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Exterior commercial Rinnai to replace existing old boiler?

samIam
samIam Member Posts: 6
in a residential application. Is this a good idea?



We live in a 1910 house that still has the original boiler converted to gas used to provide water to our hydronic radiator heating system. We need to upgrade and one contractor is suggesting the Rinnai at a really good price and says they generally last 20 years. Another heating guy is telling me that the Rinnai isn't really designed to provide the necessary pressurized water needed in a hydronic heating system and that the pump installed to give the proper pressure will end up breaking down the parts inside the Rinnai after only a few years. He suggested that the Rinnai was offered as a cheap solution, but it won't be long term. Agree?



He said he would most likely install a Combi or Modcon unit which I believe are condensing units. Does this sound like a better long term solution?

Comments

  • samIam
    samIam Member Posts: 6
    a little more info.....

    The first company suggested a Rinnai model #R94LSi-NG 15,000 - 199,000 BTU input to replace our boiler. This is supposedly a commercial unit to be used in a residential setting. From what I can tell, it is a tankless hot water heater, NOT a condensing boiler and I'm wondering if: 1-I'm being scammed, 2-it's an OK application, but not the best, or 3- it is perfectly fine. I see that Rinnai does make a condensing boiler that costs about $7,000.00 more for the unit itself than the one we were given a quote for. Thanks!
  • samIam
    samIam Member Posts: 6
    a little more info.....

    The first company suggested a Rinnai model #R94LSi-NG 15,000 - 199,000 BTU input to replace our boiler. This is supposedly a commercial unit to be used in a residential setting. From what I can tell, it is a tankless hot water heater, NOT a condensing boiler and I'm wondering if: 1-I'm being scammed, 2-it's an OK application, but not the best, or 3- it is perfectly fine. I see that Rinnai does make a condensing boiler that costs about $7,000.00 more for the unit itself than the one we were given a quote for. Thanks!
  • Jack
    Jack Member Posts: 1,045
    Don't use a Rinnai water heater for

    Space heating in a closed loop application. At one time Rinnai authorized this use but they pulled the listing 3-4 yrs ago. Tankless WATER HEATERS are excellent in their intended use. Tankless water heaters are designed for variable flow and high delta t's. In a boiler application, you get pretty much fixed flows and very low delta T's. I represent Rinnai and know this is correct.



    Rinnai does offer a line of mod-con boilers which have proven to be excellent. What is the heat loss on your
  • samIam
    samIam Member Posts: 6
    what if they convert it to open loop?

    They planned to install a water hose bib onto the system, making it an "open loop" which they say Rinnai requires for full warranty coverage. Same question though....even if they do this, is it still a bad idea, an OK application or a good one? At this point I don't know our heat losses. However, the house is a completely uninsulated 1910 house with plaster walls with about half of the windows replaced with high quality ones. We plan to insulate the attic and crawl space areas.



    It seems like a rinnai condensing unit would be more appropriate, right?
  • Jack
    Jack Member Posts: 1,045
    Well, let's see....

    You are kidding, aren't you?
  • samIam
    samIam Member Posts: 6
    ?

    I'll take your comment to mean that converting it to open loop does not make a tankless water heater an appropriate use for space heating instead of a boiler.



    Thanks
  • EricAune
    EricAune Member Posts: 432
    If its wrong and still works, is it still wrong?

    Yes, in most cases.



    Rinnai manufactures a wonderful product line with specific purposes intended.  Their tankless water heaters are not rated for space heating for many reasons, selling boilers may be one but their true intentions lie in providing you the right product for your application.  It seems the contractor who is pushing the tankless unit does not have the same idea.



    Tankless units have very high head losses, require a large amount of flow (gpm) in a radiant application and therefor should be separated in a way to achieve the needed flow.  Rinnai, and other manufacturers, have identified the possible paths of failure (and there are many) in utilizing their tankless units as space heating appliances.  Improper installation, overheating, fouling of the heat exchanger passageways due to poorly maintained systems...the list goes on and on.



