condensing or hi efficient boiler

Rick_17

I am going to replace my boiler and have been provided too many answers by too many heating specialists and I hope I can geta better direction from my question

I am going to replace my 25 year old A.O smith copper boiler was was considering going to the new Olsen Q90-200 condensing boiler (Dunkirk in the US) but I am told that there will be no benifit to the higher priced condensing boiler in my situation

I am heating a 2150 SQ FT bundalow with a walk out basment so 4300 SQ in total and my heating costs have been pretty high, so I was considering going to a higher efficienty boiler.

My heating system was designed with the ammount of copper fin to operate with the boiler at 180 deg F but last year I decided to lower the temperature and I was able to heat the house with the same amount of rad at 155 deg F with a return water temperature of approx 110 to 120 degrees, and it was very comfortable and I lowered by heat bill by approx 350 dollars and the winter was colder and longer

so my question is - would I see any added efficiecy from a condensing boiler as opposed to just purchasing a less expensive mid or high effcient non-condensing boiler and can any tell me what the range of water temperatures where a condensing boiler is effective. I have read alot of good info here and I think I understand it but I appreciate your responses

Thanks

Rick

LEAD PIPE

I saved

about half when I installed a condensing boiler. I a have baseboard (fin) system. I had problems with the install; make sure you get someone who knows what they are doing. The outdoor reset came with my boiler make sure you install one. You will not regret this decision!

Plumbob

sounds good

You have provided the answer within your question. If you heat your house even on the coldest day with a return water temperature less than 120F, you'll get the full benefit of condensing. Of course, last winter was not as cold as some, but there are only a few exceptional days anyway, so if you can do it with 120F on almost all winter days, you're fine. With outdoor reset control, your water temperature will be automatically varied depending on the weather.

Unfortunately many contractors don't take the time to ask questions, they have standard formulas that they repeat like "Baseboard means no condensing". Customers, too, are not comfortable with any answer that begins with "it depends", and most customers don't know their return water temperatures.

PS That's a very large difference between supply and return temperatures. Either your flow rate is too low or you're short-cycling. Make sure your new boiler is not oversized.

Steve Rockwell_3

John, what boiler did you have before, and what did you upgrade to?

Rick_17

My current boiler is currently short cycling and is oversized as far as I can tell. I had a heat loss done by my utility company and I was told that my house uses 115,000 BTU per hour. My current boiler is a AO smith how water 225 which has a max input of 180,000 btu and it has always short cycled.

I have gotten quotes on new boilers and every time, the contractors want to match what I have - I guess it is the easiest thing to do, but I do not beleive them and that is why I am doing my own research and the knowlege from this site and the books available ar amazing, but I still have one question

when I had a heat loss done on the house, the utility company told me that I should size a new boiler by using a 1.5 multiplier from the heat loss. I have asked many plumbers and I cannot find out how to actually size properly

I was told it all depends on the amount of rad, but after reading Dan's Hydronic Radian heating book, I new that there has to be a easy way to do it irreguardless to the amount of pipe and I know that I can add some additional pipe to make up for any heat loss based on running the boiler at a lower temp, so my question to the experienced

How do you size a boiler for a house that uses 115,000 BTU/hour

Floyd_6

I'll bet you a dozen dounuts......

that you would be quite warm in your bungalow with a WM Ultra 80...(that is unless you have NO insulation, and crappy doors and windows) Yup 80,000 BTU and modulation, with reset to boot.... you would be having to put up with the Gas Co. changing their meter because they would think that it went bad, though... :-)
Don't ever believe the Gas Co......what are they selling???? Exactly... you think they really want to have you buy LESS gas?????
With the low temps. that you say you can run, I would be installing a mod. cond. boiler in a heartbeat, and laughing every time I write the check to the Gas Co.

Floyd

Chuckles_2

I'm a homeowner, I know those guys

The people who want to match your old boiler, or who want you to multiply the heat loss by 1.5, are a disgrace to their profession and should be run out of town on a rail.

If the actual heat loss is really 115MBTU, you want a little more than that because no boiler is 100% efficient, so boiler input of say 130 will easily give you boiler output of 115. But I bet your heat loss calculation is overly conservative, they usually are. So something smaller will probably do the job just fine. Don't oversize! I have a house about the same non-basement sq ft as yours with a 80K condensing boiler in the Chicago area; however it is 2-story, so there is less outside wall area and less basement, and it is well insulated.

