gas boilers, which would you pick?

Tom S.

Hi, I am pondering a conversion from oil to gas. I am only at the beginning process of this...



My house: 2400 sq ft colonial, 3 zones of hw bb (one each floor) and a zone for an indirect water heater. I'm pretty well insulated, all walls, attic, new windows...



My own heat loss calculation is about 75k.



Anyway, National Grid (Massachusetts) offers discounts on various boilers, I am wondering which one people would lean towards - I don't know if my chimney needs a liner for some of these or power-vent or what...



These are all listed as Burnham boilers:



-Forced Hot Water ENERgy StAR® Sealed Combustion

-Freedom Forced Hot Water HE Cast Aluminum Condensing Wall Hung Boiler

-Alpine Forced Hot Water HE Stainless Steel Condensing

-CHG Forced Hot Water HE Cast Aluminum Condensing

-Forced Hot Water HE Natural draft



Thoughts? This list comes from here:



<a href="https://www.powerofaction.com/media/pdf/MA_EOF_writable.pdf">Web link</a>



Thanks,



Tom S.

j a_2

questions

1   Inside or outside chimney and what size flue?

2  Do you currently have gas in your home, if so what size is your riser...The pipe from point of entry to the meter bar..

3  How many sq. ft is the area your boiler is located in?

4  If you do have gas, and heat your hot water with it, are you going to be orphaning the water heater?  This could be a chimney issue..if you do go, sealed combustion,be it power or direct vent..Installer will help you

 Years ago your only choice was, what color boiler you wanted...As you can see today is different....So much comes into play, such as do you plan on finishing  your basement or do you use it as a workshop...etc etc....As far as boiler size a proper whole house heat loss is all you need done.  your heat loss seems a bit high,pick the size closest to the heat loss,go slightly up but don't cheap out and go down, it will,cost you more, in the end...Any boiler you pick comes with its own issues, and requires, in Massachusetts a licensed plumber to install it...with a permit.and a licensed electrician to wire it  ..just an FYI....

     It is solely my opinion, based on my personal experiences and readings that you are not a good candidate for a condensing boiler...Copper fin tube baseboard and condensers are not the greatest mix..Although others may offer different opinions, and that's fine There are  ways around it but it just does not seem worth it, to me,.buffer tanks are an option for one...Don't get hung up on rebates...As with any boiler you pick the near boiler piping is of the up most importance   .Be sure to ask your installer, as many questions as you can, the only dumb question, is the one not asked...If he stumbles, on his answers or says he will get back to you, consider someone else...Check him/ her out on the BBB or by other means....The BBB has a great list of things to look for, in your selection...Hope this helps 

gennady

boiler

this is the wrong question to ask. the right question is "how can i pick right installer?" good installer will give you few options to choose from, Regarding baseboars, they are just fine for condensing boilers as anything else. This is my opinion. The issue is amount of radiation in relationship to heat load. all houses are overradiated, as contractors tend to install excessive radiation, compared to design, and when baseboards designed for design outdoor temperature, these  conditions happen few days a year,  80% of time in the winter load is about 50% and less than design load, and it allows for lower water temperatures.

j a_2

condensing boilers and copper baseboard

I am wondering, what others think about the use of condensing boilers in copper fin tube applications....Is there any particular way to prevent short cycling without adding any expensive external additions such as a buffer tank...I f so I am very interested,,To me short cycling is what must be overcome...If someone has 3 zones in a residential home this size it does not seem possible, to me....Assuming the baseboard is/ was installed using the proper standard practices...Here in the city I see very little copper, mostly is gravity systems converted twice over..Gravity systems love condensers, just not sold on copper applications,and how a condenser will save them 50 percent...Could be wrong but I don't think so...,.

Robert O'Brien

j a

http://www.fcxalaska.com/PDFs/BrookhavenBaseBoard.pdf

Read what BNL has to say about this "issue"

A far as shortcycling,a modulating boiler will be vastly superior to a fixed input boiler,so I'm not following you?

gennady

copper baseboard

what material of radiator has to do with boiler efficiency?

Tom S.

agree on installer

right, I agree. In fact in my last house, I did use a person I found here to update my boiler. I guess I don't know enough about the program, that is, if this is a significant discount, enough for me to find the right installer and see what he might pick from this list (if any). Which still makes me curious though of the models listed, if you as an installer like burnham equipment, which you might choose.



Tom.

Tom S.

answers

Well, I am at the beginning of this journey, but here are some answers for you.



-inside chimney, not sure what size, although the chimney guy said getting a liner in there would be hard (I think it's more about angles, not sure)



-no gas



-boiler is in unfinished part of basement, about 550 sq feet



-indirect water heater runs off current oil boiler so that will be reused



Tom

Jean-David Beyer

condensing boilers in copper fin tube application

I am a home owner with a mod con boiler. I have an indirect hot water heater, a large radiant slab at grade zone, and a small copper tube with aluminum fin baseboard (Slant/Fin 2000 series). Since I was getting a condensing boiler, I wanted to have enough radiation to ensure condensing so I had 14 feet of baseboard installed in each of the two rooms of that zone, replacing 3 feet of baseboard formerly there. The additional baseboard permitted me to run a maximum supply temperature of 135F instead of 180F. I have the smallest mod-con boiler in the Weil McLain product line, but it is too big to heat just the baseboard zone, so it does cycle too often, especially in the warmer part of the heating season. I have done several things to overcome this, short of adding a buffer tank and extra circulator.



1.) In my boiler, the home owner can reduce the maximum firing rate so that the temperature of the boiler rises more slowly, giving the controller time to notice that it is heating too fast and lower it on its own. Default maximum firing rate is 94% and I lowered it to 55%.



2.) I raised the minimum supply temperature from the 80F or so that I needed in warmer weather to 110F instead. This means the zone heats up faster than it otherwise would, but the heat from the boiler will leave the system quicker so the boiler does not bounce off the upper limit specified by the reset curve so fast.



I think the best solution would be to make that zone bigger, such as by taking another room off the radiant slab and adding it to the baseboard zone. Because of history and architecture, that is completely impractical. I do not have the money or the room for a buffer storage tank.