Torpedo heater (fan forced kerosene heater)

I have 2 Ready Heater brand torpedo heaters. And older 30,000 btu unit with a spark plug and a slightly newer 60,000 btu one with a circuit board and that glowing igniter thing--both purchased at estate sales. I've used the smaller one for a 2 to 3 years but recently it started tripping off randomly. It might operate for 2 minutes or 30 minutes then it trips off. Heats well when running. Spray pattern looks good. Flame seems good. No spitting, noises, smoke or smells prior to cutting off. I suspected the photo cell was bad so I went to use the larger one. It fires up fine with everything seemingly normal but cuts off within 30 seconds. That definitely sounded like the photo cell.

I removed the photocells and tested them with an ohm meter. They both worked identically. No continuity when dark, 3 to 4 with just shop light (on the 20,000 ohm setting) and .2 with a flashlight shining in them (on the 20,000 ohm setting). I don't know what the values should be but being identical I'd suspect they are ok but perhaps both are equally bad. So I ordered a new one off ebay. Bench tested that and it gives the same readings and no surprise it also gives the same results when put in the heaters. So, I guess it's not the photo cells.

Any ideas?

Do they have any type of thermostat that could be shutting them down ? I would have guessed photo cell also. I had a universal 175,000 btu and a Mr heater 210,000 btu. After a few years neither worked right. I replaced hoses, nozzles,photocells, filters, rotor and veins in the pump and just a out everything. Took the big one into a dealer and they could not fix either. I gave up and they went out to the road on garbage day. I now heat with wood and propane. Much less frustrating !

Hold on, I might have one working--still might be photocell. No thermostats on either. I'll post results in an hour or so.

it might still be the photo cell. I think I have one working--will post results soon.

We?ve had those same issues and spend hundreds at shops on repairs with no satisfaction and others in my location tell me the same. The rule of thumb here is buy the cheapest one you can find and when they quit go buy another one. To be honest I?ve had better luck with $200 Chinese ones than $400 John Deere. They all look identical now except for paint colour name and sticker. Some may have had better luck but no one in this area seems to have luck fixing them.

I have 2 of the 30,000 btu Reddy heaters maybe 40 years old. First thing I do is put a pressure gauge on it. Mine run good at 3 to 3 1/4 pounds pressure.

Nope, still not working. Thought I had one working but now it's not. Seems to be something to do with the photocell not indicating enough light for both of them to keep operating. Maybe the electronic parts be going bad and needing stronger signal from the photo cell or ???? I thought I had a bad connection earlier but fixing that didn't help. I can keep one running if I shine a light into the photocell but not with the flames of the unit. I've got the photo cell pointed as directly at the little hole in the combustion chamber as I can and tried moving it closer etc as best I can and still can't get reliable operation.

my dad has a 40 year old 98000 unit that would start hard and only run a few minutes. he had it worked on and still did the same thing. i took the pickup line out of the tank and it had a screen that was half plugged with crud. once i cleaned it it has worked fine ever since.

There are TWO types of photo cells. You may have the wrong one. this happens when the original fails, then the owner replaces it with the wrong one. They look the same, but have different resistance values and different ranges of resistance.

I learned this the hard way. I had a heater that would do just as you described - run for a bit then shut off. The circuitry is calibrated for the photo cell that the unit is designed for.

Here is how it works. The photo cell is used as a shunt to draw current away from a heater type circuit breaker. When the photo cell "sees" the flame, its resistance drops and draws current away from the circuit breaker. This prevents the circuit breaker from heating up enough to trip. If the photo cell does not "see" the flame, resistance stays high and more current passes through the circuit breaker. This causes it to heat up to the point of tripping and shutting off the heater.

The fact that the heater starts and runs for a bit proves that the circuits on the board are working as designed.

Some things to look for:

Make sure that the photo cell is clean and has a good view of the flame.
Make sure that the flame is not diverted by something as simple as a partially clogged nozzle that could cause the flame to be too far away from the photo cell.
Check to see if there is a window of some sort between the photo cell and the flame chamber.
Check to see if there is another possible place to mount the photo cell.
Check to see if the rest of the heater is drawing more current than it should. A motor going bad and taking too much current can make the circuit breaker heat up and trip.
Make sure that you have the correct photo cell for your heater.

I had one that did that, I found a crack in rubber fuel line hose was drawing air.

These things tend to set for long periods of time with fuel in them. Algae grows in the tank on them just like a tractor or storage tank. Drain and flush the tanks. You may be amazed what you find, I was. As has been said check all hoses for cracks and loose connections. I stopped to visit with a friend last fall and he was working on his heater. Could not see any trouble with anything other than one of the hoses at the burner end was a little loose. Cut it off and reconnected its still running fine. Check and clean or replace the air filters as well as the vanes in the air pump. The vanes on the air pump can wear funny at the ends and not work well because of this. And as has been mentioned get a gage, find out the recommended pressure setting and set it accordingly. One last thing, I was told of a vent clog in the fill cap on one and it would shut down after about 10 minutes and as the tank got lower the guy said it would run longer. He decided to not tighten the cap dead tight and the issue went away. New cap no more trouble in his case.

Decided they both need a complete overhaul. I've ordered a pressure gauge to test the pumps--should be here Monday. I stripped the larger down about as far as it goes. I drained and flushed the tank--just a little junk in there. I Cleaned the fuel intake filter--removed a bit of stuff. I took apart the nozzle--it looked perfect but I cleaned with carb cleaner and a q-tip. I took the compressor apart and I'm going to clean the rotor, vanes and housing tomorrow as well as the air filters. It's possible the ball that regulates pressure was stuck--it didn't fall out on it's own when the set screw and spring were removed--took a good tap to get it to drop out. If if was stuck that might cause high air pressure. After this I'll check the pressure Monday when I get the gauge and I can also check motor speed with an optical tach I recently got. Hopefully with all that done it will work.

QUESTION, Is my assumption that the compressor pump does not require lubrication correct? A Youtube video said use graphite but I think that'll just add graphite dust into the compressed air which will have to be filtered out by one of those filters. I haven't found any manuals or manufacturer instructions they say to lube it in any way.

Aren't the little blades graphite to begin with? If so they are self-lubricating.

You know, I think your right! Thanks! I hadn't thought of that--my head was only thinking of graphite as a power. They aren't metal. Don't look like plastic. That makes sense.

Any of you guys remember the old "Knipco" heaters? Those were built with the same style of pump, nozzle, and ignitors as what an oil burning house furnace used. The only fan in them was the fan that blew the warm air out into the space being heated. They rarely ever gave any trouble, and if they did, pretty much anyone could fix them.