Condennsing Boiler Questions

Homestar Plummer_2

Hey guys, I'm new to the heating scene. I am just learnining about condensing boilers. If my understannding is correct Conodensing boilers are more efficient than normal boilers. If this is true why doesn't everyone install condensing boilers?

Constantin

...because the upfront cost is higher...

... the US market is driven to a large extent by up-front prices. Most customers don't think about operational costs until the oil crisis hits or they receive the gas bill. Yet, it is often possible for folks to pay for their heating plant as part of their home equity loan. Banks like it because it enhances the value of the property, and homeowners save more money than the incremental increase of their loan payments.

Plus, many gas networks will give you rebates for installing energy-efficient appliances. However, to the best of my knowledge, these rebates do not cover the marginal cost of a more efficient appliance.

Nonetheless, if your client uses gas as a fuel source, installing anything other than a condensing appliance is throwing money out the door. The upcharge for a properly-installed HTP Munchkin is small compared to the savings your customers will accrue over time.

On the oil side of the business, condensing appliances have a very bad reputation due to the service and reliability issues. US fuel oil is too contaminated with sulfur and other exciting pollutants to ensure the longevity of most secondary heat exchangers (where the condensation occurs).

Lastly, steam-based heating systems cannot take advantage of a condensing boiler (yet) as no one has produced one (to the best of my knowledge). Plus, getting the returns temps to be sufficiently low to allow for condensation to occur is pretty difficult. 130°F is apparently a reference point in this regard, and without condensation you won't reap any of the benefits of a condensing boiler.

So, take a hard look at condensing boilers/furnaces. They offer great energy savings if installed properly. Once you have explored condensing appliances a bit, go further and learn to appreciate the benefits of outdoor reset and burner modulation.

Even regular cast iron systems can save between 16-24% of fuel just by hooking them up to outdoor reset controllers. Considering that a modern OR Tekmar controller only costs a couple of hundred bucks, you could have your investment recup'ed in two years or less.

ALH_3

Application

It depends on the type of heat emitters used. If your system requires temperatures above 130F to perform you wont be condensing whether you have a condensing boiler or not. If a system is primarily hot water baseboard I see no justification for using a condensing boiler.

Domestic hot water production may be more efficient with a condensing boiler.

The cost of condensing boilers is generally higher than for non-condensing ones.

Condensing boilers are great for radiant floor applications. Constant circulation and outdoor reset with a modulating burner is a perfect match for this situation. However, even all radiant floors are not created equally.

It all has to do with the low return fluid temperatures. If you dont have that, there is no reason to use a condensing boiler. It requires a system approach rather than focusing on individual components separately.

-Andrew

Constantin

... that all depends on the baseboard, no?

The debate on whether condensing boilers work with BB or not has been raging here for a while. What I have taken away is the following:

• Baseboard is cheap. So run it around the room and have enough emitting surface to fulfill demand even on the coldest of design days with supply temps below 150°F.
• 95%+ of the time, the exterior temperatures are above design-day extremes. The warmer the exteriors, the lower the water temps inside the heating system, the higher the efficiency of the condensing boiler.
• Roughly 1/3 of most energy needs circle around DHW. The condensing boiler will do great under those conditions.

IMHO, if you're a gas customer occupying a home year-round and don't have steam heat, it would be fiscally irresponsible not to go with a well-installed modulating, condensing, and outdoor-resetted boiler.

Tony_8

Not necessarily so

I have an Ultra installed on bbd w/ an indirect also. Today, while "tidying up" the jobsite and taking pics, the outlet temp was 180 and the inlet temp was 162 and there was a stream the size of a pencil lead coming from the condensate trap. I imagine it will be even better now that I have the OR programmed. The water temp at discharge idled down to 124.

I'm going to post the pics in a bit, when I'm done reading the rest.

Mr Takagi

I'll Second That

I was checking on my WM Ultra 155 today and it was still condensing a small amount with 160 out and 144 return. Looks like this thing is going to work great!

Chuckles_2

> If a system is

> primarily hot water baseboard I see no

> justification for using a condensing

> boiler.


Here the Wall, which is generally populated by people who know better, it is disappointing to see such incorrect claims posted.

Tony_8

Old saying

There is none so blind as he who will not see.

Floyd_7

You can lead a horse...

to water.... but you can't MAKE him drink......
The Amish from Yatsey's neck of the woods have another way of putting it.......

"We grow to soon old.... and too late schmart......."

Floyd

ALH_3

Question

In that case, why do boiler manufacturers still make non-condensing, fixed fire boilers? Are they ignorant as well?

-Andrew

Floyd_7

Resistance to change.....

pure and simple....

Kinda like my dog when his food dish got moved......
he went hungry for a few days.......couldn't get used to the change....

