Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Rinnai Water Heater Leaking

frances Member Posts: 1
no, your venting should not be leaking, it sounds as if the venting is just not put together right.... as far as it being purple, ?????????.
the inner pipe pre heats the air coming from the outside in the outer pipe.... so your right about that.
On another note: how is the rinnai performing for you and your household? any problems in the demand you need and/or want?


  • Jay_11
    Jay_11 Member Posts: 50
    Rinnai Water Heater leaking and loud noise

    We had a contractor install a direct vented natural gas Rinnai water heater a few weeks ago. I just noticed that that the intersection of between two of the tubular sections of the air intake/exhaust vent to the outside has a very slow leak and is dripping a purplish liquid onto our basement floor. Perhaps it is the hot exhaust pipe that is forming condensation when it hits the cold intake air (in the Rinnai it seems the single vent pipe houses the exhaust pipe inside the tube that supplies the fresh air). Does that sound right or is this something I should get examined while it is under warranty.

    Also we noted that when the Rinnaoi turns on often it makes a very loud noise like an aircraft engine which subsides after three or four seconds and is replaced by the regular operational sounds. We mnentioned this to the contractor who thinks this might be due to a faulty flow regulator piece and is waiting for a replacement part to install. Anyone run into this before?

    Thanks in advance.
  • Mark_7
    Mark_7 Member Posts: 123

    Vent pipe should also be graded outward to let any condensate to drip out side.And if it's a long horizontal run a condensate collector should be installed.
  • Jay_11
    Jay_11 Member Posts: 50
    Thanks for the response

    The horizontal run is maybe 4-5 feet in length--doesn't appear to me to be graded outwards particularly--can that be adjustedeasilt--since they have already cut the hole through my outer wall for the venting and installed all the piping? Is their any danger that the condensate will drip back down the vent pipe and damage the water heater?

    As to my family's satisfaction--we replaced our direct tank storage system with this Rinnai because we didn't have enough space in the boiler room for a conventional water heater and our new boiler (which was much bigger than our existing boiler even though it has much less BTUs). If it weren't for the spacing issues I'd probably have gone with the conventional tank for cost reasons as the Rinni cost me about 3-4 times the storage tank--I suppose I'll recoup some of that in gas savings. That said, we're generally pleased. On the plus side, the hot water does not run out when my wife fills the bathtub--she always used to have as a problem with the storage tank running out. On the downside (1) occassionally when I'm showering, the water will turn cold for about 10 seconds, before going back to hot--I usually can avoid this by letting the shower run for about 30 seconds before getting in and (2) it takes a little longer for hot water to reach all the faucetts--we have 4 floors in house and I'd say it takes from 6-12 seconds depending upon which floor your on.
  • Jack_21
    Jack_21 Member Posts: 99
    The vent shuld definitely pitch to the outside.

    You do not want ANY condensation coming back into the unit. It will, over time raise hell with it. Your installer should disassemble and check the vent. the inner pipe should be 3/4" longer that the PVC outer pipe.

    As to the start-up howl I had one recently do the same thing. It turns out that the vent 90 off the top of the unit has a black plastic retainer to maintain concentricity between the pvc and the flue gas pipe. this black retainer had cracked and upon start-up would howl briefly as yours does. Replaced the 90 and the problem went away.

    Your unit is functioning correectly for the hot water output. When you shut off the water and then start it up again it takes a couple seconds before the unit is really producing hot water. You are experiencing what is called the "cold water sandwich" It is a characteristic of on demand units. I'd be interested in what your fuel bills are vs your old tank. Also, do not look only at the fuel. Compare your water usage as a function of fuel consumption. What I have found is that when you can relax and take a fairly long shower you have a tendency to do so, thereby using more water.
  • Bob_41
    Bob_41 Member Posts: 28
    Loooong showers


    >> What I have found is that when you can relax and take a fairly long shower you have a tendency to do so, thereby using more water. <<

    I can attest to this!! Over Thanskgiving at the in-laws with a Rinnai unit providing HW to the seperate living area above the garage that we were staying in ... unlimted hot water ... we had snow and temps into the low 20's so I found myself REALLY enjoying the looong hot showers .... I can imagine that if I had similar in my home that over a year I would see:

    1) Increased NG fule usage
    2) Increased water consumption

    Just too damn convenient to take loooong showers.


  • Steve M
    Steve M Member Posts: 26
    howling Rinnai's

    Jay, the howling is usually an indication of a problem with the air/fuel mixture. I would take Jack's advice and have the 90 checked. If the 90 checks out, your contractor should do a combustion analysis on the unit as per the start up instructions. He can fix the vent problem at the same time since there shouldn't be anything leaking out of it, AT ALL. All the condensation should run outside, not to the unit. The sandwich effect that Jack mentioned can be helped by adding a small buffer tank to the hot water supply line.
  • Jay_11
    Jay_11 Member Posts: 50

    Thanks for all the advie. I'll take it up with the installer when he comes to check it out.

    When you say the inner pipe should be 3/4 inch longer--I'm not sure what you mean--how does the longer pipe avoid the condensate drip?

    When you mnention the black plastic retainer, do you mean the black cap on the end of the vent pipe that protrudes from the side of my house?
  • Jay_11
    Jay_11 Member Posts: 50

    PS As to your questions, it's going to be hard to get a real comparison on gas usage since we also replaced at the same time our 20-year old Bryant steam boiler with a (hopefully) more efficient Burnham IN-5. Water usage we should be able to measure but the quarterly bill has not arrived yet--I'll report when it does, but also that number is not likely to be accurate since at this time last year we had two less people living at the house (new baby and live-in babysitting grandma)
  • Steve M
    Steve M Member Posts: 26
    the black plastic retainer

    The retainer contains the gasket that maintains the seal between combustion air coming in and flue gas going out. When you allow the air mixtures to cross, the Rinnai howls, or sounds like a jet taking off. It doesn't like to re-burn spent flue gas. The inner pipe needs to be longer so that when the pipe is pushed together, it slides into the coupling on the exhaust side. If they cut it too short, the internal pipe won't seal.
  • Davel_3
    Davel_3 Member Posts: 7
    Purple primer?

  • doitjunkie
    doitjunkie Member Posts: 1

    my rinnaie water heater was installed 13mos ago.  No problems other than those nasty cold sandwiches until 3-4 days ago.  the "pressure relief pipe" (vent) is leaking continuously.  any suggestions on what to do?
  • Jack
    Jack Member Posts: 1,047
    Resurrecting a 9 yr old thread?

    You can ask a "new" question. You say the pressure relief pipe is leaking. I have to say that on a tankless that is exceedingly rare, at least in my experience. What temp are you running, model #. With a leaking prv after 13 mos, I'd replace the valve while also checking gas pressure and water pressure. Do you have high water pressure? Temp and pressure being directly proportional adding temp to a high pressure system might trip the prv
  • j a_2
    j a_2 Member Posts: 1,801

    I have been installing Rinnai products for many years…In the beginning I had a learning curve….What I learned is howling is almost always vent related, it is sucking in exhaust,as someone already said….use the lube provided and make sure they are pushed all the way in…then use the supplied screws…If someone cuts the vent that is where you must be careful to follow procedures,very carefully,outer shorter than inner…As for vent pitch it depends on the model and if you have a condensate collector.it pitches back if not it pitches out,never a flat vent….Get the model number and simply read the instructions…Any homeowner can read,just be careful not to accomplish a task that the manufacture says must be done by a trained individual…Read the warnings in the front of the book…Installed improperly can cause death…Here in Mass not only is it code its the LAW...
This discussion has been closed.