The best way to calculate heat loss is

(a) look up on your bill how many BTU you actually consumed with your old boiler in January/February (1 therm = 100,000BTU),

(b) look up the degree-days for the exact same period (it may be on your bill)

(c) calculate the BTU per degree day by dividing (a) by (b)

(d) calculate the BTU needed during a design day by multiplying the answer in (c) by the number of degree-days in a design day,

(e) divide by 24 to get BTU/hr.

(f) Then get a boiler 10% under that because your new boiler will be more efficient than the old one, plus your meter reading probably includes domestic hot water and cooking and etc so it is too high.

PS The size of the boiler DOES NOT depend on the amount of radiation.

Rick_17

80,000 btu

80,000 btu - I have a 225,000! if that is true, these plumbers must have shares in the gas company

when you say about 80K, do you mean max input or net?

I will try these calcs that you have provided but I just recieved my slant fin heat loss and I will try tomorrow

My house has a ton of glass and the glass is a mixture of double and tripple pain and I know I have alot of heat loss as it can be cold when sitting by the windows and I have two wood fireplaces. It is 2x6 and was pretty high up there 23 years ago. I am also in Canada - Winnipeg - where we do see from about December 28th to January 29th - -34 to -40f a week at a time.

I guess another question is - should one oversize by just alittle and I do not mean just abit??

Yes, in my gas bill is also my hot water heater cost but that is 50 per month - the rest of the 3200 is the heat bill but of course tax and delivery charges and everything else that they toss at us

if these calcs are correct, I will fly you in to do my house as it is hard to find a honest guy in our city

Chuckles_2

It means nothing to quote your bill in dollars. That depends on the cost in your area. Calculate the therms or BTU consumed in winter PER degree-day. Also find out the design temperature in your area, and I'll tell you how big a boiler you need.

You should not oversize at all.

I think 80MBTU input is probably too small for you, though..

Floyd_5

Just for kicks and grins......

I run my own house on the Slant Fin heat loss calc.
Now my house is 36 x 60, brick with NO insulation.....BIG windows that rattle in the wind... and NO insulation in the attic. The window that I'm sitting in front of right now is 40 sq. ft. single pane... yup lots of window glass in this house!!!
Now, even if I don't include the 70 some K that the program says that the basement needs... I still am at 270 K!!!!

Now..... I heated this energy hog with a 100K 80% H B Smith boiler for 8 years, in temps. as low as -28, before installing an Ultra 155 last year.
If the 105 had been available then, I would have went with that.

All I'm thinking here is, be careful..... what is Slant Fin sellin????? HMMMMMMMMM.......

Baseboard........

Boilers???????

A little boiler can go a lot farther than you think.... IF....you get the heat to where it needs to be efficiently....


Floyd

Constantin

Been there...

... I am a mere homeowner myself and asked myself the same question when the time came to spec our new heating system. I bought HVAC-Calc to do the heat-loss calc and tried several scenarios (insulation, etc.) to figure out what made sense.

I am now at 106kBTU heat loss for a design day (-15°F) in a 5,300 sq ft. 3-story + basement structure. Some folks on this board think that HVAC-Calc overcalcs by 10% in radiant heat applications... I found the program to be a good idea nonetheless. Just as a means of figuring out where the BTU's were going.

Regardless, the suggestion to run the numbers backwards from your gas bill is much, much better. There is no fudging those results and they reflect the true conditions in your home in a much better manner than any heat loss calculator can model.

Rick_17

well that is what I am going to do - rin the numbers as RPG has suggested but I will take the time to comare it to what the slan/fin calc says

I really appreciate all the help everyone has provided

I sure hope that I can help others on this board with what I have learned

Does any one have any thought on the new Dunkirk quantum 90- condensing series boiler? I guess for me it's either that or the Weil-Mclain ultra but the Weil-MClain is alot more - is it really worth the extra or is the difference of cost the quality of the company??

Rick_17

He's one more for RPG

As you where wasily able to pick out based upon my out and return temps that my boiler is clycling,

if I am to put in a proper size condensing boiler, I would expect that the difference between the out and return temp of the boiler will become smaller and more into spec, so am I correct in saying that if I run my boiler at 155 or so F, now my return water temp will be higher, so I am going to loose alot of efficency of the condensing boiler, and I may be able to compensate for this by adding more rad in the house, so I can operate the boiler at a lower temp but maintain the btu put to the house maintining the required but at the same time keeping better within specs so that the boiler will et the advantage of the condensing??

