Frost fighter problems
 

Good day, having issues with my herman. Anyone with experance with these? Wondering about maybe a control upgrade?
Thanks

I wear long-john underwear and keep my herman warm in this weather.

Ha ha ha

Usually pretty simple. If you have fuel forced-air and spark they light. If it shuts down later it can be a limit switch. If it doesn’t light you either don’t have fuel to the tip, the spark is gone or no wind.

What’s happening with it ?

If it is a diesel fired unit, you might want some kerosene in this cold weather

Dealth with those damn things for years at work. Ran 2 sometimes 3 all day, every day. Constant struggles to get them lit and keep them lit once they were into a few years of service. Some basics:
Be sure diesel has winter conditioner additive.
Be sure electrical supply is adequate. Limit extension cord length and upgrade wire size.
Replace fuel filter regularly. It may say weekly on the machine but monthly should do if fuel is filtered at supply source.
Replace burner nozzle annually. Religiously.
Clean photocell. An([electric eye) monitors the flame and soot can interfere.
Replace or upgrade control module. A rental dealer can give advice on this.
The high limit sensor near the front may be adjustable for outside temp. Try playing with that.
Combustion air inlet: This is adjustable and can be crucial to proper performance.
Some models have a drain at the front to expel raw unburned fuel after lighting failure. Be sure front is lower so fuel can drain.
Be sure chimney cap is in place when machine is outside and not in use. Rain and snow call cause rust in burner chamber.
At end of season it would be prudent to replace as many components as you can and do a thorough internal clean. These things always break down when you need them most.

Thanks for replys.

I just bought a couple used ones... One will light but no fan... the other has fan but wont light... I tried swaping fans thinking the motor was shot.... but the other fan wont run on that unit either!! Is it a control box issue? Btw... Great tips you mentioned!!

Have a rental at work right now. Was having a bugger of a time to get it to run and that was the problem. Fires up like a champ after closing down the combustion air a bit

First put 110 V to the fan motor by disconnecting fan wires in control box. You can also jumper the fan switch at the control box halfway up the exterior of the heater.( the control box at the duct end of the heater is the limit switch). For the burner that doesn’t work, there is a solinoid valve to allow fuel to the burner. You can break open the copper fuel line that hooks up to the burner assembly to check if fuel shoots out. Also check the igniter if it is sparking. When the heater starts up lift the igniter up a quarter inch and look in there to see if you can see any spark. You also have a fire eye inside the burner compartment under the ignitor. Pull it off close lid and start heater. If it fires up and shuts down in 30 seconds, it’s your fire eye. After checking these item and still doesn’t start it is your controller.

So here is what I have now. On heater that doesn't have fan but fires...fan works..wired it to separate 110 and works. On other heater...I checked for fuel..cracked open line..good fuel...opened igniter box and saw spark jumping...pulled out nozzle and it's pretty wet..screen was clean. Unhooked sensor eye but it still didn't light. Would it be the controller on both heaters?

The sensor is to detect flame. It disconnects the ignitor when the burner lights.
If the ignitor is sparking but the burner won't light, either the nozzle is dirty and is making an irregular spray patern or the combustion air is incorrectly adjusted. It's usually a case of too much air, rather than not enough.
The main fan starts when the plenum reaches temperature so controller or fan switch may be faulty.
Some of the controls can be affected by outdoor temperature if they are old and weak. Bring the unit indoors and let it warm up if you can. Replacing the controller can solve a lot of problems.

Swap controller unit to unit. If the problems are the same your controllers are fine. If the problems moved from one to the other with the controllers, it’s your controllers. I’m betting the controllers are fine.

If you are getting spark your controller is ok. I would check the ignitor gap at the nozzle. The gap should be approximately 5/32, 1/8 from flat face of nozzle to ignitor rod, 1/4” from centre of nozzleorifice to the bottom of the ignitor rod

Thanks for all the help. This is my first time with frost fighters. I should have known that the fan shouldnt run until the plenuim reaches temp. Just like my old oil burnign furnace in the house..its practicly the same. The one machine works ..turned on.. lit... burned.. shut off and fan turned on.. Little embarassed there on that one. The second unit still wont light. And now I know the fan shouldnt be running right off the bat. Would that be causeing it not to light?

