Help with furnace please

[oz20x6]

Hello. We have an atwood AC-1511 system. The thermostat does not go below 60 degrees. We will be encountering 25-40 degree F weather and we don't want to burn through our propane but also don't want our coach to go below ~45 degrees. Is there a way to set it below 60? Also, in the manual it says: "the unit will heat in the heat pump mode in ambient temperatures above approx 45 degrees f. The furnace with automatically engage at ambient temperatures below approx 45 degrees." What is a heat pump, and what do we need to do to ensure the automatic 45 degrees furnace turn on? Thanks guys i really appreciate your help!

Also, we are new full-timers, been in our RV about 3 months now! 🙂

[mike_brez]

oz20x6 wrote:

usersmanual wrote:

oz20x6 wrote:

coolmom42 wrote:
At ambient temps below 45, the heat pump is very inefficient and will not keep the RV warm at all. That's why the furnace kicks on if outside temps are below 45--it's backup for the heat pump.

If you want to avoid burning propane, get some small electric space heaters to help the heat pump along.

The heat pump is not going to blow very warm air, although it will be warmer than outside air. That's the nature of a heat pump. Quite honestly you might be more comfortable with space heaters alone and leave the heat pump OFF.

I should also mention we will be boondocking in national parks. Does the heat pump only work on AC power? Also, how do we ensure the furnace kicks on automatically? Also, we don't mind dressing warmly 🙂

well does your roof AC only run on AC power? think about what we told you what a heat pump is.

No need to be condescending and rude... And we want to save propane because we don't want to run out midweek and need to go fill up or something. I work from the RV and it's a pain the move on weekdays because of the time investment.

That's what he does. A regular mister know it all.

[Ivylog]

18 gallons/week is about right...10 weeks =180 gallons and it's only October. Yes, 250 gallons which will cost you half what going and getting 15 or 25 gallons at a time will cost you.

While I usually like Doug's advice, 100lb tanks takes someone in good shape to handle and most places will not let you haul them laying down. In CA I can guarantee you you will not haul one laying down when full.

[dougrainer]

oz20x6 wrote:

Ivylog wrote:
You need to get a 250 gallon propane tank delivered. You can just turn the furnace off and let it get colder than 60.

250???? Did you mean 25? We have an 18 gallon, and it's pretty large...I can't image how big a 250 would be lol.

What I would do is get a 100 pound DOT tank and then connect it to your Motorhome tank with an "extend a stay" hose system. That 100 pound tank will hold 25 gallons. When it runs out, you operate on the Motorhome ASME tank while you get the 100 pound tank refilled. Of course, if it was ME, I would purchase 2 -100 pound tanks and just swap tanks and then get the first tank refilled at my convenience in the next few days. leave the Motorhome tank full until I really needed it. Doug

[dougrainer]

oz20x6 wrote:

dougrainer wrote:
Your model the Tstat cannot go below 60 degrees. My question is, why would you want it colder? As you have found out, you set it at 60 degrees and the Roof top Heat Pump will heat your coach to that 60 degrees or any higher setting. Atwood determined that on their Heat Pumps, the low outside temp kick off of the Heat Pump will be 45 degrees. That means once the Outside ambient temp gets below 45 degrees your inside LP furnace will come on automatically and the roof top Heat Pump will kick out. After the Outside ambient rises above the 45 degree mark, the furnace will kick out and the Heat Pump will then engage again until the outside temp drops below 45 degrees. A Heat Pump reverses the flow of coolant (410A) to HEAT instead of cool. They are not efficient below about 36 to 38 degrees outside ambient temp. It requires 120 volts to run the roof top unit in either mode. The furnace is 12 volt operated. Doug

You can disconnect the furnace from the existing Atwood tstat system and install a furnace only tstat on a wall close to the furnace that would go lower. That means your Heat Pump would have no Auto furnace backup connected to the original tstat. You would have 2 separate tstats, one for each appliance. The standard Suburban wall bi metal tstat also has a bottom setting of 50 degrees. This LCD tstat link shows an after market that goes down to 40 degrees.

https://www.zoro.com/honeywell-low-v-t-stat-nonprogrammable-th1100dv1000/i/G7493613/?gclid=CPDYoJOh9...

