Any needed service for Atwood heaters? I've got a fair amount of black outside

Discussion in 'Heating / Cooling Systems' started by Spridle, Nov 17, 2014.

  1. Spridle

    Spridle Active Member

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    Edit - I just called Marshal, the valve I have that I bought last December is discontinued, for all the reasons I experienced and more. They said the furnace problem could absolutely be from the regulator failing. Again, we don't know that yet. But getting the regulator swapped and making sure I've got full flow is the first step.
     
  2. Nandy

    Nandy Active Member

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    I agree your last step might solve your problem. If there is not enough pressure the flame will not be as strong causing the sooth. Also, I would not worry about the combustion blower for now. You have a sail switch that has to close before the furnace is anywhere close to open the gas valves. The blower has to be ruining at x amount of RPM before the sail switch closes. Put the old regulator back, I think you are up to something.
    Other than that, yes, debris and insects will cause a burner to not work properly and sooth will be a by product.

    Good luck.
     
  3. lifespeed

    lifespeed Member

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    Great, it sounds like you are on to something. No doubt they offered to replace the faulty piece on their dime. [;)]
     
  4. Spridle

    Spridle Active Member

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    Sure they did [LOL]

    It was bought just a few days shy of a year ago and warranty on the thing is one year. So Amazon is giving me a full refund. I am looking to buy the updated version which is the Marshal 253. What failed is the 9984. From speaking to tech support I have no doubt the 253 is a much better unit. But I do want to look at these more expensive units for mobile homes and large RVs. WAY overkill in terms of flow, but they are much higher quality, can be manually calibrated and can pull from both tanks when temps drop to maintain full pressure. I'm not looking to throw money away, but I'm not looking to do this three times either.

    Sail switch was staying open even as the battery was getting really run down. That's another project for next season, look at the wiring scheme and increase the gauge in the critical areas. By the time the battery hits 50% the voltage at the furnace is another half a volt or more less than that and my fancy new LEDs are starting to flicker when the voltage drops that hard while the furnace is running. Need thicker wire & maybe a better wiring scheme.
     
  5. lifespeed

    lifespeed Member

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    Everybody has a different limit on how much they're willing to spend on better quality. Personally, I've made it to a point in my life where my time is worth a lot, so any time I have to do a job twice because of junk parts it really chaps my hide. I have never regretted putting in more expensive, quality components that are still doing their job perfectly 10 years later. An engine machinist whose services I used once said "There is never money to do it right, but always money to do it over."

    As to your voltage drop issue, something is definitely wrong if you're dropping half a volt between the battery and furnace. Those blower motors use less than 4 amps, so I agree very likely inadequate wiring or a bad connection.
     
  6. Nandy

    Nandy Active Member

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    Not sure I follow you. Most Sail switches I have seen are NO. The switch will close when the air flow is strong enough meaning the blower is turning over min speed. If the sail switch is open the main board will not have power and will not operate.
     
  7. Spridle

    Spridle Active Member

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    The challenge with all of this for me is the time and money investment into a 15 year old trailer with a plastic roof. At what point am I just throwing money away? However, it's a good trailer still in very clean condition, we just put good new beds in it, new lights, new tires and replacing it isn't really in the budget so.....

    I couldn't agree more on quality. In this case I got burned (no pun intended), but there's probably thousands of these valves out there working just fine for other folks. I'm going to put in a call to Marshal to ask a couple specific questions. But so far I have not found their bigger units online at all. Meaning I'd have to go to a local source and likely pay $200+. At that point, I'll give this new valve a shot! The other option is the Rega which is also a residential grade unit for about $110 online.

    As for voltage. I was going more from feel than an actual measurement. But the wiring is pretty thin and seems to go the full length of the trailer to the inverter and then nearly the full length back up to the furnace. I really dislike the location for the inverter but there's probably no moving it now. But it makes the the wiring scheme poor and I can't reach the voltage switch with the camper closed. I'm considering changing the switch out to a 120V coil relay that in the "off" position would use the 12V to power the trailer but would energize and use 120V to power the trailer when connected to shore power.

    Nandy - The Sail switch is working as you describe. Just got sloppy in my terminology.
     
  8. Spridle

    Spridle Active Member

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    I just talked with Marshal again and we are just going to go ahead with the regular 253. The response from them is that bigger is better. Going with their resi 175 series you are going to get bigger orifices and diagrams so much less chance of blockages or freeze up casing a problem. Having said that this valve is rated at 225,000 for primary and 150,000 for secondary. So the load is roughly 10% of capacity. If I have another problem it's going to be because something failed again, not because I bought the wrong tool for the job.

    I'll check back in after I get this all cleaned up and then see how it's burning.
     
