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How to - Ventless Heater


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There are several ventless heaters on the market that can be used in the Toyhouse. I bought a Wave 3 and a small Mr Buddy. There was a lot of discussion comparing the two heaters in the following thread:

Ventless Heater Discussion

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I added a low pressure Propane hose under the stove with its own shutoff valve. The hose is 10 ft long and has a quick disconnect on one end, it comes with a small hose that attaches to the heater and then plugs into the quick disconnect.

The Wave 3 runs on low pressure and can plug right into this hose. I ran the Wave 3 for a couple days, it works great, but its not going to be able to provide enough heat on those very cold nights. This may be OK, as I can set the furnace at about 55.

The Mr Buddy can put out up to 9000 btu but cannot use the low pressure LP plumbing in the toyhouse. It needs high pressure straight from an LP tank. I had read where people had modified their Mr Buddy, to run off low pressure by removing the internal regulator and connecting directly to the low pressure valve inside the Mr Buddy.

I still wanted to have the ability to run the Mr Buddy on the 1 lb bottles, but I also wanted to run it directly off of low pressure. So, rather than remove the internal regulator, I decided to just put a "T" in the Mr Buddy low pressure line. I could then connect the Mr Buddy low pressure line directly to the Toyhouse low pressure. OR, I could put a cap on the low pressure "T" and screw a 1 lb tank onto the regulator and use the Mr Buddy normally.

WARNING
If your not comfortable tearing into a piece of equipment and turning it into a potential bomb, then don't do this modification to the Mr Buddy.



Remove the back panel and remove the low pressure tube.The valve side of the tube can be reached with the back removed, the regulator side of the tube can be reached from the side where the bottle screws unto thee regulator.

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Mark the tube and cut a small section out where the "T" will go.

Flare the tube ends and install the "T"

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Reconnect the tube to the regulator and the valve, install the "T" with the pipe thread facing the back panel, tighten everything up.

Drill a hole in the back cover for the fitting to come through. I put two large flat washers to help secure the connection through the back panel. This will need to be done with trial and error, as the thickness of the washers could keep the pipe tread from tightening up enough to prevent leaks.

The weak point of this modification - when connecting / disconnecting fittings (hose / or plug) to the back of the Mr Buddy, its possible to wiggle (twist) the back cover fitting, and weaken the aluminum tubes that are connected to the "T". I may make a bulkhead fitting to eliminate this problem.

To mitigate this problem, I use two wrenches when connecting / disconnecting fittings on the back. One wrench to hold the fitting, and the other to tighten the hose or the cap.

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The connection out the back is a 3/8 flare and a 1/4 pipe thread. Reinstall the back cover, make sure all the screws are back in.

Install a cap on the 3/8 flare fitting.

TEST FOR LEAKS - I connected a 1 lb bottle and listened and sniffed for any major leaks. I then lite the pilot to make sure I had gas pressure in the low pressure tube. I then turned the pilot back off and used a long fireplace lighter to reach up inside the heater with the flame around the connections to check for leaks. Stick the fireplace lighter through the large openings in the bottom of the Mr Buddy to check for leaks around the "T", the valve, the regulator, and also check the back panel.

RUNNING ON 1 Lb Bottle

Make sure the 3/8 flare cap is installed securely on the back panel connector. run the heater


RUNNING ON LOW PRESSURE HOSE

Something must be connected to the regulator to prevent it from leaking . Either install an empty bottle or install a brass adapter fitting with a plug on it.

(In these photos, a Disposable Bottle Adapter with a plug on the end is screwed onto the Mr Buddy regulator)

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Remove the 3/8 flare plug from the back and connect the low pressure hose to that fitting.

Operate the heater as normal. (When lighting the Pilot, I use the fireplace lighter rather than the clicker.)

To turn the heater off, I turn off the valve for the supply hose and let the heater go out. This purges any pressure out of the low pressure line before disconnecting it.

John Mc
88 Dolphin 4 Auto

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Here's an alternate use - If my 20 lb LP tank ran out, theoretically, I could connect the low pressure hose to the back of the Mr Buddy, Screw on a 1lb tank onto the Mr Buddy, and use this to supply the Toyhouse low pressure. The 1lb disposable tank could probably run the frig for a couple days, run the stove for a while, or (why would I do this) run the furnace for a while.

If I do this, make sure to leave the 20 lb tank connected to the regulator, AND turn the tank valve OFF. This will prevent any backfeeding through the 20 lb regulator.

a 1lb disposable tank has about 1/4 gallon of LP

1 lb provides about 21,000 btu of heat.

1 gallon provides about 91,000 btu of heat.

Plan Accordingly

John Mc

88 Dolphin 4 Auto

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  • 1 year later...

I thought I read somewhere that you could buy an adapter that would enable you to use a 5 gallon propane tank with the Mr Buddy Heater? Does that adapter exist or am I imagining that I read that?

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I thought I read somewhere that you could buy an adapter that would enable you to use a 5 gallon propane tank with the Mr Buddy Heater? Does that adapter exist or am I imagining that I read that?