We only want it colder to save propane. Won't keeping it 60 degrees when it's 25-30 degrees outside use the propane up super fast? Also, I was contemplating building some sort of styrofoam insert for the fan systems (we have 2 fans) for extra insulation in the winter. Would this make much difference or would it be a waste?

OK, You have me confused. 60 degrees is pretty cold. Are you going to be IN the RV when it is 25 to 30 degrees? If you are going to be IN the RV, does that mean you are going to be bundled up in long johns and coats to just save LP? Also, what about the possibility of your Water system FREEZING in the sub 30 degree weather??????? What do you mean by fan systems? Doug

[Old-Biscuit]

oz20x6 wrote:

Old-Biscuit wrote:
Are you connected to AC power source or running on battery only


You talk about AC Fan and then also state boondocking in National Parks???????


NO you can NOT bypass T-stat to set it lower

You probably can replace t-stat but still will have a lower set point limit.

Or you using AC power or NOT???

Only AC power will be when running generator to charge batteries back up.

Air Conditioner FAN and HEAT PUMP will NOT run/operate W/O AC POWER
SO unless you run generator while boondocking you can forget heat pump

Furnace will run off DC from battery but come morning battery will need a very long recharge via generator

And based on how many gallons propane tank holds you can figure out how much propane will be used.

Furnace will cycle on/off during night keeping 60*F inside RV.
How much propane?? Depends on how leaky/drafty your RV is ---how long it has to run.
IT will use more battery then propane per night.

Space heaters will only work when you have gen running (AC Power)


ON EDIT:

I see you posted how big propane tank is-----18 gallon

That is roughly 57 hrs TOTAL burn time (20,000 furnace, 10,000 water heater etc). say 8 hrs of burn time each day that's 7 days worth.

[oz20x6]

Ivylog wrote:
You need to get a 250 gallon propane tank delivered. You can just turn the furnace off and let it get colder than 60.

250???? Did you mean 25? We have an 18 gallon, and it's pretty large...I can't image how big a 250 would be lol.

[Ivylog]

You need to get a 250 gallon propane tank delivered. You can just turn the furnace off and let it get colder than 60.

[oz20x6]

dougrainer wrote:
Your model the Tstat cannot go below 60 degrees. My question is, why would you want it colder? As you have found out, you set it at 60 degrees and the Roof top Heat Pump will heat your coach to that 60 degrees or any higher setting. Atwood determined that on their Heat Pumps, the low outside temp kick off of the Heat Pump will be 45 degrees. That means once the Outside ambient temp gets below 45 degrees your inside LP furnace will come on automatically and the roof top Heat Pump will kick out. After the Outside ambient rises above the 45 degree mark, the furnace will kick out and the Heat Pump will then engage again until the outside temp drops below 45 degrees. A Heat Pump reverses the flow of coolant (410A) to HEAT instead of cool. They are not efficient below about 36 to 38 degrees outside ambient temp. It requires 120 volts to run the roof top unit in either mode. The furnace is 12 volt operated. Doug

You can disconnect the furnace from the existing Atwood tstat system and install a furnace only tstat on a wall close to the furnace that would go lower. That means your Heat Pump would have no Auto furnace backup connected to the original tstat. You would have 2 separate tstats, one for each appliance. The standard Suburban wall bi metal tstat also has a bottom setting of 50 degrees. This LCD tstat link shows an after market that goes down to 40 degrees.

https://www.zoro.com/honeywell-low-v-t-stat-nonprogrammable-th1100dv1000/i/G7493613/?gclid=CPDYoJOh9...

We only want it colder to save propane. Won't keeping it 60 degrees when it's 25-30 degrees outside use the propane up super fast? Also, I was contemplating building some sort of styrofoam insert for the fan systems (we have 2 fans) for extra insulation in the winter. Would this make much difference or would it be a waste?