Does this seem like I am on track

Rick

Floyd_6

Comparison of condensers.....

Check this out, there are some major differences betweeen the two.... labor and parts warranty, reset control, freeze protection,modulation, etc.....

You really do get what you pay for.....

Floyd

If someone can resize that, it would help......
I scanned it and the way it came out really stinks.....
resizing it would make it much easier to read.

Thanks!!

Rick_17

Floyd - this comparison is amazing and you brought up a new question re the quantum 90-200 and the weil Mclain Ultra

When I read your comparison is leads me to beleive that the quantun does not work with a outside temp control as the boiler does not support modulation - am I correct on this or do you know if it does

I could not find this anywhere in the brouchure

Rick

Chuckles_2

no connection

> comparison is leads me to beleive that the

> quantun does not work with a outside temp control

> as the boiler does not support modulation - am I

> correct on this or do you know if it does


There is no connection between the two things. Any boiler will work with outdoor reset, the reset controller turns the boiler on and off to maintain the temperature. If the boiler does not have reset built in, one from Tekmar can be used.

Look at the Munchkin, Monitor MZ and Viessmann boilers as well.

Chuckles_2

that' a long sentence.

> He's one more for RPG

>

> As you where wasily able

> to pick out based upon my out and return temps

> that my boiler is clycling,

>

> if I am to put in

> a proper size condensing boiler, I would expect

> that the difference between the out and return

> temp of the boiler will become smaller and more

> into spec, so am I correct in saying that if I

> run my boiler at 155 or so F, now my return water

> temp will be higher, so I am going to loose alot

> of efficency of the condensing boiler, and I may

> be able to compensate for this by adding more rad

> in the house, so I can operate the boiler at a

> lower temp but maintain the btu put to the house

> maintining the required but at the same time

> keeping better within specs so that the boiler

> will et the advantage of the condensing??

>

> Does

> this seem like I am on track

>

> Rick

Chuckles_2

wow

Let me see if I understood your sentence.

More radiation is ALWAYS good, it lets you run at lower temperatures. Costs money, though.

The delta-T depends on two things, the heat load and the circulation rate. If you have outdoor reset, in warm weather the water will come back at almost the same temperature (I'll make up some numbers, say 100F out 97F back), but on a record cold day the water will start out hotter (say 160F) but it will cool more by the time it returns (say 140F). A rule of thumb is that on a design day, when you are drawing the "full" BTU and you've reached steady state (circulator has been running for a while), there should be a 20F delta-T (difference between supply and return). If you have a converted gravity system with fat pipes, reduce that number to 10F or less (i.e. increase the circulation rate).

If you are short-cycling, you will never get to a steady-state condition where you can measure the correct delta-T. The cold water in the pipes starts to return, a little bit of warmer water returns, then the thermostat stops the process. What I am talking about is the delta-T during steady state, which you don't really know for your house.

Another rule of thumb is that the water flow rate through the boiler should be 1 gpm for every 10,000BTU design load. If you have that, you are OK. If you have more than that, delta-T goes down so your return water is too warm. (Converted gravity systems need some extra flow, though.)

Hope that made sense, I am merely a homeowner, but I have learned a good bit from this forum.

jerry scharf_2

some help with the chart

> Floyd - this comparison is amazing and you

> brought up a new question re the quantum 90-200

> and the weil Mclain Ultra

>

> When I read your

> comparison is leads me to beleive that the

> quantun does not work with a outside temp control

> as the boiler does not support modulation - am I

> correct on this or do you know if it does

>

> I

> could not find this anywhere in the

> brouchure

>

> Rick





Rick,

First, I want to congratulate you on having so many answers on the first round. The fact that you included the return temperature on design day was the exact thing that was neeed. A condensing boiler will work great for you and should save you a fair amount.

You are right, the quantums are not modulating. The rule in sizing a modulation is to get the first size that is above the demand, it will fire down as needed. You don't want to go too big, because it limits how far down the unit can modulate and makes it less optimal during shoulder seasons.

