The right boiler Best of the Best

BPH

Any one of them that meets heat loss calc.

Eastman

I think combi units will eventually dominate the industry, however I'd rather have a tank. No minimum flow rates, no potential for reduced water pressure, less complexity, smaller combustion air supply and exhaust diameters. Also, a typical indirect in a typical installation has essentially endless hot water. Also, a tank can handle a much larger transient peak load.

BPH

To suggest that a condensing boiler in condensing range can meet his heat loss with 70' of bb is optimistic.

njtommy

Literally the smallest. I know Crown makes an Aruba series that's 38,000 btus

BPH

Any one of them that meets heat loss calc.

Eastman

I know of at least one heating help member that used a fire tube Loch for a small baseboard system. They direct piped the boiler and also utilized the control's modulation rate limiting features. He reported what I would consider to be excellent cycle run times for a small low mass baseboard system.

BPH

slant fin se70-50000 ibr or s60 44000 ibr. Please tell me what condenser can provide needed output based on linear feet of bb in condensing range and provide the added cost benefit to install such a product

BPH

Remeber I'm gonna direct pump it no-condensation piping to add in...yearly service cost nominal This boiler will last 20-30 years low head hx minimal control wiring add in outdoor reset..?!? Explain why not.

Gordy

The only reason combi's would/could ever dominate is low cost, and some major improvements. Major improvements on low end modulation which is not possible right now to get the high fire needed for DHW. TDR will have to go up to 20-30:1.

Eastman

Are you asking me?

BPH

Homeowner wants domestic production?? Ok I add a Tekmar 260 and a small indirect... I give him both OD reset and domestic priority. Show me a condenser that that can provide the same cost benefit and I'm all over it

Gordy

Eastman said:

Are you asking me?

Telling

Gordy

@BPH how many days a season will you need that high output? Everything else could easily be in condensing mode with BB.

Eastman

@Gordy
Actually, that question was aimed at BPH, but you must have posted your comment right in between there.

Regarding combis taking over... What do you think of a setup like the viessman 222F? Also, I can see perhaps two 100k combi units being used in cascade mode to achieve the desired TDR.

Gordy

The 222F is certainly a nice machine. Cascading combi's gets you back up to 1 mod/con ,and indirect. You can get a no frills HTP UFT80, and a indirect for that no frills is certainly not an insult. You don't always need all the control features other mod/cons offer.
I like the indirect with higher storage temps mixed down to leverage your capacity. At least if there is a break down you still have a tank of hot water for showers etc. with a combi that is it done.

If you really want redundancy go back to stand alone DHW, and a boiler,

Eastman

I just pointed out the cascade configuration because I think that it is probably preferable from a manufacturers's perspective.

Zman

BPH said:

To suggest that a condensing boiler in condensing range can meet his heat loss with 70' of bb is optimistic.

I think you are missing the mark.
The house is obviously over radiated.
Sure, on the few days of the year that he actually sees design temps he may need to run ~150 degree water.
For the vast majority of the heating days the boiler will condense....

BPH

Look I dig the high efficiency thing I've installed hundreds of these. I get the mental gymastics involved with this percentage and that percentage....but at a certain point the cost benefit analysis becomes irrelevant what I'm looking for for my customers is...what is the appropriate system I should install based on their situation. In this particular situation it is my opinion that a condensing boiler is not necessary and quite the contrary indulgent. Just my opinion.

Paul48

OK.....But that still leaves you to address the cycling issues that go along with your recommendation. I might agree with you, if you can come up with a solution for that.

BPH

Outdoor reset. It works wonders...formerly exclusive to condensing boilers...well not really the dead men used it frequently with success but that's another story that seems to fall on deaf ears at present. There's a to be learned from those irrelevant dead folk.

Zman

BPH said:

Look I dig the high efficiency thing I've installed hundreds of these. I get the mental gymastics involved with this percentage and that percentage....but at a certain point the cost benefit analysis becomes irrelevant what I'm looking for for my customers is...what is the appropriate system I should install based on their situation. In this particular situation it is my opinion that a condensing boiler is not necessary and quite the contrary indulgent. Just my opinion.

There is nothing wrong with a small cast iron for this application. The extra mass will help with cycling.

First rule:
Listen to the customer.
A cast iron boiler is certainly not "the best of the best" and absolutely not a Corvette or Ferrari.

I am thinking cast iron = Chevy Cavalier?

BPH

No....cavalier never ran how about.,,,,350 small block? Yeah I like that still by parts to fix it today

Gordy

ODR on a ci boiler only gets you down to 160 supply 140 return on a BB emitter. Then you still need boiler protection.

With a mod/con, and ODR you could get sub 130 return temps easily especially in shoulder season, and oversized emitters. An emitter survey is prudent, and of great service to your customer to make the best choice.

We can beat our head against the wall which has better ROI when fuel is cheap. Will that always be the case 5-10, 20 years from now? When fuel costs sky rocket the mod/con will reap returns.

