Torpedo heater

[300jk]

I have a Mr. Heater 210,000 btu forced air kerosene heater that doesn't work right. This is what happens. Start the heater and at first everything is good for about five minutes. The cone is nice and cherry red and no fumes. After 5 minutes or so cone darkens and lots of bad fumes. Real bad. I am just getting it ready for the cold weather. I use it to warm up my plow tractor before I go out. So far I have replaced : all lines, filter in tank, air pump filters, ignitor, flame sensor, and nozzle. I have also taken the air pump apart and found no obstructions. Everything is pointing to low pump pressure. So I took the vane and rotor assembly out of a different heater and it there was no change. I had Mr. Heaters tech guy on the phone and he was no help. I am going to order a rotor and set of vanes tomorrow just to sure to eliminate that for sure. Is there any chance the aluminum pump housing is wore so bad that it wont make enough pressure ? Any insight is greatly appreciated. Thanks.

 

[Bob0465]

is one of the pump ports on top of the pump a place you can put a gauge? Some on oil burners say gauge on them and you remove a plug and install one. Pressure should be about 100 lbs if I remember right. There is an adjustment screw on the pump. Some oil burner pumps have replaceable screens in them. I would not think there would be much sludge in there using Kerosene.

 

[300jk]

Hey Bob. I think we are talking about two totally different heaters. The one I have is portable on two wheels. Sometimes called a salamander heater. According to the manual it should have around 10 pounds operating pressure. I am guessing you may think it is like the oil pump that fuels my boiler in the house.

 

[Duner Wi]

I would say you should put a pressure Gauge on it.
I have a old gauge from way back before Fuel injection and it works fine on my jet heater.
Most of the time it is the vanes and rotor that give me problems on one of my heaters. If I pay attention I can hear a vane sticking and my pressure drops. I think a pressure gauge is a huge help in figuring
out why it smokes.

 

[Mike(NEOhio)]

I don't know if they have the same kind of ignition now, but my dad had a Master heater when I was a kid and there was a pair of electrodes that had to be reset once in a while.

 

[Angle Iron]

I worked on one for a friend last winter that was doing much the same thing. It would work great for 10 to 15 minutes then start to sputter,flame out and smoke. After a good bit of work I discovered a mass of algae floating in the tank. I drained it and of course it was full. There is a drain plug in most of them after I had the fuel out I stuck a garden hose in the tank and let it flush for about half an hour. It was hard to believe the slime that came out of it. The heater was pretty old and had never been drained. It is recommended to drain and flush every year. Setting the air pump is very important and varies from one heater to the next. Pump kits are easy to put in and the air filters need changing as well. Do a you tube search lots of video help out there.

 

[GarryinNC]

I had a different brand, 40,000 btu, heater doing something similar. In it one end of the motor shaft drove the pump and the other end drove the fan. The motor's rotor had gotten somewhat loose on the shaft and would slip. It would start out okay and after several seconds the pressure would drop and the safety would shut it down. Found a new motor on the web. Does okay now. Had a heck of a time figuring it out. Put a pressure gauge on it, but could not figure why the pressure was dropping. Finally noticed the fan slowing down while the motor sounded like it was doing normal speed.

Garry

 

[Brad Gyde]

(quoted from post at 16:12:56 11/29/16) I have a Mr. Heater 210,000 btu forced air kerosene heater that doesn't work right. This is what happens. Start the heater and at first everything is good for about five minutes. The cone is nice and cherry red and no fumes. After 5 minutes or so cone darkens and lots of bad fumes. Real bad. I am just getting it ready for the cold weather. I use it to warm up my plow tractor before I go out. So far I have replaced : all lines, filter in tank, air pump filters, ignitor, flame sensor, and nozzle. I have also taken the air pump apart and found no obstructions. Everything is pointing to low pump pressure. So I took the vane and rotor assembly out of a different heater and it there was no change. I had Mr. Heaters tech guy on the phone and he was no help. I am going to order a rotor and set of vanes tomorrow just to sure to eliminate that for sure. Is there any chance the aluminum pump housing is wore so bad that it wont make enough pressure ? Any insight is greatly appreciated. Thanks.

