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Mod/Con Heat Exchanger Designs

knotgrumpyknotgrumpy Member Posts: 207
As this heating season is easing up a bit (I hope!)  I'm looking to replace my W-M CGi with a mod/con this summer.

Seems there are 3 main heat exchanger designs out there right now:

1) Fire tube ala Triangle Tube and Lochinvar

2) Giannoni ala Burnham Alpine and Lochinvar Cadet

3) Aluminum ala WM Ultra and Buderus

It is a little confusing to consider these choices.

I read a lot of negative things about the Giannoni type exchanger, yet US Boiler continues to sell many boilers with that design and has a new model coming out (K2) that appears to use the Sermata made Giannoni as well.  If it is so horrid a product, why would they subject themselves to service headaches?

I read some good and some bad about aluminum heat exchangers, yet I think WM is on the 3rd generation of its Ultra model.  Aluminum exchangers seem popular in Europe.  I am sure that WM would not continue to advance the Ultra design if it was costing them a lot of money in replacement exchangers.

No one seems to have a beef with the fire tube designs.  Foolish to look at the other designs with this heat exchanger out there?

I'd appreciate any thought on the different styles of heat exchangers and what you guys have encountered in selling and servicing them.  I'm sure there are other homeowners that have similar questions.




  • gennadygennady Member Posts: 677
    another one

    you forgot to look at Inox-Radial heat exchanger
    Gennady Tsakh

    Absolute Mechanical Co. Inc.
  • knotgrumpyknotgrumpy Member Posts: 207

    Is that the Utica/Dunkirk design?
  • RichRich Member Posts: 2,224

    You forgot one , in my opinion the best. Cannot make it short cycle even with the smallest size being what we would all consider oversized .  I have used this so many times on all kinds of systems and had stellar results .
    You didn't get what you didn't pay for and it will never be what you thought it would .
    Langans Plumbing & Heating LLC 732-751-1560
    Serving most of New Jersey , Eastern Pa .
    Consultation , Design & Installation
    Rich McGrath 732-581-3833
  • TonySTonyS Member Posts: 849
    Follow the money and easy..aluminum casting was 8th grade metal shop.

    Giannoni and others.....bend and stamp. Remember o rings in Giannoni,finally after many failures welded the tubes.

    Triangle....robotic far and away the most expensive and complexed way to build an exchanger but you are no longer limited.
  • Mark EathertonMark Eatherton Member Posts: 5,582
    Inox = Viessmann

    No other message

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • knotgrumpyknotgrumpy Member Posts: 207
    Thanks Mark

    You have a favorite design?
  • heatpro02920heatpro02920 Member Posts: 991
    Gonna have to say TT

    I have now put in enough to say I really like the product, the control is very nice, the design is nice, a real nice product, price is on the low side of the mid end.

    I started selling them because the people were asking for stainless and I was installing gb's.. I first wanted to have them in the line up to fill the SS wanting orders, but now its my go to mod con... I have installed every one except the 399, I have installed at least 6 LP models, a bunch of excellence and I did an install with 2 60's.. I haven't yet taken their class to get certified but hopefully can make some time this summer season...

    I have 4 more signed proposals including one system with 2-110s... I think the next step in mod cons is going to be for someone to come out with a control/gas valve assembly that is the same in a bunch of boilers, so let honeywell make the controls and sell them to other manufacturers so they will be available in the future without going to the boiler maker, like buying a 8148 control, it will be on the shelf...
  • GordyGordy Member Posts: 7,102
    Fire tube

    Stick with that.

    From there it's about what's available in your area for parts, service etc.

    Which brand comes in closest to heat loss calc.

    Comtrols ring in there to. You may not need all the bells, and whistles so that's consideration.

    Don't forget HTP elite ft.
  • hot rodhot rod Member Posts: 7,013
    fluid quality

    is critical to all types and designs. The MZ Monitor, with a fin tube HX, lasted long in part due to the INIBAL inhibitor that was shipped with it.

    When seals fail, typically harsh fluid conditions are to blame, pretty much EPDM and silicone have been used for years to build hydronic sealing rings and gaskets, like pump flange gaskets.

