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Roof Air Heat Pump Units


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#1 Guest_2driftrs_*

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Posted 15 September 2009 - 05:32 AM

Anyone out there have roof-mounted heat pumps? We're about to install two Carrier Air V units in our 10-year-old rig. It would be great if someone out there made the switch and could pass along any comments, pro or con.

Jan and Barry

#2 wolfe10

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Posted 15 September 2009 - 07:43 AM

I can't help with the heat pump part of that, but last year we switched out original Colemans for 2 Carrier low profile A/C's and are happy with the switch.

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#3 TBUTLER

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Posted 15 September 2009 - 07:50 AM

We've had heat pumps in both our rigs. We use them when the weather is moderate. Our Duo-Therms work well, putting out plenty of warm air. The one disadvantage is that the warm air is put into the rig at the roof and it tends to stay there. The floor will be the coolest part of the coach. Louise doesn't mind the cold floor if the weather and the floor aren't too cold. When it gets really cold, she wants the furnace. Using a fan on low would help circulate air and move more warm air to the floor.

Having heat pumps gives us flexibility in fuel choice. We can use the heat pumps if we are parked for a while and the propane is running low. Currently we are in my mother's driveway and we'll use the furnace if necessary to avoid running up her electric bill. In moderate weather, they should generally cost less to operate than the propane furnace depending on the rates for electric and propane. Having dual sources of heating also helps if the furnace quits working!

Using the heat pumps gives us zonal heating. We can use the front or rear or both as desired. Our ducting is connected throughout the motor home so some heat from the back comes to the front and vice versa. This allows us to do the same we do with the air conditioners. We can use the rear AC during the day and the front at night which minimizes the noise level where we are.

I think you'll be very happy with your modification. It makes your motor home more versatile. When you are full time, that is important.
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Tom and Louise Butler
2004 Monaco Windsor, Cummins 400 ISL
Roadmaster Sterling Tow Bar, Brakemaster, GMC Acadia, BikeE Recumbent Bicycles

After 9 1/2 years full time in our motor home and being Winter Texans we are now living at Sandpipers Resort in Edinburg, Texas. Now we are Summer Chickens!

"The tipi is much better to live in; always clean and warm in winter, cool in summer, easy to move... If the Great Spirit wanted men to live in one place he would have made the world stand still." -- Flying Hawk, South Dakota Oglala Sioux


#4 Guest_2driftrs_*

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Posted 15 September 2009 - 08:25 AM

Thanks, Tom, appreciate your comments. We also run the front at night and the rear during the day - - that's a great tip for anyone with dual roof air. I'm hoping the new units will work even better that way because they're both 15K btu units. Our current rear unit is a 13.5K.

Re the heat on the ceiling, we have the same problem even with the furnace, so we put a small fan (4") on the dash pointed up at the ceiling at night to move the air around. Works fairly well. I'd much rather have ceiling fans like we saw in some of the new rigs at the Greensboro, NC, show last week, but we're a tad short on head room.

For anyone considering heat pumps, remember that the roof units won't function at outdoor temps from about 40F and below. I'm not sure about the basement units.

#5 JackNichols

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Posted 15 September 2009 - 03:58 PM

My two DuoTherm heat pumps work very well down to 35 degrees - I have not had shore power below that, so had to depend on the furnace. This winter I will be in Oregon with 50 amp service, and will use the heat pumps when my new Lasko ceramic heater tower will not keep the coach warm. My idea is to use (and use up) up a $45 heating source, rather than continually run an expensive-to-replace heat pump. I also have another little cheap resistance forced air heater for emergencies. Those two stand alone heaters really use the watts, so I have them plugged into their own circuit, apart from the coach systems.

My coach has a thermostat in the water tank bay (fresh and grey and black) that turns on the furnace to heat that area when temperatures get down to 30 degrees, and I will minimize its use by providing heat tapes on the tanks and on the water and sewer hoses. And, if it gets too rough, will skirt the coach to trap warm air under it.

