Replacing 1897 Gravity Boiler

taylorm

Hello, we want to replace our old 1897 American Radiator hot water gravity boiler with a new standard or high efficiency hot water boiler. We have a two story, 1280sq ft home but plan on doing an addition of approximately 1200 sq ft in 3-5 years. The reason we're replacing the system now is that we're having drafting issues up our chimney. The chimney above our roof was actually removed because it was unstable. The costs of rebuilding the chimney are very high and we would like to spend money on a new system if possible.



Our house has qty 6 cast iron radiators (American Radiator). We would like to keep these radiators in place and then put in radiant heat in our addition, probably baseboards in the future. I've been getting a lot of different recommendations from contractors. Some are saying that high efficiency boilers are not recommended for cast iron radiators like ours and that we should go with a standard efficiency cast iron boiler. I recently got a recommendation to go with a Weil-McLain GV90+ high efficiency because it has a cast iron heat exchange.



Is it true that a high efficiency boiler won't be efficient with cast iron radiators? Do the new Weil-McLain GV90+ high efficiency cast iron boilers work better with cast iron radiators?



Another big consideration for us is how we're going to vent given that our chimney has been roofed over. Should we look into venting somehow above our house or to the side?



Thanks so much. Any help would be greatly appreciated. Best Regards.

Ironman

Somone Doesn't Know What They're Talking About

A converted gravity system is the perfect candidate for a high efficiency mod/con boiler. There are some things that have to be done, but it's relatively simple if you know what to do. A mod/con can also be side wall vented - usually with pvc.



Finding a knowledgeable, competent and honest contractor is the most important thing you must do. Scratch the one(s) who told you not to use a mod/con, they don't know what their doing.



Also, check out this article on gravity systems. After reading it, you'll be better informed about them than most "heating contractors".



http://www.heatinghelp.com/article/332/Gravity-Hot-Water-Heating/72/Gravity-Hot-Water-Heating-FAQ

kcopp

I have to ....

laugh when I hear that "mod/cons don't work well w/ a lot of cast iron" I am aggreement w/ ironman. Perfect set up IF done properly.  Do your homework... that way you can figure out who has a grasp and who does not. The house I grew up in had a gravity system that i learned a few ways not to pipe.... then I came here. I am surprised that your old boiler lasted over 100 years. Very cool. Where is the home?

taylorm

Thanks so much

for the replies. We're going with a high efficiency boiler replacement and thanks for the tip on the contractor who said standard cast iron is best for our radiators.



We have two contractors that we like and they're both recommending similar installs. One is recommending a Weil-McLaine GV90+ which has a cast iron primary heat exchanger and a stainless steel secondary heat exchanger. If our heat capacity is more than 140 than they'll go with a Weil-McLaine Ultra series which has a cast aluminum heat exchanger. They're also recommending a Weil-McLaine Gold Plus indirect water heater.



The second contractor recommends the HTP Elite model #EL150, the side arm is HTP SuperStor model #SSU-60. The boiler has a 316L stainless steel heat exchanger.



Do you recommend Weil-McLaine or HTP for the high efficiency boiler/indirect water heater? Also, is the Weil-McLaine GV90+ boiler a more reliable boiler over the Ultra series? The contractor says that it has a longer warranty b/c the primary heat exchanger is cast iron. I think the warranty is 20 years whereas the Ultra series is 15 and the HTP Elite is 12 years.



Yeah, our boiler is ancient but it still works. I'm sure it's not very efficient. We live in Denver, CO. Who knows how long it would last. We just feel that spending money on fixing the chimney to draft the old boiler may be a waste of money considering how old the boiler is.



Again, thanks for all your help. It is very beneficial in our decision making. I had no idea how much new technology and innovations have been made to boilers over the last 10-20 years. Seems like it's a growing industry. Best Regards.

taylorm

Another Question

Are there any considerations I should factor in with connecting a high efficiency boiler to our old copper pipes and cast iron radiators? I had an HVAC friend of mine say that the potential for rust coming off of the pipes/radiators through the high efficiency boiler is an issue. He recommended Triangle Tube boilers because they have larger pipes running through the boiler.



I'm just trying to determine what details I need to factor in to decide which contractor to go with. I'm in now way considering doing any of the work myself. It's been alarming that all of the contractors we've had out haven't expressed any concerns connecting a new system to our old pipes/radiators. Thanks again!

Ironman

Use a Strainer

Have your contractor flush the system and put a strainer in the return line before the boiler. Or even better, a dirt separator.



As far as the make of boiler goes: find the right contractor and go with what he recommends. We all have our preferences and they vary based on our own experiences, product design, availability, factory service, application, etc.



If you're in the Denver area, I would highly recommend that you contact Mark Eatherton. You can find his posts all over this site. You won't find any better than Mark.

taylorm

Thanks again

for all of the replies. It has really helped me with the process. Take care.

Paul Pollets

System cleaning

The system should be cleaned (and flushed) using proper boiler cleaning chemicals to remove rust and sludge prior to commissioning the new boiler. You don't want the crud that's in the pipes and radiators fouling the new heat exchanger!! A strainer will not be adequate.