Basic furnace operation question

[Klc]

We are anxiously awaiting warmer weather so we can go on our first outing. We will be taking our 3 year old grandkids with us and I know the nights will be cold. I figured out how to start the furnace, but I need to know if the generator needs to be on along with the propane. I feel overwhelmed with everything we need to know. I can't find anything on the furnace in the information that was given to us. It is a suburban shd-2542 furnace. Thank you.

[Pat & Pete]

Your furnace should function nicely with 12 volt power and propane .

 

Here is a manual for your furnace :

 

http://www.bdub.net/manuals/Suburban_Service_Manual.pdf

 

I'd download it and put in a folder with other RV related info .

[Klc]

Thank you Pat & Pete. I really appreciate your quick response.

[Klc]

I forgot to mention that we will not have electric hookup. Also I cannot find anywhere in the manual above on how to operate furnace. Thanks again.

[RV_]

You turn on the propane and then set the thermostat where you want it. Click through these videos and I think you'll get it: http://www.bing.com/videos/search?q=operating+the+RV+furnace&FORM=HDRSC3

[lenp]

Keep in mind you will need GOOD fully charged batteries to run the furnace for any length of time. Plug in the trailer several days BEFORE you leave to make sure they are fully charged.

 

The fan draws 5-7 amps when it is running. If you have a single battery, don't expect to get more than 5-6 hours of furnace running on a single charge. Very important to run you generator to recharge the batteries every day IF your using the furnace and other 12 volt (lights, TV, etc.) very much.

 

You should try to keep the batteries above the 50% charge level - it is hard them to totally discharge them.

 

Have fun!!!

 

Lenp

[Al F]

How many days are you going to be camping w/o elect hookups? One night and w/o the TV on, you will be fine, assuming your batteries are good. If you are going for a week you really need to have someone check the condition of your batteries. You probably have 2 deep cycle batteries. I'm guessing from the nature of the question you have no way of knowing what the condition of your batteries are. Your motorhome is 5 going on 6 years old. If the batteries have not been cared for and maintained, they may not last the night.

[Kirk W]

If you have an Atwood furnace, the owner's manual can be found here for it. While the furnace operates on 12V-dc power and propane, it is best if you have either 120V shore power or the generator operating just to be sure that you don't loose heat during the night. You probably have two batteries and they should keep the furnace running all night if they are in good condition and are fully charged when you start the furnace, but there is good security in having another power source. While the generator and shore power are both 120V-ac you also have a converter that converts that 120V-ac into 12V-dc power to keep the batteries charged and all things operating. You have not said where you plan to go, but you will need to recharge the batteries at some point if you do depend upon them. The blower will typically stop heating but blow cold air if the battery voltage drops to about 10.5V due to battery discharging.

[Klc]

Thank you for these responses. It is just what I wanted to know. We are in Michigan and I have made reservations at the state park by our home for memorial weekend. I could not get a site with electric, as they were all taken. I believe quiet time starts at 8pm and generators are prohibited after that. I don't know what condition the battery is in. I have been plugged into our house electric for the couple weeks we've had it. It should not be freezing cold at that time,but in Michigan you just never know. If it was just us I wouldn't be too concerned but we are taking the 3 little ones and I want to make sure they are comfortable. Thanks again. I am slowly learning how our soon to be full time home works.

[Kirk W]

Be sure to check the batteries for proper electrolyte levels as that contributes to their ability to hold a charge. If they are at proper levels then you should be able to keep the furnace running all night. You could test before you go by unhooking the power and try running the furnace all night to see what happens. Of course, very cold weather could change the demand on it. If the batteries are the original ones from 2011 there is reason to doubt. Best of luck!

[Klc]

Kirk, sorry to be a pest, but this is all so new to us and I don't want to mess it up. So, I should unplug the electric from the house, wait 24 hrs, then check and see what the reading is? Plugged in it reads from 12.5 to 13.5. If the battery is good, how long should it hold a good charge not using anymore than an occasional light? Thanks so much for your help and patience.

[Kirk W]

With nothing but lights, it should power them for several weeks at a minimum. What I was thinking of was to unplug the motorhome and then turn on the furnace to a normal living temperature and allow it to operate that way over night, or a bit longer. Then check to see if it still heats, or does it just blow cold air? As the battery power is used the voltage will slowly drop, until at somewhere between 11V and 10.5V the blower runs but the propane does not light and so air but no heat.

 

When your RV is connected to shore power the reading of 12.5V seems a bit low, but where are you measuring it? The best way to get an accurate reading of what the batteries actually hold is to lift the negative cable from each one and then measure the voltage between the two battery posts. Measuring with shore power connected you are actually measuring what your converter is supplying to the batteries, and not the battery charge level.

[Ray,IN]

Kic, I highly recommend reading this very informative article to learn about your 12V battery system: http://manmrk.net/tutorials/RV/12voltSideofLifePart1.htm

[jtown]

You can get a basic battery tester for 20 bucks from Amazon or a fancy one for $50-100. A basic tester will put a 100 amp load on the battery and display the voltage. You use a chart to determine what your voltage should be based on the CCA rating of the battery. It gives a basic gist of what kind of shape your battery is in. The fancier testers give more accurate results, taking into account the type of battery you're testing. And, even if the batteries test fine, do a trial run that's longer than you'd expect to be on battery power. (Unplug the electric from the house during the testing and trial run, of course.)

 

Check the rating of your unit's 12V power converter to get an idea how long you'll have to run the generator during the day to replace the energy you used the night before.

 

As for voltage while connected to shore power, 14-14.5 volts is normal while charging and 13.5-13.8 volts when the batteries are full or near full. If you're plugged in and seeing 12.5 volts at the battery, that could indicate a problem. If you're unplugged and seeing 12.5 volts that's good but you still need to have a decent load to know if your batteries are good. That's what the battery testers do.

 

Also, there should be a "control panel" somewhere that shows you the status of the batteries, holding tank levels, generator run time, etc. When you're doing your trial run, you can keep an eye on the battery level.

 

Definitely test the batteries. When I bought my RV (used), I brought it home and plugged it in to run the fridge and test various things. Make sure it all worked. I left it plugged in to keep the batteries charged. A few weeks down the road, my power went out. "Ha, ha! I've got a 5kw generator. No roughing it for me." The coach batteries were so dead the generator starter motor didn't even click. By the time I got home with new batteries, the power was back on.

 

Bring sleeping bags (or lots of blankets) as a backup. I've slept snug as a bug in a blizzard with no heat but a good sleeping bag. I wasn't happy about it but I was comfortable. Also, you probably have high and low speeds for the fan. Low speed will use less power. If it's not particularly frigid, that's an option to extend run time.

[SWharton]

You might want to make a dry run sooner than later just to make sure all is well and you know what you are doing, without the kids. Even if it is in your driveway. To learn how your RV operates with 3 little ones is dangerous for you marital health.

[Klc]

Thank you everyone for the great advice. We are thinking seriously about taking her out for our 45th anniversary in May. Perfect 1st trip in her. Our honeymoon was in a tent at Mackinaw under the bridge. You can't do that now. Anyway, I totally agree, need a trip before taking the Triplets.