As for outdoor reset, this is a boiler optimization that helps the system run more efficiently, especially with condensing boilers. It can be done using any boiler. Some boilers have the logic built right in that does it, others have it as an option and still others require external controllers (i.e. tecmar) to implement this. The external route can have varying degrees of benefit depending on exacty how the system is designed. The built in ones are harder to screw up.

jerry

Maine doug

My home and studio are in

the same brick building. I now heat the basement and main floor (14 foot ceilings) with two 80K Biasi triple pass boilers. Radiant floor downstairs, flat panel rads on main floor. Bought HVAC-Calc several years ago and ran the numbers. Even with the addition of a room on the side of the building and heating the basement with radiant, the heat loss calculated to be less than half of the existing steam boiler. We also took out the drop ceilings to restore the tin.
My oil consumption is about half of the steam system, I am heating more area and my shop is open year round. I also use an Ergomax for DWH. I can turn off the boiler and have enough reserve for two days of activity, three if you don't fill the tub. I have since found a leaking aquastat well in the Ergomax as a result of poor factory QC and have a rusty mess so my opinion of their products has dropped.
In the tween seasons, one boiler handles heat requirements. I hope to get the outdoor reset functioning this fall, am relocating outdoor sensors as part of renovation.
All my system design was done from Dan's books and info from the Wall. So I am happy with my savings. I have not calculated ROI.

Rick_17

RPG - I understand what you are saying - what I can tell you is that, in october, and until mid november, when it is not really that cold - the return difference is less and the boiler does stays on longer, but after mid november, and especially in December when we have our real cold canadian winter - the return is alot colder and cold enough not to heat the end rad and the boiler goes on for, let's say 3 minutes (never actually timed it) and when it warms up to set temp, shuts down, circ still going, but the boiler than comes back on once it cools down within maybe 30 seconds or so, and may stay on for 30 seconds or a minute and the process starts all over again until all the zones are satisfied,

Why there is such a difference in the return temp - I cannot tell you. My belief was that either my runs are too long, my house is using everything it can get, or my boiler is just shutting down too soon but I did put new acustats right on the out and return pipes as I no longer trusted the boiler controls - maybe there is also alot of scale in the pipes and the flow rate is just too slow, but The copper runs - well they do get hot

The funny thing is, I had a energy test done by our utility company in the spring. The test told me based how much gas I should use for the year - I laughed at the gent and told him - I used that much as in 1/3 of a year , so I told him there where three potential problems - my boiler is using it all, the gas meter is bad, or his test was flauded

The reason that I first wanted a condensing boiler was the return temp was in spec, but if I do get a proper sized boiler, from what you say, the return temps should increase unless my house is using everything it can get but if the return temps do increase, I may not get all the efficiency from the condensing boiler, as if I am correct from what I read on this site, a condensing boiler requires return water less that 140 deg F. but if that is the case, I will add or change some rad's and let the outside controls do the rest - now I hope I make more sence

Rick_17

question re Jerry's response

Hi Jerry

Thanks for response, but if I properly size or take the next size up from the demand, as RPG called the Delta T, should I expect the differential between the out and the return to decrease because of my short cycling boiler or after reading some of these post, or would you thing that my colder returns are because my is using everything it can get?? I wanted to turn my boiler up to 180 last winter to do a test and see if I had heat at the end rad on a very cold day, but I found that with my old 24 year old A.O smith, that I started to get more air in the lines after I turned up the temp to 165, so I turned it back down below 160 but as I mentioned earlier, the house was comfortable at this temp.

there where some real cold days (-40) yes (-40) where my largest room with lots and lots of windows would not go above 21 F if I turned the thermostate up to let's say 25, and I knew if I turned up the water temp, I could propably get the temp up, so I am just going to either add more rad or a kicker

what I did do, is put an additonal stapon temp gauge on the outgoing and two different temp guages on the return and checked them every two to three days through out the start of winter until I shut the unit down for the summer, so that I could have all the data that I required to solve my boiler issues and very high gas usage

Rick

jerry scharf_2

I'l take a stab at it

Rick,

First, the great thing about -40 is it doesn't matter whether it's C or F.

Let's look at how the system cycles. You have a certain amount of water in the pipes, and that water can hold a certain amount of heat energy as it warms and cools. You put in n BTUs per minute, some of it goes to heat the house, some of it goes to raise the water temperature. So we need to know: how much energy you're losing, how much water is in the system, how much heat you're adding and what the cut in and cut out temperatures. The closer the heat input is to the load, the less you cycle. The wider the range between the cut in and cut out temperatures, the less you cycle. The more water in the system, the less you cycle. Can't be more exact, but you get the idea. Modulating the burner is a way to match the boiler output to the load without having to turn the boiler on and off.

What are the cut in and cut out temperatures for the boiler? I was wondering whether when you lowered the temperature you may have also reduced the spread and thus increased the cycling.

