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Mod/Con Reliability

Robert O'BrienRobert O'Brien Posts: 3,012Member
Is the perceived lack of reliability actually reality? CI boilers are nowhere near as troublefree as they were pre 2012, although anecdotally still better than Mod/cons in general. Is the race to the bottom cost wise undermining component quality? Can these components be made more robust or is it the nature of the beast to be somewhat troublesome?
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Comments

  • ratioratio Posts: 1,540Member
    I think the common opinion will be that the install causes most of the reliability issues. Good install, good reliability for the most part. Bad install, poor reliability.
  • hot rodhot rod Posts: 8,419Member
    The more parts involved, the more potential for failure. The quality of components can vary widely.

    Add to that water and gas quality, supply voltage stability, initial start up procedure, proper piping and pumping, etc

    Cast iron is still fairly simple and reliable, compared to mod cons.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • NY_RobNY_Rob Posts: 1,086Member

    Can these components be made more robust or is it the nature of the beast to be somewhat troublesome?

    Maybe a combination of both?

    I see standard capacitors vs. metal caps on the control board of my mod-com. I don't see heat sinks on most the IC's, and the coils are open vs. potted. Address all the above and you've increased component life on the control board.

    When a computer controls the gas flow rate and the blower motor RPM based on sensors... it adds lots of parts.
    My (comparably inexpensive) HTP UFT-80W has seven different sensors, two "boards", a computer controlled negative pressure gas valve, a computer controlled blower motor and plastic vents.
    I could only imagine the number of parts/sensors on a high end mod-con like the Knight series.
    Lots of parts to go bad, and almost any component failure will cause a no-go situation vs. limping along till fixed.

  • David107David107 Posts: 1,363Member
    And how do mod-cons stack up against the oncoming Air Source or Ground Source heat pumps? Don't they have almost as many parts?
  • EBEBRATT-EdEBEBRATT-Ed Posts: 4,086Member
    I have limited mod-con experience. We had one go down last weekend. Prestige Solo. Pats ordered Monday and had to be overnighted. I am 90 miles from Boston so not in a remote area at all. Now, the boiler is 8 years old and probably has never been serviced. Parts are high $$$$ and not readily available. Can't buy just the blower wheel have to buy the whole motor, housing and fan
  • hot rodhot rod Posts: 8,419Member
    Economics, it really comes down to the manufacturing cost and what customers will spend $$ for.

    Ever see a cutaway of a Viessmann Inox radial hX compared to other water tube brands?

    Pretty much any component on a boiler could be built to last 10 years or 20 years, the difference between a switch or component designed to 100,000 or 200,000 cycles, for example.

    We have seen this delicate walk before, where is the sweet spot for quality and price.

    The old Viessmann Biferral was designed to be a 50 year plus boiler, I'm told. I suspect most new boilers shot for 10 year life expectancy, maybe? Probably parts availability is also targeted for around 10 years.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • Stephen MinnichStephen Minnich Posts: 2,022Member
    I think we're still years away from where modulating condensing boiler manufacturer's will settle in. The issue of low water content and the difficulty of decent firing at 10% modulation are already being addressed by Viessmann with the Vitocrossal CU3A. It's a 5:1 boiler but who cares? The smallest model holds 18 plus gallons of water. No need for a 10:1 with that. No need for a buffer tank or a hydraulic separator with that. And, they're becoming competitive in the North American market. I wouldn't be surprised to see this boiler driving the market in a few years.

    I have no skin in the game here either. I've been a Lochinvar guy for a long time but it's hard not to be blown away by the CU3A. I already bought one for my home which has, dare I say it, forced air.
    Steve Minnich
  • Solid_Fuel_ManSolid_Fuel_Man Posts: 1,001Member
    Anything can be made to be reliable for the long term. It is a cost/profit/being competitive I believe. My mod-con has a 10 year warranty, pro-rated of course.

