How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask Plumbing Pro Your Own Question

Plumbing Pro
Plumbing Pro, Plumber
Category: Plumbing
Satisfied Customers: 1284
Experience:  Licensed plumbing contractor state of Il, & Chicago
Type Your Plumbing Question Here...
Plumbing Pro is online now
A new question is answered every 9 seconds

We have a Rinnai R85i-1 tankless waterheater that is 3-4 years

Resolved Question:

We have a Rinnai R85i-1 tankless waterheater that is 3-4 years old. We're on a well, and when the water heater was installed, we had the plumber install turbidity and carbon whole-house filters on the cold water inlet to the house (fortunately with bypass valves.) Because of the initial carbon dust in the water, we switched the valves to bypass the filters and never got around to using them until yesterday. When the first filter went into its backwash cycle, the water heater started leaking. Taking the cover off the Rannai, the water is coming out of the exhaust fan, so it seems to be leaking in the heat exchanger above the exhaust fan. When the backflushing stops, so does the leak, and if I bypass the filters again, the water heater is not leaking.

When in backflush mode, the filters should be drawing water out of the system and discharging it out the backflush valve (since there is an airgap and the drain is by the filters, I can confirm it appears to be backflushing properly)...if anything, there should be a pressure drop, not an increase (I have a hose bib right before the inlet into the house and the water heater, and if I open that valve to cause a pressure drop, the Rinnai does not leak.) If I recall correctly, our water pressure is only about 50 psi, and the filter does not have a pump, so even if the backwash valve was not operating correctly and was somehow flushing back into the supply line, the pressure shouldn't be high enough to spring a leak. If there is a seal, joint or pipe leak in the heat exchanger, once it started, I would think it would leak regardless of whether or not the filters are in backflush mode.

Any thoughts on what I should do now. I'd rather be able to use the filters, but I can leave them bypassed, if the water heater is otherwsie going to be ok. I can use the flush valves to isolate the water heater and manually backwash the filters (a PIA), or...?
Submitted: 3 years ago.
Category: Plumbing
Expert:  Plumbing Pro replied 3 years ago.
Welcome to Just Answer, I will do my best to Answer your question to the best of my professional ability. things happen on coincidence, when ,or if you had a leak it would be all the time and not come and go . Water is under pressure so if you had a leak it would be all the time and not stop it self . If you had a leak in the heat exchanger then the heater would be shot and need replacement there is no fixing it, but it would leak all the time . If you are having water come out the pressure relief valve then , the valve might be bad and need replacement . The other thing is if yo u have filters that need back wash then that discharge hose needs to drain somewhere and you could just be seeing the water from the back wash , that would be normal , expect the hose should be placed into a drain so it doesn't leak all over , but a filter that does its own back wash means that it needs a drain to drain the contaminates. The other thing would be if you see water coming from the flue pipe then you might just be seeing water coming back in from the flue , as hot air rises it cools off and could fall back down the flue pipe and look like its dripping.
Customer: replied 3 years ago.
I understand water is under pressure and it should leak all the time, but it is not - it is only leaking in backflush mode. There is a backwash discharge hose from the tank valve on the filters that goes through an airgap to a nearby drain. The leak is clearly coming from the water heater, and it is more water than a bit of condensation from the flue pipe. Is there a pressure relief valve above the exhaust fan housing in the heat exchanger? If so, how do I get to it to replace it?
Expert:  Plumbing Pro replied 3 years ago.
the panel removes by unscrewing the little screws that hold the face panel on, there is a pressure relief valve , and they do go bad over time, and could need replacement. Other then that if your heat exchanger is leaking in any way then the heater is shot and will not be fixable. These thankless heaters do not recommend home owns to do there own repairs or service and strongly recommend calling a certified professional, or you will void any warranty that you might have, the heater should have a 10 years parts warranty and a 3 year warranty on labor if you contact the manufacture you can find out if your still covered.
Plumbing Pro, Plumber
Category: Plumbing
Satisfied Customers: 1284
Experience: Licensed plumbing contractor state of Il, & Chicago
Plumbing Pro and other Plumbing Specialists are ready to help you

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future. Jimmy Bagley, IA
< Last | Next >
  • You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future. Jimmy Bagley, IA
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
  • Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know. Robin Elkton, Maryland
 
 
 

Meet The Experts:

 
 
 
  • Marc

    Plumber

    Satisfied Customers:

    996
    Plumbing heating & home maintenance contractor
< Last | Next >
  • http://ww2.justanswer.com/uploads/VE/Veillplumb/2011-8-31_155028_IMG1104.64x64.JPG Marc's Avatar

    Marc

    Plumber

    Satisfied Customers:

    996
    Plumbing heating & home maintenance contractor
  • http://ww2.justanswer.com/uploads/plmqwk/2010-08-28_151844_profile_pic.jpg Plmqwk's Avatar

    Plmqwk

    Master Plumber

    Satisfied Customers:

    850
    20+ years in plumbing field. Licensed master plumber, commercial plumbing inspector
  • http://ww2.justanswer.com/uploads/JE/jerrymassie/2011-1-15_45937_1111055.64x64.JPG Jerry's Avatar

    Jerry

    Plumber

    Satisfied Customers:

    777
    over 20 years residential plumbing experience.
  • http://ww2.justanswer.com/uploads/PL/plumber171/2011-8-13_11445_plumber.500x500.64x64.jpg Mario's Avatar

    Mario

    Master Plumber

    Satisfied Customers:

    604
    Master Plumber, Fire Sprinkler, and Jobbing Spec.
  • http://ww2.justanswer.com/uploads/ABSBoss/2009-03-25_163017_2007-1031_046.jpg Bud's Avatar

    Bud

    Plumber

    Satisfied Customers:

    538
    22 Years Field Experience - 17 Years Business Ownership - Residential or Light Commercial
  • http://ww2.justanswer.com/uploads/TH/theplumber717/2011-11-24_34039_DSCF7012.64x64.JPG Theplumber717's Avatar

    Theplumber717

    Plumber, Hvac Tech

    Satisfied Customers:

    520
    Lic Plumbing contractor, 27/yrs res,com,repair,Universal HVAC Tech
  • http://ww2.justanswer.com/uploads/skibum0101/2008-12-16_015819_just_answer.jpg Rick Mather's Avatar

    Rick Mather

    Building Inspector

    Satisfied Customers:

    494
    Assistant Building Official, HVAC Tech