  9. Nandy

    Nandy Active Member

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    On pup ups you go by condition rather than age. So if it is in good condition then the age dont matter much except for a few appliances.
    Good luck, keep us posted.
     
  10. Spridle

    Spridle Active Member

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    Agreed - Except I have the Coleman ABS roof, so somewhat of a ticking time bomb.
     
  11. Spridle

    Spridle Active Member

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    The valve showed up already! Definitely feels more solid and has a nice plastic vent cover as well. The weather outside is frightful, but maybe I'll tow the trailer back into the driveway tomorrow and tinker a bit.
     
  12. Spridle

    Spridle Active Member

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    I case anyone is still tracking this thread from the fall. I just made it out last weekend for the first trip. The new marshal valve is vastly superior and worth buying, the furnace is still making soot. So I'll have to focus my attention on that.
     
  13. Davylee

    Davylee Camping = Life is Good

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    I had a similar problem with soot and it was a dead moth blowing around inside the heater although it was a different brand if I remember right.
     
  14. Spridle

    Spridle Active Member

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    I was just reading the service manual and read about makeup air. It's possible I'm choking it off. I have a solid panel between the furnace and the storage compartment next to it. Sounds like I need 4 square inches of makeup air in that side panel. Not sure that's true but that's what it sounds like. I thought it pulled all the combustion air through the outside vent though. Seems like if I'm choking anything off it would be the heat flow, not the combustion air flow.
     
  15. Nandy

    Nandy Active Member

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    So here I went and wrote an entire essay and the website went down so I lost it. Actually, worst, I actually selected it all and copy it to the memory then when the site went down started doing other stuff and poof! I copied something else to memory... dang it...
    So here is the compendium.

    First off, bummer that the regulator did not fix it. And no, you are not choking it, however, you should have those minimum clearances around it. The heating exchanger pull outside air inside the exchanger which also holds the flame/gasses and purges the gases and heat outside at about 300 deg f, maybe more... If you get combustion gases inside the camper your heater exchange is cracked or the rust poke a hole in it. Very dangerous from the gases perspective and the fire hazard.

    Now, get some compressed air, pull the furnace out and blow the heat exchanger good from both outside ports to make sure you dont have any debris causing your problem.
    IF all clean, take a gander over your burner head. Make sure there are no plug holes and it is clean.
    If that checks out then the last thing to check is your gas valves to be closing. I know, you have dual inline valves BUT they can get compromised specially with small debris. If that happens you will have a very small pilot like flame that since the blower is not working will starve for oxygen giving you.... soot... The flame will eventually die, or might stay on long but it probably wont be hot enough to trip the limiter.

    Good luck!
     
  16. Spridle

    Spridle Active Member

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    Thanks Nandy, and sorry for your posting trouble. Even after doing a copy and paste, you still get shafted. Insult to injury!

    I think at this point if I could find a quality mechanic to look at it I would do that. But at the moment I don't know any. The one I do know who works for the local RV shop and is supposed to be great, is the guy who sold me the furnace to begin with....in perfect condition, even though it turned out to be full of mud dauber nests, the bearings in the motor were gone.....

    I'll have to get this figured out one way or another. Realistically it will probably sit again until we start getting closer to cold weather camping. The manual does talk about setting the regulator, not sure if they mean on the furnace or at the tank. They also list dried up gaskets as being a cause of soot. So perhaps I just need to pull that gas valve for a close inspection of the valve and the chamber and replace the gaskets while it's out.
     
  17. Nandy

    Nandy Active Member

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    I would definitely go back to him and let him take care of it or at least find you the culprit...
     
  18. Spridle

    Spridle Active Member

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    Understand the sentiment completely but I want nothing to do with him. A lot of time has now passed too. When I bought it he said he would come over and flare the new lines for me. Never showed up, so I did it myself. When I found the nest caked inside he said "really?". When the bearings started screaming at the first sign of cool weather he said "Oh that's too bad". I bought it off craigslist, so it's my problem. In general I have made some very very good buys from CL, this was not one of them. Having said that, it has gotten me through and with a new motor and new fan it spins very smoothly. If I can get it burning cleanly it could outlive the camper.
     
  19. Nandy

    Nandy Active Member

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    Oh, I see... If you do business around Charlotte nc let me know. Might be able to work something off.
     
  20. Spridle

    Spridle Active Member

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    One of my largest projects ever was down in Charlotte, but that was many moons ago. Started late 1999 and ended sometimes 2001. I enjoyed it, but I"m told it's even more developed now than what I saw then. Closest I will probably get to Charlotte is a race down in at VIR, which is probably still 4 hours north of Charlotte.

    Thank you though. And I will post back with what I find.
     

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