NY_Dutch
Well-known member
A faulty ignitor board could cause the problem. Dinosaur makes a high quality replacement board.
Strange Atwood Heater Symptoms
- Thread starter CncDean
- Start date
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If you have answers, please help by responding to the unanswered posts.
JayArr
Well-known member
You could remove the ignitor so it dangles out of the furnace. Hook a wire on it from the mounting flange to ground (do you have any wires with alligator clips?)
Using a lighter for a flame have an assistant heat the ignitor while you turn on the furnace. Using a second longer lighter, like the kind used to light BBQs have a flame ready to light the main burner when the gas kicks on.
Do NOT blow yourself up! Don't turn the furnace on and then go fumbling to light the second lighter, the gas will build up and ignite all at once!
The second "long" lighter needs to be lit and in place before you turn the furnace on.
You're trying to fool the circuit board into thinking the main flaime is good and igniting the main flame manually so you can see if it's proper size and capacity.
Have a fire extinguisher on hand in case you make a mistake.
If you feel uncomfortable about any of this or don't understand anything do NOT try this.
IF the furnace turns on and the heater flame is small and it doesn't provide much heat then you have either a bad valve (not letting enough fuel through) or a blocked orifice in the burner or a restricted line to the furnace itself. If the lighter on the ignitor will keep the furnace running without shutting off then the ignitor and the circuit board are OK.
If the lighter on the ignitor won't keep the furnace running and the main burner seems to be large enough and hot enough then you likely have either a bad ignitor or a bad circuit board.
Using a lighter for a flame have an assistant heat the ignitor while you turn on the furnace. Using a second longer lighter, like the kind used to light BBQs have a flame ready to light the main burner when the gas kicks on.
Do NOT blow yourself up! Don't turn the furnace on and then go fumbling to light the second lighter, the gas will build up and ignite all at once!
The second "long" lighter needs to be lit and in place before you turn the furnace on.
You're trying to fool the circuit board into thinking the main flaime is good and igniting the main flame manually so you can see if it's proper size and capacity.
Have a fire extinguisher on hand in case you make a mistake.
If you feel uncomfortable about any of this or don't understand anything do NOT try this.
IF the furnace turns on and the heater flame is small and it doesn't provide much heat then you have either a bad valve (not letting enough fuel through) or a blocked orifice in the burner or a restricted line to the furnace itself. If the lighter on the ignitor will keep the furnace running without shutting off then the ignitor and the circuit board are OK.
If the lighter on the ignitor won't keep the furnace running and the main burner seems to be large enough and hot enough then you likely have either a bad ignitor or a bad circuit board.
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JayArr: I have all the things to attempt this and am pretty sure what you mean. At first I was thinking that you were saying to light the main burner of the stove to see if the flame was effected by the additional burner. But after a couple rereads, I see that you mean to stick the lighter inside the furnace burner hole.
I’ll attempt this later today and report the findings.
Thanks.
To the others that made suggestions, although I would like to believe that a newer igniter isn’t my problem, I know that they can still fail.
Same goes for the new mother board.
Are there any multimeter test I can do on the board to check if it may be faulty?
I’ll attempt this later today and report the findings.
Thanks.
To the others that made suggestions, although I would like to believe that a newer igniter isn’t my problem, I know that they can still fail.
Same goes for the new mother board.
Are there any multimeter test I can do on the board to check if it may be faulty?
So I tried this but the wind of the blower prevented me from lighting the burner.
I ordered an igniter just in case but my next step would be to test the volume of propane or get a new regulator since the site full/empty function doesn’t work.
Should I buy a $30 manometer first or go with a regulator since I was always eventually going to replace it.
I’m going to poke around with grounds and see if there’s any change.
Still only getting 10.65v at blower. I checked and cleaned all grounds except for behind the furnace casing. The ground block that’s riveted to the wall is cleaned up. The only other ground wire I see is outside the case in the wall and it’s wire nutted to other wires back there. If I remove the blower cover or possibly the fan cage then I could reach back there and check it.
Any advice to check if the igniter board is causing low voltage to the blower?
Keep in mind that I did attach a battery to the blower and even with 12.6v the furnace still did the same thing.
Click click click, and whoosh then nothing.
Is there an ohms test to check the furnace regulator thing?
It’s just so weird that I’ve been using it for a month straight and one day it just started acting up.
