Do you agree that heating systems with less use last longer?

heatpro02920

OK, I recently had this conversation with a fellow tech who I have much respective for and learned a lot from. He and I can NOT come to agree or even find even ground on this..



His point is a boiler full of water is constantly "ageing" and "shortening its life...



My point is, sure of course it is ageing, that kind of goes with out saying, everything is ageing even if it was sitting in an unopened box... And of course being full of water is ageing it faster than being in a sealed box.



One system that brings me to believe the system will last much longer when not used frequently is a customer of mine.

He divided a piece of property up and built 4 houses on the separate lots, all pretty much identical, stick built 1970-80s style houses, he sold 3 of the houses and lives in the 4th. All 4 houses got Hydrotherm gas boilers {you know the one, Dunkirk made it for them}. The only difference between the houses was his had 2 wood stoves, one monster in the basement {I never seen another like it} and another one on the first floor.



Now Chris {hes the customer} owns a lot of land, and makes it his business to clear is, and because of this never is short on wood, so burns a lot of wood to heat his home... I service his boiler {for a long time now} and it is like BRAND NEW, I mean this thing should be in a museum. He says the boiler really only runs a 1-2 months a year, he has a hot water tank for DHW and with the wood burning it doesnt get used much...



Now, the other 3 houses weren't built with wood stoves {1 has one but I was told they hardly used it, and it has changed owners a few times} and all 3 of them houses have new boilers, I changed one of them other contractors did the others, and I was told one is already on its third boiler {which shouldnt be, but its the info I got}...



So what I get out of this story is, the boiler that only gets useda few months a year lasts much longer, even though its full of water year round.. That 33 year old carrier unit is still running with no leaks.... the others were all used regularly and are now long gone...



And this isn't the only evidence I have, I have seen many systems way past there time that are still working because the customer left for half the winter, had wood stoves, ect...



My boiler hardly runs, I built this house in 08 and installed a Buderus GB, Ill bet it only had the use of one year on it... I just replaced it with a TT 175 which also is hardly going to run...



I use a Rinnai for my DHW, Heat pumps down to 47*, and run the coal furnace when it is very cold... plus add on that the lenox gas fireplaces my wife just loves to throw on when ever we have company or she feels like it {3 fireplaces and they will heat the house alone}. I would expect this boiler to last 40 years easily...



If you look at last years temp graph you can draw a line from 47* down and thats when my boiler ran, then about 40% of that time under 47* I am running the coal furnace. The hopper runs for 3 days and I run it once a week {Fri, Sat, Sun} almost like clock work now...

heres a graph of RI 2012 temps

<a href="http://fs.weatherspark.com.s3.amazonaws.com/production/reports/history/year/000/031/334/2012/temperature_temperature_f.png">http://fs.weatherspark.com.s3.amazonaws.com/production/reports/history/year/000/031/334/2012/temperature_temperature_f.png</a>



So what do you think, low use = long life or use doesn't matter time is time?

Zman

Cars

I think it is kind of like cars. A 1980 buick with 50,000 miles is better than a 1980 buick with 250,000. It is still a 1980 buick and will still require maintenance.



You favor a strategy of multiple heating appliances. It is fun to have a bunch of cars but in the end, It costs more money to purchase and maintain them all. In the end they will all need to be replaced.

Gordy

I think it depends

On the complexity of any type of equipment. Sometimes it's actually harder on equipment to not be used than to be used.



Take a car you could leave it in the garage, and seldom use it but the tires will soon dry rot along with the belts etc. while using it still would give wear to those same parts, but would have served Their purpose, and gotten useful life out of those components.





On the other hand a boiler depending on its complexity could have those same hurdles. Old boilers lasted over 30 years with out frequent maintience. On the other hand a mod/con does not fair so well.



If both were allowed to sit on the ready line for a decade I think my money would be on an old behemoth to fire up before a mod/con.

heatpro02920

A agree... and disagree

Carl- I like the car analogy , but as most of you know I do favor a separate DHW system and central heating system, specifically a tankless water heater and a boiler. As far as cost there is very little difference, maybe 10% before rebates. its not that I am against indirect water heaters, I just don't see the sense in heating water all day and night 365 days a year when it has been proven we use it for under an hour a day. Sure the new tanks have amazing standy by loss numbers and are very efficient, but its keeping 60 gallons of water 140* all day and night, which brings up another point, you heat is to 140 to cool it to 115 at the point of use... but I'll stop there this isnt tankless vs tank, we have done that already lol...



