having a new boiler installed, I'm trying to decide between installing a indirect HWH tank or keeping the standalone gas HWH. The boiler we are considering is the weil-mclain cga-5. The chimney needs work so I need to decide how many appliance I will be attaching. Will the heating of the water in the boiler during the summer months negate the savings the more efficient indirect.

thanks in advance
Joe P.

 

How many years of life you figure are left on the existing water heater?

Why not keep it until it takes a crap, and have the installers 'stub out' the new boiler for the later addition of the indirect if you decide to go that route later?

Why are you considering a huge boiler like the CGA-5 ? Unless you live in a McMansion, chances are you can get by with a properly sized boiler of say 3 sections or so, 4 tops.

Weil Mclain , Weil Mclain Boilers , Weil Mclain CGA Boilers - SupplyHouse.com

How many square feet is your home?

Has anyone done a HEAT LOSS ESTIMATE on the home before selecting the boiler? If not, DO IT! Why install a 'too large' boiler that you will have to live with for a long time?

READ:

http://www.doityourself.com/forum/bo...nt-boiler.html

and

http://www.doityourself.com/forum/bo...lculators.html

 

Here in the Midwest, where natural gas has been available for many decades, indirect (or direct) HWHs are unknown. Standalone HWHs are the name of the game. (But admittedly, trends, such as hula-hoops and skirt lengths tend to reach us a bit later.)

A standard, cheapo but name-brand, standalone gas heater should last at least 15 years and probably longer. Then, assuming you still own the house and are a DIYer, you buy a new 40-gal unit at a big-box store for $300 or so, and install it yourself (get a strong friend to help schlep the old, limed-up heater out of the basement).

Our Crane gas heater lasted 50 years, when I replaced it solely out of caution. But current models probably won't last that long.

As a DIYer, I perform my boiler maintenance and system improvements during the summer, when my boiler is completely shut down. With my standalone HWH, I'm under no time constraints. But, you might ask, what if the standalone HWH shoots craps? Sears, Home Depot, and many local plumbers, offer 24-hour heater replacement (but surely for extra cost). A DIYer should be able to replace one in a similar timeframe, assuming access to a pickup truck to pick up the replacement heater.

Whomever you call, expect to be up-sold on a custom, condensing, HWH. Resist. I get a handle on the cost of gas hot-water heating from my summer gas bills - it is almost negligible compared to space heating, even combined with clothes drying, cooking, and outdoor grilling.

 

thanks
the house is a 1700 sq. ft. ranch "really a bungalow with 4 extensions" the original bungalow which we rent out has very poor insulation and it accounts for about 500 sq. ft. of the house. when I bought the house there was no insulation in the bungalow so I had it blown in. How good a job was done, how much settling, and how many walls were miss is anybody's guess.
The current boiler a slantfin from the 70s has 125 btu input and works hard on a cold day. I'm figuring a little extra incase I add the indirect or another extension. I did toy with the slantfin calculator, but because of the differences in each part of the house and values the program lacks its still just a guess how big a boiler I need. My gas bill for last year was $1400.00 with three people showering daily and 2 kitchens cooking daily "about $50.00 a month in the summer". So how much could I hope to save by putting a smaller boiler. vs . the cost of having to do the job again if its too small.

 

As Trooper indicated, the boiler you're being sold is way over sized. Cancel your order and reboot, with somebody else, after you run a heat-loss calculation.

 

Not doing the heat loss because of 'differences in each part' is just lazy. What values does the program lack?

It's a bit foolish to 'guess' at an appliance that is expected to last 25 years or so, don't you think?

And that could be because there is not enough heat emitter installed in the home. Knowing how much heat emitter you need is part of the heat loss program. It will tell you how much you need in each room.

It's your $$$, all we can do is advise. If you don't take the advice, it's your loss!

Just for a bit of comparison, I'm down by the Jersey shore... my home is about 2000 square feet and my boiler is the smallest Burnham MPO model at 85K BTUH. It LOAFS along during the coldest winters and heats the home with no problem at all.

