Big Buddy heater hookup and derate propane furnace

Topic: Big Buddy heater hookup and derate propane furnace (Read 1065 times) previous topic - next topic

Big Buddy heater hookup and derate propane furnace

November 14, 2016, 06:07:15 pm

It's getting cooler at night, and I'm staying in the RV for a bit and don't want to freeze. A friend let me park in his yard and I am plugged into a 15amp outlet on his porch. It works great, since I don't need A/C. And, it's enough power to run an electric oil filled radiator to keep the bedroom warm when I sleep, but that won't warm the rest of the RV (windshields are not very well insulated).

The furnace works well, but it's like an incinerator when it is on, and kind of noisy. Also, it uses a fair amount of DC juice to run (fan motor, gas valve (1amp), relay (1amp).....it adds up when boondocking.

Also, the furnaces are only about 80% efficient. And, since I have a 34', I only have one 40,000 BTU/hr furnace. It does a great job of heating the bathroom and bedroom, but up front stays a little cooler.

Combine all these factors, and I have been planning to rig a hookup to my stove propane line to hook up a radiant propane heater (in this case, Mr Heater Big Buddy). The big buddy doesn't need any electricity. It does have a little computer fan on it, and I've rigged up a USB plug on it so I can run it off 5v USB chargers. Anyway, parts are coming, but Mr Heater makes a 3/8 flare hose that hooks right up to the quick connect on the buddy heater. If you aren't family with them, the radiant buddy heaters are amazing.

Since they don't vent outside, they are 100% efficient. Just have to watch the moister added due to combustion.

The line is 3/8 flare to the stove. I'm putting in a TEE and then a gas shutoff valve which will be connected to a 60inch Gas appliance stainless line that will route behind the drawers to the floor and then I will connect it to the 3/8 flare connection on the buddy 12 foot hose. There is an air return to the furnace that I can stick the hose out of. In the summer, I will tuck it all back in the cabinet (there is lots of empty space, just have to pull a drawer out to get back there).

This will help get warm air up to the front of the RV when I watch MacGyver on my rarely used TV.

Another task that must be done is replacing the blower motor on my furnace. The bearings are shot. The furnace is actually too powerful. I did some digging, and from what I can tell, the same frame furnace came in 40,000 and 35,000 BTU/hr. The only difference is the orifice size and I think the exhaust (I need to look at parts list closer). So, when I replace the motor, I'm going to attempt to make my furnace 35,000. With the same airflow, this should lower the outlet temp of the vents too. I don't think I can go lower without major mods (airflow reduction).

Another idea, that didn't work out, was to see if I could convert the furnace to a 2stage unite. Atwood makes a 2stage unit that uses most of the same parts as my hydroflame 8900-III. But closer examination showed it wasn't practical due to many different parts. The 2stage has another computer board, requires a digital thermostat that uses some sort of multiplexing (it doesn't have traditional discreet inputs like most thermostats).

Future mod: run a wire from the front A/C to the rear A/C so the furnace "call-for-heat" can be controlled by the rear A/C unit, which then would allow rear temperature sensor to be used.

Another note: Empire has made in USA blue flame and radiant heaters that have built in thermostats (a drawback of buddy heater) Vent-Free Room Heaters - Empire Heating Systems Lastly, the funace in the side of the RV make a big hole that cold air can come in. I'm in the mid-South, so nothing too cold here, but I wouldn't want to be in Wyoming! The aqua-hot would help up there.

Re: Big Buddy heater hookup and derate propane furnace

Reply #1 – November 14, 2016, 06:20:46 pm

I would worry about the CO problem with the non vented heater. As far as the windshield not being a great insulator, we got a roll of 4' aluminum coated bubble wrap at Lowes and made a couple of windshield insulators. They work great, and reflect sunlight when you don't want the heat gain!
Len

Re: Big Buddy heater hookup and derate propane furnace

Reply #2 – November 14, 2016, 06:24:41 pm

We use a small electric space heater and set it up front on the "hump" between the seats. I rigged an old computer fan that runs off 120V and have it mounted up near the ceiling and turned so it blows air towards our bedroom in the coach. Amazing how circulating the air and not letting it stratify makes such a difference.

