Mr Heater Buddy heater has strange pilot flame and will not stay lit

Kenword

I have an old Mr Heater Buddy heater that has date code 5102. I think that means 51st week of 2002, so roughly 23 years old. It has been used vert little and is in excellent condition. My problem began last year when I took the heater out of storage. I had not used it for several years. At that time the Pilot would not stay lit, going out immediately after releasing the control button. Since then I have cleaned the pilot assembly and thermocouple several times with cotton swabs and rubbing alcohol. Now the pilot lights and stays lit, but it is a blue flame with ragged edges and makes a faint roaring sound. When I try to run the heater on high, there seems to be not enough gas flow. There are intermittent surges of bluish flames over the combustion tile along with a puffing sound. After several puffs the tile will begin to turn orange, but soon the blue pilot flame leaves the pilot opening and disappears, then everything goes out. I have tried partially covering one of the two air vent holes in the pilot tube assembly and the pilot becomes a normal steady cone-shape. This suggests it's getting too much air causing lean combustion. I suspect the regulator, which is original, is not delivering enough gas flow and pressure. I have another regulator I used for an RV furnace. Could I use the RV regulator to run the Buddy heater for testing? The heater says it needs 11" W.C. Any help is greatly appreciated. I e-mailed Enerco, who makes Buddy heaters, over a week ago and have received no reply.

mattmia2

you need a monometer to check pressures. are you sure the tank is full?

mattmia2

be extremely careful with that because if it isn't burning right it will make far more carbon monoxide than normal

Kenword

I think my tank pressure is OK, as I've run it using a disposable tank that runs a propane torch normally and a 20 lb cylinder through an adapter hose and the results are the same. I don't have a monometer. I had one years ago when I did on-site RV service, but I left it at the dealer when I retired. I'm considering finding an adjustable regulator or using the valve on a 20 lb tank to adjust the gas flow and see what happens. I am well aware of the danger. The heater only runs for about 4 or 5 seconds before shutting down, and I've not noticed any unusual odor or other effects. I plan to work with it in an insulated garage with plenty of ventilation. I personally don't trust ANY ventlesss heater and have only used this for temporary heat in well ventilated locations.

hot_rod

I think those have some sort of oxygen depletion sensor that cuts gas when they are not burning properly.

Kenword

They do claim to have a sensor, but as far as I can tell, that's just the standing pilot. If there is too little oxygen, the pilot flame flame cools enough that the thermocouple shuts off the gas supply. These are the simplest gas appliances made. They run pretty much the same way as older residential or RV furnaces with standing pilots. The main differences are that the pilot system has a tip-over switch, is not adjustable and is so sensitive to temperature that any restriction in gas flow will cause the gas valve to shut down.

I am finding it impossible to find any meaningful service or trouble shooting advice for these other than cleaning the pilot orifice. I was hoping to find a service manual but apparently there is none, at least not one that is readily available. I guess these heaters are considered disposable and attempting to repair one is a waste of time. I found out my old RV furnace uses the same manifold pressure so I will try running the Buddy heater with the RV regulator and see what happens.

mattmia2

there isn't a lot to put in a service manual. any gas tech knows that x amount of gas flows through a hole size y at pressure z. they just need to measure and figure which if any is wrong.

then it is about combustion analysis and controlling primary and secondary air to get the right stoichiometry.

Kenword

You make a good point. What I was hoping for was a simple troubleshooting procedure along the lines of: If this does that, then pressure is Low/high and you need to replace or test this specific part. The thing is so simple, the problem can only be one of three things: gas valve, regulator, or thermocouple / pilot assembly (for some reason thermocouples are not sold separately). Parts are cheap enough it's worth it to me to replace one of them, but how do I know for sure which one? Obviously a manometer would really help, but it doesn't make sense to spend even $30 for a cheap digital one to fix a heater I can probably buy for $50. The best I can do is to swap the regulator with one I already have, then maybe take a picture of the pilot flame and submit it here for further advice. Out of curiosity, are their any low-priced digital manometers that are any good?

mattmia2

you can make a monometer with a piece of tubing and some water.

EBEBRATT-Ed

Yeah it doesn't have to be digital. Go buy a piece of clear plastic tubing about 3' long. Lay it out straight and make a mark 3" from the left hand end and mark that with a sharpie. Then put a mark every inch. form it into a U and staple it to a board with romex staples. Line up the two end marks at the end.

Kenword

Thanks guys! I'm surprised I didn't think of that! I know manometers can just be tubes full of water, and I even looked for them on Ebay. All I found were expensive ones made by Dwyer. The cheapest were all digital. 30$ really isn't bad considering the convenience. I may yet buy one. But for now all I really need are ball-park figures, and I could easily get down to about 1/4" WC. with a tube and water. I suppose I could even put a ruler along the tubing for easier reading. Does it matter what size tubing I use? Thanks for your help, and Merry Christmas to you all!

Kenword

I finally got around to running the heater with my other regulator. I had the regulator direct-connected to a 20 Lb cylinder, then through a hose to the heater. It worked perfectly. I noticed when I turned off the gas at the cylinder, the pilot flame "blew away" from the burner tube, with the tip traveling to the left before disappearing, just like it did before. Now I'm confident the problem is in the regulator, my gas supply, or the adapter hose. I will do more checking soon and let you know what happens.

mattmia2

the drawdown rate of those small tanks is pretty limited, especially in low temps too but that would start out ok then die down and go out after some period of time that might be small or large.