    Boilers, and some water heaters, are the appliance of choice for hydronic heating systems for a reason.  Warranty is a big fat reason and I would suspect failure of a tankless unit to coincide almost exactly when said warranty period has expired, never-mind the true or actual application.  Go with the boiler guy, he seems to be the only one who knows what he is talking about.  
    "If you don't like change, your going to like irrelevance even less"
  • EJ hoffman
    EJ hoffman Member Posts: 126
    Rinnai website



    Heat exchanger: 12 years* for residential and 5 years* for

    commercial and hydronic applications; (10 years* if used with the

    Rinnai Hydronic Air Handler); all other parts 5 years*; labor 1 year;

    (* 3 years if used as a circulating water heater within a circulation

    loop, when the water heater is in series with a circulation system

    and all circulating water flows through the water heater

    http://www.rinnai.us/documentation/downloads/R98LSe_SP.pdf

    The above was copied from the rinnai website  and the link is for the spec sheet for the unit I would guess the other contractor is suggesting.  I won't speculate on this situation for the pricing but be educated on the warranty. This specific  product is approved for  these uses by the manufacture.  Unless the website is wrong? We all know take everything you get off the web with a grain of salt.
  • Jack
    Jack Member Posts: 1,045
    The hydronic system warranty

    Is for open loop systems only. Otherwise the warranty is correct as stated in the previous post. We have had success with the water heaters driving the air handler and providing hot water. This open loop system allows flexibility of the burner in the hot water mode and therefore have proven to be reliable. Evdryone makes their own assessment of whether they like open loop systems.



    Eric, thank you for your post. I was speechless;) and those who know me will find that to be a stunning admission!
  • CMadatMe
    CMadatMe Member Posts: 3,085
    Nicely Said

    Eric is on point. I would only add, If a specific product was meant to be used for heating it would have an "H" stamp and be rated as such. No stamp, No rating..equals NO INSTALL for me.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Ironman
    Ironman Member Posts: 6,581
    SEND THEM PACKING

    You need to add a "0" to your scale of 1 to 3. "0" being this guy is not only trying to scam you but he knows nothing about hydronics.



    You really need to consider a good mod/con from a contractor who has a good reputation and is well versed in hydronics, particularly converting an old gravity flow system.



    If you'll post your city/ town, maybe some of the guys on here could point you toward a good hydronic contractor.

     
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • samIam
    samIam Member Posts: 6
    I'm in Eugene, OR...

    I have additional bids coming in from Comfort Flow and from Home Comfort. While Home Comfort gets rave reviews on Angie's List, I get the impression they don't do as many Hydronic systems as Comfort Flow. Any other suggestions would be appreciated.
  • EJ hoffman
    EJ hoffman Member Posts: 126
    Oregon vs. the web

    I posted below the warranty info.  I am in Lake Oswego Oregon,I am a radiant contractor/plumbing contractor. I have had success with on demands in your situation, but note the warranty trade offs vs. the price trade off.   Most of Oregon is very mild and if the on demand is set up correctly it will work very well. But it can also fail prematurely and have its warranty voided by a manufacture.  If I were you I would preform my due diligence as a consumer, get referrals, look at installs. check the CCB record.  If you want to discuss this further off the board e-mail me back and I will give you my experience from Oregon.
  • Steamhead
    Steamhead Member Posts: 14,850
    When you say "open loop"

    do you mean a system where potable water mixes with heating system water? 
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,195
    There are places with full codes to protect consumers

    from dangerous installations. One of those places is Massachusetts where open systems are not allowed in any shape or form. We may have high taxes but we also have less legionella out breaks and I am happy I call the bay state home. Open systems are not a choice they are a time bomb.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
    https://heatinghelp.com/find-a-contractor/detail/charles-garrity-plumbing-and-heating
  • Jack
    Jack Member Posts: 1,045
    Sorry, Charlie!

    That is not correct. There are all kinds of these systems in apt building all over the place in the Commonwealth. The big apt developers (Avalon, etc) drove this through. They use a tank water heater to both the tap and to an air handler. I believe they are pretty much limited to those installs, but they are happening. There was a heck of a battle over this a couple years ago, but they were able to get it through. They are illegal in ME.
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,195
    Just because they do it

    Does not make it legal. Show me where it is in the code?
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
    https://heatinghelp.com/find-a-contractor/detail/charles-garrity-plumbing-and-heating
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