Fixing a Furnace Leak Draining an Expansion Tank

If your furnace's pressure valve is leaking, it may be the expansion tank. John walks you through how he drained the tank on their 20 year old furnace.
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[@sirjohndoeofpa3292]

This was the fix for my oil burner. Big THANKS from the 17901 (Pottsville, PA)

[@StoneHouseHomestead]

Awesome, we're glad it helped.

[@sirjohndoeofpa3292]

@@StoneHouseHomestead you got a new subscriber

[@StoneHouseHomestead]

Thanks, we really appreciate it. 👍

[@metx9915]

It don’t matter is gas or oil if this happened often then there is a problem. . Several thing. Your coil might have a pin hole causing excess pressure. You fill valve Minh be passing bad tank , excess over heating , etc check all and never ever cap the relive valve . You be surprised what you see out there

[@StoneHouseHomestead]

These are good things for others to consider when facing similar issues. This past fall, I had a complete checkup on the furnace (boiler) and sub-systems. After maintenance and parts repair, the 24 year old system should be good for another 10 or more years. None of the replacement parts involved the pressure tank system or coil.

[@felipetelleztorres967]

Really thankful for your tutorial hope you can teach us more about boiler s which I have one at home

[@StoneHouseHomestead]

You're welcome, Felipe. I sure will.

[@felipetelleztorres967]

I drained the expansion tank so how do I regulated my boiler because it drained itself two days ago (valve relief) and right now I have drained the expansion tank so It will need to pour more water? Thanks

[@globeflicker9216]

Felipe Tellez Torres My amigo! Call a professional, this guy means well but he don’t know what he’s doing…at all.

[@StoneHouseHomestead]

Interesting, Globe Flickr. What I've shared has worked for me and many other people and that includes the licensed HVAC service, tech who showed me how to do this. What am I doing wrong, I would like to know.

[@globeflicker9216]

StoneHouse Homestead The tank has a snorkel on it something like an ‘extrol’, but you can’t check that because vent is frozen, you could not open it. What you need is that tank if proper sized is to be 1/2 maybe 2/3 full of water at about 12-14psi (assuming it’s 2 story, don’t know the radiators, standup, cast iron b/b, cu fin tube but that’s a volume issue again). So boiler gauge should read 12-14psi max when Aquastat hits high limit around 180F. The problem is when you add new water to a closed heating system you need to boil off the gases it absorbs as it cools down. That boiling occurs around 130F and hotter or there about. If you think your system is full, watch the boiler gauge pressure & temp . If it starts moving up the primary two culprits are air in the system and or expansion is inadequate. That’s the primary death of a bladder type expansion tank. Hope that’s helpful. It’s more complex than it looks and simply easy to understand. Lol 😉

[@margaretjames1579]

I have same exspansion tank boiler and 135 year old chimney. Will go look for nipple and faucet on tank. Have not seen them.

[@StoneHouseHomestead]

I hope it works.

[@Supanova70]

Great tip so it`s ok to just drain the tank once in a while? or is the tank bad when t`s full? or was the pressure reducing make up valve bad causing to much pressure?

[@StoneHouseHomestead]

In the case of my system, I drain it once a year. The only time it would need to be replaced is if it leaks.

[@raindogs451]

That red arrow is one of danger. A HW should never be at 30 psi

[@StoneHouseHomestead]

This past fall, I had a professional change out the gage and pressure relief valve. Maybe it's life will be extended another 24 years. 😉

[@johnamerican1578]

Boilers heat water! Furnaces heat air ! Looking at the relief tube it been leaking a long time oxygenated new water is eating the boiler from the inside! Air can be compressed but water cannot!

[@StoneHouseHomestead]

You are correct, but most people still call them furnaces.

[@jstavene]

do you need to refill the lost water? first before starting?

[@StoneHouseHomestead]

The expansion tank needs air in it so that the water can expand into it. In my case it didn't need it.

[@purplemonster2239]

Thanks for the video. Just wondering, if it went bad once and pressure was too high, why wouldn't it happen again right after the tank fills back up or in the not too distant future?

