Motor spins, glow lights, fuel sprays but it won't light. I removed the cover to check and with the cover off,and my hands actng as a fan cover, it will fire up. When the cover is installed, it will not fire. Can you help?
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The safety is turning it off because it is not lighting. You did not mention if it was actually trying to light, or if it was just the motor running. If it is not lighting, take the top cover off and watch the ignitor. Depending on the type of ignitor, it will either glow or spark when you plug the heater in. This should happen before the fan starts running. Once the fan starts, you should be able to see a mist of fuel coming out of the nozzle. If there is no fuel spray you may have an air pump problem, which is on the back of the motor, or the fuel screen in the tank may be plugged.
1. Check for ignition source
2. Blower motor should start, if you have ignition
3. Fuel should spray out of nozzle, if not check filter and check for air flow out of the pump.
4. If you do not have any air flow, or not enough air flow check the pump. Pressure out is critical.
5. If pressure is too low check for leaks around the pump. Spray soapy water on the back side of the motor/pump housing. The plastic pump cover is bad about cracking, and the cracks are very hard to see. The plastic cover could also be loose on the pump.
6. While on this end of the pump; the filters need to be clean, as they will affect the pump pressure and upset the whole apple cart.
Take the top cover off of the unit. Plug it in and look inside the burner can to see if the ignitor is glowing. If not you probably need an ignitor. You can remove it to check the heating element to see if it is intact, but be very careful, it is more fragile than glass. If it is intact, you may have a control board issue. The ignitor should glow before the fan starts. Be careful to stay away from the fan blades while doing this. If the ignitor glows, and the motor starts, you should then be able to see fuel spraying out of the spray nozzle. You may need a flash light. If the fuel does not spray out of the nozzle in the correct amount, the unit will shut down. There is a photo cell that detects ignition. If the fuel pattern does not look even, you could have low air pressure out of the pump, a dirty fuel nozzle, or a plugged fuel screen inside of the tank. The air pressure comes from a pump on the back side of the blower motor. Insure that the filter are clean on the pump; there are three of them, and the plastic end cap needs to come off to access them. If they are dirty, they need to be replaced. The air pressure off of this pump is very critical to proper fuel delivery. The rated output pressure of the pump is on the heater data plate. You will need a low pressure air gage to check this pressure. Another source of low air pressure is the plastic end cover over the filters. They tend to crack with age. Spray soapy water on the end cap while the blower is running to look for leaks.
Remove the top of the heater and turn it on. Look for the igniter to start sparking if it uses the spark plug type igniter or if it uses a HSI type, look for it to start glowing. Next, use a flashlight to look for fuel spraying out of the nozzle. If it isn't check the nozzle for a clog. Check the fuel filter. Remove the filter cover on the back of the motor and check the air filter. If this doesn't get the fuel going you will need to get a pressure guage to screw into the left hole in the filter cover and check the air pressure going to the fuel nozzle. It should ~3.5#. You can adjust it by turning the adjusting screw in the other hole in the filter cover. That plug should have a hole in it.
Is there a reset switch? Is there an in line fuse? If no to both we have some work to do here and hopefully in an hour have you up and running. Remove the top half of the heater, this exposes the burner tray and fan motor. Try spinning the fan motor by hand, should be free not bound up, use a light oil and oil front and back of fan motor at the bearings. Work the oil in by spinning the motor by hand and spin it until you feel that it is as free as it can spin. Now lets check all the other things I do yearly on mine.With the burner tray removed locate the fuel nozzle and remove it, they say you can not clean these. I say with a q-tip tooth pick and carb cleaner you can with out any damage, so clean it, now in behind the nozzle is a screen assembly these corrode clean it as well.Now put it back together and lets clean the flame sensor, locate it and now clean it with windex and soft terry cloth rag. Put the sensor back together and now reinstall the tray, make sure the sensor has a clear unobstructed view of the flame. At the back of the heater you will see the fuel pump and it has an air filter in it, remove it clean it and dry it real good put it back in. Inspect all fuel lines for holes, cracks, or dry rot. Follow the fuel line down to where it comes thru the tube, now remove the side cover and you will find the line and fuel filter. Remove the line from the filter and using a compressor blow air backwards thru the filter, instantly clean. Put everything back together and try firing it up, it should now work.
The fan motor runs regardless of the igniter as it is also the fuel pump. Possibly you may need to replace the motor but try this first. Remove the top section of the heater this exposes the fan motor, try spinning the motor by hand,it should spin freely if it does not try some light oil in the front and rear bearings of the motor and turn it by hand until it frees up. You may need to do this several times!! Now that it is spinning free put the heater back together and try it out. If it does not work a new motor is in your future. Hope this works out for you.
Remove the top cover, plu it back in and see if the hum goes away, if it
doesn`t look to see if the fan is stuck, if it is unplug and try to spin it
by hand, if it wont spin replace the fan motor
With power off, go on roof & try spinning fan at rear through cover with a stick, or something, until fan has made 2 or 3 revolutions, then try fan mode only & see if it starts. If no luck, remove cover on roof (watch for bees & wasps) and spin fan good by hand a few times & try again, if no luck, replace fan start capacitor.
Odds are, your air pump is locked up. Remove the cover on the back of the fan motor, remove the pump cover and carefully remove the air pump rotor and blades. If the motor spins freely and will start when plugged in, the pump housing plates probably have a bit of corrosion on them. Lightly clean the pump housing end plates with fine grit sandpaper, wipe clean and re-assemble. Should fix the problem. Does the breaker trip when this happens?
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