None of these effect the delta T of the water returning from the loads. The things that control the delta T of the system are: the load of the house, system losses, heat output efficiency and flow rate. The first three determine how much energy comes out of the water, the final one deterines how much water there is to give that heat. As you increase the flow for a given set point, the delta T drops, the mean emitter temperature rises and overall output increases. As you slow the water down, all the opposites happen.

jerry

Plumbob

suggest reading some books, hydronics is complicated

> Thanks for response, but if I

> properly size or take the next size up from the

> demand, as RPG called the Delta T, should I

> expect the differential between the out and the

> return to decrease because of my short cycling

> boiler or after reading some of these post, or

> would you thing that my colder returns are

> because my is using everything it can get?? I


The delta-T has nothing to do with the boiler size (as long as the boiler size is adequate). As I already said,it depends primarily on the heat load and on the circulation rate.

If you run your system in steady state (continuous circulation) rather than short-cycling, your delta-T will be smaller, but so wll the supply temperature needed, because you are no longer heating the house with bursts of hot water.

> there where some real cold days

> (-40) yes (-40) where my largest room with lots

> and lots of windows would not go above 21 F if I


You mean 21C, I hope. That's reasonably warm. Why would you want to go to 25C?

Plumbob

can't help you here

> RPG - I understand what you are saying - what I

> can tell you is that, in october, and until mid

> november, when it is not really that cold - the

> return difference is less and the boiler does

> stays on longer, but after mid november, and

> especially in December when we have our real cold

> canadian winter - the return is alot colder and

> cold enough not to heat the end rad and the

> boiler goes on for, let's say 3 minutes (never

> actually timed it) and when it warms up to set

> temp, shuts down, circ still going, but the

> boiler than comes back on once it cools down

> within maybe 30 seconds or so, and may stay on

> for 30 seconds or a minute and the process starts

> all over again until all the zones are

> satisfied,


I dpon't know enough to explain this. You have a problem of some kind.

S Davis

flow rate

It sounds like you might have issues other than just the boiler being over sized, your system delta is pretty high which says to me that your flow rates are to low, that will constipate your system, that is it will give off less heat than it could with proper flow rates wich will worsen the short cycling issue with the over sized boiler, this will cause your fuel bill to be higher through higher standby losses and repeated firing, I think I would try to get the flow rates where they need to be by calculating your system head loss and resizing your system pump also I would look at getting a outdoor reset control wich will help with your boiler cycling, you might be surprised how much this will help and it would be alot less expensive place to start. JMHO

S Davis


Apex Radiant Heating

Rick_17

why above 21 deg C

RPG - I wanted to see if I could actually got the room hotter, as a boiler test

Did some good reading over the evening - what a way to spend saturday night, and came up with alot of questions, for which I had alot answered this morning (re the new boiler) but still have quite afew which I hope to have answered by a plumbing wholesaler tomorrow.

I have also remeasured my house, my copper fin, windows, doors and so on and will send this all off in te morning to the plumbing wholesaler where I will get my boiler for a heat loss calc and sizing and I want to see what they say. I will also know after this, if I have enough copper fin or not.

I will decide between three boilers being the weil-mclain, the Olsen Q90 (dunkirk in the US) and maybe take a quick look at the viseman.

The weil-mclain offers modulating but only at 20% and 100%, so this may help with the heat bills abit, but will not add to efficiency. I will also look at the cost of the outdoor sensor for the weil-clain. The Quantum 90 series does not offer the modulating or the outdoor reset, but I know that the outdoor reset can be added to any boiler, so I will look at the cost of doing this.

I was told that the viseman is very expensive but is one of the better units with better modulating than the weil-mclain

I think the word modulating that some of the manufacturers use is wrong as for example the Weil-clain is either 100 % or 20%, and those are the only two settings as far as I understand.

I will get an outdoor reset but I will also look to see if I can get a true modulating gas valve and outdoor temp controls if the price is not to stupid.

I will approach my system in two ways as you have mentioned

I will seperate the boiler from the copper fin and I will install the new boiler and maybe some additional fin and see what happens this winter and make adjustments in the spring or if winter says away for a while, maybe I will have time to do some this year. the biggest problem when making changes is that I have one return line, so if I add some rad, I will have to drain the system and I will not do that in december or January unless it was really necessary

I appreciate all your advice and help and I will post what I have done and my results.

I just wish that the so called heating experts that I have talked too would explain abit and maybe they would get my business.