Yes, I've seen many hooked up directly to large propane tanks. Mr.Heater sells the adapter hose as part # F27301

I always figured the Buddy/Mr.Heaters were cheap little heaters not intended to last very long. But can't say I've used mine a whole lot. I bought one once in pinch to use in a van I was driving that had no heat.

The adapters are made to hook directly to a large tank with no regulator on the tank.

I'm wondering . . . why won't a Mr.Heater work when hooked up to the regulator on the tank? Does it require a minimum inlet pressure? If so that is sort of unusual. Just about all propane applicances have their own regulators besides the one (or two) on the tank and work fine.

With the Buddy/Mr.Heater - I can't say I ever tried. For RV use - I have the Procom heaters. I love them. Direct hookup to any propane tank that has it's own regulator and built rock solid. We've had several in our house for years. We have a few 30K BTU models and two 6K BTU models for small bathrooms. We heat when it's real cold with wood. But when it not real cold out and the wood-furnace isn't fired up yet - we use the so-called "ventless" Procom heaters. Also have a 10K BTU that I use in my RVs. None are really ventless and all require a X amount of fresh air depending on BTU output.

A two-stage propane system has # 1 regulator dropping to 10 PSI. Then # 2 regulator dropts pressure to 1/5 of a PSI (11 WC).

A one-stage propane system drops from tank pressure to 1/5 PSI (11 WC).

Most propane appliances have their own built-in regulators that also limit pressure to 1/5 PSI (11 WC).

So again - how come Mr. Buddy is different and won't work with regulated propane comng in? I never thought about it before.

Mr.Heater/Buddy adapter hoses:

http://www.northerntool.com/shop/tools/product_200362084_200362084

http://www.northerntool.com/shop/tools/product_349927_349927

I've used these two ProCom heaters in RVs. Work very well and hook directly to any RV gas that comes from the regulator on the main tank. No open flame, no electricty, and thermstat controlled.

ProCom Vent-Free Propane Ice House Heater — 10,000 BTU, 300 Sq. Ft. Heating Area

Measures: 14 1/8" x 6 3/8" x 19 1/8"

http://www.northerntool.com/shop/tools/product_200442161_200442161

ProCom Radiant Vent-Free Natural Gas Heater — 6000 BTU, Model# MN060HPA

Measures 14 1/8" x 6 3/8" x 19 1/8"

http://www.northerntool.com/shop/tools/product_200307975_200307975

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Hey thanks for the info! Do you know why the little 10,000 BTU ProCom requires a 100 gallon propane tank and the 5500 BTU ProCom requires a 20 gallon propane tank instead of regular ol 5 gallon tank?

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Hey thanks for the info! Do you know why the little 10,000 BTU ProCom requires a 100 gallon propane tank and the 5500 BTU ProCom requires a 20 gallon propane tank instead of regular ol 5 gallon tank?

None of them require any specific or minimum size of tank to run properly - that I know of. They run fine from any propane souce with at least a 1/5th pound of pressure (water column of 11). I suspect they post those sizes to avoid legal liability. I do not know of any so-called "ventless" heaters that are advertisted as being allowed to be hard-mounted into an RV. All these "ventless" heaters are called "ventless" because they do not use a hard-mounted dedicated vents. They do however still require fresh air venting. Because so many people have been using these heaters in RVs with inadequate fresh air venting, many sellers now list requirements for big tanks to avoid use in most small RVs. Not many small RVs will have 100 lb. tanks. As why one shows a minimum 100 pounder and another at 20 pounder? I don't know. Perhaps just an editing problem in playing catch-up with law-suits and lawyers. In many states, unvented heaters are allowed in houses either. Oddly, here in New York they ARE allowed.

The Mr.Buddy has no screw-mounts to fasten anywhere permanently so I guess being sold as a "portable" unit they don't worry so much about liability.

All these "ventless" heaters run up around 99% efficiency and most come with low-oxygen auto-shutdowns. Pretty safe - but I'd still never sleep in an RV with one going.

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One is intended for a fix location in a living space the other is portable. The small one has no regulator of it's own the portable one does it uses a 20# tank (BBQ) not 20 gallons. Neither one is intended to be used in a sleeping space. They do make RV heaters that are safe but they are very pricey. http://www.ventedcatheater.com/

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One is intended for a fix location in a living space the other is portable. The small one has no regulator of it's own the portable one does it uses a 20# tank (BBQ) not 20 gallons. Neither one is intended to be used in a sleeping space. They do make RV heaters that are safe but they are very pricey. http://www.ventedcatheater.com/

Both the ProCom "non vented" heaters have their own regulators built into the heaters. So when hooked to a propane tank that also has a regulator -there are two regulators in the line.

The heaters you linked to are hard-powervented heaters. Just as the conventional RV heaters are. The specs show an 1 1/2" exhaust vent for them. Maybe they're more efficient then the standard RV propane heater but the company has no efficiency specs posted that I can find.