You may think this is nuts, but try to put a shop towel (or piece of furnace filter, or some kind of coarse slightly restricting) over the air intake end and try that. I have one (however a different make) that had similar issues. After a ton of parts, time, and trial and error, I somehow accidentally plugged some of the intake end and it worked fine.. All I can come up with is the grille on my intake end got broken, and with the missing piece it was pulling too much air through it.. Been using it with a shop towel over 1/2 the intake end (covering the broken part of the grille) for 4-5 years now, and never another issue. Might be worth the attempt.

Brad

 

[rustyfarmall]

My experience with those heaters (any brand) is that the cost of just a few new parts can quickly add up to the price of a brand new heater, ready to go.

 

[jimg.allentown]

Actually, if I recall correctly, the working pressure is more like 4 to 5 psi. The heater operates by forcing air through a venture tube to the nozzle. Fuel is drawn up from the tank and atomized by the venturi effect. From your description of the problem, there is no obvious problem with the pressure. A gauge would prove or disprove that. In the fuel system, the most common problem I have found is that the rubber hose that goes down into the tank deteriorates and collapses shortly after the heater starts. Look that over closely and replace if it is not in perfect condition.
Next, the safety system. Your symptom resembles a problem with the photocell. The photocell senses light from the flame. This causes a change in resistance that the safety module senses. If it does not get the correct signal, it shuts off the heater by tripping the breaker. First, make sure that the photocell is in the correct position to "see" the flame, and has not worked its way out of position. Next, make sure that it is CLEAN. If it gets sooted up, it will not give the right signal, and will shut down the heater. Also note that there are TWO different photocells, and they are NOT interchangeable - even though they look alike. The safety module allows the heater to run for a few minutes when it is started up to allow for the photocell to generate a signal - actually a change in resistance.

 

[Leroy]

I have never heard of drain every year, I have 2 heaters, both Knipco 95000 BTU and they have never been drained in the about 40 years that I have had them since new. They have had nothing but kerosine in them.

 

[Bob]

Why haven't you checked the air pressure, and watched to see if it changes when the heat output drops? I really doubt that's going to be the problem.

Is the suction tube metal from the nozzle holder all the way to the dip tube in the tank, or is there hose involved?

If hose, it can fit loose at the connections ("barbs") and let air enter as it warms up, slowing the pickup of fuel, and letting the fire decrease, so the nose cone cools and it starts to smoke.

If there's hose and it's at all questionable replace it. I have used "Tygon" hose from a recreational engine shop.

Also, have you checked/cleaned/replaced the nozzle?
All sorts of info at this site

 

[Angle Iron]

(quoted from post at 07:53:52 11/30/16) I have never heard of drain every year, I have 2 heaters, both Knipco 95000 BTU and they have never been drained in the about 40 years that I have had them since new. They have had nothing but kerosine in them.

ust telling you what the manual said and in this case I believe there was algae in the tank from setting. Had the tank been drained and cleaned this may have been avoided. I would think there are a large number in the junk that never were drained and some may be there because of alga so just a heads up as to what can happen and how to fix it that's all.

 

[300jk]

Haven't drained the tank in 2 or 3 years. Figured cause the
strainer on the pickup tube was clean that wouldn't be an issue.
Adding that to the list now. Ordered new pump rebuild kit
today. 40 bucks with the shipping. Worth a try. Also in
response to other replies I have replaced the rubber fuel and
air lines with fuel rated hose. Which I used hose clamps at all
joints. I was wrong to say I replaced the flame sensor. I
replaced what they call a cad cell. This is the only sensor on
the heater according to the manual. I was also wrong on the
pump pressure. I thought it was 10. Manual says 8.5 max.
Operating pressure. Hope I can figure this out. Heater was
around 400 dollars when I bought it about 10 years ago. Going to
drain tank and double check lines again. With so many new parts
in it there isn't much left that could be causing this. Will go
through every bodies suggestions and see what I come up with.
As soon as I get the pump kit and get it installed I'll give an
update. Thanks everyone.

 

[58Deere]

We had the same problem with them at work. They would only last a month or two when new. They are junk. We now have Master Heater brand heaters. They are a few years old and still work great. We use a tank of fuel per heater a day.