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Pulling out my First Rinnai:-(

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  • Pulling out my First Rinnai:-(

    New customer called with a 10 Fault (Blocked vent). After 2 hours of investigation and a waterside
    descaling I see that the incoming gas pressure is @ 11" w.c. (MAX recommended is 10.5") and stays this high with the unit firing as well.

    I shine a bright flashlight down through the top of the exchanger but can't see any light through the flame observation window... Trouble for sure.

    I pull out the trusty Ridgid Explorer and get a few up close looks at the fins SOOT!

    I have never seen a rinnai actually soot up and clog an exchanger to the point that it would trip a blocked vent fault code.

    The owner has decided he wants to have a tanked water heater again.... ( I will take a few pics next week when I pull it)
    Last edited by OkieBill; 06-24-2011, 10:25 PM.

  • #2
    Re: Pulling out my First Rinnai:-(

    Originally posted by OkieBill View Post
    New customer called with a 10 Fault (Blocked vent). After 2 hours of investigation and a waterside
    descaling I see that the incoming gas pressure is @ 11" w.c. it stays this high with the unit firing as well.

    I shine a bright flashlight down through the top of the exchanger but can't see any light through the flame observation window... Trouble for sure.

    I pull out the trusty Ridgid Explorer and get a few up close looks at the fins SOOT!

    I have never seen a rinnai actually soot up and clog an exchanger to the point that it would trip a blocked vent fault code.

    The owner has decided he wants to have a tanked water heater again.... ( I will take a few pics next week when I pull it)
    This is why I want no parts of installing or servicing of tankless.

    Comment


    • #3
      Re: Pulling out my First Rinnai:-(

      had a 4 year old noritz the other day that's a 9.3 model 250,000 btu. he started to experience the unit not starting and had to go to the garage to power it on and off to get it to work. noritz told him to flush the heater. so i did. but the heater was spotless as it has a softener installed in front of it. 1 hour of flushing and the bucket was still clean.

      told him to take note of the error code next time and we can look it up.

      rick.
      phoebe it is

      Comment


      • #4
        Re: Pulling out my First Rinnai:-(

        I service / install a lot of tankless. Most of the time the problem arises (either immediately or later on) because of installation error or poor installation. If it's not installation error than its typically a pc board (Rheem), descaling (all mfg), gas valve (Bosch) or a clogged water servo. I became a dealer and service provider for Rinnai because I've found them to be the least troublesome. I wish I could be there to look at the installation. Did you call Rinnai and ask them?
        Ray

        “Wealth is the product of man's capacity to think.”— Francisco d'Anconia
        Atlas Shrugged (Part 2, Chapter 2, Page 411)

        www.mauiplumbinginc.com

        Comment


        • #5
          Re: Pulling out my First Rinnai:-(

          With it being sooted up like that, makes me wonder if there was a vent obstruction either on the fresh air side or the exhaust. Either can cause it not to burn right and cause the sooting up as described. I would look at the venting and see if the outer jacket been crushed ( that the intake air part) or if a bird made a nest in it. Also make sure the venting was installed properly. The thing I liked about the Rinnai is it uses the concentric venting which means it getting its combustion air from outside.

          First time I ever came across a sooting problem was on a pair of Lochinvar boilers that was suppling hot water for a restaurant. Turned out the make up air vents where installed wrong and way undersized. This went unnoticed for years since other guys when they where servicing them the doors to enter the mechanical room where left open during their troubleshooting. When I went there I had the door open fired up the heater all looked good, soon as I closed the door, the flame started to loft around and eventually die out. So I corrected the fresh air intake issue cleaned out all the soot, and all was good.
          Last edited by SewerRatz; 06-25-2011, 09:19 AM.
          Ron Hasil Lic #058-160417
          A-Archer Sewer & Plumbing specializing in:
          Tankless Water Heaters | Drain and Sewer Cleaning
          Sump and Ejector Pumps | Backflow RPZ Testing

          Comment


          • #6
            Re: Pulling out my First Rinnai:-(

            From experience with setting up oil burners, this sooting problem is definitely an air problem.

            Comment


            • #7
              Re: Pulling out my First Rinnai:-(

              I've seen the sooting issue from the gas pressure being set improperly, Rinnai's have a gas test port for a monometer and rinnai can provide the chart, theres a little adjustment screw to tweak the gas flow.

              speaking from experience, don't try it with an anolog monometer.
              No, it's not rocket science, it's plumbing and unlike rocket science it requires a license.

              Comment


              • #8
                Re: Pulling out my First Rinnai:-(

                Ron, I spent the first 2 hours pulling apart the the concentric venting (UBBINK brand) from the unit to the roof to check for obstructions and pulling the combustion air path apart inside the rinnai to include pulling the boot at the combustion air fan to examine the squirrel cage. All were clear which got me looking at the fuel supply...

                MOJourneymen, I don't think I have ever looked at a Rinnai's natural gas supply pressure in town but I have installed a few LP gas Rinnais so I have dialed them in with a Yellowjacket 7680 diaphragm gauge. I have a buddy that works for the gas company that will loan me a U-tube:-)

                Comment


                • #9
                  Re: Pulling out my First Rinnai:-(

                  Originally posted by Flux View Post
                  From experience with setting up oil burners, this sooting problem is definitely an air problem.

                  I too have set up oil burners and have to take exception to it "definitely" being an air problem.