[dougrainer]

Your model the Tstat cannot go below 60 degrees. My question is, why would you want it colder? As you have found out, you set it at 60 degrees and the Roof top Heat Pump will heat your coach to that 60 degrees or any higher setting. Atwood determined that on their Heat Pumps, the low outside temp kick off of the Heat Pump will be 45 degrees. That means once the Outside ambient temp gets below 45 degrees your inside LP furnace will come on automatically and the roof top Heat Pump will kick out. After the Outside ambient rises above the 45 degree mark, the furnace will kick out and the Heat Pump will then engage again until the outside temp drops below 45 degrees. A Heat Pump reverses the flow of coolant (410A) to HEAT instead of cool. They are not efficient below about 36 to 38 degrees outside ambient temp. It requires 120 volts to run the roof top unit in either mode. The furnace is 12 volt operated. Doug

You can disconnect the furnace from the existing Atwood tstat system and install a furnace only tstat on a wall close to the furnace that would go lower. That means your Heat Pump would have no Auto furnace backup connected to the original tstat. You would have 2 separate tstats, one for each appliance. The standard Suburban wall bi metal tstat also has a bottom setting of 50 degrees. This LCD tstat link shows an after market that goes down to 40 degrees.

https://www.zoro.com/honeywell-low-v-t-stat-nonprogrammable-th1100dv1000/i/G7493613/?gclid=CPDYoJOh9...

[oz20x6]

Old-Biscuit wrote:
Are you connected to AC power source or running on battery only


You talk about AC Fan and then also state boondocking in National Parks???????


NO you can NOT bypass T-stat to set it lower

You probably can replace t-stat but still will have a lower set point limit.

Or you using AC power or NOT???

Only AC power will be when running generator to charge batteries back up.

[Old-Biscuit]

Are you connected to AC power source or running on battery only


You talk about AC Fan and then also state boondocking in National Parks???????


NO you can NOT bypass T-stat to set it lower

You probably can replace t-stat but still will have a lower set point limit.

Or you using AC power or NOT???

[oz20x6]

Ivylog wrote:
It sort of sounds like your are hooked up to shore power? Yes/No? If yes go buy a 1500W portable electric heater and use it when the heat pump will not keep up... turn the propane heater OFF. When it gets to 34 degrees outside you need to use the propane furnace to keep your water lines from freezing. Turn the electric heaters OFF. Unhook the outside water line before it freezes.
You do not need to upgrade your furnace, you need to buy a portable electric heater or two. It would help if we knew what rig you have?

I have the 2017 Forest River FR3. I found that the furnace is Suburban brand, but havent determined which model. Is it possible to override the minimum heat setting on thermostat or perhaps replace the thermostat with one that will go lower?

[Ivylog]

It sort of sounds like your are hooked up to shore power? Yes/No? If yes go buy a 1500W portable electric heater and use it when the heat pump will not keep up... turn the propane heater OFF. When it gets to 34 degrees outside you need to use the propane furnace to keep your water lines from freezing. Turn the electric heaters OFF. Unhook the outside water line before it freezes.
You do not need to upgrade your furnace, you need to buy a portable electric heater or two. It would help if we knew what rig you have?

[oz20x6]

Jim@HiTek wrote:
If you're serious, I'd recommend buying a catalytic propane heater and forgetting the heat pump altogether. Reason is that the heat pumps are setup to use 120Vac, use the AC compressor for heating by routing the hot exhaust air into the home not the cold air, aren't very efficient, etc.

Catalytic propane heaters are very efficient, use zero to very little electric (only use electric if it has a fan), and can be plumbed into the existing propane system. Disadvantage is that they pump out moisture so you need to keep a window cracked, and are relatively expensive.

Might try to find places to stay that have mobile propane refilling services. Also, there are many, many remote areas that have nearby propane companies that lease out large propane tanks by the month and can plumb them into RVs.

Here's some: ***Link Removed***

How do I figure out which kind of propane heater my furnace is? Should I consider upgrading it? Ill dig around for manuals to try to find the one for the furnace part.