I had one plumbing company give me a price for a 2000 dollar boiler (dealer cost) $ 4500.00 plus install.

The markup here is just gone stupid amd some of the markup is worth it if we as home owners are given proper advise but we are not, so thanks to every one that has helped so far and thanks to Dan for this website

Plumbob

> the Weil-clain is either 100

> % or 20%, and those are the only two settings as

> far as I understand.


A good rule of thumb is, if it sounds unreasonable, it is probably wrong. The WM Ultra modulates in multiple steps over the range.

> I had one plumbing company give me a

> price for a 2000 dollar boiler (dealer cost) $

> 4500.00 plus install.


Talking price is discouraged here. As a homeowner I want to save money too, but labor is expensive and getting a good installation can be worth it. Yes, there is a difference between the list price and contractor price of boilers, just like anything else, but the only relevant number is the bottom line of your contract. What are you getting for your money (The boiler is only one part of it), what are you paying for it total, and can you get it done better by someone else? If you can get the same boiler and same installation work done cheaper, go for it. But it sounds like you haven't found a contractor yet who knows modern hydronics. When you do, be prepared to pay a bit more for a good job.

Rick_17

boiler setting

Hi Jerry

the previous year, I had the boiler set to start at 160 and stop at 180, but I did not get alot of heat and had a cool winter - I decided to disable the boiler acustat and but on some new one's right on the out pipe and set it to 155 to 160 for it's cut off, so the boiler comes on at approx 135 I think and cuts off at 155 (20 degrees difference. The second acustat in series was set to 180 for a high level cut off if one failed. This is how I ran all of last year and with my retun temps between 110 and let say around 125.

the return temps where higher in the beginning of october when it was warmer and the boiler stayed on longer

Bottom line - I am changingthe boiler and I will decide which one this week. As I mentioned to RPG I am going to get another heat loss done and I will provide tomorrow, all the info required including the amount of fin that I have and let the wholesaler's engineer run the numbers.

I will look at three boilers being the weil Mclain, the Quantum 90 series and maybe the viseman but also look to see if I can get a true modulating gas valve and outdoor controls that will properly modulate the boiler flame as opposed to the two setting of 20% and 100% that are offerd by the weil-mclain.

As far as how much water do I have in the system - that I do not know. What I do know is that there is sure alot of pipe, 5 zones and at -40 - well there all open.

Alot of my problems are probably due to my 24 year old boiler just being tired and I have know idea how well the old owner of the house kept it up.

I will add some rad before heating season which is just around the corner and I guess I will see what happens

Just by upgrading the boiler should save on the bill immediatly, and wit a new boiler, I will be able to run it hotter (or should be able to)during the colder months if I do not have enough rad,and add more rad next spring, so I will than be able to run the unit at a lower temp which should increase the savingings - the cost of the additional rad.

I will post my results and what I have done and why I made my choices and let others know.

Floyd_5

Rick,....

Just have to clear you up on a few things.....
First... the Ultra IS a true modulating boiler.... whoever told you that it only runs 20 or 100% is full of soup... they don't know what they are talking about. It will modulate ANYWHERE within that range.
Next,... the outdoor sensor IS included with the boiler, all you have to do is hook up two wires to it.
The next point some here will take a major exception too, but here goes anyway.... the V boiler is not worth the extra... the WM boiler is a very good unit for much less money and the ROI for a V is definetly not worth it. Just my opinion....
Lastly, you have a circulation problem, pure and simple....you are not getting enough water moving through the system, now either your punp is too small, doesn't work properly, your piping is too small, there is too ong of run of radiation for the size of the piping and /or pump, etc.... it's really very simple... not enough flow for the amount of btu's jumping off the train... means the train is moving too slow.
Oh yes there is one more thing.... how do you know that the wholesaler know one iota more about heat loss calculations than you do???? Just because he DOES them doesn't mean he has a clue!!!!! Plus they are a bit in the same wagon as the Gas Co., they are in business to sell you a boiler and such...the more they can sell you the more profit they potentially stand to make. At the very least get a couple of opinions as to what you heat loss actually is, and if you at all can, try to double check their figures yourself.

Btw, just for your info. even if you aren't condensing with a WM Ulta, the boier will still be running over 90%. I've checked it with my combustion meter. don't ask me how or why, I just know that it does.....

Good luck!!! I think you on the way to avinga ton of money.

Floyd

LEAD PIPE

I had an

old burnham boiler, not sure what model. I noe have a w.m. ultra 230, I should have got a 155 but sadly I found this site after the install. Oh well it still works great!