Any advice to check if the igniter board is causing low voltage to the blower?
Keep in mind that I did attach a battery to the blower and even with 12.6v the furnace still did the same thing.
Click click click, and whoosh then nothing.
Is there an ohms test to check the furnace regulator thing?
It’s just so weird that I’ve been using it for a month straight and one day it just started acting up.
Kirk
Well-known member
If you are measuring the voltage between the supply and some place other than the ground connections, the grounds would have nothing to do with your reading as you are not using them. If you have a good ground for the negative probe of your meter you should read supply voltage, if the circuit is open. If it is in operation you can measure across the blower motor to see what voltage is actually applied to the motor. If in doubt then run a wire from the negative terminal of your battery to where you are working and use that for your negative probe in order to get the most accurate voltage readings.
JayArr
Well-known member
I don't know if this helps but I bought a used manometer on eBay and it helped me out of a jam. I had a water heater that would light and heat the tank to the proper temp but when the valve turned off the gas the pilot would also go out. I had to relight the pilot every morning when we got up and after every tank heating.
I went nuts replacing orifices, and thermocoples etc and then I put a manometer on the gas line and found that the brand new regulator I had installed was mis-adjusted at the factory. It was an inch and a half too low! I was reading 9.5 water column inches when I should have 11. The solution was simple, I lit the stove and the oven, opened the fridge door until it warmed up a bit and the flame for it came on and then I turned on the furnace. With all the gas appliances running I took the cap off the regulator and turned the adjusting screw to achieve 11 inches under full load then replaced the cap.
I haven't had the pilot blow out on the HW tank since. $30 well spent!
I went nuts replacing orifices, and thermocoples etc and then I put a manometer on the gas line and found that the brand new regulator I had installed was mis-adjusted at the factory. It was an inch and a half too low! I was reading 9.5 water column inches when I should have 11. The solution was simple, I lit the stove and the oven, opened the fridge door until it warmed up a bit and the flame for it came on and then I turned on the furnace. With all the gas appliances running I took the cap off the regulator and turned the adjusting screw to achieve 11 inches under full load then replaced the cap.
I haven't had the pilot blow out on the HW tank since. $30 well spent!
I just installed a new Camco dual auto select regulator.
Same issue.
At this point the only odd thing going on that I can tell is the voltage at the blower is low. I dont know why.
Does anyone know of a voltage test I can do on the igniter board to rule out a faulty board?
Or the gas valve on the furnace itself? What can I test to rule things out?
Same issue.
At this point the only odd thing going on that I can tell is the voltage at the blower is low. I dont know why.
Does anyone know of a voltage test I can do on the igniter board to rule out a faulty board?
Or the gas valve on the furnace itself? What can I test to rule things out?
I tried an external battery source in the blower and no difference.
New igniter/flame sensor coming in next week.
I just put the igniter closer even though I had it at 1/4”. Now it’s at 1/8”.
It wants to start but puffs out.
New igniter/flame sensor coming in next week.
I just put the igniter closer even though I had it at 1/4”. Now it’s at 1/8”.
It wants to start but puffs out.
Atwood 8535 attempting to light
Here’s a video I made of it trying to light. I didn’t know how to add a video so I posted it to tiktok
Here’s a video I made of it trying to light. I didn’t know how to add a video so I posted it to tiktok
JayArr
Well-known member
I can't see anything, no spark, no flame.
You hear it click a bunch and then whoom, and another whoom a second later. Like starting twice.
I’ve never been able to actually see a spark or flame because it’s all behind the wall in the burner. And just heat comes from the exhaust port.
Kirk
Well-known member
Your furnace has a sail switch that must be closed by the combustion air movement for the propane valve to open and the ignition to fire. Unless that switch has failed closed or been bypassed, the air movement meets the designed requirements.
CharlesinGA
Well-known member
Bad gas valve.
richclover
Well-known member
My furnace was nearly brand new when it suddenly failed to light off. The blower would run, but no fire. After a few minutes the blower shut off. A service call had it fixed in less than an hour. The almost new sail switch had failed.
Any test I can do to confirm it? At this point it’s either the gas valve or flame sensor.
Although I do have the low voltage to the blower but it must be enough to activate the sail switch if it’s firing off.
The new igniter will be in today. I may bring the board to get tested when I go to town.
