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Munchkin HX leak---what are my options?

Nom_DeplumeNom_Deplume Member Posts: 51
Homeowner here. Opened up my Munchkin (2004) for its annual cleaning, to see a thin spray of water from about ten o'clock. I have drained the system, but it is getting cold tonight here. What are my options?

Can a pinhole in a HX be repaired?

If not, will warranty replacement (HTP pays 50%) take days, and is it worth it?

If I should get a new boiler, I can't afford a Viessmann. What do you recommend? Should I walk away from mod con? I don't need this!

Thank you very much for your advice!


  • nicholas bonham-carternicholas bonham-carter Member Posts: 6,540
    edited October 2013
    Strange water chemistry?

    Contact your local water company, and see what the chemical analysis is. Some areas have excessive chlorides which attack the heat exchanger. Someone here should be able to spot whether your water has a problem, and could recommend an alternative.--NBC
  • Nom_DeplumeNom_Deplume Member Posts: 51
    but can it be repaired?

    Thanks...our water is good Lake Michigan water.

    Can the HX be replaced as a routine maintenance procedure?

    Can I put some solder (the stuff used for copper) on the area of the leak, and thus keep it going until Monday or Tuesday?
  • hot rodhot rod Member Posts: 7,063
    tough to solder stainless

    without special flux and the correct solder. A replacement is the best option.

    What does the HX look like? Is the stainless discolored, or plugged between the coils? was it serviced every year.

    In some cases the HX will fail if they have been overheated caused by improper flow, air lock, or mineral build up inside the HX tubes.

    I have had good luck with that style HX in various brands of boilers. proper installation and routine inspection makes a difference.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • You might try

    epoxy to fix the leak until you come up with a solution.  I see for sale in hardware stores specifically for fixing water leaks and from what I've seen from weekend warriors (homeowners), it works.
    Often wrong, never in doubt.
  • Nom_DeplumeNom_Deplume Member Posts: 51
    epoxy, and questions

    Yes, I thought of using "JB Weld steel reinforced epoxy" (rated to 550F)  as a temporary measure. But unlike other homeowners' leaks, in this case I am putting the epoxy over a flame, and epoxy doesn't conduct heat too well and so will get hot (although steel-filled epoxy should be slightly better). Will it be OK?

    The HX is badly discolored. It does get vacuumed out and CLR'd each year. But over a year a lot of coffee grounds collect...I don't know if the stuff leaches out from the HX.


    1. How long will it take a pro to replace an HX? 2 hrs? 8 hrs?

    2. Is there any place in Chicago that would stock this part, or would I have to drive to Milwaukee (Hot Water Products)? I'm desperate...we have an important event at our house Wednesday.

    Many thanks to all for the help!
  • kcoppkcopp Member Posts: 2,771
    Its a full day......

    job and pretty much the whole boiler.
  • IronmanIronman Member Posts: 3,532
    edited October 2013
    Heat Ex.

    That style heat ex. (Gianonno) requires more than just vacuuming. You have to take a credit card and clean out the crevices between the tubes.

    If the heat ex. is discolored, then you're probably scaled up on the water side which would come from excessive make up water being introduced because of a leak(s) on the system.

    I don't know where to tell you in the Chicago area to find the heat ex. or who to recommend. It may have to be ordered from HTP directly.

    Personally, I would recommend replacing the boiler if you can afford it. I would look at the Lochinvar WHN wall hung, the Triangle Tube, or the Dunkirk/Utica Laser Tube. They all have a superior heat exchanger design which is also virtually self cleaning. Don't take that claim to the extreme though; yearly maintenance should still be done.

    Make sure all system leaks are found and repaired or else you'll be back to the same place in matter of time.
    Bob Boan

    You can choose to do what you want, but you cannot choose the consequences.
  • Nom_DeplumeNom_Deplume Member Posts: 51
    no makeup water

    Thanks for the reply. There's no makeup is shut off and the pressure held just fine (until the HX leaked).

    I'm told the entire boiler must be replaced. I would love to get rid of the el cheapo Munchkin, but I don't get warranty coverage (50%) unless I buy another HTP product. Plus they apparently still sell the identical model so drop-in replacement, no repiping necessary. So not having to spend thousands of dollars makes it a a tough call. The alternate models you recommended sound good.
  • hot rodhot rod Member Posts: 7,063
    is it piped correctly?

    Primary/ secondary or with a hydro-separator? If it is discolored it probably has had inadequate flow. if you do replace it be sure it is getting required flow.

    That style HX can, and does last 15 years or more without breakdowns if they are maintained properly.

    The brown coffee grounds is by products of the fuel and air combustion. Some present that, others not, but the build up between the loops of the HX coils need to be clear for the heat to transfer.

    Here is an example of an abused HX, not a manufacturer defect.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • nicholas bonham-carternicholas bonham-carter Member Posts: 6,540
    Boiler replacement

    This would be a good time to check your building heatl-oss, just make sure your replacement is the right size. The SlantFin app for smartphones make it easy.--NBC
  • IronmanIronman Member Posts: 3,532
    Flow Issue

    It's definitely a flow issue as Hot Rod mentioned. Whether it's improper pumping/piping or scale build up. Or both.

    If you could post some good pics of the near boiler piping and give the pump model and boiler size, we can tell if that's correct.

    If HTP doesn't want the heat ex. back, then cut it open and see what the water side looks like.

    Also, the most important thing is getting a qualified installer/services for whatever brand you choose.
    Bob Boan

    You can choose to do what you want, but you cannot choose the consequences.
  • Nom_DeplumeNom_Deplume Member Posts: 51

    Many thanks for the helpful responses.

    Of course it has good primary-secondary piping; absolutely no problem with the piping so I won't post a photo. But I can't say if the flow was good. The boiler is supposed to sense flow, no? I should have looked at the water to see if it was brown, but I didn't think about it.

    I like the Triangle Tube Prestige recommendation, but I collect the 50% warranty reimbursement only if I buy another HTP product. What about the HTP Elite FT: isn't the hardware basically the same as the TT?
  • HenryHenry Member Posts: 720

    The heat exchangers that we have replaced this past year were discolored and blocked. I have seen many problematic installs that had flow rate problems. They use the same size pipe as the boiler connections. WRONG! One needs to know the flow rate required and size accordingly. They size the pump for a 35 Deg Delta T, assuming they will get better efficiency. WRONG, use a max of 30 deg with the proper pipe sizing for the flow rate. Wrong pipe sizing = wrong flow rates. We see this so often on trouble shooting other peoples installs. Some of them will not fir 100% because of insufficient flow.

    The coffee cruds usually happen in propane installs or badly adjusted burners.
  • IronmanIronman Member Posts: 3,532
    Elite FT

    The Elite FT has the fire tube heat exchanger, the regular Elite has the same Gianonni heat exchanger that you have now.

    The fire tube design greatly reduces the head loss that the Gio produces and in many cases reduces or even eliminates the need for the large primary circ. That needs to be calculated and confirmed on site though, as each system is different.

    I'd go with the fire tube, hands down.
    Bob Boan

    You can choose to do what you want, but you cannot choose the consequences.
  • Nom_DeplumeNom_Deplume Member Posts: 51

    Why check heat loss? I know how my gas consumption varies with degree days, so i know my heat loss exactly.

    The problem with heat loss calculations is that they vastly over-estimate the heat loss.
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