atwood furnace ,no heat

Jeremy888 · 01-29-2019, 04:14 PM

This is in a 2017 3950 BR Montana. Atwood AFMD35131_A Furnace .There are 2 thermostats one in the Kitchen one in rhe bedroom.They are combo thermostats, fan,cool (air con) and furnace. The bedroom thermostat seems to only run the air con unit over the bedroom . It will not start the furnace . ( is this by design or broken?) The kitchen thermo. does operate furncae ...starts the blower but the burner will not light .Gas lpg , is getting there because i can smell it out the exhaust vent outside. I took off the outside cover and checked all wires, they are tight and corrosion free . There is an off / reset switch near the control board. With the thermostat set to start (set it at 80 )in side temp about 75 i used the off reset switch to try to get it to light about 6 times, no luck.I did not hear a clicking sound like it was trying to light The blower runs about a minute, then shuts off , no restart attempt happens automatically. I tried the fridge on gas ,it fired right up, full tank of LPG. I read the manual ,it talks about hard and soft lockouts . I followed on off procedures, waiting for over an hour in case its a hard lock out. no luck. I can not see or find the led for a code flash sequence as per manual on the control board...Should it be visible from the outside? Where should it be?, im looking at the control board from the side . Some one draped a plastic bag over the side or the edge of the c board facing the outside , im guessing for water ingress. No sign of water ingress. There is 13+ volts at the switch . I have found the electrode and decided to ask some experts here at the forum before proceeding any farther. I have replaced control boards , heating elements and electrodes on dometic rv fridges and got then going again from dead. Just lucky and careful, but not too much hvac experience .. Help please I can not afford the dealers , Owners manual is useless . No troubleshooting tips in the manual . Please help

**chuckster57** · 01-29-2019, 07:52 PM

I got your PM.

I’m thinking your issue is either the flame sensor/ igniter or the board. Only way to test the board is to pull it out and use a special tester. Tester isn’t cheap, and you can get quite the shock trying to test the igniter.

Do you have any bee/wasps in your area? The big “can” on the control board is the igniter and develops high voltage, the large wire carries the current to the tip of the igniter causing sparks.

Not hearing any clicking can mean a few different things. Since you say you smell gas, I’m thinking either the igniter is faulty or the board is faulty. If you have bee/paper wasp issues it’s possible they built a mud nest on the burner and covered the probes.

Removing the furnace is easy. Since you took off the outside cover and can see the control board, just snip the 4 wires: 12V positive, 12V negative and thermostat signal ( often times blue). Not critical to connect the blues back the exact same way.

Access the furnace from the inside and remove the ducts from the plenum. They will turn and a tab will align with a slot. Then go back outside and look for screws in the corners, there may be a single screw on the “back side” inside the plenum.

Turn off the LP and disconnect. You should be able to remove from the outside. I seriously doubt your Sail switch is bad as it wouldn’t allow the gas valve to open if it was.

There is a way to “bench test” a furnace but you’d need a regulated gas source and good 12V source. If your no longer in warranty, and your positive you don’t have a bee/wasp problem, I might try replacing the board.

Your furnace may have a 2 year warranty, I would check that. If not then replace board with “Dinosaur” brand.

Jeremy888 · 01-30-2019, 06:05 AM

Thank you Chuckster57, There are bees here (San Diego)but I haven't seen any wasps. We winter in this RV ,and it was covered the 7 months we were gone .So it is probably not wasps, but I will remove the unit as you suggest and first check for a mud dauber/wasp over the ignighter . I bought a control board from Dinosaur before, saved a bunch of $ , the dealer wanted 500$ for the board i got for 168$.. Thanks for reminding me ,i had forgotten their name. I have a full plate til after the Super Bowl so i probably will not get to this til next month . I will try to take the cover off again today and snap a few photos for you to look at. As I said in my post I havent found the LED on the board . I would like to find it and see if the flash sequence can help you narrow it down even more . Maybe the fact that I can not see it when the blower shuts down is indicative that the board is bad as you predict as a possible cause. To acess the inside will take a while . I will have to remove lots of "stuff" from the garage/basement to acess it . Predicted rain may hinder me so this probably won't happen til after the game . Since I'm an old fart i tend to move slow and careful on stuff like this so I dont screw it up and make it worse .My motto "never too old to learn " Its not too cold down here so we make it on the electric heat we have . But its nice to have the furnace to take the morning chill off quick. I'll go take some pics when it gets light outside . Here is the code flash sequence chart . No warranty ,i bought this RV used. This will be the 10th repair ive made , so im learning about it. I Thank God for rhis forum ,since I cant even get a wiring diagram out of Keystone and the owners manual is practically useless. Thank you very much for your help. Jeremy

**sourdough** · 01-30-2019, 08:44 AM

Jeremy here are a couple of links that might help;

https://www.amazon.com/Atwood-31501-...34170090&psc=1

https://pdxrvwholesale.com/products/...tune-up-kit%20

The first is of the control board I think you probably have. It shows the location of the LED on the board. If yours fails to flash at all I would think it is a board malfunction. The 2nd is from a parts house but shows the parts of the furnace. You can blow the pic up so you can see it better. Hopefully they might give you a little insight into your problem.

