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  1. #1
    Join Date
    Oct 2010
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    Ruud Achiever 90 Plus burner goes out

    I have a Ruud Achiever 90 Plus unit. New in 2007. The burner randomly goes out, sometimes right after the fan kicks on and sometimes it will run for a few minutes and then go out. The burner will light everytime but won't stay on long enough to heat the house. I get a 2 blink error code everytime the burner goes out, 2 blinks means pressure switch. I replaced both pressure switches, did not make a difference. There is no moisture in the vacuum lines going to the pressure switches. Checked the P-trap and drain hoses connected to it, there was moisture but just a few drops...there is almost a steady trickle coming out of the furnace drain pipe when it is running so I think it is draining well. I did some tests to see if I could narrow down which pressure switch was causing the issue. After the exhaust blower turned on I put a jumper between the terminals of the pressure switch connected to the exhaust blower. It seemed to run really well with the jumper on. I let it run for about 20 minutes and it didn't miss a beat. So I'm thinking either my pressure switch is bad and so was the one I replaced it with. Or else wind is coming in through the exhaust which would reduce the amount of vaccuum and possibly cause the pressure switch to open (it exhausts horizontally through my wall). I live in North Dakota where it is always windy. I did prop a wheel barrow up against the outside of my house to try to deflect the wind around the exhaust without blocking it. My last thought is that the exhaust blower could be going out...it sounds fine when it is running.

    Are there any other things that could give me a pressure switch error code? Also wondering how hard it would be to check that the exhaust blower is working correctly?

    Thanks for the help!

  2. #2
    Join Date
    Dec 2007
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    wheelbarrow is not a good idea if it blocks the exhaust from accelerating away from the house!!! it may also cause recirculation of the exhaust into the combustion/intake air which is not good either.

    there are a few other things that may cause what is happening including, but not limited to incorrect intake/exhaust venting, bad inducer or even a cracked heat exchanger.

    at this time, changing parts would probably cost as much or more than having a qualified tech service and diagnose the issue.

    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
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  3. #3
    Join Date
    Oct 2010
    Location
    SW Michigan, near Battle Creek
    Posts
    921
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    yeah if you have a bad heat exchanger (not likely but possible) you could change every other part on this thing and still not fix it.

    pressure switches are seldom bad out of the box (maybe two in the last 16 years Ive been fixing furnaces)

  4. #4
    Join Date
    Jan 2004
    Location
    PA
    Posts
    74,863
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    Time to call a service contractor to come out and fix it for you.
    Instead of buying parts that not only are needed. But were probably under warranty.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  5. #5
    Join Date
    Oct 2010
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    Thread Starter
    FYI, I fixed the problem. There were actually 2 problems.

    Problem #1: My exhaust venting was slanting the wrong direction. This caused a puddle to form in the exhaust. When it got below freezing outside the puddle would freeze and restrict the flow of the exhaust. This tripped the pressure sensor and shut down my furnace. I couldn't believe that the installers could make such an obvious mistake. When I looked behind my furnace, I noticed that a hanger bracket had broken for the exhaust...so it wasn't really an installation issue (other than they installed the bracket sideways causing a lot of stress on the hanger which is why it eventually broke). I corrected the tilt of the exhaust and replaced the hanger with something a little more sturdy.

    Problem #2: So I was all excited that I fixed my furnace and then a few days later it started cutting out again. Then the next day it worked fine. A few days later started cutting out again. I eventually figured out that it would only do it on windy days. Outside temperature did not effect the furnace at all. My exhaust exits the side of my house and there is a 45 degree elbow on the end (facing down). I went down to the local big box store and picked up another 45 degree elbow and attached it to the end of my exhaust (also facing down). So now my exhaust is pointing straight down after it exits my house. I havn't had a problem since. There have been some very windy and cold days since then and it hasn't missed a beat. So my 2nd problem was from wind causing resistance in the exhaust, which also tripped the pressure switch.

    Hope this helps someone else that is having problems with their furnace.

  6. #6
    Join Date
    Nov 2010
    Location
    Kansas
    Posts
    2,705
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    The way your installer had the exhaust installed was incorrect per manufacturer specs and so do you and it can cause problems the way you have it installed if I understand you correctly.

    Did he vent two pipes outside or just one?
    Can you post a pic?
    Last edited by beenthere; 12-10-2010 at 05:53 AM. Reason: removed DIY aid
    .


    The statement below is my signature and just my overall feeling towards our industry and does not necessarily pertain to you nor this thread.


    There really isn't a legitimate excuse for not doing the job correctly!

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