Even if your home requires a ridiculously HIGH heat input of say 50 BTUH / square foot, you are looking at an 85K BTUH boiler. The reality is that you can probably heat that place with a 50K BTUH boiler... but ONLY if you have enough heat emitter installed.

Remember this: You could have your own private NUKE plant in the backyard and even it won't be able to heat the home if you don't have enough heat emitter installed.

There's two parts to the hardware equation:

You need to be able to PRODUCE the heat in the boiler, and you need to be able to MOVE and OUTPUT that heat into the home. If you don't have enough baseboard or radiators installed, there is NO boiler that would be able to heat the home properly.

I say this because you said the current boiler 'works hard'. It would have to if there's not enough radiators.

 

Your size house your looking at about 45k btu boiler. The cga5 is 102k btu... Can you see the difference?

Also dependent on what type heat emitters in the home. What type and how many feet? Cast, copper?

If you only have 50k btu of emitters putting a 102k btu boiler is not smart as you cant get more heat out of the emitters then what they are rated for at 180f boiler temps..

You may just need additional emitters and size the boiler properly.


How does it work hard? If sized right on the coldest day of the year the boiler should never turn off... ( A rarity)

You should find a new installer IMO.... And stop that install asap until you do the heat loss..


edit: Sorry troop, we posted similar times..

 

S'ok! The fact that we all agree should lend to truth to what we're saying!

 

I expected to be told that the boiler was too large. I did do the heat loss calculation with the slantfin app. the result was 68k btus. I had to do some guessing on some of the inputs, the house has gaps between extensions where instead of connecting one extension to the other they built a new wall next to it leaving a gaps of varying sizes, uninsulated and open to the crawl space, attic and only sheathing on the outside edge. We addressed what we could during renovations still most are as described. I treated these walls as if they were abutting unheated space. also as I said a large part of the house was uninsulated we had blown insulation added but I'm not sure the job was done properly some of the walls seem to have large cold spots either at the top or bottom. I treated them as 3.5" with 1" foam (foam actually 3/4" no option for it in program). also most of the ceilings are vaulted I wasn't sure what to do with ceiling height so I split the difference. It starts at 8' goes to 14' I put 11' and the biggest number for ceiling insulation was 6" I have at least 12" in the non bungalow side.
as for get a new contractor I had 5 estimates they all wanted to put a larger boiler than I'm considering at a cost of between $9-$14k. I knew from what I read that they were way off. I didn't think I was that far off.
can a professional heat loss assessment be done in the summer? And how do I know if the person doing it knows what there doing?
one more question how big a deal is it if the boilers too large. Are we talking just a small loss of efficiency or something worse.
sorry for running on and crappy grammar writings not my thing.
one thing I noticed when I did the s/f app. it says I have way too much baseboard. Most rooms have 2 full walls of baseboard
thanks again

 

I hope my questioning of your advice is not taken as I know better than you.
I spent the last couple of months reading this and other forums and I think I'm smart enough to know I don't know much. I'm sure the boiler in question is too large. I just haven't been impressed with the contractors in my area. When I suggested that the boilers they were recommending were to large and filled with efficiency technology that I wont live long enough to justify the cost. I was told they would not guaranty a smaller less efficient would keep me warm.

 

You would be nuts to pay that...

And thats why you are here.. We can guide you every step of the way..



Not that we size a boiler this way, but look inside the covers. Tell use how many zones you have. Measure the element only and tell us how many ft you have. Thats the element with the aluminum fins on it.. ( You may just have dummy covers.)

Give us this info and we can talk more...

 

there are 3 zone the 1) original bungalow 4 rooms each about 10'x10' 2 w/20 ft. of base board 2 with about 15 all live w/ aluminum fins "poor insulation runs a lot"
2) my kitchen 22'x12' about 24' live w/fins this zone almost never runs because its 3 ft. higher than the rest of the house and the heat seams to find its way up.
3) 3 rooms bedroom 14'x12 26ft. baseboard living room 20'x10' 10ft baseboard
master bath 9x9 7 ft. base board. all live all fins
zones 2 and 3 all the base boards are new with nice straight clean fins
in the bungalow from the 70s and not so much clean or straight.

