Strolling Amok

Intrepid Heat

The Mr. Heater Buddy, with filter and hose.

When I first started out on this crazy fiasco, the Mr. Heater Buddy I acquired for use in the Defiant quickly became my friend while wintering in Quartzsite, Arizona, and it still does sole duty. That’s mainly because the Defiant’s built-in furnace has a faulty overheat sensor that I’m loathe to have fixed. That’s because vented furnaces are relatively inefficient, using more propane than unvented systems, plus their tendency to burn through batteries if left on overnight. Many a new camper has discovered this in the morning, when they awaken to find that the furnace has killed not only their coach battery, but their tow vehicle’s starter battery as well, thanks to their dealer not mentioning that a battery isolator would be a good thing to install. That little adventure is due to the power draw of the furnace’s fan, which on heartier systems must be big enough to push plenty of air through an abundance of ductwork. On the Defiant, the furnace fan also replicates the aural ambiance of the deck of an aircraft carrier, and its old-school “analog” thermostat is a bit too sloppy for holding a consistent temperature.

The Mr. Heater Buddy is the middle-sized model of quasi-ceramic radiant heater, able to crank out either 4,000 or 8,000 BTUs. It can heat the Defiant’s 200-square-foot interior in a shirtsleeve manner on its high setting, down to a windy 30 degrees outside. Its low setting can generally pump interior temps at least 20-25 degrees over whatever it is outside, depending on wind or rain. Being a radiant heater, it sometimes helps to plug in a fan to get its heat distributed better throughout the long trailer. It thoroughly bakes whatever is directly in front of it, but as a warm-air device, it’s wanting. But hey, the price is right, and it’s efficient.

So naturally, when the decision of how to heat the new Four Wheel Grandby A.K.A. Intrepid came up, my first thought was to save the horrifying $600 furnace option cost and stick with my trusty Mr. Heater. After all, the pop-up truck camper may be “fully insulated” with foam sheets in the walls, floor and roof, and I did spring for the optional “arctic pack” that adds a second layer of vinyl to add a dead air space next to the outer fabric. (That was as much to slow down summer heat as winter cold.) But in the end, a conventional pop-up is really just a glorified tent when it comes to cold and heat. Heat off, the Defiant will generally settle to about 10 degrees over whatever the outside nightly low is outside. I doubt that I’ll be able to say the same for the Intrepid. There may be a few nights here and there where I’ll have to leave something rolling to avoid cold-air lung difficulties. Gonna need some heating horsepower available to break the chill.

Then I thought more closely about the Mr. Heater system as it would apply to the comparatively tiny Intrepid, and its slam-dunk aura faded a bit. Okay, it faded a lot. The issues:

• Floor-space taken up. It’s not too bad by itself, but the hose and propane tank add markedly to the issue. On the plus side, the Mr. Heater can accept little 1-pound propane bottles directly, but they don’t last more than a few hours apiece – about 3 hours on high, and 6 hours on the low setting. That becomes a cost issue, since I can fill a 20# propane tank for $13 or less, while the little 1-pounders retail at around $5 apiece. One camper I know, Richard, is pleased with his way of refilling a stockpile of the bottles from his 20# tank when he’s at his home base. On the road, he works his way through the pile. The challenge of this solution is that the bottles should be cooled before refilling, otherwise they won’t hold much propane – nothing like the original fill. Even cooled, the results are so-so. That means reserving them for really uncomfortable conditions only, or cabinets filled with refilled spares, or both. I’m not anticipating a lot of space to spare in the Intrepid, and get all pouty about the idea of piling a heap of canisters in cabinets or truck cab, or continually stepping over my 20-pound tank and hose. That’s just me. You may chafe less at the prospect.
• In use, the Mr. Heater products put out a heap of heat in one direction. In the right setup, that’s good. I don’t expect it to be so good in the Intrepid’s layout, where the only practical placement is in front of the exit door on the floor, with the tank and hose behind it, or on top of precious counter space with nothing in front of it. That directs the blast toward the dinette, which would be good, except that the radiant heat produced is mighty strong, which leads us to…
• There’s no way to throttle the heat output. Once you reach a sweaty bake, you must turn it off, only to cycle through a long siege of sweat and freeze cycles. I’ve hit this in the Defiant, and it would be intensified in the quarter-scale truck camper. Perhaps I’m just touchy, but I find this uncomfortable and annoying. The only way I’m aware of to dampen this is to find window openings just large enough to let cold air in, with the goal of watering down its output enough to let it run full time. This uses propane up to the point that its vaunted efficiency literally goes out the window.
• The Mr. Heater is advertised to run up to 7,000 feet elevation, beyond which its oxygen depletion sensor kicks in (for safety) and may prevent it from lighting. I’ve found this to be true in practice, and it’s disappointing to discover that, when it occurs on frosty mornings when the cabin temps are in the 40s. Firing up the stove to fill in the heat gap is not only ineffective in practice, but a bad idea from a carbon monoxide point of view. You need to crack windows open, pretty much canceling out any hope of getting temperatures up to any degree, so to speak. And, there goes your propane efficiency.
• This type of heater must be aggressively protected from desert dust, or it will not only fail to fire, but can’t be cleaned off effectively enough to bring it back to life. It must be replaced. If there’s one thing the great Southwest has, it’s plenty of wind and dust. Fortunately, a common shopping bag slips snugly over the model I have, and pretty much works. It’s easy to tell how much contamination the unit has suffered when you light it up, since any overnight dust on the ceramic plates glows brightly until it burns off. The trick is to keep that contamination light enough that the thing can still fire up, or you’ll wind up with a rather heavy and expensive paperweight.
• Fire hazard. The connection standard when 1-pound bottles are not used is to connect a standard hose to the supply tank, along with a “filter”. The filter is necessary to catch as much plasticizer as possible, since plasticizer will also kill the heater over time. That plasticizer comes from the rubber hose, and is what keeps it flexible without cracking and leaking. It’s actually the high gas pressure in the hose that drives out the plasticizer, sending it along to the heater. The problem here is that I’ve come across filters with sealing surfaces so bad that they can’t possibly be screwed into the heater tightly enough to not leak. The result is a 1-foot flame jetting out of the joint the instant that the heater is fired up, and reflexively shutting off the heater control of course does nothing to stop it. The excitement doesn’t stop immediately when you scramble to close the supply tank’s valve, either – assuming that you can get to it. It takes awhile for the gas in the 10-foot hose to burn off, giving you ample time to consider whatever used to be out of harm’s way at the heater’s side or above it. In such a confined and overused space, that strikes me as undesirable.