I know the nozzel is fine.. I swapped them from unit to unit and they both worked in the working unit.

On most units the main fan doesn't run right off the bat. I've seen a few that do. Not sure why that is because the Combustion air motor clears the flame chamber before lighting.
Anyhow, if the main fan runs as soon as you plug the unit in, it should stop at some point and then the burner should light.

These units run just like a furnace. The burner fires up and heats up the combustion chamber where the fan switch is located. When the fan switch’s predetermined temperature is reached it turns on the blower fan. If the blower fan comes on right away then more then likely the contacts in the fan switch are welded together from arching. Also on the newer model there was a relay in the junction box where the contacts would weld together from arching off and on.

That makes sense. I'd replace the fan switch. Or swap it out first with the other unit to see if that cures the main fan coming on when the unit is cold.

If the burner runs for awhile, then shuts off, then the fan comes on later, it's because the plenum got too hot and the high limit switch kicked it off. It got too hot because the main fan didn't start soon enough to cool it down. Again, it points to a faulty fan switch.

So apon further inspection of the unit that wont light.... It seems someone direct wired the fan to run steady. They just made a wire that connected the two red wires that connect to the fan switch. I dissconnected them and put them back on the fan switch just to see what would happen. I plugged it in... the fan didnt run.... the combustion motor turned on... the light at the top blinked so I held it to reset... then it did its thing and it actually ignighted this time... huge smoke probably from all the failed attemps. It went for 30 seconds and quit. Strange that it ignighted this time with no fan running. Anyways Im assuming the fan switch is bad in that one, hence why someone wired it direct.

Too much wind to establish a flame-front. If you light it again and jump the fan switch again after 15 or so seconds I bet it keeps running.

Correct. You could temporarily wire in a toggle switch. Turn the fan off to light, turn on after a couple minutes warm up, though you should replace the fan switch because you might forget to turn it on.
One other thing; Always switch the unit off to let the fan continue running instead of simply unplugging when you're done using. Some things (like the fan switch) can become overheated without the cool-down phase.

The fan running has nothing to do with the ignition of the burner flame. It’s purpose is to blow cold air across the combustion chamber and out the opposite end of the heater with warm air. If the temperature switch doesn’t work it can be jumpered which allows the fan to run all the time. The only way to turn it off is to unplug the power cord. For the burner to ignite you need the proper fuel pressure, airshutter setting, and proper spark on the ignition electrodes. Also check to make sure your extension cord has the proper polarity. This can cause weird things to happen with the burner cycle. I’ve repaired hundreds of cords with reverse wires in the plug. Also use a 10, or 12 gauge extension cord for proper voltage supply.

You would think it has nothing to do with it.. I thought maybe it was blowing some air by the combustion motor and making it get to much air? I did feel some air moving there when I had my hand there. Maybe the burner has to be started first with the wires hooked up to the switch and then taken off and jumped? I unhooked the wires from the switch and used the jumper wire again and it did not light with the fan on. It only lights with the fan off witht eh wires on the switch.

What is your voltage reading at the heater plug with the fan running. If the, voltage is around the 97 volt range which is very low , it can cause issues with the controller. Pull the plug and the extension cord apart slightly without disconnecting and take a reading on the two prongs while the fan is running and turn on the burner switch. Also the unit should be on it’s own circuit.

Well a little update on my one working heater.... Works great but outside in the cold it took a few times to light ... I narrorwed it down to being breezy out and I slide down the combustion air slide and that did the trick. Kept my barn nice and toasty, and dried out one cold Calf that was born at 4am.. Thanks for all the help. I plan to get the other one going and ordered new fan swirtches.