Or, I may chicken out and go back to Phoenix where I spent last year. ;*)

As was said on another web site, "My plans are chiseled in jello", but that is the idea at this point with 78 degrees and clear skies.
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#6 jc2566

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Posted 15 September 2009 - 05:46 PM

My two DuoTherm heat pumps work very well down to 35 degrees - I have not had shore power below that, so had to depend on the furnace. This winter I will be in Oregon with 50 amp service, and will use the heat pumps when my new Lasko ceramic heater tower will not keep the coach warm. My idea is to use (and use up) up a $45 heating source, rather than continually run an expensive-to-replace heat pump. I also have another little cheap resistance forced air heater for emergencies. Those two stand alone heaters really use the watts, so I have them plugged into their own circuit, apart from the coach systems.

My coach has a thermostat in the water tank bay (fresh and grey and black) that turns on the furnace to heat that area when temperatures get down to 30 degrees, and I will minimize its use by providing heat tapes on the tanks and on the water and sewer hoses. And, if it gets too rough, will skirt the coach to trap warm air under it.

Or, I may chicken out and go back to Phoenix where I spent last year. ;*)

As was said on another web site, "My plans are chiseled in jello", but that is the idea at this point with 78 degrees and clear skies.

Our motorhome has/had (2) Coleman Mach 3 AC-HeatPump combos that worked very well until recently. The front unit quit cooling and it was determined to have a leak in the plumbing, thus losing the freon. Since the units donot have Schrader valves for checking/refilling, you're optionsusually are to replace the unit. In light of their relative newness, I was really disappointed that Coleman(RSVP) would not not even consider going 50-50 on the repair. Just shows the lack of quality that seems to be prevalent in the RV industry today. I went to the next larger size on the replacement, 13500 to 15000, when I ordered the unit from PPL parts online and so far have been extremely satisfied in the output. If our rear unit ever goes out, I will probably replace with another 13500 instead of the larger as I believe (2) 15000 units would be overkill and possibly result in short cycling. The bottom line in this Loooonnnng response is you will not regret getting the AC/Heatpump combo. :rolleyes:
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#7 Guest_2driftrs_*

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Posted 17 September 2009 - 06:57 AM

Thanks, everyone, for your responses.

To jc2566, try a top-notch AC repair shop. They might be able to install the Schrader valves in your old unit and save you a bunch of bucks. I had this done with an old DuoTherm unit many years ago. I haven't installed my new Carrier units yet, so I'm not sure if they have the valves installed or not.

To JackNichols, here's something to think about. Your ceramic heaters draw 12.5 amps at 120 volts and put out 5,120 btu's. Your heat pump draws the same amount of power and puts out 12,000 to 13,000 btu's in the heat mode. I'd be willing to bet that in the past 20 years, Janet and I have spent more on portable electric heaters than we did for the heat pump units and never did get enough heat output to keep warm.

If we can ever sell our house and finally hit the road full time, our plan is to never stay anywhere if the temperature will go below freezing. But, like Jack said, ...plans chiseled in jell-o...

#8 PIPEWRENCHGRIP

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Posted 17 September 2009 - 09:06 PM

Anyone out there have roof-mounted heat pumps? We're about to install two Carrier Air V units in our 10-year-old rig. It would be great if someone out there made the switch and could pass along any comments, pro or con.

Jan and Barry

My new Monaco came with 2 Carrier heat pumps. They work good down to 40 degrees, then the controll system switches to Furnace Mode automatically. My only problem, we have remote control themostat and they are not at all accurate. Niether in heat or cool mode, sometimes as much as 6 or 8 degrees off. We have learned to live with it.

Bill
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#9 Guest_2driftrs_*

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Posted 18 September 2009 - 06:42 AM

Thanks, Bill. When you say it's off by 6 or 8 degrees, do you mean from the set point? Like, you set it for 70 but it stays at 76? Or do you mean a 6 or 8 degree drift, like you set it at 70 and it wanders from 66 to 74? I can deal with the set point being off, but a 6 or 8 degree drift will cause me and Carrier to have some very serious conversations.