I personally think tanklesses last longer than tanks, and a tankless is always repairable, you have a bad tank and that is exactly what you have, it will need to be replaced, so IMO tanklesses win the overall cost of operation war...



But anyway, the tankless gets used year round, and thats not quite what I was going for in this conversation, I am more curious as to what wallies think about equipment that is used less...



I think about it this way- a furnace runs only for the heating season, and the blowers and controls last for 30 years, but when you put A/c on that unit, you can bet on changing that blower or some controls by the end of 15 years....



Gordy, I als agree with you, BUT Im not talking about sitting around for 5 years with no use, if you look at my temp chart the unit will only go 5-6 months with out being fired, I don't see that as being the same as a car sitting long enough to get dry rot and flat spots on the tires.



My 39 ford hot rod, sits for 8 months a year, sometimes it will sit there for double that if I never take it out and the tires are fine. Now if it was there for a decade, with outdoor climates beating it up, sure it would be better to drive ti around once and a while...



All the issues I ever see techs bring up {I have had this conversation with a many people over the years, including inspectors that come and say "why a water heater and boiler"?

and some bring up condensation issues and even birds or insects nesting in the vents, all of which if you were really worried about {and I wouldn't take either of them issues to heart, because they are not really issues, no new water introduced so no serious condensation issues, and bugs and birds???} you could put a control on the boiler to run it for a cycle every month and cure the issues or just throw a cover on the vent so nothing crawls in there...



Someday I am going to keep a house long enough to keep a heating system to the end of its life, it hasn't happened yet, since I always end up changing it out for something new before the boiler is 5 years old. But some day........................ Then I will be able to say, "this boiler lasted 50 years with out service because I only used it for heat...." problem is, I don't have 50 years left, lol so it may have to be my son saying it, but same effect...

Gordy

Boilers specifically

A lot can play into their longevity.  Water quality, near boiler piping, frequent addition of makeup water, return temps as to CI boilers.



Like anything you could have 5 of the same product, and maybe only one or two will exceed expectations on normal life span.



The old boiler lasted 41 years before replaced, and was converted from fuel oil to NG in that life span. Present boiler is 20 years old still going strong. They have always been seasonal usage with no indirect. so 5-6 months a year on average.



The present boiler is piped with a typical boiler bypass per WM install manual. But it regularly drinks sub 95** return water all heating season. No signs of condensation damage whats so ever. Actually i'm letting it go piped this way so I can kill it to install a mod/con, but being way oversized I think low return temps are a non issue. Also being oversized it gets out of condensing temps rather quickly, and typically the heating call is over by the time it hits 160 so its always cooling from a high temp before the next call for heat which usually the boiler is at ambient temp by then. So the only stress really is boiler shock which as stated the boiler never gets a slug of cold return temp because it is cooled before the next heat call.





So variables, and constants in the right combination can be the real key to boiler life span.

vaporvac

Maintenance

I think one reason your customer's boiler may have lasted is that he maintained it better. Without knowledge of the schedule the other three houses had for caring for their boilers it's hard to put it down to use alone.

I heated my house with both wood and steam for years and then moved entirely to steam. It didn't seem to affect the life of the boilers I've been through either way, but we didn't really know any proper maintenance besides a weekly blow-down.

heatpro02920

I agree, the unit I maintained was done to perfection, lol

I never really cleaned it or anything like that, just kept it running, I can not look up the service history going that far back, but I want to say I did a circulator and a gas valve, maybe a transformer and a few couples..... Its been a while...



I would like to think, that when you build a house, you get a 30 year mortgage and everything will last at least that long.... Shingles, siding, all mechanical devices, light bulbs, ect, lol but its not that way, when I do new construction I like to meet with the home owner and the contractor to nail down what they are getting, I have learned in the past a company can get a bad name by working for general contractors with tight pockets {ie all gc's}... And the home owner would easily pay the extra cost for a cast iron boiler over a steel unit, and would much rather pay the difference to have an extra zone here and there vs a 2300 sq ft home on one thermostat {I have done it for contractors more than once}.... I don't know where I was going with this but, while how the unit is treated over its life has a huge impact on longevity I think a lot of guys bypass the use it sees having even more...

I wish there was some tests on this, I am very curious...