Rick_17

Hi Floyd

when I was talking about either 20% or 100% modulation, I wastalking about the Weil-Mclain

I may be wrong, but I will find out this morning. As far a the second heat loss calc - compare it to what I have now and I also will do what RPG said can calculate backwards if I can figure it out.

And I do agree with you that I will save just based upon the efficency of the condesning boiler itself

I feel that part of the problem with my system is number 1 - way to over sized - I looked at the boiler again this morning. It's net output is 180,000 btu - I rechecked it as I thought it mas a max input of 180,000 but no max input is 225,000

This is what I belive will happen

I will properly size a new boiler and the brand I pick will either be the Weil-Mclain Ultra or a Quantum 90 series - big price difference but I will make part of my decision based on features and cost to add these features to the quantum series (thanks for the provided comparison - very big help)

Once I have the new boiler installed, I will know that I have a proper working boiler and than I can address the amount of fin on a seperate issue

I am fairly confident that if I ran the boiler at a higher temp, outgoing and return would be closer and the heating system would work better, but I can still add some rad

with the outdoor controls, I should be able to contol the boiler better so I am more efficient during the warmer months of winter but obtain more heat during the very cold period between December and the end of January

My house is 24 years old but was built very well - all 2 x 6 construction, tons of insulation, and the biggest area of heat loss are the tons of windows, the high A frame catherdral ceiling and the two wood fireplaces.

And if I have to next spring - rip out the finished basement ceiling, I will change some of the pipeing and convert alot of the pipe to infloor from wall radiant

Also maybe I will change some of hte rad this year as I have to drain the system to make some changes but if I am correct, there is better rad that provides a higher BTU output, and this would be a quick and simple change

The guy who origionally built the house owned a plumbing and pool company, so I guess 24 years ago with gas being so low, he proabably did not care and just added a big boiler

As far as the lenth of the pipes go - yes the runs are long as it is a fairly long bungalow, and this may add to alot of the loss of performance and I do not get as much heat at the far end - and if I have too small of a pump - well that kind of makes sense now

The wholesaler has a couple of good engineers, so I will see what they day and from all the compiled info, make my purchase decision - Cannot wait too much longer - winter is on it's way

That comparison chart that you supplied was fantastic and is an invaluable peice of info, but one last

does the weil-mclain ultra provide modulation between 20% and 100% or just at the two settings?? and are there third party controls that can be added to any boiler that will add modulation to a boiler

Rick

Rick_17

Hi Again RPG - I guess I should not have mentioned price - sorry. Bottom line - I have no problem paying a contractor to do the job and expertice. I am in business and I do the same, but what I have a problem with are some of the contractors that have quoted me - who tell me that a condesning boiler should only be used with infloor heat and not with retro-fits, and like you said earlier - it depends and I have had alot of that. I asked one contractor about going to a boiler with a cast mono block aluminum heat exchanger - He told me that I would be foolish to do this, but he also told me that I should consider the weil-clain ultra series. They are one in the same, but he does not know wwhat he is selling. - Very large company

Last week - one of the boiler manufacturers reps told me that I will see no benifit with a condensing boiler and I was foolish to look at it and that I should stick with a mid efficient as again he said - condesning boilers where designed to only work with infoor heat and not with copper fin rads. - a boiler manufactures rep!

Now tell me - how comfortable am I supposed to be with these answers. I am in a business where I do supoort for a couple of the larger plumbing firms in my city and I should be able to use there services, but I cannot - If I wrote a book on some of the things that I am told - but in all fairness, maybe the newer boilers are just too new for our area and some of the contrators are not up too speed - at least I hope that is what it is

I am sure if a heating consultant put on a better way to heat your house seminar in our city and charged at the door - the consultant would pack the house 2 x over

I have always said - to fix my heating problem - I need a old experieced boiler guy, who can walk in and undertand the way things where done 20 years ago but I also need a more current boiler guy who can apply the new technology to the job

It is amazing that afew days on this forum - how much knowlege one can get and I know that knowlege can be dangerous but it allows a home owner like myself to undertand better and ask better questions and I kink of think I know what is wrong with my house now. I deals with two issues

One being the old, tired oversized boiler and the other being either I am running the boiler at too low of a temp or the pump is undersized and cannot push the water fast enough and the house is using all it can get and the end rads never get warm as the water is cold by time it gets there.