    Giannoni claims to have over 11 million HXers in service, I believe it is a proven design if it is filled, pumped, setup, and serviced properly.

    I too like the HTP high volume type. I run a Solar Phoenix in my shop. I installed it in 2007 and have not touched it since, no burner removal, flame rod, nothing. It runs nice long cycles, ramps to low fire and rarely shuts down at design or near conditions.

    I added a FP HX for instant DHW production with the Phoenix running a 130F setpoint.

    Brand, parts availability. local reputation are other considerations.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • JasonJason Member Posts: 293

    The whole Gianonni bashing is on all the really old stuff. The funny part about it back then they were not having the problems in Europe just when it was introduced in the states. Our systems are different and normally run higher temperatures.We as an industry have memories like elephants instead of forgiving souls.

    In my area up to about say 2-3 years ago you could not hardly give away a Grundfos circulator due to their starting problems from the eighties. The truth of the matter is when problems exist the manufacturers make changes and the Gianonni heat exchanger has gone through multiple changes for upgrades and improvements over the last decade plus, just like everyone else's  product.

    Admittedly they are a higher pressure drop for circulators but also offer more fireside heating surface than most.

    Since your choices are limited what else is there to look at. The control. Who offers the best control features needed or not. Remember this is programing and adds no cost to the control.

    All the boilers are about the same efficiency so that can be removed in the decision making process especially since the boilers are not the rated efficiency during most of the operating period. They only meet the rated efficiency with 120f return and 140f supply and proper flow rate, proper sizing etc.

    So let's look at the newest Alpine control.

    They have changed the PID so it modulates down faster. The big thing is on boilers manufactured this year if you go to central heat paramters they had a response speed which was adjusteable from 1 - 5. One was slower modulation and 5 is faster modulation. Now they have added if you press 1 the boiler will light off and go into a low fire hold for 2 minutes and modulate up to where it needs to go. . Between that and the new IQ zone panel they introduced I guess they are saying why ever fire higher than you have to. They also can do a wireless OD sensor now.

    If you did not see the new IQ zone control at the Javits Center in January they had on display and will be introducung a zone control that is pretty cool. We know the largest fuel savings we can off the end user is the proper sized boiler and probably the second highest fuel savings is system efficiency. All mod/cons already off ODR to assist in raising system efficiency. This new control is a 4 zone expandable to 4 panels (16 zones) by cat 5 cables. You can name each zone and each zone will show a cycle rate. The neat thing is you can input the BTU loss for each zone and the boiler will limit it's firing rate to that BTU input or minimum fire. They will allow you to put in real low numbers, way less than minimum fire but of course the boiler will only go as low as minimum fire. It will keep adding togather the inputed btu's and stay at minimum until the total is higher than minimum input. Once the imputed btu's is above the minimum input the boiler can still modulate between that number and minimum.

    Since boilers and boiler controls are close I feel this is more exciting than boiler efficiencies since they are so high and very close. The next step had to be addressing system efficiencies. Good job guys!
  • ChrisChris Member Posts: 3,056

    Controls are all smoke and mirrors to this point and that includes the new zone control being used with the K2.

    From a total platform and I'm a Viessmann guy I'd look at Lochinvar for one reason and one reason only...I can control my boiler/primary pumps flow rate to match the boilers modulation rate.

    Honestly, I could care less about the HX's at this point. If you're installing correctly and servicing correctly they will all last. This debate over HX's is like the debate of which Pex Tubing is better...They will all last if you do the right thing
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Mark EathertonMark Eatherton Member Posts: 5,582
    My preference...

    Would be the Fire Tube designs that everyone is jumping onto (ACX?).

    I don't believe ANYTHING is "maintenance free", but this design has been around for a long time, and I've not heard any major issues from folks in the field.

    I like the INOX radiant design, but fear long term issues with heavy metal particles coming out of suspension in the HXer area when applied to older cast iron radiation systems.

    Time will tell for sure.

    I have had good luck with the Giononni's, but they do require annual maintenance, and it seems that non one is doing it… Bad for us.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • JasonJason Member Posts: 293
    Agree - disagree

    Even though we don't agree on the controls sounds like we agree on the heat exchangers.
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