 

and yes I would have to be nuts to pay that which is why I'm drafting some friends for a self install.
I think that gov. and keyspan rebates and the after effects of sandy has really driven up the price.
they were all quick to tell the state would pay for 1/2 the cost, of course I don't qualify.

 

I will do this calculation with a greater heat loss. But you may want to replace the elements if its really bent up.. Take a pic. This may be why they are not producing heat.

10x10 = 100 sq ft x 35 btu = 3500 btu needed for that room of that size.

You have 20 ft baseboard x 550 btu @ 180f temp boiler water per ft = 11000 btu for that room...
( You have plenty of base board and are 7500 btu over what you need.)

For the 15 ft BB x 550 = 8250 btu.. ( again plenty)

Again this is a heavy calculation for a non insulated or minimully insulated house.

You can do the math for the rest? If not I will figure later..

But 137 ft baseboard total if I added correct.

137 x 550 = 75k btu max out put. Thats all the heat you will get out of the baseboard so sizing a boiler bigger then that is not smart..

Additionally a boiler that big would only be needed if say it was all one big zone. Because its not, and zones dont often run at the same time, you do your heat loss on a room by room bases with the slant fin calculator.

Any one zone should not be more then 63ft also I believe.

How many t stats in the home? 3 right?

Doing math on the boiler you need bases on a higher heat loss I get 59,500 btu boiler needed. And thats probably too big..

Do your heat loss carfully again and put the correct t stat settings and outdoor air temps. What are you using as temps?

Hope this helps so far..

 

I think you directed this to me... no, not at all, I've been at this long enough to have a pretty thick skin...

But, likewise, I hope you didn't get offended by me implying that you might be lazy or foolish! When I read that back later I thought I should probably edit it... but then forgot to.

 

And please add to my post #14 troop if I missed anything...
( I type faster then I think sometimes..He he)

 

I think ya pretty much got it all Mike...

but I'll 'recap' a bit if you don't mind.

Example:

A home has 100' of fin-tube baseboard at 550 BTUH per lineal foot with 180° water.

Anything larger than a 55K BTUH boiler would be a waste.

When designing a system, the room by room heat loss estimate allows one to install the proper amount of heat emitters in each room. If MORE heat emitters are added PROPORTIONALLY to EVERY room, it allows one to heat the home with cooler water, thus saving some energy.

MORE HEAT EMITTERS than needed is not a bad thing. If the home has the wall space for extra fin-tube, and the budget allows it, heating the home with say 160° water saves fuel.

MORE BOILER than needed is a waste.

AGAIN though... the additional baseboard must be added PROPORTIONALLY, otherwise some rooms will be too hot, some will be too cool.

 

no offence taken it just occurred to me I was arguing with the experts and I didn't want to be.

 

I never push it over 160 I don't want push my luck with a rusty old boiler.

 

My two cents is- how well is the original boiler being cleaned, especially if it is too big? Many of the boiler "techs" don't do a very good job. If this is a pin boiler, it is very hard to completely clean all sides of the pins, as silly as it sounds,and if they ae not careful, they will damage the refractory, when the brush goes into the firebox from the top. That said, the 86% probably drops to 70 or 75%. You can tell by the stack temp. I never liked pin boilers, as you can tell.
Sid

 

As far as I know its never been cleaned

 

I got 4362 btus for this room.
I used zero for outside temp and 70 for inside temp.

 

Is the cga-4 a better choice.

 

That's a lot.

What did you use for your 'wall factors' and such?

 

2x4 walls 3/4 foam (.06) 2x4 ceiling (.07)

 

Well I assume it dont matter because you have 20ft in there. Thats 11000 BTU..

Are the covers on the baseboard? Are they dinged up really really bad? I cant believe that 10x10 room would be cold. You are sure its all element under the covers right?