A new condensing boiler is the first place to start and I am sure once I have a confident boiler, all the other issues will become more understandable.

I will add some additional ball valves if possible so I will be able to make suttle changes throughout the winter such as adding a larger circ pump.

Anyway - I am not trying to trash the industry - I have just been unable to find the right contractor. I know there are excellent knowlegable installers in the boiler field but I have become afraid to ask any more based on my experieces.

Again - I really appreciate all the help. My sense is that you must have had a similar experience andthat is why you had to do your own research and have become very knowlegable

Thanks

Rick

Joe_51

heat loss calculations...

Great thread for the HO Rick ! If I understand your posts your going to do another heat loss calculation. Please post the results you got from the various programs you used. I did/got 3 heat loss calculations done on the system I'm finishing up in my house as we speak. Lowest was 32k to 58k for the same house.......

Plumbob

"does the weil-mclain ultra provide modulation between 20% and 100% or just at the two settings??"

Your question has already been answered twice. Why ask it again?

Rick_17

Attn: S.Davis

Thanks for the recommendation

everything that has being mentioned by yourself and others makes alot of sense. I did replace the pump a couple of years ago, but I just replaced with the same size. One other contractor said that it may have something to do with the pump but was not exactly sure.

Ithink that part of the problems that I have experienced is that the contractors that I have had working for me a good at servicing the products but when it comes to design modifications, they either do not have the time as they have other calls to do, or they do not have the tools available - (programs)

I have provided one of the local wholesalers all the info that they require to do a heat calc and sizing or pump and the amount of rad.

They where told do do the design as if it was a new house and I will compare this to what I have for boiler, pump and the amount of copper fin

It really does make sence that the circ is undersized as during the real cold months, the end rad does not provide heat and if I understand this correctly, with a slower flow and the house requireing alot of heat - it's all used up before it reaches the last rad

Rick_17

sorry - to much intake in such a short period

Paul_28

math

Can you give a example of these calculations. I am not sure what a Design day is.

Plumbob

it is...

A design day is the day that your heating system is designed for. It is not a record cold day, but it is not a typical winter day either. Something in between. You can search the web to see if you can find this information for your area.

Degree-days is the difference between 65F and the day's average temperature.

My January gas bill says there were 700 degree days in the billing period, and we consumed 210 therms using our old, inefficient boiler. One therm is 100,000 BTU. So we consumed 210*100,000/700 = 30,000 BTU PER degree-day.

Our design day is -10F, so there are 75 degree-days in our area's design day. So on a design day we would consume 30,000*75 =225,000 BTU.

That was for a whole day, so on a design day we would consume 225,000/24 = 94,000 BTU/hour. That's with the old, inefficient boiler.

So we got an 80,000BTU Munchkin. Based on the little heating we have needed this fall so far, it seems that this boiler is still oversized, because the Munchkin is so much more efficient. But...two guys who did heat load calculations both said we needed a 150,000BTU/hr boiler! Two incompetents who counted radiators both said we needed a 200,000BTU boiler!

Rick_17

Hi Floyd - if your still coming back to this form

I agree with your comments and I am going to get a condesing boiler - just waiting for a heat loss to come back

did alot of reading and calculating (not heat loss yet) but cost saving calcs, where condesing boielrs become more efficient, how to control temps and so on

I also agee that I have a cir problem but if I would have operated my boiler at 180 out as opposed to 155 out - maybe not as there would have been plenty of heat to satisfy the house and return hotter water

Becasue I know that I can heat my house at lower temps, I will get the condesning boiler but during the realllllly cold months - I may operate at a higher temp and yes, I will loose some efficiecy during that time but I will save during the rest of the winter

I will install outdoor reset

I sparked up old faithfull last night (old a.o smith hw225 - sure get's the water hot fast , but do not touch the flue
lots of waist - but I actually thing that the old girl has a small leak , so i shut her down - little chilly but the new unit should solve alot of problems

thanks

Rick

Mr Takagi

Weil Mclean Ultra

Hey Floyd, I tried resizing your chart, which by the way is a great tool. Rick, I installed an Ultra 155 in my 110 yr old home this summer. It hasn't been cold enough yet to have it run much more than an hour at a time, but I can tell you it heats the system water up much quicker than my old system did, condensing the entire time. I noticed you said you estimated your water volume at around 75 gal? I don't know how you estimated, but in my system with 10 radiators in a converted gravity system, I measured 150 gallons when I drained it. If you go with the Ultra, I don't think you will regret it!

Mike