An effective approach to addressing this is to not use the crappy filter at all, which is possible to do through two avenues. The first is to ignore the stock setup and use Mr. Heater’s F273704 hose, often referred to as their “green” hose. There is no need for a filter with this hose, leaving only two smoothly-machined brass fittings to deal with. Its only drawback is that it is reputed to be less flexible in cold temperatures, something I’ve not found to be a problem for me in practice.

The second avenue for the Mr. Heater Buddy is to use their newer 12-foot F273077 or 5-foot F273076 hose, both of which include a pressure regulator at the tank end. This chops pressure in the hose to the point that plasticizer is not driven out of it, and the resulting assembly retains its flexibility. I’m assuming that these are also a workable way to connect a 4,000 BTU Little Buddy to a large propane tank.

Those using the more powerful Big Buddy should use a different hose (F271803) that is similar but connects to the unit with a “quick coupler”. The Big Buddy is equipped with twin regulators (to control the two 1-pound bottles it will accept), but the quick-coupler bypasses these, so a separate regulator is needed upstream to lower pressure in the hose.

The fire hazard issue is not ended with these, however. No less an expert than Bob Wells of Cheap RV Living suffered an on-board fire not that long ago, due to a crack in a hose, which he attributed to age and flexing. Fortunately for him, nothing combustible happened to be close to the split. He decided at that point that it would be a good policy to change out hoses every three years to prevent another such scary incident, and that’s probably a pretty good idea, especially for any hose that’s handled regularly and packed away. I’ve found that supply hoses exposed to sun will crack and leak at the 2-1/2-year mark, but most heater hoses are kept out of the sun.

In any case, I’ll remind you that mishaps can and do occur with these systems, and that it would be a good idea to avoid trapping yourself with the heater and tank. In other words, always leave yourself an exit when positioning things, as well as access to the control valve on the tank. You wouldn’t want to put the heater in the front of a van, and sit in back after having rendered your back doors inoperative with storage or a loaded rear hitch platform. That makes the Mr. Buddy somewhat of an issue in the Granby Front Dinette, since it really needs to be located at the rear door, with the tank behind. The Grandby does offer an emergency window exit forward on the passenger side, but access to the tank assumes that the door is left unlocked. With no access, the camper and truck under it, well, could enter an unhappy scenario. Using any other heater types than indoor-approved ones in such a compact space is also a bad idea, and not just in theory. I still recall reading the sad account of a man and his grandson found dead in a truck camper, asphyxiated by carbon monoxide. Whether he used the rangetop or an unsuitable heater was not mentioned. How sad is that?

So between the space, elevation, dust and safety issues inherent to the Intrepid, I decided to go with the small vented furnace they offer as an option. In my mind, it just makes too much sense for my application. It’s completely out of the way, offers zero monoxide instead of acceptably-low levels, is considered to have a very quiet and electrically efficient fan, fires up at any elevation, and segregates itself from the propane source, which is held in an outside-vented compartment on the opposite side of the camper. Rubber hose connections to the tanks are within that compartment, making deterioration and replacement a nuisance instead of a fire hazard. I do not yet know whether the lines to the heater are sections of hard pipe, but that is common practice in the industry and I’ll have a look, once I get my hands on it. The thermostat is new-age digital, also reputed to hold a tight tolerance on temperature variation. It’s all good.

The only remaining concerns with it that I have will be just how much propane it uses, which will hopefully be a non-issue with my planned one-week stays. I’m more spoiled than real hale-and-hearty campers though, and won’t be breaking out of a zero-rated sleeping bag to jump into three layers of clothing. Its two 10-pound tanks should handle it. The power draw of its small fan should be a no-brainer, mainly since I have yet to find one complaint with the factory 80-160Ah batteries that it’s built for. Most folks stick with 80Ah in much harsher weather conditions than I plan on coming across, with the factory isolator protecting the truck’s starter battery(s). I frankly don’t expect the furnace fan to make much of a dent in the 400+ amp-hours I plan on stuffing in! My “concern” is more of a power-geek issue than a practical one.

As with everything else, it’s going to be a “we’ll see” thing but, on occasion, I’ll be very surprised if the Grandby’s little furnace doesn’t become the most beloved feature it has going for it.