But really... there are both types of customers out there... the ones that want the absolute cheapest possible install.... and the ones that acutally do some homework and want to have the boiler that is on the absolute bleeding edge of technology.......

I'll sell both......but I'd rather sell up.....and I try my best to be the best darn informed contractor that they can talk too.....would never talk someone out of what they want...give them the options... explain them intelligently and most of the time you will sell them the top or next to the top option......

I was going through my spiel more than once about the different options, only to have the homeowner stop me....
"which one will cost me the LEAST to operate??? That's the one I want"

I got the message....

Many contractors haven't got the message yet... they sell cheap....


Floyd

ALH_3

Time and Money

I'm not saying there is no benefit to using modulating, condensing boilers in higher temperature applications. Since even non-condensing boilers are running at near-optimum efficiencies, there is a finite amount of efficiency that can be had by modulating the boiler. As far as the latent heat is concerned, I would be very interested in the volume of condensate produced each day at higher temperatures. From my very rough calculations it could be around $150 a year if the boiler produced an average of 10 gal/day for 8 months of the year using natural gas at current rates.

Depending on what the two boilers and control systems are it could take up to 20 years to recoup the price difference at that rate. What is a reasonable payback period for a Vitodens? An Ultra? A Munchkin?

Are life expectancies different when comparing a cast iron boiler to an Ultra? It seems to me these new boilers are more similar to a dishwasher in life expectancy. There are a lot more parts to wear out. There are also a lot more parts to become obsolete. Electronics dont stay the same for long. Will replacement parts for Vision 1 controls be available in 2020?

Based on these statements I believe that using a modulating, condensing boiler in marginal applications is not something I would recommend to a customer. When longer payback periods are involved, the value of paying the money out over 10 years may be better than paying it up front. There are a ton of variables involved, and it's impossible to predict the future. If they leave all the doors open, the condensing boiler will pay for itself sooner. I think there is an economy of scale here. ;-)

Last I checked, Tekmar hadn't stopped making the 363, so I can only assume they agree that fixed fire boilers aren't obsolete yet.

To sum it up, I respectfully disagree.

-Andrew

ALH_3

Cheap

Non-condensing boilers aren't always cheaper or of inferior technology. The Vitogas 100 is certainly not cheaper than a Munchkin. Which is the up sell?

I do agree that the condensing boilers are the future. I don't necessarily agree that a $20 a month lower operating cost will offset an extra $1000 investment financially. I love to save fuel. It's just a question of how much fuel is really being saved. Again, scale and application are important.

Informing the customer is key. As long as the customer realizes how his system will operate, and it isn't something that simply wont work, everything is great.

I dont think it's as simple as condensing boilers always being better than any CI boiler.

-Andrew

LEAD PIPE

Pay back

I saved 40% after having an Ultra installed in my home. I have baseboard heat. At this rate it will have paid for itself in 3 years. If I get 15 years out of this boiler I will be happy. I almost hope it doesn’t last longer. Why? Because what will be available 15 years from now? Maybe I can save even more. Then I wont have to make the same difficult decision I did last year, remove a perfectly good working boiler and replace it with a more efficient model. (Best decision I ever made)

Tony_8

I have

installed a modulating, non-condensing boiler to replace it's sister and saved the customer 30 % on their gas bill. I had a hard time believing it until it continued a second year and I checked 4 years worth of gas bills. That was a Teledyne Endurance replacing a Trianco Heatmaker. There's a comparison of 2 types of apples.

In my experience, CI boilers' efficiencies aren't all they're cracked up to be. And, when you increase AFUE efficiencies the savings does NOT match the differential percentage. It seems to be close to double. This is strictly my observation of my own sales and is not "lab tested", but very consistent.

Now, if only we could get oil fired equipment as good

DaveGateway

I assume

most of that 40% savings was just from replacing a boiler that was only running at 60% efficency in the first place and probably oversized, not the miracle of condensing. Reset controls also played a part, but that can be added to any boiler. As said, each application has to be looked at to find the best cost/benefit ratio. Hybrid cars are the future, but not for all of us yet.

Constantin

$20 a month?

Andrew, if I take your $20/month savings and extrapolate, that's $240 a year. By year 5, your customer will be saving more than their initial marginal expense for going with a condensing appliance. How does that compare with the returns from the stock market or worse, CD's, bonds, or other financial instruments?

Furthermore, the savings are usually greater than that. Homeowners on the Wall have reported 10-25% fuel savings after installing a condensing boiler. In high-energy-cost markets like Boston, the marginal cost can be made up by year 2. The savings only increase if homeowners also elect to go with a IDWH to replace a gas-fired unit (or worse, an electric one).

