplate). You can set different temps in the two zones. Each zone has a sensor, usually off-white, about the size of an old fashioned bottle cap somewhere in zone 1 (typically LR/Salon) and zone 2 (typically Bedroom) around 4.5' off of the floor to monitor temp's in that zone.

For general all zone cooling, if rear A/C can't keep up, set Zone 1/2 for same temp. For separate zones, set desired cooling by zone, and open vents in bedroom unit.

[firekat96]

I do have the temperature sensor in the bed room but if I don't have it on zone 2 then it shouldn't be reading that room temp. Mine is reading 12* hotter than it actually is. I asked my dealer about this when they had it repairing the ductwork and he didn't have an answer, even said he didn't know anything about my thermostat because it was a brand new style Keystone just started using. So he was no help with this.

[Face Down]

I was wrong in my previous post, the bedroom has only one roof vent not counting the two that are on the bedroom AC unit itself. All vents blow (from garage to bedroom) regardless of which AC is on and the flow is stronger with both AC's running at the same time. We keep vents closed on the units themselves with the exception on the bedroom one that is directed towards the bed. 1/2 of the round vents are to the left of the C/L on the camper and the other 1/2 are to the right...so a racetrack design seems plausible. Temp sensor in the bedroom in head height, I assume that the thermostat is the temp sensor in the other room.

Bedroom register showing where you can open close vents and that I need to Clean my filters!! ;)
https://db.tt/OfPkPiom

Temp Sensor in bedroom:
https://db.tt/ffHfVv9T

Dual Zone Thermostat:
https://db.tt/sfk9Xds9

[firekat96]

I was wrong in my previous post, the bedroom has only one roof vent not counting the two that are on the bedroom AC unit itself. All vents blow (from garage to bedroom) regardless of which AC is on and the flow is stronger with both AC's running at the same time. We keep vents closed on the units themselves with the exception on the bedroom one that is directed towards the bed. 1/2 of the round vents are to the left of the C/L on the camper and the other 1/2 are to the right...so a racetrack design seems plausible. Temp sensor in the bedroom in head height, I assume that the thermostat is the temp sensor in the other room.

Bedroom register showing where you can open close vents and that I need to Clean my filters!! ;)
https://db.tt/OfPkPiom

Temp Sensor in bedroom:
https://db.tt/ffHfVv9T

Dual Zone Thermostat:
https://db.tt/sfk9Xds9


That's the same thermostat that I have. Have you noticed if yours is not reading correctly?

[Face Down]

That's the same thermostat that I have. Have you noticed if yours is not reading correctly?

It is within a degree or so from my phone, not sure which one is more correct but it seems to be reading fairly accurate. I would see if there is a way to calibrate the thermostat, and if not ask for a replacement.

https://db.tt/fYgyLguu

[firekat96]

It is within a degree or so from my phone, not sure which one is more correct but it seems to be reading fairly accurate. I would see if there is a way to calibrate the thermostat, and if not ask for a replacement.

https://db.tt/fYgyLguu

That's a lot closer than my 12* difference.

[MontanaMike]

My thermostat (same as above) is about 2 degrees off from the cheapo I have to test the temps in the refrigerator.