Is this boiler hot water or steam?

clickhere

So I have this old boiler converted from NG and I've had one contractor tell me it's a hot water system and another tell me it's steam. How can I be sure? There looks to be four pipes connected to the boiler. My radiators have 2 pipes. And there is something in in my closet ceiling that might be an expansion tank. There is no circulating pump.

Thanks.

clickhere

One more pic

Jamie Hall

I'd say -- based mostly on the thermometer! -- that that is a gravity hot water system. And the tank in the closet ceiling is probably an expansion tank.

I do hope that the system isn't currently in use?

clickhere

It is not in use, but it does work.

SWEI

Large diameter piping from both sides of the boiler top and bottom says gravity hot water. Why not in use? If the rest of the system is as unmolested as the boiler, you have a treasure on your hands, and the potential for a seriously efficient system just by installing a modern boiler.

clickhere

We had some kind of explosion and so we are looking at getting the boiler replaced. Any other ways to confirm that it's water? What should I be asking my contractor as we move forward?

mars_6

If your contractor is not sure what kind of a system this is I would say it may be time to look for a new contractor. Just my 2 cents.

SWEI

Where are you located? We might know someone qualified who can help.

I don't think we have a set of questions for potential hydronic boiler replacements like we do for steam. We need to work on that. Competent boiler installers may be licensed for HVAC, plumbing, or both kinds of work depending on the jurisdiction. However, none of these licenses actually guarantees any level of competence with boilers.

Ask any potential contractor to provide photos of a recent install showing a modern high efficiency boiler mated to an old gravity system. If he can't, find another contractor. If you post the photos here, we can tell you pretty quickly whether they know what they are doing or not.

JUGHNE

I would avoid the guy who thought it was steam. The altitude gauge, thermometer and lack of a sight glass on the boiler should be a quick indicator to anyone in the business.
By the way, there are probably many on this site who are "coveting" that altitude gauge, me included. It could be connected to a new system just for kicks and as a memorial to the old boiler. I wouldn't let a contractor "get rid of it for you"; that includes all if any brass piping and stop valve going to it.
As SWEI says you need someone who has done a gravity conversion to pumped system. There is advice in the library on this site.

clickhere

Awesome, great info guys. I like the idea of reinstalling the brass gauge on the new system. It for sure has a cool retro look.

Steamhead

Definitely a gravity hot-water system.

That boiler is what we call a "snowman"- an old asbestos-covered round boiler originally designed for coal. One of my Dead Men's Books says these are no more than 40% efficient on oil, and they are probably just as bad on gas.

Where are you located?

RobG

As Steamhead said, that is asbestos on the boiler and the piping. It needs to be professionally remediated prior to boiler replacement.

Tinman

She's a beauty! I once had about 50 of those old brass gauges...only 3 or 4 of them left. Love the size of those old valves.

Jamie Hall

Bottom line is our OP could have a really good system -- old gravity systems which haven't been messed with are just wonderful -- for not too much more effort than replacing the boiler and some near boiler piping work.

clickhere

I'm having asbestos removed next week and then my contractor will start removing the boiler. Looks like a big heavy job. His plan is to make two zones since there are two sets of pipes that go in toe different directions. The he will have to reduce the pipe size to match up to the new boiler, and he said this won't be a problem. He sized the new boiler by measuring all my radiators.

We are pretty excited to get started.

Tinman

Boiler should be sized by a heat loss load calculation, not by figuring EDR of radiators. That's only done for steam systems.

JUGHNE

There is a good chance that you have more radiation than the house requires. It may have been originally sized for absolutely no insulation and to leave the windows open overnight. Excess radiation is good as you can use lower temp supply water and gain cooler return for a condensing boiler. But you may end up with a much larger boiler than needed and they might only turn down to 20% firing which might be more than you need on a mild day causing short cycling. Send us a picture with the old gauge installed on new boiler, please.
Also the few gravity systems I have seen all have 2 sets of pipes; that is usually a split to the right and left of boiler. One does the right 1/2 of house both floors and the other does the left 1/2 of house both floors. It depends upon your floor plan if this is good or not for you.

nicholas bonham-carter

Go to the SlantFin website, and download their free heat loss program, and run the numbers for the house. As was said, you have hot water, and the heat loss determines the boiler size, unlike steam, where the radiation size is used to size the boiler.
this is doubly important when splitting the system into zones, where one zone maybe needing only a tenth of the maximum output of the boiler on a mild day. maybe TRV's would be a better and cheaper solution.
there is a lot of information in the "museum" here on the correct way to adapt an old gravity system to a new boiler.
I hope your contractor knows well what he is doing, and can make the old system sing.--NBC

SWEI

What type and size of of boiler did the contractor propose?

Please, please, PLEASE listen to the wise words above. Do not allow anyone to replace the boiler without performing a heat loss.

icesailor

Your Wethead contractor needs to go to Freeschool right here at Heatinghelp.com. So he can become even more proficient at Hydronics that than the guy that thought that it was a steam boiler.

