Hey Russ How you doing?

[mskobier]

Russ,
The manual that came with the furnace does not have a template, it does however give the dimensions of the hole. The hole is a rectangle
4-7/8" x 2-1/2" and it is measured from the top of the furnace down and
1-3/4" from the left side.
The furnace you ordered has more options on how to get the warm air into the CT. You stated in one of your posts you purchased the 18,000 BTU unit. The one I purchased can only be front discharged. The one you ordered can be front or side discharge. There is also a difference in the current draw between the two units. The 12000 BTU (8012-II) I purchased draws 1.8 amps. The 18,000 BTU (7920-II) you purchased draws 3.4 amps.
The battey I am going to be using is rated for 160 amp/hrs. The 50% discharge would be approx 80 amps of useable current. You can discharge the battery to much lower than that, but it tends to shorten the battery life. So my unit drawing 1.8 amps could run a total of 44 hrs. Divide that amount by the expected run time of 30 minutes per hour, and that would give me a an estimated operating time of 88 hrs or 3.6 days. Now this assumes there are no other items (lights, pump, fan etc) being run off of the battery. In your case, the time will be about half that. Assuming the same battery of 160 amp/hr rating and a 50% discharge, and same operating time per hour, you could run the heater off the battery for 47 hrs or about 2 days.
Your propane useage will also be higher due to the larger BTU rating. On these units, the BTU rating is the input rating of the furnace. In other words it is the amount of propane it will burn each hr for a given amount of heat output. The amount of heat put into the CT will be somewhat less. According to the manual that came with the unit (and downloadable from the net), the input to my heater is 12,000 BTU with the heat output of 9120 BTU. The one you have is rated at 18000 BTU with a heat output of 13,680 BTU. It should do a fine job of keeping you warm! A 20lb bottle (approx 4 gallons) of propane should last you about 2 days at the the 30 minute per hour run time. Now turning the thermostat down during the day when you are at work will extend the propane supply considerably. All of these run times are assuming that you maintain the heat at a constant level. Reducing the thermostat setting will exend all of these numbers. In my case, the 12,000 btu furnace will use up a bottle of propane in about 2.5 days. Remember, the furnace starts the blower for a couple of minutes before it allows gas to flow and be lit by the electronic ignition, then runs for couple of minutes to cool down after the flame is shut off. Again, these are worst case numbers. longer or more frequent run times will all significantly effect the propane/battery useage. So with all of that said, the battery and one bottle of propane should last about the same amount of time. In your case and heating habits, you should see similar operating time on a bottle of propane that you currently get. At least you will not have to get up in the middle of the night to light the blue flame anymore.
Insulating your CT espically the ceiling will make a significant difference in the performance of your new heater. Even if you aquired some of that aluminum coated bubble wrap and taped/stapled a couple of layers up on the ceiling would make a big difference. Maybe not too pretty, but better than nothing.

Mitch

[southpennrailroad]

I think I can keep the same days as I have now (7-9) as there are times that I just leave it on and get totally over heated because I am to lazy and busy writing or on this blog to get up and shut it off. Like NOW! I always say to myself Self! I wish I had a shut off switch right next to my bed so I could shut the heat off. Then say to myself once more Self! I wish I had a turn on switch next to my bed so that I would not have to get up and turn the heat back on. I seem to think I might even get to 10 days.

I have two separate batteries. I will have the furnace on its own battery as I have it in storage now but will retrieve it once I get the furnace hooked up. Well it didn't come today.

Did you install it yet?

[jjjonz]

Keep warm Russ and Merry Christmas.

God Bless

[mskobier]

Russ,
No, I have not installed it yet. It will be after the holidays before I can get back to work on the CT. I have installed other RV furnaces in the past. It is not hard at all. On these, it's just a matter of deciding where you want it, measuring and cutting the hole for the intake/exhaust, putting the furnace in place, screwing it down, cutting the intake and exhaust to the appropriate length and inserting through the wall from the outside, and hooking up the propane line and electrical connections. It really is pretty easy. Now, just so you will be forewarned, when you first fire it up, it will smoke a little and stink as the oils are being burnt off of the heat exchanger metal. That should only last a couple of cycles. After that, just hot air.