[@StoneHouseHomestead]

I was told by the HVAV tech at work that releasing the pressure is an annual maintenance item whether the pressure valve has popped. So yes, it will eventually fill up again and need to be purged.

[@roccanit]

Shit is getting real in the front yard!

[@globeflicker9216]

Just a tip, you got a auto vent on a bladder-less tank. That’s a no go. I can see you’ve been through this drain the tank circus before, but that’s actually just making it worse. That boiler was put in by someone who just didn’t know what they were doing … it happens a lot.

[@StoneHouseHomestead]

Thanks for that tip, I'll look into it. I wish I could honestly say that your opinion of the Installer was misguided but as it turned out, this company was not fully honest with me when the boiler jacket developed a crack and it needed to be replaced. Thanks for the suggestion.

[@globeflicker9216]

StoneHouse Homestead No problem, no shade intended. I’m a licensed boiler guy so this stuff is obvious. It’s common unfortunately.

[@Supanova70]

@@globeflicker9216 Great tip so it`s ok to just drain the tank once in a while? or is the tank bad when t`s full?

[@josueayala9106]

i tried draining my tank the same way, but my boiler continues to over pressurize every time it comes on. i find myself having to drain the tank slightly every time it comes on to bring the pressure back down

[@StoneHouseHomestead]

You definitely need to get that pressure release valve looked at by a professional. If that isn't working correctly it could cause an explosion.

[@josueayala9106]

@@StoneHouseHomestead the valve itself is working, its constantly dripping like the valve looked in the beginning of the video. i guess what i meant to say is that the pressure keeps wanting to go higher than it should

[@josueayala9106]

@@StoneHouseHomestead after persistently draining the tank and pushing air into it to get it to purge i was finally able to empty it, turns out it was water logged like a mofo. Its working good now and the boiler is keeping the correct pressure. Could not have figured it out without you video. Thank you very much. also, any idea if those old compression tanks are still obtainable? i was looking all over online and i couldnt find it to purchase

[@StoneHouseHomestead]

I'm very happy that the video helped.. A good place to check for another tank may be just around the corner from you. From time to time I check out Habitat for Humanity Re-Store. Many times I've found vintage items taken from older homes there. Another source is professional plumbing supply houses. Some will sell to the average homeowner but you may not get the wholesale price.

[@johnkosick1464]

If the water bucket shown at the 2:40 mark of the video is the only water you took out of that BIG Tank, then I'm certain you left a ton of water still in that tank. That tank holds a LOT of Water, I know, i have one. You have to get air into that tank to get all the water flowing out. Did you do a follow-up on draining more water out? Just my thoughts.

[@StoneHouseHomestead]

You're correct, I couldn't get the bleeding valve open, so I left the tank alone and let the water gurgle out for a long time. Many people have complained that my videos are too long, their heads would have exploded if I set the camera up and recorded that process.😀

[@johnkosick1464]

@@StoneHouseHomestead OK....... the best videos are cut and edited to just show the important issues. I assumed you didn't get all the water out of the tank because without more air in the tank you will get "Airlock" and the water will not drain. I replaced my old valve ( no bleeder) with this one. Its worth the price/time it takes to drain the tank, and it should be done yearly. **** This is what I bought******** DT-2 Drain-O-Tank Air Charger SKU: 113041 Brand: Bell & Gossett

[@StoneHouseHomestead]

Thanks!

[@larrycurrier290]

I think that expansion tank is outdated. Why not upgrade to a bladder expansion tank? And it's very visible that you have antifreeze in your system I would suggest you check the ph. Antifreeze becomes very corrosive when it reaches an acidic stage.

[@StoneHouseHomestead]

Thanks for the suggestions. The system doesn't have antifreeze. It is straight public water, which is high in iron and other minerals.

[@larrycurrier290]

@@StoneHouseHomestead if it doesn't have antifreeze in it now it did at one point the signs are there. All that green corrosion and every joint and gasket show signs of antifreeze. Seen a lot of it and forty years in the business

[@StoneHouseHomestead]

The pipes are copper, and copper turns green when they corrode. Do they not?