Unless he is planning on using a Modulating/condensing boiler, he would be wise to consider using a Taco "I" Series 4-way mixer (or some equal type) that will give you boiler protection and the ability to run whatever water temperature the outside will require and the boiler at whatever temperature it wants. Split the two sides into zones with zone valves or circulators. Your system will be a thing of wonderous beauty and will give you comfort like you have never known.

Those old dead Wetheads knew their wind and weather. They usually split the system by North & South. They sometimes added a little more radiation on the North side to compensate for those nasty cold winds that our friends to the North (Canada) are always sending us. Something about retribution for us trying to steal their land in 1812. Some people never forget a slight. Splitting the system in half allows one side to work better with the other. Like the North side gets cooler because of the nasty Canadian Air, so they put that extra radiation in. That gets blown to the South side. That overheats.

And any improvements you make with insulation and weather stripping makes the system need less that when the old dead Wetheads installed the system

IMO.

OBTW, that explosion causing gas burner might be museum quality. It looks almost as old as dirt. Certainly older than I am. And I'm not dirt, yet. Perhaps Tim can date it.

KC_Jones

SWEI said:

What type and size of of boiler did the contractor propose?

Please, please, PLEASE listen to the wise words above. Do not allow anyone to replace the boiler without performing a heat loss.

To the OP listen to these wise words before the contractor does ANY work. This website is filled with people that either didn't heed the advice presented or went into a replacement blind and then come back here asking how to make it work. A lot of the times the answer, after it is done is to rip it out and start over. Listen to what is being said here, get it done right the first time or you may end up paying twice to have it done over again. And for water boilers, if you haven't realized are not sized by radiation. I would honestly be scared if your contractor is proposing that. You need a room by room heat loss done anything less is wrong...period.

Zman

@clickhere,
What happened? Please tell us you did not hire the first guy that figured out what type of boiler you have.

As mentioned above, measuring radiators to determine boiler sizing is for steam not hot water. The piping layout for the conversion is critical, especially for a conventional boiler.

You have the opportunity to install a really comfortable and efficient system. Installing the boiler that measuring the radiators will give you will be larger, more expensive and less efficient.

At least post a description of the home and the boiler proposed. There are countless posts on here from people that did not do their homework up front and ended up regretting it.

clickhere

So we got some cold weather and are putting off the replacement a little. Looks like good thing too because based on all the comments, I'm having doubts.

My house is a an all original 3 bed house built in 1899, 1800sqft. No upgrades to windows or insulation that I can see. The proposed boiler was a 175k btu/input.

How can I determine how this sizes up? Can I do my own load calc?

Thanks for all the input.

Ironman

Go to SlantFin's website and down load their free heat loss calculator. Follow the directions, take measurements and input the necessary data. It's easy to use and if you have any questions, post them here.

I would not recommend using any heating contractor that doesn't know how to do a heat loss calc or that doesn't know that a hot water boiler should be sized by that - nothing else.

175k btu's for an 1880 sq. ft. house?? Seriously? That's over 97 btu's per sq. ft. I've done load calcs for 35 years and I've never seen a house that even needed 40 btu's per sq. ft. Not even the oldest, leakiest ones. Send that guy packing.

clickhere

Ok, I'll give it a shot.

clickhere

So I am coming up with about 85k btuh heat loss. Is that what I want my boiler output to be???

Ironman

clickhere said:

So I am coming up with about 85k btuh heat loss. Is that what I want my boiler output to be???

That still sounds a bit high but much more realistic.

You did it pretty quickly; go throught it again and double check everything to make sure you chose the correct construction values, etc.

With a little bit of attic insulation and tightening up the envelope, you should be able to get by with an 85k btu boiler like the Lochinvar WHN 085 wall hung with the fire tube heat exchanger.

Remember, you only need the full output of the boiler on the coldest night of the year (design temp). At any higher outdoor temp, you need less output. The closer you can size the boiler to the actual load, the more efficient, comfortable and long lasting it will be. That's why modern high efficiency boilers like the WHN are designed to modulate, not only their firing rate, but the water temp to match the actual load.

ChrisJ

I suspect for hot water it's typical to add 15% to the heatloss calculation?

Also, I have a feeling those rules may not apply to a gravity hot water system.

OP, please, please find another contractor that knows how to make that system work right. If you use the guy you have now you will have problems and will be sorry, it's almost guaranteed.


I know close to nothing about hot water, but I know you don't size the system based on radiation like steam. I also know gravity systems can work amazing, but they have special rules.

D107

HO here. On first photo there is a large plate door below the thermometer which looks like it reads 'water boiler' on the bottom.

EBEBRATT-Ed

as everyone has mentioned it's hot water for sure. Has an old 3 wire aquastat high limit in the picture. You need to find someone who knows what he's doing to do that job.