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rinnai ru98 not always working


we built a house last year and installed a ru98 rinnai water heater. It worked great for about 8 months and in the last 4 months or so it doesn't start up sometimes. I would just wait 30 seconds then try the hot water again and it would work. It has got progressively worse until last night it wouldn't start at all. i had to reset the hot water heater ( un plug ) 5 times before it worked. it was flashing a code 11 so no flame present. i double checked the tank and lots of propane. what else can i look at ? sensors need cleaning or anything i can look at? we are on well water but have a filter system. please point me in the right direction. I am mechanically knowledgeable, just need help starting the trouble shooting. the nearest rinnai service is about 300km away. there is no point hiring the local plumber because i am better then he is.


  • JackJack Posts: 1,026Member
    I would call the propane company to check their regulator first.
  • agabryshagabrysh Posts: 9Member
    I just set up a service call for them . i will rule that out this afternoon.
  • agabryshagabrysh Posts: 9Member
    It was not the regulator. any other suggestions?
  • JackJack Posts: 1,026Member
    11, failure to fire could be either air side, gas valve or PCB. Most times with a board, it is either good or bad, so I'd inspect the inlet air side for clear or debris.
    Put a hose on the hot serice valve and control the flow at the unit so you can see what is going on. Sequence should be pre-purge, spark, flame and then micro amps, if it starts. Are you getting spark? Gently, try the connections at the sparker and others to see that there are no loose connections. If it gets to the gas valve you will need a digital manometer and at that point I'd want you talking with Rinnai Tech. Number is on the side of the unit. 800 621-9414
  • agabryshagabrysh Posts: 9Member
    i just showed a friend a picture of our gas install and he noticed potential problem. from the regulated to the tank there is only about 6 inches of black iron pipe then into the hot water heater. he said there should be few feet from the regulator to the the unit for the gas to have proper levels at all times. does this sound correct?
  • JackJack Posts: 1,026Member
    I am not sure. I have not seen that problem before. I do know that every system has a personality. We just hope that it is more Jeckyll than Hyde. A digital manometer will show gas delivery issue. Without out it I can only remember the times long ago when I held onto a pipe and thought, "yeah, I think I have flow". Did you try my water flow test?
  • agabryshagabrysh Posts: 9Member
    yes i did that and the unit does go pre-purge, spark, flame when it works. i tested it 10 times in a row and worked fine. I got a call format the wife a few hours later that it wasn't working. I did manage to be there when the unit didn't start and it went into code 11. I opened the hot water valve on the bottom and it tried to start. you can hear the pre purge and it trying to spark and no fire. I put my hand on the air intake on the inside and it flashed up right away. Everytime i choked out the fee ash air a little it fired up. Does this mean anything? it shouldn't make a difference if the front cover is on or off the unit right? i appreciate the help on this Jack.
  • agabryshagabrysh Posts: 9Member
    i also checked the vent to the outside and there is no blockage. the unit is installed in the basement on the outside wall and vented direct. the vent length is no more then 1 foot so easy to see a blockage.
  • SnowmeltSnowmelt Posts: 929Member
    Yes it does.
  • TomTom Posts: 546Member
    Can we get a picture of the setup? Stand back a little so we can see the whole thing
    Montpelier Vt
  • Aaron_in_MaineAaron_in_Maine Posts: 315Member
    If it's on a two pound LP system it does sound like the regulator or Maxitrol is too close to the unit. Your gas manometer wil get funky readings because of that. I put mine a couple of feet away from the inlet of the unit. Pictures would help.
    Aaron Hamilton Heating
    [email protected]
  • JackJack Posts: 1,026Member
    Also, check the altitude dip switch settings. Review all of the settings in the installation manual. Don't get creative, just confirm the settings are correct for your location.
  • agabryshagabrysh Posts: 9Member

    Here are 3 pictures. Let me know if they work ok. Yes it is a 2lb system.
  • JackJack Posts: 1,026Member
    That is awfully close. It "may" be impacting operation. Have you checked the dip switch settings? Without a manometer and what it will tell you it is difficult to assist beyond this point. The UEI model EM201 is the one I recommend.
  • agabryshagabrysh Posts: 9Member
    i appreciate all help. i am installing a u of black iron. 1 foot x 1 foot x 1 foot and i am also going to get a manometer double check it.
  • JackJack Posts: 1,026Member
    Actually, if you are going to do this, why not raise that regulator up to the ceiling and put several feet on blk iron on it. You should be able to get precut nipples in 1, 2, 3, or 4'. I think it would give you a better result.
  • icesailoricesailor Posts: 7,265Member
  • agabryshagabrysh Posts: 9Member
    ok sounds good. make the regulator as high as i can then black iron down towards the unit and then 90 into it. done and done. i will let you guys know what the results are in a few days as the problem is hit and miss
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