Re: Big Buddy heater hookup and derate propane furnace

Reply #3 – November 14, 2016, 06:39:48 pm

We were using a big buddy this weekend. We have a way to tap directly off the propane tank and run the hose through the kitchen window.I had the heater sitting under the microwave. Used a small electric heater at night with the bathroom door closed. That kept the bedroom warm. In the morning we fired up the big buddy which warmed up the living area pretty quickly. No problem keeping it at 70 with the heater on its low setting. Also used a small fan to circulate which worked well. We kept the kitchen window cracked and the vent by the passenger seat. Outside temps were in the 40's.

Re: Big Buddy heater hookup and derate propane furnace

Reply #4 – November 14, 2016, 06:44:11 pm

The Buddy heaters are rated/approved to use indoors and will automatically shut down if low O2 occurs. There is a CO detector in my RV as well. The risk of CO from a furnace is just as great (due to failure of components), if not greater than a buddy heater.

It is 100% efficient because all the fuel is converted into usable heat inside the space.

The RV is hardly air tight, which lowers risks even more.

Amp draw of furnace was mentioned for true boondocking....with no 15amp service.

The purpose of this thread is to share what I did with others that may be interested in it. We all have input, and we make our own choices---I made the choice that I agree with the designers and testing organizations that rate these vent-less heaters safe to use in living spaces.

Re: Big Buddy heater hookup and derate propane furnace

Reply #5 – November 14, 2016, 09:51:53 pm

We use the propane fueled Buddy heaters in our ice fishing shanties.
For those who don't know, we don't fish for ice. We drill holes in the ice and fish for fish.
Ice is the stuff you southerners put in your drinks. Up here we have so much of it in the winter we can drive our cars & trucks on it.

Re: Big Buddy heater hookup and derate propane furnace

Reply #6 – November 14, 2016, 10:18:52 pm

Coach too or is that farther north?😁

Re: Big Buddy heater hookup and derate propane furnace

Reply #7 – November 14, 2016, 10:58:59 pm

We have a permanently plumbed in blue flame ventless heater in our coach. That's the only heater we use. We don't go north in the winter so it works out well for us.

Roland

Re: Big Buddy heater hookup and derate propane furnace

Reply #8 – November 15, 2016, 12:38:45 am

Moisture is a byproduct of the combustion process and should not be underestimated. It can ruin your coach as the vapor pressure builds inside and starts to condensate in places you can't see causing expensive damage. It may also contain sulfur and form a very mild sulfuric acid when it condenses. If you have to run an exhaust fan to prevent this moisture build up you are chasing your own tail for 10-15% perceived savings as the gas radiant heaters ARE not 100% efficient. Maybe get an electric blanket and let the coach chill out until you fire the propane furnace

Re: Big Buddy heater hookup and derate propane furnace

Reply #9 – November 15, 2016, 09:42:49 am

I have converted almost all our interior lights to LEDs, and both TVs are LED TVs. So our electrical consumption is way down.
So when hooked up to an electrical supply pedestal where our electric is paid for independent of our RV fee, we are a bit ahead of the "game" because of all the LED usage.
When hooked up where the electric is included in our RV fee we are still conservative when it comes to usage. If we know we might end up in cold weather we just include our 10 degree rated sleeping bag in our bedding supply. Easy to throw on the bed. Easy to take off, and zero electrical consumption---environmentally friendly!!
We don't even take the Big Buddy heater along when we go anywhere, simply because of space (both storage & our narrow coach width), the humidity buildup in such a small area at nite, unless a window or windows are left open, which defeats the purpose of the heater.
The humidity increase from two adults & one cat is enough to cause all the windows to sweat if it is cold enough outside.

Re: Big Buddy heater hookup and derate propane furnace

Reply #10 – November 15, 2016, 10:27:06 am

For those that are curious, I did a little more research into furnace parts for different BTU/hr outputs.