I did hook mine up temporarly to test it. Thats how I know about the smell. It worked great. I measured the output temp of the air, and it went up to 150 degrees F. The ambient air temp was 65 degrees F.

You will definately enjoy just setting the thermostat and letting the furnace keep it nice and comfy.

You also will not have to keep the ceiling vent open anymore. Since the intake and exhaust air for the furnace is from the outside, there will not be any exhaust gases or condensation from the furnace on the inside of your CT. You may want to leave it open just a little bit for some extra fresh air, but if your CT is assembled anything like mine, there is plenty of air leakage from numerous openings. I know in mine, the bottom of the wall cavities are open to the underside of the trailer except where the wheel wells are. I plan on sliding the foam boards down as far as I can below the floor to reduce those air paths

Have you decided where you are going to mount the thermostat? It is highly recommended not to mount it on an exterior wall. If you have to mount it on an exterior wall, then you should build a standoff and place at least a couple of inches of insulation between the thermostat and exterior wall so that the cold of the trailer wall doesn't cause the heater to come on when it iis not needed and stay on longer than it should. When I finish building the counter/cabinets in the front of my CT, I plan on mounting my thermostat on the outside of the wall seperating the refrigerator compartment from the open counter area. This placement places the thermostat about 2ft from any exterior wall and about 3ft above the furnace. That way, the hot air has to make a circuit from the front along the floor to the rear then up the rear wall and back to the front. That should keep the temp faitly stable throughout the entire enterior.

If you have any questions about your installation, please do not hesitate to ask. I will do the best I can to help.

Mitch

[southpennrailroad]

Yep

I plan on having the thermostat just above my bed. as to shut it down very low at night. I sleep for only about six hours at a time so the temps will most likely not freeze inside. I have monitored my temps inside through the night and when I wake in the morning it never is below 35.

I have a white plastic over the toilet cabinet box I removed from my house B4 I moved out and installed it on the wall just near my head. The side is just above my bed and that is where I plan on mounting the thermostat less the 1/2 an arms reach and 8 inches away from the wall. Just above the wheel fenders inside wall. I already know the walls are cold so I planned to keep it in the air space and not on the wall.

Last night I went to bed about 11:00 and just got up at 4:45 and never shut the blue flame down. Woke up heated up. Vent is open at 1/4 on the ceiling. Temps 75 inside 30 outside.

I just checked the temps for next week. Wednesday and Thursday it is suppose to be sunny and 29 Wed and 30 on Thursday so maybe that is when I will install the furnace. During the period B4 that would be a good time to build the cabinet.

I was just going to have it on the floor and a wood board above it to be the first shelf. Then have the sides go almost near the ceiling creating a divider between the toilet space and the kitchen. Putting shelves to hold items I can't get at but want that now I have on the floor cabinet beneath the bed. That is just the first place I was thinking of putting it. The other just beneath the bed at the door entrance so the air would blow into the trailer away from the door so most of the heat would stay inside the trailer if the door was opened even for a minute. I think that is truly the space I want to install it. Also to have the heat race across the floor beneath the bed to warm the area back to the battery section in the back of the trailer.

I was just thinking this is one of those decisions I have to choose from. I love days like that where I could go out and winter photographing the abandoned railroad so do I stay and do the furnace. I do have a basement as a temp work shop to build the box inside

[mikeschn]

Hey Russ,

Here's some more pictures for you. This is the forced air furnace that I put into my Baja Benroy...

Mike...

[southpennrailroad]

Good morning Mike

You were searching while I was writing.

That is some real fine work. Would it be alright to have the furnace on the floor. I was going to put shelves above it for can goods and other things.

I do like the idea of a removable cabinet just incase of a break down.