Jeremy888 · 01-30-2019, 09:09 AM

photos

opening to outside

switch off/reset

moisture evidence, although there was no direct evidence of water coming from outside cover ,there is evidence of mousture in the compartment. Had a flooding issue from faulty/leaky plumbing

ignighter/electrode. It appears there is a small screw to the right of the electrode on a small brass plate. Can I remove this where it is without takung unit out to inspect electrode?

control board removable by one screw( 2 views. ) no evidence of water on the board . Still do not see the LED . Perhaps I can first remove electrode (If possible) and inspect it. If it looks good (Ill send photos) then i can try a board change out ,also without removing unit .

I removed fuse and checked to make sure no voltage present at switch before removing board. Put it all back together as rain is coming . Your thoughts please Chuckster57...Thanks Jeremy

**sourdough** · 01-30-2019, 09:33 AM

Quote:

Originally Posted by Jeremy888

photos

opening to outside

switch off/reset

moisture evidence, although there was no direct evidence of water coming from outside cover ,there is evidence of mousture in the compartment. Had a flooding issue from faulty/leaky plumbing

ignighter/electrode. It appears there is a small screw to the right of the electrode on a small brass plate. Can I remove this where it is without takung unit out to inspect electrode?

control board removable by one screw( 2 views. ) no evidence of water on the board . Still do not see the LED . Perhaps I can first remove electrode (If possible) and inspect it. If it looks good (Ill send photos) then i can try a board change out ,also without removing unit .

I removed fuse and checked to make sure no voltage present at switch before removing board. Put it all back together as rain is coming . Your thoughts please Chuckster57...Thanks Jeremy

Bottom picture, left side, above the capacitor there is a connector with blue, black and a red wire....just above that is the tip of the red LED. When powering up it should blink with an error code if there is a problem if I recall (been a long time since I troubleshot/replaced mine).

Edit: no blink on power up would indicate, to me, either no power or bad board.

Jeremy888 · 01-30-2019, 10:10 AM

To Sourdough and Chuckster57, Ok I went back out removed cover again and tried to start it again . Armed with the knowledge Sourdough gave me of the LED location on the control board Thanks . 30 seconds after blower started , I got a whiff of propane out of the exhaust port. 30 seconds after that the blower stopped and I was able to see the LED flash dimly, 3 flashes wirh 3 second pause ,the code for " ignition lock out fault" " soft ( 1 hour retry)

Also looking at the parts for the tuneup Sourdough gave me ,it looks like i can get the electrode out without removing unit ... if i have enough wiggle room to snake the bend out . Advice please

**chuckster57** · 01-30-2019, 01:28 PM

You may be able to get the igniter out if you have a long enough screwdriver. I would try it first, we generally remove the furnace and perform a series of tests to rule out various components.

Jeremy888 · 01-30-2019, 05:06 PM

OK ill give it a try, Chuckster57. Is your diagnosis the same in light of the 3 flash 3 second pause sequence? If the electrode has no foreign insect stuff on it ,can I rule out wasps and spiders? Also since the control board is flashing this probably does not rule out a bad board..yes? it still can be defective yes?. Is there a way to test the electrode to see if it is sparking out side of the burn chamber ? Like holding it close to ground with gas off and purged. Trying to avoid it but I will still pull the unit if I have to . Im waiting on a price quote from Dinosaur for a control board . Amazon wants 86$ for one . Thanks for your help

Jeremy888 · 02-01-2019, 06:46 AM

Thank you very much Chuckster57 . Before I proceed to take it out I am asking you if your original Diagnosis of either igniter or control board is the same in light of the new info.(the 3 flash 3 second pause code , the code for " ignition lock out fault" " soft ( 1 hour retry.) I could not get the electrode out with the unit installed as the gas plumbing prevents its removal . So I will be removing the unit next week when the rain hopefully stops . Of course when it rains it pours , the electric water heater went out last night...So i have another project to fix . lol any advice glady welcome.

**JRTJH** · 02-01-2019, 07:33 AM

Hmmmmm

You said in your last post that the electric side of the water heater went out last night... What (exactly) is the water heater doing? There are thermostats (2) for the water heater, one for 12 VDC/gas operation and one for 120 VAC/electric operation. They are both located in the same space on the water heater. I wonder if possibly there is some corrosion on the thermostat/temp limiter that's causing your problem....