    I will speak to the air and water source heat pump question: mod-con will win the longevity. I've been putting many controls, coils, and a few compressors in them. r410 has such high pressures and paper thin Chinese copper are not stacking up well.
    Master electrician specialising in boiler and burner controls, multiple fuel systems, radiant system controls, building controls, and universal refrigeration tech.
  • clammyclammy Posts: 2,055Member
    The reliably of a mod con will never meet a cast iron.A cast can go years with out even decades with out anything while a mod con not set up and installed properly with provision to service shall go the way of the dodo and dinosaurs. I see more improperly installed mod con then i see crappy ac installs and there like neck and neck .Weather installed by a truck slammer or by a larger supposedly reputable company its the guy whos selling it and the guy doing the install the two usually never meet . The most astounding 2 suspects are lack of knowledge concerning piping,pumps and loads and short cycling and installing a system that can be serviced lol The one thing they know for sure is how to trim there install price on there end . As it was explained to me Every company wants return purchases and that nothing is made to last otherwise there would be no future sales ,every company wants return sale everybody wants a piece of the consumers money just like the auto industry free money ever few years welcome to the future just remember those folks also have to put food on the table and making great products that lasts does not increase your revenue its counter productive .I personally have just about stopped installing mod cons just sick of the free services calls and the hassle of having to talk the HO into getting maintenance done and the lack by most supply house to stock the most simple parts .Its a tough road to ride .These days i do a lot of head scratching and shaking from the totally shabby installs to the ultimate unacknowledged dont give a crap service and best is the web based geniuses who if only spent more time learning then bull shitting there customer real huckster like a dime a dozen .Thank god i work for myself and maybe at best have 10 years more before im done. thank god peace and good luck clammy
  • gennadygennady Posts: 701Member
    I switched to Viessmann brand years ago because it is most reliable and trouble free boiler on the market. More reliable than atmospheric boilers.
    Gennady Tsakh



    Absolute Mechanical Co. Inc.

    www.AbsoluteMechanicalCoInc.com
  • hot rodhot rod Posts: 8,419Member
    The chain of manufacturing. Think of what is involved with say, building an electric motor. The manufacturer sources many of the components, bearings, wire, casing, switches. Each one of those sub manufacturers depend on metal suppliers to provide the quality metals they need. So many steps where something can go wrong. Consider a mod con may have thousands of parts and manufacturers when you break down every component.

    If one part is cheapened, or built below spec, along the process the entire product can fails. As manufacturers look for way to reduce cost it could be some components or materials are on a fine line of being able, or unable to handle the task.

    Now add poor shipping & handling and sub-par installation, plus questionable fluids, poorly blended fuels, combustion, dirty power, yikes!
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • HenryHenry Posts: 820Member
    It is nearly 20 years that I have designed mod-con boiler rooms. I have not replaced one due to wear and tear. I have had to replace a few due to flooding. In the early years, we had ceramic burners fail, air switches fail and circuit boards fail. A properly designed and installed system will last. The usual maintenance items are ignition sources and flame rods. If the combustion air intake is 2 feet from the ground, after X years it will block the burner with pollen etc. I stick with HTP and Lochinvar. Viessmann has its own problems like blocked condensate drains with no sensor warning.
  • ScottSecorScottSecor Posts: 166Member
    edited June 28
    Since “high efficiency” residential boilers were introduced I asked the same questions. In the 1980’s early 1990’s we used Weil McLain boilers most of the time. We suffered with the HE, VHE (floor standing), and AHE (wall hung) boilers that were supposed to save our customers fuel. In hindsight the mercury flame sensors, the draft inducers, the air proving switches and the funky piping connections on the VHE drove us nuts. I suspect other brands that incorporated these same devices also had serious reliability issues to attain perhaps (at the time) unrealistic government efficiency standards. I am certain we lost a few customers over this due to our recommendation that these were the ‘best’ boilers money could buy at the time, only to have the customer hate the boiler (and us) when they had no heat and or hot water when they needed it most.

    Then around 2000 we started to install the next wave of high efficiency equipment. This time it was HTP Munchkin boilers, Weil McLain Ultra boilers and MZ gas boilers. Overall I feel they were certainly more reliable than the VHE boilers, but they still did not rival the ‘Plain Jane’ cast iron boilers. The weak link to the cast iron boilers from this era were the stack dampers. Thankfully every supplier we dealt with was willing to stock the dampers and eventually the damper motors. This was easy for them as every atmospheric cast iron gas boiler they sold was fitted with the ‘energy saving’ damper.