No, the US simply has not made conservation and energy efficiency a high-priority target (witness the cars people drive). Hence, local manufacturers had no reason to spend the considerable R&D to develop condensing boilers that have the same reliability as the cast-iron ones they replace. Furthermore, the US boiler industry seems to be locked into a long-lasting price fight, never a great motivator for investors.

Next, folks have preferences based on prior experience. Europe prefers steel-based boilers. America still leans towards CI. ASME code calls for 1/4" thick walls in pressure vessels, DIN code allows for less mass if the steel is good enough. Etc. In other words, humans are resistant to change... and in many instances, rational thought has nothing to do with it.

Lastly, there are applications where non-condensing boilers are better suited. You shouldn't be installing condensing boilers in steam systems. Condensing boilers are also a likely no-no on the oil side until the US drops it's allowable fuel contamination levels to 300PPM or less.

I'm a mere homeowner, but I respond a lot better to contractor that offer "good, better, best" options than the ones who decide for me what I want. Putting together a simple table-chart would only take a few minutes. Put in the pros and cons of each system choice, then let the customer decide what is best for them. This is not to say that you give away the farm (i.e. listing heatloss and other useful info that the customer might pass on to the competition) but that you simply describe the technologies in general terms, side-by-side.

ALH_3

The actual cost difference depends on which condensing boiler is chosen. Say it’s the difference between an ECD-155 with a 363 versus an 11-44 Vitodens. Both are high quality reliable systems. Both deliver the same comfort level. The Vitodens requires two big pumps; perhaps 26-64’s or 26-99’s. These are a lot more expensive than 15-42’s or 15-58’s. Then there’s the low loss header, the expansion board, basic vent kit, and neutralization unit. The pump panel for the ECD would also not be inexpensive, but even that does not make up for all the price differences. The price difference between these two systems could be significantly more than $1000.

You’re assuming 12 heating months in a year. I would say it’s closer to 9 in most locations. Next, I’d say most people aren’t paying cash for their boilers. The interest paid on the price difference is also costing them a significant amount of money. The amount of fuel the customer uses in a year will definitely affect how quickly increased efficiency will pay for itself.

Boiler replacements are an incredibly inaccurate comparison between boilers. Of course the old boiler is at the end of it’s life or it wouldn’t be replaced. Adding outdoor reset is a major improvement in itself. Some of the newer cast iron boilers are more efficient than the old ones were even when new. I would like to see hard numbers on just how much the condensing portion is saving them. Granted modulating burners are a better approach to low temperatures than injection or mixing. How much better wrt fuel consumption is another issue.

Informing the customer is why heating professionals exist. Our knowledge, skill, and experience is all we have to offer. Simply telling someone a condensing boiler is better in all cases except steam is a gross simplification in my opinion. If I’m going to suggest a customer purchase a more expensive system I want to know it’s actually worth what I’m proposing they spend. There is a salesman’s approach and an engineer’s approach.

Then again certain boilers have a real cool factor associated with them. Vitodens and Biferral’s are two of my favorite designs, but it all depends on what the customer wants. Then there are the customers where price is not an issue….

In my opinion it’s much more of a case by case situation than is being presented here.

-Andrew

Boilerpro_3

Condensing steamers are available!

But only in larger sizes. Also return water temp does not always determine condensing ability. My Dunkrik Quantum uses cold return temps to condense in the primary heat exchanger and then uses the very cold intake air to condense in the secondary heat exchanger. This preheats the gas mixture entering the combustion chamber. This is an old concept like that used for "economizers" on commerical equipment. In addition, I believe boilers like the Vitodens also use the cold intake air to condense the hot, moist exhaust. Simpler designs like the Munchkin and Ultra do not have this secondary heat exchange occuring, from what I can see, but I will let those more in the know comment on this.

Its from this secondary heat exchange that you an probably build a condensing steamer...How 'bout it boiler manufacturer's!

Boilerpro

Andy_14

"Granted modulating burners are a better approach to low
temperatures than injection or mixing."

I am a homeowner and had a ? about this statement.
Does using a modulating heat source w/outdoor reset eliminate the need to mix/inject down temps?

RickP

WM Ultra Condensing boiler

Hello all,
I just stumbled upon this site and found some great stuff here. I have a WM Ultra installed for nearly a year and am just thrilled with it. I have a Levittown house that had the orginal GE boiler still!!! and I mounted the ultra in it's place. It was certianlly time for an upgrade.

For those curious so far I am 378.30 bucks ahead of the curve compared to last year.

I restored the floor radiant heat and threw out the BB and this boiler seems to be a perfect match for it.

My only concern is finding a qualified service mechanic should something go wrong. I could try to fix it myself, but I'd like to have a back up to fall on.
RickP