It appears they all use the same fan wheel on the combustion air side. The smaller model units have a slightly different burner ($15), smaller orifice, and ht 8500 series uses a different inside blower squirrel cage, but all 8500 use the same. However, the motors change as they get smaller within the 8500 model line. The smaller motor appears to have the same shaft, it's just the body is shorter (less magic magnetism). So my educated guess is the smaller motor makes less shaft HP and through affinity laws, the fan spins slower, and also smaller motor draws fewer amps.

The 2stage furnace uses all the same stuff as the single stage, it just has a different motor, a different gas valve (2 for hi + 1 for low) and two control boards. Atwood has a patent on it and it had some info saying it just gives lower voltage (about 1/2) to the motor to run on low. Looks like PWM from the board arrangement. And as far as I can tell, the thermostat controls the whole thing through one wire but sends differing voltage signals for fan hi/low and heat hi/low (maybe 2, 5, 7, 10 volts...or maybe some frequency signal, but I'm not an electronics guy). Motor looks similar, but it's probably slightly different to run continuously at 6 volts.

Dual pane windows ease condensation issues, but there always will be some potential, but this occurs even with no extra inside heating (I get it on the windshield in the South...up north is much drier in the winter). Several folks on here mentioned they use gas space heaters in their RV with no issues. Main reason for use is localized heating, quiet, and no electricity consumption....much like the reasons I love the propane fridge.

Re: Big Buddy heater hookup and derate propane furnace

Reply #11 – November 15, 2016, 01:40:24 pm

We use a DeLongi oil filled electric radiator, No flames to worry about with convection heating. Last moth we were up at 9400' with overnights in the low 20's and ran the heater on medium of the 3 choices during the night and had to get up to turn it down a bit. The DeLongi works really well for warming coffee cups and butts

Re: Big Buddy heater hookup and derate propane furnace

Reply #12 – November 15, 2016, 01:46:58 pm

My oil filled radiator works great to keep me warm in the bedroom too.................when I'm hooked up to a power pedestal.

Re: Big Buddy heater hookup and derate propane furnace

Reply #13 – November 15, 2016, 01:52:21 pm

Quote from: Olde English – November 15, 2016, 01:40:24 pm

We use a DeLongi oil filled electric radiator.

We have two them, stern & bow. We're going up to Taos NM ( almost 7k) for a sad funeral next week, and without them, we'd not go, since the loud furnaces make it impossible (for us) to sleep.

Re: Big Buddy heater hookup and derate propane furnace

Reply #14 – November 15, 2016, 06:00:40 pm

We do not have double pane windows. Yes in some areas and under certain conditions we have moisture on our windows which we wipe off. Shucks we get moisture build up at times without running the heater. The majority of the time our blue flame heater poses no moisture issues. As far as air circulation from outside, I don't know about all your coaches but ours is about as tight as a leaking water bucket. So no problem there either. Had the same setup in our fifth wheel and ift wasn't any tighter than our coach. Fresh air is not an issue.

Roland

Re: Big Buddy heater hookup and derate propane furnace

Reply #15 – November 15, 2016, 06:57:46 pm

Got my buddy heater hooked up. It's nice to be able to move it and aim the heat right at my feet!

Re: Big Buddy heater hookup and derate propane furnace

Reply #16 – November 15, 2016, 07:52:08 pm

Add to your project list a CO detector or two for your bedroom walls. Much better to wake up to an alarm, than not waking up.

Re: Big Buddy heater hookup and derate propane furnace

Reply #17 – November 16, 2016, 08:05:02 am

I said it before, and I will say it again. Get another fire extinguisher and mount it alongside your bed. If a fire starts, for whatever reason, you might be able to put it out while it is small. Or at least knock the flames down so you can get out. It gets more difficult to exit via a window the older we get. In fact, injuries may happen just from the "drop" to the ground from the window.
Many years ago we had a house fire and I learned the value of having a fire extinguisher by the bed, not on the other side of the fire. Unfortunately this knowledge was after the fact. The DW and I made it a point of buying a fire extinguisher for each member of our family and close relatives, for Christmas. AND, we insisted they put it alongside their beds.
It made sense because we, my parents, two uncles, and my grandparents heated their homes with wood. (they lived "up nort dere hey")

Re: Big Buddy heater hookup and derate propane furnace

Reply #18 – November 21, 2016, 06:24:04 pm

All the parts came in and I complete the install. The flex line ended up being a tiny bit too short, so I'm going to add another one and secure it to the wooden framing. I broke one slat in the return vent grill and fed the hose through it. It all works like a charm.