    Today we install a few different brands of condensing boilers; however the vast majority are Peerless. With the units we’ve installed or serviced in the last few years it’s definitely the draft inducer that causes the most headaches. Customer paid big bucks for the “rocket ship” boiler and he now has no heat in the dead of winter. We try to hunt down a blower only to find we cannot get one within one hundred miles. Customer is mad at me and I’m mad at the suppliers, the manufacturer and everyone along the way. New blower finally arrives and we install it immediately. When customer receives the invoice for a lot of money I now have an irate customer (again). They typically ask, “Isn’t this covered under warranty,” and until very recently I have to reluctantly respond with “no.” I gather some extended warranty programs are coming out very soon that will help alleviate these exact warranty issues, hopeful it works out for the contractor and the customer.

    Finally, back your original question. In most things mechanical the items (parts) that move often fail first. With mod/cons the moving parts are typically the fan and the circulator(s). Somehow circulators seem to last pretty long for us; however I cannot say the same for the fans. I suspect the lowest price to install will almost always prevail. If cast iron boilers stay the cheapest I suspect they will also be the most popular. If plastic boilers finally catch on and they’re deemed reliable, they will likely become the high efficiency king of the future. I'm hopeful the some manufacturer will come up with a fan/motor that will last at least ten years in the near future.

    I’ve read figures over the years with regard to reliability vs. energy savings. I cannot offer the numbers but I suspect there is a breakeven point that varies from three years to over fifty years with regard to return on investment. I suspect at the end of the day, most people on this website want to keep the boiler they already own and hope it lasts a long time.
  • Stephen MinnichStephen Minnich Posts: 2,022Member
    When I started, I was servicing furnaces with cast iron burners and heat exchangers so thick they’d never crack. Everything had a standing pilot and non-electronic controls, belt drive blowers with motors that could withstand decades without maintenance. Everything was made here. Every data plate and name tag was made of heavy gauge steel and riveted in place. Lowboy furnaces came knocked down and it took half a day to assemble them. Even the furnace jackets were heavy duty.

    I liked things that way.

    With today’s stuff, I sometimes break things I’m working on unintentionally because they’re made so poorly. You’d have to drive an 18 wheeler in order to carry all the OEM parts necessary in today’s market. And like hot rod said, the parts will be outdated sooner than later. I’m older and beat up but I can still carry some boilers down stairs, into the boiler rooms, and hang them on the wall solo. I’m not saying weight defines quality but there seems to be a correlation.

    I love putting together mechanical systems but I’m also glad I’m moving on.
    Steve Minnich
  • David107David107 Posts: 1,363Member
    Does the European market have the same issues?
  • JackJack Posts: 1,021Member
    Scott, be careful what you wish for on the upcoming "extended warranty" programs. Manufs don't like extended warranties as they have to carry them as a liability on their books. After-Market Warranty companies step into the breach. Look up Triad and EWC warranties. They introduce them as the greatest thing since..., sell many millions of dollars worth and in +/-10 years declare bankruptcy and all hell breaks loose.
  • bob eckbob eck Posts: 734Member
    Condensing boiler and condensing combi boilers are not like CI boilers of the past that were installed and forgotten about.
    Hi efficiency condensing boilers and condensing combi boilers need the following to make them run efficiently and to make them last 10-20 years.
    Boiler needs
    1- To be sized for the heating load not the domestic hot water needs. Short cycling will kill parts early on a boiler.
    2- Must be piped in correctly. Must have a good air elimination unit.
    3- Must be vented correctly.
    4- Water quality needs to be looked at and addressed. Old system should be cleaned with chemicals and flushed before installing the new condensing boiler / combi boiler. Should have a good dirt eliminator on the system. If needed add chemicals when starting the system.
    5- outdoor reset needs to be installed with these boilers.
    6- boiler needs to be set up with testing equipment to see if anything needs to be adjusted. Keep record of readings so when you come back to service the boiler you can check and see if anything has changed.
    7- homeowner needs to have yearly maintenance on their boiler to makes sure the boiler is still set to factory spect plus check the water quality flushing out the dirt eliminator and checking to make sure the vent pipe and fittings are still good and not letting exhaust gas escape and into the house.