[@larrycurrier290]

@@StoneHouseHomestead if copper turns green then why isn't it all green. Note it is only at connections and gaskets. Regular water will not cause this. Boiler water is essentially distilled water with no corrosive properties. Go look at a couple of your friends boilers that have water in them and see if they have the same green corrosion that you do. Like I said forty years in the business I know what I'm looking at

[@StoneHouseHomestead]

Because the basement is humid and due to capillary action, water condenses at the connections during the summer. Larry, I know for a fact that my ancient system does not use antifreeze in the pipes. I've been draining that tank for over 20 years.

[@Keegeth]

Boiler lol Furnace heats up air, a boiler heats up water. It's a common mix up so don't feel silly.

[@StoneHouseHomestead]

I purposely used the word "Furnace" because most people don't know what a boiler is. ;)

[@Keegeth]

@@StoneHouseHomestead you're actually right. I've never heard someone call a furnace a boiler, it's only been a boiler called a furnace.🤓smart man

[@mr.redneck2715]

I never saw a furnace with a expansion tank!!!!!

[@StoneHouseHomestead]

I know, it's special. ;)

[@raindogs451]

That's not the correct indicator! That boiler should be psi static pressure, and 12-18 maybe firing. It should never be above 20 psi ever. Even 18 is a little high; 12-16 firing is the sweet spot.

[@petediamond7263]

It's a boiler not a furnace!

[@StoneHouseHomestead]

You know that, I know that, but most people refer to them as furnaces.

[@MelancoliaI]

Here's my problem. I can't find that neat little shut-off valve what connects the boiler to the expansion tank. Plenty of tubes, plenty of valves, plenty of god-almighty bobbles and bangles. But I cannot find that valve. So if I attempt to drain my overhead tank, I starve my boiler.

[@StoneHouseHomestead]

Its important to note that the system that is in my house was initially installed 50+ years ago and has been updated by different companies over the years. If you can't find a cutoff you may ask the serviceman to install one the next time you have your boiler's yearly tuneup. IDK, maybe if you system has other cut-offs at the boiler's supply line, distribution lines, and at the circulation pumps, closing them might prevent the system from bleeding out when you drain the expansion tank. If you still can't determine the cutoffs in your system, it's best to have one installed by a professional.

[@MelancoliaI]

@@StoneHouseHomestead Hey thank you for the helpful reply! I found the cutoff, it was literally right next to the valve that opens the expansion tank. 🤦

[@StoneHouseHomestead]

You're welcome, I'm glad it helped.

[@MelancoliaI]

@@StoneHouseHomestead Also my situation is similar, with an old system that has been updated by different companies/outfits over the years. I guess no two are the same lol

[@johnamerican1578]

That valve wasn’t installed on every expansion tank! Sometimes just a drain valve was ( boiler drain) that valve was designed to drain and allow air into the tank at the same time!

[@deshevldmusic]

It's a boiler, not a Furnace... Oil boilers are never more than 87% efficient. Gas gets into the 90s. Your boiler needs work from what I see here. Please have it tuned up and maintained by a professional or you'll be into some serious money down the road due to lack of maintenance. Your piping looks corroded and your air eliminator is covered in oxidation and likely isn't working

[@deshevldmusic]

Also, that relief valve should be replaced after it blows. They seals tend not to reseat

[@StoneHouseHomestead]

Thanks for your suggestions. Most people wouldn't know that it's called a boiler so that's why i refer to it as a furnace.

[@Keegeth]

I ran into a viessmann with a Riello burner and the efficiency was 89, I was like damn son lol

[@AmericanFarmerHVAC2024]

For god sakes. It's a boiler. 🤦

[@StoneHouseHomestead]

You know that, I know that but most people still call it a furnace.

[@AmericanFarmerHVAC2024]

@@StoneHouseHomestead and I educate each homeowner that says that, thoroughly.