Gordy

I should add mass of the emitters plays a huge role in cycling. Over abundant Standing iron, ci baseboard, and radiant are exceptional mass emitters. More so radiant.

Paul Pollets

I use Viessmann and only Viessmann. If the installer isn't familiar with the product, It doesn't matter if the the appliance is top of the line.
A contractor's website is a good way to start vetting the contractor. Are there ample pics of boiler/mechanical rooms? Is the piping square, plumb and laid out well? Are there testimonials from customers? Is there a list of references provided so you can call customers with a very satisfactory experience?

BPH

Hatters...44000 output Ibr Gordy why are you asumming 160* supply with a 20 * diff?? Rarely will a baseboard system see a 20* dt more like a 10* dt. I also take exception to 140* being condensing range? Aggred with a condenser you could get in condensing range however it requires the OD temps to cooperate and in my life time it has rarely worked out. Ok let's say a condenser proves it's worth i.e.: it's in condensing range...how often will that be and in the end will your customers reap the benefits??

Paul48

@BPH

There's a lot to be learned from "Mental Gymnastics"

BPH

Yeah well?!?

Gordy

With a delta t ECM circulator you can darn near make your delta what you wish. It will be what you set it to. 5- 50* if the system can fall into a 2218's curve. The circ makes sure of that.

There needs to be more of the designer/installers controlling the system not the system doing what it wants. Technology has helped to make that possible. However it needs competant application.

Sure you can take the RWT to 135 push the edge of condensing on a ci boiler. Better have a good insurance policy in place to make sure that happens

Gordy

Design temps happen 2% of the heating season on avg. the other 98% would be cooler AWT. Of course things need to fall in place.

Emitter sized larger than heat loss. Usually the case especially if envelope up grades were done after system was in place. Old systems were usually oversized.

Proper tuning of the ODR controls. Takes time, but you can get down, and dirty if you know how.

Boiler sizing again sized to the load.

njtommy

.

Will82

Keep in mind this is what I have in the house now.
Burnham model 204NS-TEI2
Input 96,000 BTU
D.O.E HTG cap 80,000BTU
I'm just worried if I'm missing something because why would someone put in that big of a boiler in 2000 if the house only needs 40 to 50,000 BTUs.
So if I go with a NBC-150E Combi I will be dropping the size of the house BTUs down by 36,000 BTUs. Or if I go with a Lochinvar KHN055 I will be losing 41,000 BTUs. I will try to find a model for the baseboard I know it is larger than standard baseboard like Home Depot or Lowes sells. I still need to find a installer but the cost of the boiler I am not worried about because I work for a large company and I can get wholesale pricing on boilers. It is interesting to read that the KHN055 is 160 pounds and the Navien is 66 pounds.

I just want to thank everyone for the input. Just trying to put in the best boiler that I can because I do not want to do this again in a couple years.

Thank you

Eastman

Surveys conducted by the Department of Energy indicate that, statistically speaking, residential heating sources are oversized by about a factor of 2.

Zman

What makes you think the original installer knew anything about sizing boilers?
Start calling around and ask random contractors and how they determine boiler size. Let us know how many say "Heat loss calculation". My guess would be less than 1 in 10.

You will hear "rules of thumb (good if you are working with thumbs)", "we just go with what was there", "50 btu/ft north of the mass pike", "you have to match the size of your indirect". "that's the way my dad sized them" and on and on...
I am not making this up, I'm not that funny.


In your case a heat loss is probably not needed because you can't buy a boiler small enough to match your heat loss.

The cost of buying the boiler is irrelevant. Oversized boilers causes short cycles. This greatly reduces their efficiency and causes premature control failures. If the bigger boiler was 1/2 the price of the correct size, it would still be the wrong decision.

Will82

I know I have already had three contractors out to my house and not even one of them have walked into any bedroom. Two of them recommended Navien 80,000 and I am still waiting on the third one.
Even at 50 BTUs per square foot only puts me at 53,800 BTUs. So I know they are still oversizing me. That's why I decided to do the research myself to make sure that I don't get a oversized and a boiler that is not any good.

Gordy

Back in the day when oversizing was rampid two things let it run wild.

Fuel was cheap.
No call backs do to underperforming equipment. No one complains so long as they have heat.

Those habits transcend today through generations of teachings that inspire the newer generations to unknowingly do it wrong.

Today those complaints still exist however the phone calls that come could prove embarrassing.

Why does my new heating plant cost more to operate than my older less efficient one.

Why when it is cold out can I not get my house above 62....

Nothing replaces do diligence in the math when sizing equipment.

Eastman

I think forced air should be oversized. I want each cycle to be over and done with as soon as possible.

njtommy

@Eastman you want it to be undersized or just right. Long run times and low cfm. Slow and steady wins the race with forced air.

Eastman

It's a race to insanity.

Eastman

I think that's more a function of the cooling load in relation to the dehumidification demand.