That said, back to your furnace issue. In the first post you indicated that there are two thermostats in your RV. You "alluded" (but didn't state) that they are identical. If they are identical, before pulling the furnace (something you may have to do anyway) have you considered swapping the thermostats? You may have a bad "heating circuit issue" on the thermostat that controls the furnace. If they're identical, then swapping them out would provide a "new, never used "heat control circuit"..... Just a thought, but might work to fix the problem and certainly would rule out a thermostat issue. If you do it, be sure to mark the wires and how they're connected at each thermostat. They may not both be wired the same.....

**sourdough** · 02-01-2019, 08:10 AM

Quote:

Originally Posted by Jeremy888

Thank you very much Chuckster57 . Before I proceed to take it out I am asking you if your original Diagnosis of either igniter or control board is the same in light of the new info.(the 3 flash 3 second pause code , the code for " ignition lock out fault" " soft ( 1 hour retry.) I could not get the electrode out with the unit installed as the gas plumbing prevents its removal . So I will be removing the unit next week when the rain hopefully stops . Of course when it rains it pours , the electric water heater went out last night...So i have another project to fix . lol any advice glady welcome.

A couple of things to consider: When mine failed it did the 3 flash, pause cycle. I could reset it by removing power (or, I eventually learned, turning off the thermostat). Mine however was igniting and would run one cycle then never reignite. It turned out to be the control board.

Jeremy888 · 02-01-2019, 11:48 AM

Thanks sourdough , that helps . i have new issues
see next post ... I appreciate and value your advice .

Jeremy888 · 02-01-2019, 12:00 PM

Sorry my post is so long, got a lot of issues going on .please suffer thru it ! Thanks

To : JRTJH , and anyone else..thank you for the come back . Re: Furnace /Thermostats , YES! they are identical. I will try the swap out . They are both multi function Thermostats (see photo) .I will swap them out . From experience using them ,it seems that the one in the bedroom only controls the air con over the bedroom independently from the air con unit over the kitchen , when i try to turn on the furnace with it nothing happens although the green LEDs light up. The kitchen thermostat operates the air con over the kitchen and the furnace. I will try the swap out when i get the water heater going again. She is wanting a shower of course !! ..murphys law.

Re: water heater and fuse & switch panel

Water heater would not start on either power or gas. Light was not illuminated on electric water heater switch and the red LEDs for tank levels was not working and or blinking on for a second and then going off. Loose wire like symptoms . To make matters worse. the fuse panel was also on the blink . Yesterday I had removed the furnace 12 v 15amp fuse to safely remove the control board and electrode and the red led came on as it should. I found this morning that the red LED was not lit . Futhermore the green led on the extreme right side of the fuse panel which was rapidly , continually flashing before today is now flashing once every 5-6 seconds. So I attempted to reset both water heater reset buttons on the heater itself and neither felt like it was in the popped out position . ( Dont know which is 110 and which is 12 V) Checked the four 25 amp 12 v fuses above the green led hole and they were all good. Then to confuse the issue even more the light on the electric water heater switch came back on when tried it again . Am now awaiting to see if water gets hot .. I can not find any thing in my stack of manuals and installation instructions that tell what the green flahing codes signify. Again owners manual completely useless . Also so far have not found any thing on the manufacturer's web site Progressive Dynamics Inc. Unit is a PD4500 series Power Control Center (#PD4575K18L) . Any one have the codes? Help!!!!

To Chuckster57 Sourdough JRTJH and or anyone else

Back to the Furnace
Replaced the fuse on the furnace , reset it by using the off/reset switch (shown previously) to see if any thing changed there and no , still has the same symptoms .(blower start but no ignition)The red LED came back on when i pulled the fuse again...so i am guessing that the fuse board is designed that way. I am happy to be back to this point .

Since it looks like i will need a new control board , I also want to know if anyone knows who makes a better control board. Sourdough gave me a link to an Atwood 31501 board and Chuckster57 recommends Dinosaur boards. I noticed the Dinosaur board (fan 50 plus pins) has a 5 amp fuse on the board . Does anyone have experience or recommendations with these ? See photos ,im leaning towards the Dinosaur because it has a fuse and the Atwood has a few negative reviews I am not sure the Fan 50 + pins board will fit and am waiting to hear back from Dinosaur .

Any way I will wait to see if water gets hot and if not try the gas again .Done

Water heater not working on 110, but now gas mode is working . Wife happy!
So this leads me to believe that the Electric and Gas water heater issues were /are related to the loose wire symptoms explained above . This trailer vibrates to no end when washer/ dryer runs... which is daily. I will look at thermostat connections as per JRTJH advice and get back to you.

Summary : Need codes for flashing green LED on fuse panel.

Need input on furnace control board preference and why.

