Gravity Boiler?

Travis_R

Hey all, first time poster. I’ve stumbled across this forum trying to do a bit of research on the heating system in my new to me home, and it seems there is a wealth of knowledge in here! I’ve bought an old cape cod two story in central Wisconsin built in 1910. From the research I’ve done, I believe it’s a gravity boiler system based on the expansion tank in the attic with sight glass, and lack of a circulating pump. The only voltage going to the boiler is I believe 24v off of a transformer in the basement. I believe there is a drain from the expansion tank in the attic, back down to the basement that would drain into what used to be the cistern. Someone in the past has put a bit of expanding foam in this pipe, I’m guessing because they seen a bit of water draining off of it and didn’t realize it was supposed to drain off excess? Looking at the sight glass in the attic, it looks like the tank is full, but it’s very hard to tell, and it sounds empty when I knock on it. But I’m guessing the 7/8 psi on the gauge would indicate that the system has at least some water in it if it’s not full. I’m hoping someone in here with experience can confirm my thoughts? There is a spigot in the basement plumbed to the boiler, is there any harm in clearing the expanding foam, opening the spigot until water comes down from the expansion tank pipe into the cistern area? Any insight, advice, confirmation, education would be greatly appreciated! I’m not finding any information on the boiler itself, not data plate or anything, and I’m struggling to find any info online on these heating systems.

Steamhead

How many floors in that house?

Travis_R

Steamhead it’s a two story.

mattmia2

That pipe I think should be open to the tank, you fill the system until water starts coming out of that pipe, it is a way to observe the level in the tank from the basement.

Travis_R

mattmia2, the one in the basement that would drain into the old cistern that now has expanded foam in it, correct? That I believe leads up to the expansion tank and is like an overflow, or a relief from what I gather?

mattmia2

https://forum.heatinghelp.com/discussion/comment/1808010#Comment_1808010

yes, that one, look at exactly how it connects to the tank, but that was common to have an overflow in to the basement so you could tell when the system was full from the basement.

leonz

You have a very efficient gravity hot water heating system.

Your radiators will be/should be full of water and the water in the expansion tank should be half way up the sight glass.

The gauge on your boiler indicates both the system pressure and water temperature.

Please provide us with pictures more pictures of the piping connected to the open to air expansion tank as well as the top of the tank as the vent pipe is either on the top or high on the side of the tank.

If there is no riser coming off the side of the tank and passing through the roof your expansion tank drains to the basement floor drain. please Provide us with an image of that piping.

Please take more pictures of the radiators in your home and all the connecting piping as we need to determine if the radiators are top fed from a central riser that reaches the top floor and is connected to the base of the open to air expansion tank.

If the gravity hot water system is bottom fed the upper floor radiators should have/will have orifice discs in them to reduce the flow to these radiators and send the hot water to the first and second floor then the third floor and provide you with a system that has the proper balance.

That closed cell foam in that piping is not something that should be there. We need to see where this pipe leads please.

You should have a plumber that is experienced with gravity hot water systems or steam come and service the boiler and install a low water cut off to bring it up to code and clean the burners.

On your to do list you should purchase CLASSIC HYDRONICS and HOW COME from the heating help bookstore page to educate yourself about your gravity hot water heating system and how it works. your system is designed to create slow even heat in your home and provide you with warm floors as well.

We need to more pictures so we can be nosy about all your piping to enable us to tell you more about your radiators and the piping.

You should have your system serviced now by a licensed plumber "ONLY" to avoid having to wait a long time in the fall to have it done as you need a low water cut off switch to bring the boiler up to national plumbing code standards.

Travis_R

That makes sense. Just wanted to be clear and fully understand this system. I have city water supply, so it must just rely on the city supply pressure being greater than the atmospheric to push the water up to the attic. I don’t see a check valve at all.

Jamie Hall

There may not be a check valve. The city water pressure is more than adequate to push the water up to the attic — so there has to be some way to shut it off. Otherwise that tank would be overflowing all the time, like an unattended bathtub.

So… the must be at least a shutoff valve on the city water feed, and it is remotely possible on a system that age that there might be a pressure reducing valve. Very remote. More likely is that the water level was (and still can be) controlled by the simple expedient of looking at the pressure gauge on the boiler and, if it seems low, opening the shutoff on the city water and letting water in until the tank in the attic overflows (which is why you don't want that overflow pipe plugged!)… unless you can go up to the attic from time to time and look at the level in the sight glass. Which should be about half way up the glass.

Travis_R

The expansion tank in the attic has two pipes, one to the bottom of the tank, and one high on the side. Hard to be 100% certain as they go straight down through two floors, but I believe the pipe on the bottom of the tank goes down to the cold water inlet to the boiler. I marked that pipe with a blue circle in the photos. The pipe on the high back side of the tank I believe goes down to drain into what was the cistern. I’ve marked that pipe with white in the photos. The green colored broken wall in the basement was previously the cistern, but that has been broken out and the cistern is now a full bathroom. Looking at the sight glass, the glass is either all the way full or all the way empty. There is not visible water line. My guess would be full, but it doesn’t sound full when I knock on it. The home is a four bedroom two story. There are a total of eight radiators, one in each of the two bedrooms upstairs on the second story, and the remaining six on the first floor. I’ve attached a few photos of them as well. I appreciate the helpful feedback!

Travis_R

There is a gate valve that also falls in the blue circle in the photo above that is controlling the water supply from the city supply in the house to the boiler.

Jamie Hall

If I'm not seeing things, the water level in the tank sight gauge is about an inch from the bottom.

EBEBRATT-Ed

You should take the gauge glass off the expansion tank and clean and reinstall it with new washers. Have a spare gauge glass or two they are easy to break. You can buy a gauge glass cutter and the other stuff on supply house.com if you can't find it locally.

You want to get the water in the gauge glass about 1/2 full and mark the level on the glass with a sharpie or a wire ty. Once you get it halfway mark the pressure on your pressure gauge with a sharpie. Then you will now if you have enough water in the system by checking the pressure. You may want to put a second pressure gauge on the boiler drain valve temporally just to check the boiler gauge

leonz

They apparently turned the tank upside down and used the dome connection for the riser pipe to the tank and the pipe on the side for the drop pipe to the basement.

The pipe you have circled in blue is the cool water return from all the radiators to the boiler sump where it will be heated and rise again.

You should map out how the radiators are routed or ask the plumber to do it do you what is what and where.

You need new gauge glass and a glass cutter and new gaskets as Ed has said.