From the ProCom manuals showing the built in regulators:

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Procomregulator_zps89f706ac.jpg

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OK bad chose of words the living space heater requires two regulators for good reasons the portable ones don't you must install a regulator at the supply tank if you are going to mount it in a living space. The same goes for an RV they have two. The vented RV heaters have a small forced draft fan and are far more efficient then the noisy open flame RV heaters that require blower fans and lots of propane. I would buy one in a heart beat if I did a lot of cold weather camping.

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The vented RV heaters have a small forced draft fan and are far more efficient then the noisy open flame RV heaters that require blower fans and lots of propane.

That is an assumption I would not make without some actual specs posted. I've yet to find any company that is selling a vented catalytic propane heater that posts the actual input BTUs and output BTUs so a buyer has an idea on how efficient it is. The conventional RV furnaces DO post all those specs. All I know of are 70-75% efficient. It's possible that the catalytic vented heaters aren't much more efficient then the standard RV furnaces when required fresh air venting is used. I can't say for sure but I do wonder why the makers of the vented catalytic units post NO specs? I assume that if they were MORE efficient they'd post the specs.

And open flame versus catalytic? ProCom lists specs with all their heaters. The open flame and the catalytic models both are rated at 99.9% burn efficiency. They DO however require fresh air venting so the actual usable heating efficiency comes down. The point is - the actual burn efficiency between the open flame and the catalytic heaters are near the same although the open-flame models tend to output slightly more CO.

So - a conventional RV furnace is 70-75% efficient overall. it's flame is probably near 99% efficient but 25% or more of the heat is sent out the vent. The hard-vented catalytic furnace you posted a link to has a "burn" efficiency of 99% - but they do not give info on how much heat is lost out the power-vent.

Again - I don't know since I've to seen any test-specs.

I'd like to find a more efficient furnace for my RVs - but so far I don't know of any. Any "non-vented" is more efficient until you open a window to let cold air in. So far, the only propane furnaces that can achieve 90% efficiency for overall heating are "condensor" furnaces and I don't know of any made for RVs.

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I have see the vented heaters in use they can not be beat use far less propane just as warm and make all most no noise and safe to be used in a sleeping space only draw back they are not cheap. Inferred heaters make a lot of sense because they do not heat the air. Most of the RV propane heaters lose huge amounts to the venting/cooling you can not put your hand in front of the exhaust. There is no other reason they need to be rated as high as they are as far as output to heat such a small space. I don't know about any one else but I can not sleep through a furnace cycle in my MH and when it's really cold they do that a lot.

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I spent the night about 50 miles south of Chicago. 17 deg outside with wind blowing 30mph.

The Mr Buddy did a good job set at 9,000 btu. I opened one of the top roof vents about 3/4 inch to provide exit, I have enough air leaks in the MH to supply air.

I set the furnace at 55, it did not come on once all nite.

The only drawback to the ventless heaters is the amount of water they put out. All the windows had frost on the inside.

John Mc

88 Dolphin 4 Auto

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John, do you think a well-sealed fiberglass Sunrader coach would only need a top vent open 3/4" or do you think it may require more venting than a motorhome like yours with conventional construction?

I spent the night about 50 miles south of Chicago. 17 deg outside with wind blowing 30mph.

The Mr Buddy did a good job set at 9,000 btu. I opened one of the top roof vents about 3/4 inch to provide exit, I have enough air leaks in the MH to supply air.

I set the furnace at 55, it did not come on once all nite.

The only drawback to the ventless heaters is the amount of water they put out. All the windows had frost on the inside.

John Mc

88 Dolphin 4 Auto

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A "unvented" propane heater needs approx. 15 cubic feet of fresh air let into the camper for every 1000 BTUs of heat made. Or . . . 1 square inch of fresh air opening per 1000 BTUs. A 9000 BTU heater would call for a 9 square inch opening at the minimum. That would be a 9" square vent opened up to an inch.

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Stevo, I'm not sure about the Sunrader being that air tight. One air leak is the trucks heater, as long as the heater is set on fresh air rather than re-circulate, also the truck has a lot of air leaks around the doors. All these seem to supply more than enough air supply. ( you can always open one of the trucks wing windows a little to supply additional make up air.

Air exhaust is also important, I use the roof vent, If the wind is blowing, I point the truck into the wind to ensure the roof vent is not blowing air in.

NOTE - The coldest I seen it on this trip was -2 ( no wind). The 9,000 btu Mr buddy kept it warm inside, but there was a lot of frost on the inside of the windows.

JOhn Mc

88 Dolphin 4 Auto

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Waiter...the way to test for gas leaks is with soap bubbles, not fire!

(but I guess you were reaching way inside the unit and couldn't see or access bubbles)

Edited by douglitas
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  • 4 weeks later...

Yah, bubble solution would be the preferred, but you can't get it up in there to test., so I did a "nose test" to see if there were any major leaks. after that, the long fireplace lighter can reach up in there to find any small leaks. Obviously you don't want to do this in an enclosed area, AND you want to be quick about it, i.e. don't turn the propane on, then dilly dally around looking for the lighter. Can you say "BOOM" real loud. :-(

JOhn Mc

88 Dolphin 4 Auto

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