                  Natural gas combustion is one of the simplest cleanest forms of combustion we have though the low specific heat of natural gas and how it relates to distribution can still make fuel oil economical. That being said Oil burners even set as good as you can will always produce a certain amount of soot. I can attest to this fact by the many seasons I have spent covered in soot doing seasonal maintenance:-)

                  Oil burners just as any combustion system are a balance of both fuel and air, an oil burner is also dependent on fuel oil pressure since the fuel pump is attached to the burner,cleanliness of the Fuel oil filters, proper fuel pre heating (where required), cleanliness of the nozzle/orifice and proper flame / cone shape, any one of these issues can lead to sooting of an oil burner and are independent of combustion air and venting issues...

                  Last edited by OkieBill; 06-25-2011, 05:35 PM.

                  Comment


                  • #10
                    Re: Pulling out my First Rinnai:-(

                    Originally posted by OkieBill View Post
                    I too have set up oil burners and have to take exception to it "definitely" being an air problem.

                    Natural gas combustion is one of the simplest cleanest forms of combustion we have though the low specific heat of natural gas and how it relates to distribution can still make fuel oil economical. That being said Oil burners even set as good as you can will always produce a certain amount of soot. I can attest to this fact by the many seasons I have spent covered in soot doing seasonal maintenance:-)

                    Oil burners just as any combustion system are a balance of both fuel and air, an oil burner is also dependent on fuel oil pressure since the fuel pump is attached to the burner,cleanliness of the Fuel oil filters, proper fuel pre heating (where required), cleanliness of the nozzle/orifice and proper flame / cone shape, any one of these issues can lead to sooting of an oil burner and are independent of combustion air and venting issues...

                    Absolutely agree with what you said, but you're a little off on your oil assessment. See If you're covered in "soot" doing seasonal maintenance, the burner is not set-up right after the initial cleaning, unless the guy prior only did a "dust and adjust" instead of pulling the baffle tubes, pulling the flue down etc. But my customers go 2 years between cleanings, and I'm not covered in soot. The only time I'm covered in soot is when I encounter a burner that hasn't been set-up right or cleaned in 3+ years..not seasonal.

                    Someone is doing something seriously wrong if a boiler is that sooted up in 1 years time,and they probably shouldn't be offering burner service. I made that mistake once, and never made it again in my career, and it sooted the boiler badly in 1 years time.

                    I don't know anything about tankless water heaters...nothing... but I should of said combustion instead of just air.
                    Last edited by Flux; 06-26-2011, 02:00 AM.

                    Comment


                    • #11
                      Re: Pulling out my First Rinnai:-(

                      Rinnai has pressure sensors that shut it down if gas supply is too low I would think there is one for too high of gas pressure as well. The unit goes into a hard lockout if it's too low. I see that a lot. Our incoming gas pressure here is rarely above 8" of W.C.

                      Has there been an ongoing lockout issue with this heater leading up to this replacement?

                      Comment


                      • #12
                        Re: Pulling out my First Rinnai:-(

                        Originally posted by plumberscrack View Post
                        Rinnai has pressure sensors that shut it down if gas supply is too low I would think there is one for too high of gas pressure as well. The unit goes into a hard lockout if it's too low. I see that a lot. Our incoming gas pressure here is rarely above 8" of W.C.

                        Has there been an ongoing lockout issue with this heater leading up to this replacement?
                        The Customer has been running out to the garage and resetting this Rinnai daily though the problem was not reported to the owner / landlord for about a month. The owner informed me that this unit had never had any kind of maintenance performed on it as well (6 year old install)

                        I doubt there is a high gas pressure sensor as the high temp sensors could pull double duty on this, the more i think about it is the low gas pressure sensor actually looking at the incoming gas pressure or is it a flame rod that is simply looking at the condition of the flame in the combustion chamber?

                        Comment


                        • #13
                          Re: Pulling out my First Rinnai:-(

                          Okie, if you were getting a code 12 several things could be going on. Not grounded properly, bad wire connection, dip switch setting, venting issue, and gas pressure. If it is too low it will code out with a 12 and if pressure is too high it will code out with a 12. If the gas mixture in the combustion chamber is not correct it cause improper burner operation. Which leads to the sooting up. I cleaned a burner and combustion chamber on one the other day that was so bad I had to leave the room to let the dust clear out. No call back yet. This unit had way too much pressure due to a bad install on a two pound gas system. Unit probably was never checked for high fire and low fire settings either.

                          Comment


                          • #14
                            Re: Pulling out my First Rinnai:-(

                            Originally posted by plumbertim1975 View Post
                            Okie, if you were getting a code 12 several things could be going on. Not grounded properly, bad wire connection, dip switch setting, venting issue, and gas pressure. If it is too low it will code out with a 12 and if pressure is too high it will code out with a 12. If the gas mixture in the combustion chamber is not correct it cause improper burner operation. Which leads to the sooting up. I cleaned a burner and combustion chamber on one the other day that was so bad I had to leave the room to let the dust clear out. No call back yet. This unit had way too much pressure due to a bad install on a two pound gas system. Unit probably was never checked for high fire and low fire settings either.
                            As I said most problems with tankless heaters are due to improper installation...
                            Ray

                            “Wealth is the product of man's capacity to think.”— Francisco d'Anconia
                            Atlas Shrugged (Part 2, Chapter 2, Page 411)

                            www.mauiplumbinginc.com

                            Comment


                            • #15
                              Re: Pulling out my First Rinnai:-(

                              Originally posted by mpm View Post
                              As I said most problems with tankless heaters are due to improper installation...
                              I think back to a job my buddy did, he is a GC who put one in for a customer of mine. I think back now and HOPE and PRAY he did it right... Of course the customer had and still has no clue that she needs to do any sort of maintenance to it. I would be afraid to touch it, a bazillion pipes and valves to confuse anyone besides a knowledgeable professional.
                              We don't have preventative maintenance around here, we have CRISIS MANAGEMENT!

                              Comment

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