 

[QUOTE
Are the covers on the baseboard? Are they dinged up really really bad? I cant believe that 10x10 room would be cold. You are sure its all element under the covers right?/QUOTE]
Definitely have fins a little beat up , dusty and blocked by furniture.
Also bungalow was a good amount or pipe in the crawl space some of it wrapped some not.
Crawl space cold and not well sealed

Not much I can do with apartment because tenant keeps it full of stuff

Are the cga boilers a good choice , are they dependable.

 

Weil mclain would not be my choice as the sections are assembled with a type of o ring. I have seen failures during overheat conditions...

IMO slant fin or burnham would be a better choice.. They use push nipples.

 

slant\fin s-90 or burnham series 2 (204) or series 3 (304)

 

Is all your near boiler piping copper? Big cast pipes? Can you take any pics?

Did you redo the total heat loss? What did you get?

IMO I would do an s 60 slant fin or a a 203 series 2 burnham...

Fix the baseboard...


Pics pics pics... it will help us help you...

 

I will do the heat loss again, this time I'll try the taco program.
The current boiler setup has steel manifolds to the circulator and check valves,
Copper after that . I will post pics when I get home tonight.

 

Taco program stinks IMO... Very difficult. Stick with the slant fin calculator...

Determine how much BB is needed in each room and compare it to what you have.

If there is dust and stuff piled in front of the BB there is no boiler that will overcome that..

Example: My neigbors house during a cold spell would not get above 58F. I took a look at his BB and you could not even see it... Furniture, rugs, books, dust...etc. I told him you need a gap and space around the BB. Told him to clean them. He did not really do anything.

As a favor I raised the temp of his boiler to 200F. That solved the problem. Now if he cleaned all his bb properly he would have been able to run the boiler at a lower temp and heat the home.

Mind you it was -2F outside when we had that cold snap in NJ...

Conclusion: you running the boiler at 160F does not sound like a good idea and that also may be your some of the issue... You can run a big boiler at 160f or a properly sized boiler at 160f and you will get the same result. One boiler will use more fuel though...

Sound logical???

 

Thanks for the heads up on the taco program.
The lower running temp is an attempt to keep the pressure down on a rusty old boiler.
It is very damp where I am I'm about 15 ft. Above sea level and there is a stream about 15 ft. From the boiler room. Also when I bought the house there was no fresh air intake for the room as a result the makeup air came from the crawl space. And worst of worst the dryer vented directly into the boiler room.
These are the reasons why I believe the boiler is on borrowed time. That and rhe pile of rust I sweep up each year.

 

If it's that bad and you don't replace before next heating season, you damn sure better get the internal flue passages cleaned out.

 

chimney guy is coming Thursday. getting estimate on lining/raising current chimney or replacing with steel stack thru roof.

 

hope I did this upload right

 

here's a few more pics

 

Boiler looks ok...

Its only 87k btu IBR.

Changing the boiler will probably het you $0 in savings.

As trooper mentioned have the sections inspected and flue/chimney looked at...If all is good clean it up inside/brushed and fix you baseboard... Nothing wrong with a boiler that's not leaking...

Clean burners etc... Make sure proper pressures and raise the temp to 180f...

Just a note my boiler is 40 yrs old at least... Im not changing it until it leaks...I clean it every other year or so... Old cast iron burner...

Is it pretty? No!!! Does it work? Yes!!!!

 

You may even have other issues, such as flow controls not working. If a zone calls for heat, all other zones may be trying to heat too.. This alone would cause a cold house possibly...

You need a competent boiler guy to inspect and run the system to see if its working accordingly. I would have that baby tuned up to purr like a kitten..

You could have issues like I said not related to the boiler at all. As we said, bent dirty BB, controls failing/failure, low pressure, condensation, clogged heat exchanger... etc.. If condensation issue it can be cause by a few things. Near boiler piping will fix that, such as a boiler bypass of some sort...

We are not there, but its IMO if its not leaking why replace? ( never replace a boiler for fuel savings alone)

 

Lets see how bad the BB is... Pics of that?