    Anything I missed?

    If you are not doing taking these steps and following the manufactures installation instructions and parts fail or even the heat exchanger fails while under the warranty period your warranty claim could be denied by the boiler manufacture.

    What do you tell your customer their 3, 4 or 5 year old boiler is no longer under warranty and they need to pay for the failed parts. That will be one very upset customer.

    Many condensing boilers / combi boilers are being installed because the home owner sees gas utility rebates and some states have rebates plus the 95% AFUE of the boiler.
  • NY_RobNY_Rob Posts: 1,086Member
    edited July 8
    bob eck said:

    Anything I missed?

    You covered a lot, but...

    -HX needs to be flushed every 1-3yrs (depending on water hardness) with cleaning solution. That's a $$ service call.
    -Condensate media needs cleaning & replenishment every 6mo or so. Can/should be done by the homeowner, but nowadays when they can't change a light bulb- what's the chance they will maintain the neutralizer media themselves?


  • David107David107 Posts: 1,363Member
    magnetic separator--esp. where ECM circ is installed.
  • GordyGordy Posts: 7,989Member
    The bottom line is the majority of homeowners are not infatuated with their hvac systems along with many other household peripherals. They just want it to work, and last for the smallest amount of upfront costs, and maintenance.

    They also want to put the smallest amount of effort to accomplish all this.

  • NY_RobNY_Rob Posts: 1,086Member
    ^ in fairness, they (the homeowners) are probably not being informed about the frequency and amount of maintenance up front during the sales pitch for the mod-con. And, from what I've seen locally... no one is sitting them down after the install and telling them "here's what you need to do or get done every 6mo and every year".
  • Robert O'BrienRobert O'Brien Posts: 3,012Member
    I'm eliminating failures during to poor installation and lack of maintenance. Strictly component failure. Is 10 years an unreasonable expectation for component lifespan?
    To learn more about this professional, click here to visit their ad in Find A Contractor.
  • AMservicesAMservices Posts: 376Member

    I'm eliminating failures during to poor installation and lack of maintenance. Strictly component failure. Is 10 years an unreasonable expectation for component lifespan?

    For what it cost $ervicing a con boiler just to keep it running good for 10 years, when something fails, its 10 X more expensive to fix.
    I try to inform customers of the long term cost when selling condensing boilers.
  • GordyGordy Posts: 7,989Member
    edited July 11
    NY_Rob said:

    ^ in fairness, they (the homeowners) are probably not being informed about the frequency and amount of maintenance up front during the sales pitch for the mod-con. And, from what I've seen locally... no one is sitting them down after the install and telling them "here's what you need to do or get done every 6mo and every year".


    Many installers choose to eliminate that part initially before the install for fear of the homeowners going for the cheap. On the other note who wants to sit the homeowner down after the sale, and install to tell them tjey will need to spend x dollars, at x intervals to get the most out of their fine piece of equipment. See the connection?
  • GordyGordy Posts: 7,989Member
    No I don’t think ten years is that long even do to poor maintenance. Nothing is made robust anymore.
  • David107David107 Posts: 1,363Member
    edited July 11
    As a homeowner with hard water who's been researching this for quite a while I can say I can live with the upfront cost but not with the short-lived parts, complicated and expensive maintenance requirements--even with a fine contractor who can install it properly but still suggests to me to keep $1000 worth of parts on hand for emergencies since they would take a few days at best to procure from the distributor. There apparently has been a big change in the amount of parts kept in stock--and for how many years for a particular model. It seems the installer's supposed to keep the inventory but how can he and survive financially?

    I'd be curious as to what percent the overall price of a boiler would increase if robust parts were made? 10% more? 20%? I'd gladly pay it for longevity and reliability. I give credit to the manufacturer's for coming up with ingenious designs but to last for just ten years?