Need advice on trouble shooting elect. water heater, and switch control board (loose wire ) issues. I will shut down power and look for loose and or corroded wires .

Need further advice before pulling entire furnace unit and purchase of new control board if thermostat swap doesn't work

Any input or advice is really appreciated. Jeremy

**sourdough** · 02-01-2019, 12:29 PM

Just a quick reply about the control board. Mine was replaced with an Atwood about 3-4 years ago and I've had no trouble since. Others have had issues with the factory boards and those with more experience than I replacing them, including Chuckster57 if I recall, recommend the Dinosaur board and I would too based on what I know. I sent the link to the Atwood because you were looking for the location of the LED - not as a recommendation for a replacement.

The thermostat changeout might be a something to try first. About 6 weeks ago I had to replace mine because the furnace would come on, never get hot, go back to blowing cold air, kick on and repeat. Not the same problem you have but a weird problem - it might cause what you are experiencing - seems far fetched but changing out the thermostat takes about 3 minutes.

Jeremy888 · 02-01-2019, 01:37 PM

thank you sourdough , sorry about saying you recommended it . And it did let me see exactly where rhe LED is. Im working on the water heater issue at present and plan to swap the 2 thermostats and see what happens . A new thermostat will probably cheaper than a control board . Thank you !

**sourdough** · 02-01-2019, 02:44 PM

My thermostat replacement was $43 - I bought 2. They were exactly like yours but a newer model.

**JRTJH** · 02-01-2019, 03:24 PM

I'm a "firm believer" in dinosaur electronics. I've used their replacement boards for over 20 years and never had a failure or "dead board". I can't say that for Suburban, Atwood, Dometic, Norcold or Coleman. I don't know which furnace you have, but most boards are essentially "interchangeable" so dinosaur can tell you exactly which board you need. Having the 5 amp fuse on the control board does eliminate one problem, a burned out diode in the ignition circuit, but it's a "double edged sword" in that "who remembers to check that fuse" until after the furnace is out and on the bench, then it's a "forehead slap and a DAMN".... So if you do install a dinosaur board and have a problem, "check the fuse" !!!!!

With all the "concurrent problems" you're facing, I wonder if it's possibly a 12 VDC issue ???? It sure does sound like a lot of "stuff happening" all at once for it to be "separate problems with multiple systems"...... I'd focus on your plan, but while you're checking things, I'd disconnect the battery, check the battery output and while it's disconnected, I'd also verify that the converter output is correct. It should be 13.2-13.4 VDC and the battery should be 12.6-12.8 VDC.

Jeremy888 · 02-01-2019, 06:25 PM

Thank you JRTJH, I will buy the Dinosaur control board if i need to. I believe you are correct that too many things are going wrong at the same time to not be related some how . Since my last post I have :

Shut down the 220 to the RV and disconnected the battery by pulling the
" battery disconnect key " ,which is supposed to completely shut battery off to RV.
Battery voltage was 13.14 in this condition .
Inverter output was 13.58 when power back on.

While power off I pulled the switch panel and found all wires tight and clean. The circuit board for the tank levels also had no sign of heat damage .

Also pulled rubber cover off the reset/t-stat on water heater to check wires .all dry ,clean and tight.

Also accessed the water heater tank body inside and all wires are clean dry and tight ,no sign of heat damage .

More support for your theory are :

The erratic behavior of the tank level lights, and the lights not working on the water heater gas and elect. switches were simultaneous . The green LED was 1 flash every 5-6 sec.

Now the green LED is again flashing continually like it was when the furnace first went out . Both water heater switch lights are again working but neither gives heat to the tank . The gas function did work for a while ,(long enough for her shower��) but will not come back on since I shut the power off . The DSI /FLT light was working when both switch lights were out , but now is not .

Also I tried another start on the furnace to see if green LED changed sequence again , it did not, Also shut off power again to see if green LED changed..it did not .

I hope some one will come up with the green LED sequence meanings. I am finished for the night , baby sitting , and will do the thermostat swap first thing in the morning .. Thanks to all who are helping .

Jeremy

Jeremy888 · 02-01-2019, 07:46 PM

Last post for tonight... I found the attached chart on the Progressive Dynamics (PD)web site . The green LED is apparently to determine what mode the inverter is in. Boost,Regular or Storage. Duh ! One would think that Keystone would at least supply this info to the RV owner who might store his RV plugged in to maintain his batteries ! Nothing given at all in my Keystone RV literature .
So I have not pushed the wizard button but my LED has changed from Quick Flashing to Flashing 5-6 seconds !!! In other words it appears to be a Wizard 2 that automatically gone between storage and regular mode . My inverter DC output was 13.58 matching tbe 13.6 regular mode rate given on the chart below .. Any ideas welcome .. As usual PD says what Keystone says ....Call the Dealer !!!

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