I have other plans for the furnace once I get back home and can take it apart (and don't need to use it).

Pics below. The buddy heater works great. It doesn't have a thermostat, but on low it only is 4,000 BTU/HR. It would be possible for a tinkerer to rig up a solenoid gas valve like one furnace/waterheater/fridge and connect it to a thermostat.

Re: Big Buddy heater hookup and derate propane furnace

Reply #19 – November 22, 2016, 07:00:41 pm

Update: Big buddy works great! And on low at 4,000 btu/hr that theoretically about 24 hours per gallon of propane.

Update2: I'm going to move forward with converting my furnace to 2stage. I already ordered the 2stage valve assembly off ebay. I need to replace my blower motor anyway, so I'm going to order the 2 stage unit (it's actually cheaper than the single stage). Other than that, all the other parts are nearly identical. Will report if it works or I fail miserably!

edit: some more nerd info. the Sit 630 is the thermostat that empire heaters uses. They aren't that expensive, in any tinkerers have any ideas: Thermostatic controls

Re: Big Buddy heater hookup and derate propane furnace

Reply #20 – November 23, 2016, 08:18:48 pm

For those wanting a radiant heater with thermostat, here ya go! This is best prices I found so far (and free shipping). The Empire brand is assembled in USA (parts from all over...valves seem to be Italian, etc). The Hearthrite brand is assembled overseas, but appears to use many of the same parts as Empire. Both have part numbers in the manual, but Empire seems to be easier to get.

EDIT: This place looks even lower prices HearthRite Vent Free Gas heaters @ Thermalinc.com

Empire Radiant Vent Free Room Heaters

Empire also makes Blue Flame heaters, that are more convective instead of radiant. I feel this is pointless in the RV as it will just heat the air that rises up to the ceiling and my feet will still be cold.

One thing to note, is the thermostat radiant units are either on/off and don't allow varying the number of plaques burning (blue flames vary the output, within range...then shut off). However, looking at the manual, it would be easy to disconnect a plauge and cap the line going to it, if desired.

I will probably be ordering one of these for the house or RV and report back my test. It likely would replace the big buddy heater in the RV

Re: Big Buddy heater hookup and derate propane furnace

Reply #21 – November 24, 2016, 08:16:49 am

One thing about Big Buddy`s, at least on mine. You can't use it going down the road. Every little bump it shuts itself off. Apparently a super sensitive tip over switch.

Re: Big Buddy heater hookup and derate propane furnace

Reply #22 – November 27, 2016, 10:13:14 pm

Quote from: nitehawk – November 16, 2016, 08:05:02 am

I said it before, and I will say it again. Get another fire extinguisher and mount it alongside your bed. If a fire starts, for whatever reason, you might be able to put it out while it is small.

This is a great idea. I went and bought an extra extinguisher after your post! In fact, you saying this was a "NO SH*T" moment for me and I am going to go on a extinguisher buying spree for all the bedrooms for my brother's house, my house, etc. Thank you

Re: Big Buddy heater hookup and derate propane furnace

Reply #23 – November 28, 2016, 12:35:49 am

Nitehawk, I too have a large one hanging on the wall of bedroom below the tv at foot of bed. I have another in living room area and should get 1 or 2 for the engine compt.
JohnH

Re: Big Buddy heater hookup and derate propane furnace

Reply #24 – November 28, 2016, 08:42:27 am

Thanks, guys.
There is an old saying that fits: "Better safe than sorry!"
If asking folks to get a fire extinguisher saves one life it is worth all the time we put in reminding folks to get one and where to put it.
One more note: Keep in mind that there are "general application" extinguishers and there are "specific application" extinguishers. Buy the one for the application you think you may need it for. Engine fires are different from house fires.

Affiliate Notice