    Have many boiler companies issued stock and therefore are driven by the need for immediate profits to please shareholders? Many cars used every day probably won't last much more than ten years either but most of us can't have too many expensive appliances with such short life spans....

    I have pretty much resolved that when I change boilers I'll go cast iron, Outdoor Reset, even if--with the chimney liner--it will cost about the same as a mod-con. Or I'll wait for an air source heat pump hooked up to a hydronics system when they're viable with NY area electric rates (never) and prove to be more reliably made than mod-cons. Just wondering what's the next technological advance after mod-cons, or it just better and more robust mod-cons? Do they last more than ten years in Europe? I feel bad for the good installers out there--the system is letting them down.
  • hot rodhot rod Posts: 8,419Member
    I doubt all mod cons need expensive repairs on a regular basis. I have a 16 year old Laars Mascot that I haven't touched in years, probably 5 years since I even opened up. It's a combi so it cycles most every day multiple times an hour on some days. I see 20 year old Munchkins still in service.

    I think the amount of parts, and complexity compared to a basic cast iron boiler has more to do with the required service and repair, not necessarily lower quality components.

    Not a lot of room for error with paper thin heat exchangers. Water quality, perfect combustion adjustment, clean voltage, proper installation and flow rate, many variables.

    What % of mod cons get installed without a combustion analyzer being used, I wonder.

    In some cases equipment gets upgraded in Europe due to changing energy standards, pumps and boilers for example.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • NY_RobNY_Rob Posts: 1,086Member
    edited July 11
    David107 said:

    ...There apparently has been a big change in the amount of parts kept in stock--and for how many years for a particular model. It seems the installer's supposed to keep the inventory but how can he and survive financially?

    One thing I can tell you with 100% certainty is that mod-con parts can have a "shelf life" because the control boards, display boards, etc.. all have software revisions that constantly get updated. Who wants to stock obsolete parts that will not work?

    I replaced the control board on my mod-con that was only six months old due to a known firmware bug. Unfortunately, the replacement board I received from the supply house was two firmware revisions older/behind my bad board's firmware. So it took another 10 days for the supply house to get a current revision control board drop shipped directly from the manufacturer to us. Add to that... the display board then had to be upgraded to the latest firmware as well... so we had to wait another week for that to arrive.

    There is also the case where parts are upgraded due to a flawed design that was discovered in the field after months/years use. So now the supply house is sitting on a stack of useless parts that again can't be used because they are flawed.

    Add it all up, and there's no incentive for supply houses to stock a large array of mod-con parts. Order as needed from the manufacturer or their rep with overnight shipping.


  • SteamheadSteamhead Posts: 12,220Member
    edited July 12
    NY_Rob said:

    ........Order as needed from the manufacturer or their rep with overnight shipping.

    Customers do NOT want to hear that on a 5-degree night. Advantage: Cast iron.

    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    https://heatinghelp.com/find-a-contractor/detail/all-steamed-up-inc
  • NY_RobNY_Rob Posts: 1,086Member
    edited July 12
    Steamhead said:

    NY_Rob said:

    ........Order as needed from the manufacturer or their rep with overnight shipping.

    Customers do NOT want to hear that on a 5-degree night. Advantage: Cast iron.

    1000% agreed!

    It's a sobering thought that you are literally a $6 part failure away from a completely non-functioning mod-con at any time of the year.... and the nearest replacement part is 2 days away.

    It forces sane people to come up with a backup heat plan ;)

  • pitman44pitman44 Posts: 8Member
    Our oldest mod/con install is just over 15 years so we have a decent baseline by now. I don't recommend them to folks who have baseboard or other high temp distribution systems. They're not going to get the advertised efficiency. Couple that with increased boiler cost, increased installation cost, the likelihood of increased cost and frequency of repairs and a shorter lifespan. Throw in parts availability and we've become very picky just where we do recommend a mod/con.