#10 Guest_2driftrs_*

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Posted 16 December 2009 - 07:05 AM

Here's a follow-up to our last post:

We installed 2 new Carrier roof mounted heat pumps a couple of months ago. They function beautifully down to about 37 degrees F outside temp, when they shut themselves down to prevent freezing. If desired, you can hook them up to your LP furnace so they'll turn on the furnace when they shut down. We haven't had any real hot weather since we put them in, so can't really comment on AC output, but I'm sure it will be the same if not better than the old 15kbtu units we replaced.

Installation isn't that difficult if your handy with tools and electric. If not, best leave it to the pros. The biggest problem we encountered was getting these 100 pound units up on the roof to begin with. That, and having to relocate a wire bundle that was right where we had to install a mounting bolt.

These unit have a remote control, which is NOT a thermostat. It simply controls the set points of the unit, like temperature, fan speed, etc. The actual temperature sensing is done at the roof unit itself. So, the remote is like changing channels on the TV. BUT, temperature sensing at roof level can be a real problem if you have roof ducted vents that disperse the the air horizontally. Whether in heat or cool mode, the horizontal vents will direct air at the AC/HP unit itself causing excessive cycling. It also keeps the warmed air at the ceiling in the heat mode so your feet will be darn cold!

To resolve the air distribution problem, we're replacing all 12 of our AC ducted vents with new ones that allow the air to be directed from nearly horizontal in any direction to almost straight down, and anywhere in between.

As a PS, we disabled the heat pump furnace feature and installed a separate wall mounted thermostat to control the furnace. The digital furnace thermostat keeps the rig at a far more uniform temperature because it is 1 degree plus or minus from turn on to turn off.

Our recommendation - - if you need a new roof mounted AC unit, go heat pump instead of just plain AC. Cooling output is the same, heat output is 2.5 times as great as a heat strip (13,000 btu's vs. 5,100) and our Carrier units are quieter and draw less juice than the ones we replaced.

Jan and Barry

#11 BlueBounder

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Posted 08 January 2010 - 10:06 AM

With the Coleman Heat Pump, you might be able to open the "fast cool" vents on the bottom of the unit for heating.
We do this and it pushes most of the heat to the floor.
We stay quite warm ( down to 40 degrees outside).
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#12 elisowski@sbcglobal.net

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Posted 08 January 2010 - 10:40 AM

Esther and I have had heat pumps in our last 3 units and love them. The ones in our Class A automatically go to propane when the temp gets below 32 degrees which makes it nice. We save propane and it keeps the coach nice.
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#13 Guest_Wayne77590_*

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Posted 08 January 2010 - 11:46 AM

elisowski,
Welcome to a great forum. Many questions can be answered here.

I noticed that you used your email address as a user name. You may want to consider asking the administrators to change that to just the "elisowski" without the @xxxxxxx.xxx. The forum is open reading to the world. You may be getting more spam than you bargained for. (oops! Do we bargain for spam?)

Just my humble opinion.

Welcome aboard.

Happy trails.

#14 wolfe10

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Posted 08 January 2010 - 01:06 PM

I am fairly new to the RV world. I have an 08 Tuscany with 2 heat pump/AC's. I haven't been able to figure out how to turn the heat pumps on. These are Carrier units.

Thanks,
Ron

If you don't have your Carrier A/C owners manual, go to: http://www.airv.carr...ETI1977,00.html

Click on "Product Manuals" on the left side and select the manual for your unit. Note, not all Carrier A/C's are heat pumps. Some are A/C only and some are A/C with heat strips.

As a fall back position, call Carrier with your Carrier serial numbers: 1-866-GO4-AIRV (464-2478) Monday - Friday between 8 a.m. to 5 p.m. E.S.T. for immediate customer assistance.

Brett Wolfe
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#15 buddyzds

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Posted 08 January 2010 - 01:37 PM

Hey Tom,

Here's an idea. You could provide Momma with a "contribution" to pay for the electricity you use. I'll bet the electricity is cheaper than the propane.

You wrote: "Currently we are in my mother's driveway and we'll use the furnace if necessary to avoid running up her electric bill. "

I pay Momma (actually mother-in-law) $30 per month for storing a bit of gear and pay my son when I stay at this place and plug in. What am I going to do? leave it for the Federal Govt. to inherit? Ha, Ha ! I'm always looking for an excuse to give Momma a little $$$. She won't take a straight gift but does seems to be content to take the "rent" money for the items in storage in her shed.