[mikeschn]

Putting it on the floor is fine, as long as there are no combustible materials in front of it. BTW, that cabinet was no longer removable as soon as I run the copper tubing...

One thing to think about is how the air flows when the heater is running. I've always put it at the bed level, to get the maximum breeze through the trailer. Although in our small trailers we don't always have a choice where to put it.

One of the designs I worked on had it on the floor.



Although my current design might have it here:



Mike...

[southpennrailroad]

I just thought of a third possibility. I have my fridge squarely dead center of the front wall of the trailer and some plastic draws on the left side. I could switch the fridge to the left front corner and get rid of one of the three tier draws and place the furnace beneath the two remaining draws that would allow air flow to sweep across open floor to heat the back as well as the main standing area in the front. Heat rises as well as being forced across the floor to the back beneath the bed. It also causes the piping or furnace to be directly close to the propane supply sitting on the tongue. The only problem with that is that I will need to cut through the diamond guard as well as the alum behind it to put the gas line and exhaust in.

As for the other drawer, I could still use it and place the fridge on a wood shelf above the third remaining plastic drawer and this would also allow me to not have to bend over as much saving a foot off of the floor to reach in and get food from the fridge better.

[mikeschn]

Although it sounds good, that means you have to vent it thru the front, right? I'm not sure I'd vent something thru the front again. Too easy for the water to get in when you are towing.

Mike...

[southpennrailroad]

Although it sounds good, that means you have to vent it thru the front, right? I'm not sure I'd vent something thru the front again. Too easy for the water to get in when you are towing.

Mike...

I was wondering about that. Thanks

I see that you did that on the Ben and therefore I think I will do the side nearest the door just in front of the fender. That way it is partly in front and partly under the bed. I had access to a trailer where I was looking at how they had it from the old days and think that is the best place. A little more propane pipe needed but good in the center of the room but facing towards the dead center of the room. The way I see it it would shoot across the floor and then travel both ways under the bed as well as hit the front as the heat rises at the same time.

[S. Heisley]

Russ/Mike:

Putting cans of food, etc above a heater worries me because I don't know how hot the furnace can get. Also, heat rises. I would worry that some cans might get too warm and start to spoil or explode. I had a couple cans of tomato sauce blow once. I don't really know, though. You are the experts. I just thought I'd mention it.

[southpennrailroad]

Russ/Mike:

Putting cans of food, etc above a heater worries me because I don't know how hot the furnace can get. Also, heat rises. I would worry that some cans might get too warm and start to spoil or explode. I had a couple cans of tomato sauce blow once. I don't really know, though. You are the experts. I just thought I'd mention it.

Thanks I thought about that as well. All input taken with respect. I am leaning more and more towards putting the heater at the base of the bed just to the front of the fender and the side door. I want as much heat near the floor and then what is left I sure will rise. I am going to make a diagram of the trailer. Ah hell I will just photograph where I will place it. Be back, this will take some time.

[southpennrailroad]

Russ/Mike:

Putting cans of food, etc above a heater worries me because I don't know how hot the furnace can get. Also, heat rises. I would worry that some cans might get too warm and start to spoil or explode. I had a couple cans of tomato sauce blow once. I don't really know, though. You are the experts. I just thought I'd mention it.

Also I down loaded the PDF and it shows 0 clearance of the furnace installed inside a wood box. So I suspect that placing goods above it would not do harm. However I would not think about can good directly above the heater but maybe a second shelf above that. Also the shelves would be open to surrounding air for circulation purposes and easy to access.

[mskobier]

Russ,
Sounds like you have most of the issues figured out. One thing to caution you about, is the exhaust gas from the heater. It is well over 350 degrees F when it exits the furnace. I couldn't measure any higher with my digital therometer. It could be much higher. So you need to keep the exhaust clear of anything combustible or anyting that has the potential to restrict the exhaust.

I will be away from my computer for the next few days.

Merry Christmas to all.

Mitch