    If the upfront cost is $2-$3k more to begin with and the customer's savings "might" be $100 a year in fuel savings, are we doing the best for the customer in recommending a mod/con?
  • BrewbeerBrewbeer Posts: 452Member
    Having back-up heat anywhere the weather can get to 5F for an extend period of time is a smart play, whether you have a mod-con or not. I have a gas fireplace insert that carried me out of the heating season a few years back when the old scorched air furnace in my house died.
    Hydronics inspired homeowner with self-designed high efficiency low temperature baseboard system and professionally installed mod-con boiler with indirect DHW. My system design thread: http://forum.heatinghelp.com/discussion/154385
    System Photo: https://us.v-cdn.net/5021738/uploads/FileUpload/79/451e1f19a1e5b345e0951fbe1ff6ca.jpg
  • NY_RobNY_Rob Posts: 1,086Member
    edited July 13
    What do you pro's do in a case where the part isn't available for a couple of days and no backup heating system in the home and it's going to be below freezing temps? With more and more mod-cons being installed this may become a major issue in the future.

    I see in my area that when old homes are sold to young families, they pretty much gut the home and along with new everything they replace the boiler. I've seen a couple of mod-cons installed around our neighborhood lately.
  • NoelNoel Posts: 156Member
    Good point to consider. Years ago, I observed that in Canada and northern USA, most people have back-up heat installed permanently. South of there (southern NH, VT, ME, MA, NY and west), people have temporary heat (portable electric, wood, pellet, gas, kero) available to use in an emergency. Deeper south, they don't have anything, they put on a sweater.

    In the greater NYC and CT area, they call a lawyer when the heat goes off. It isn't their responsibility to have a back-up source of heat.

    I guess it depends on how fast a house freezes its pipes.
  • David107David107 Posts: 1,363Member
    edited July 13
  • JUGHNEJUGHNE Posts: 4,444Member
    Our local utility company has several 120 volt 1500watt cube/milk house heaters which are loaned out for such problems. I have probably 3-4 myself. Only one can be plugged in per circuit and if run on the low setting there is usually no problem.
    I also have a 15 KW electric furnace from a change out.
    It is usually used for temp heat in construction, here HVAC/electrician is expected to furnish one. SR mudding and painting is hard on new equipment, (may not be ready for operation anyway).
    That could be connected to the range outlet if one element is disabled. Connect directly to panel in basement for full heat.
    Most houses built here in the last 25 years would not freeze up for quite some time, provided they were up to temp when the equipment failed. Most have heated basements or crawl spaces.

    If a mobile home they know to leave the water run and I advice running the fan as the water lines are usually run along the duct. One case the furnace failed they had a wood burner in an attached porch which kept the living area livable but the water froze up underneath. I am usually too busy to work on mobile home HVAC BTW :* .
  • Solid_Fuel_ManSolid_Fuel_Man Posts: 1,001Member
    Think about it, with one source of heat all your eggs are in one basket. If my family of 4 only had one car and it needed repair what would I expect? When we only One heat source and it fails what do we expect? Portable electric heaters are your friend. Or that old wood stove in the basement, I've advised customers to turn on the electric range leave the oven door open Etc.

    I like boilers with standardized controls, the mod/con in my own house has standard controls. But I also have a wood stove, wood boiler, several electric heaters, a generator, I think you get the point.

    I'm still of the mindset that on a true low temp system, a mod/con will save much more fuel than any atmospheric boiler would. The cost/benefit ratio on a proper install is very good.

    Not talking prices here, but a mod/con is really only less than 20% more money than cast iron. Plastic vent vs. fry your eggs 6" sheet metal vent, I'm sorry but that's more than 15% savings! Not to mention all the air an atmospheric boiler sucks out of the building.
    Master electrician specialising in boiler and burner controls, multiple fuel systems, radiant system controls, building controls, and universal refrigeration tech.
  • Stephen MinnichStephen Minnich Posts: 2,022Member
    To me, it’s simple. If you’re going to offer a specific mod con, you have to stock the parts. If I were the customer, that’s the expectation I would have.
    Steve Minnich
  • David107David107 Posts: 1,363Member
    @Stephen Minnich So, as it was mentioned before that parts get updated often, how does the manufacturer or distributor handle a contractor whose parts just became outdated. Is he stuck with his outdated inventory or entitled to some kind of refund?
  • ratioratio Posts: 1,540Member
    Some times you can't just plop in the current version of a board, you must use a specific revision.
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