Just a thought,

Let's Roll
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#16 Ldaly

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Posted 08 January 2010 - 05:31 PM

Remember that the 2 1/2 to 1 energy efficiency for Heat Pumps is at 70 degree's. As you get closer to the 35-40 degree mark, this will get closer to 1-1 like resistance heaters.

Also as previously stated, the warm air will tend to stratify near the ceiling and is difficult to bring down to the level where it is needed.

I have used them all through the years and ending up liking the radiant heaters along with the propane furnace. Radiant heaters heat objects and can be directed where you need it the most.
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#17 TBUTLER

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Posted 08 January 2010 - 07:04 PM

Hey Tom,

Here's an idea. You could provide Momma with a "contribution" to pay for the electricity you use. I'll bet the electricity is cheaper than the propane.

You wrote: "Currently we are in my mother's driveway and we'll use the furnace if necessary to avoid running up her electric bill. "

I pay Momma (actually mother-in-law) $30 per month for storing a bit of gear and pay my son when I stay at this place and plug in. What am I going to do? leave it for the Federal Govt. to inherit? Ha, Ha ! I'm always looking for an excuse to give Momma a little $$$. She won't take a straight gift but does seems to be content to take the "rent" money for the items in storage in her shed.

Just a thought,

Let's Roll


I've given up on paying that stubborn German woman anything!!! I love her but she is way too proud to take payment from one of her children. She has a to-do list for me every time I come so I work it out in labor of one kind or another. So I try to minimize our impact on her utility bills as best I can.
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Tom and Louise Butler
2004 Monaco Windsor, Cummins 400 ISL
Roadmaster Sterling Tow Bar, Brakemaster, GMC Acadia, BikeE Recumbent Bicycles

After 9 1/2 years full time in our motor home and being Winter Texans we are now living at Sandpipers Resort in Edinburg, Texas. Now we are Summer Chickens!

"The tipi is much better to live in; always clean and warm in winter, cool in summer, easy to move... If the Great Spirit wanted men to live in one place he would have made the world stand still." -- Flying Hawk, South Dakota Oglala Sioux


#18 wolfe10

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Posted 09 January 2010 - 09:43 AM

Well, I'm at a kinda quandary. The cover inside the coach says its a heat pump. The remote only has Furnace, Cool, Dry, Fan in the mode features. And the owners manual doesn't mention heat pump. nor does it mention heat strip. When the unit was off I pushed the "emergency heat" button and it started blowing warm air. So I guess I either don't have heat pumps or the dealer gave me the wrong remotes and manual. Go figure. :rolleyes:
Ron

My suggestion is to look in the manual for the location of the model number. Copy that down and call Carrier for the FACTS. And if a heat strip model, check to see if yours is on the recall list.

Brett Wolfe
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#19 DWChris

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Posted 12 January 2010 - 09:27 AM

We have dual heat pumps and I really like them. When you're in climates that aren't extremely cold and are looking to knock the chill off they work well. When the temp really drops however, the furnace will kick on and take care of the job of heating your coach. They will save you propane and work well above certain temps. One disadvantage is the fact that the heat pumps distribute the heated air through the coach's A/C vents (in the ceiling). Next to the floor the air will be cooler and tough for the heat pump to warm. We solved that problem with some good house shoes! :-)

This is the first coach I've had with heat pumps and I really like them. We travel mostly in the southern states so they really work well. If you're a real "cold weather" camper however, you'll find yourself utilizing the furnace most often. Our system (which I assume most would) automatically switches and if the heat pumps aren't getting the job done the furnace will kick on to suppliment the heat, so it works well and we stay warm and toasty.

Good luck.
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#20 Guest_2driftrs_*

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Posted 13 January 2010 - 02:32 PM

We replaced our roof AC vents with ones that let you control where the air goes, sideways, down, any direction. Big improvement over the strictly horizontal along the roof vents. See them at dwincorp.com




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