What Is Going On Here?

New England SteamWorks

@Fred

Supply A:



Supply C



Supply C& B Tee



Supply B



Supply D Transition to return



Supply A Drip




Supply D Transition to Wet (End)

Fred

@New England SteamWorks , I guess that shoots my theory. Lol

New England SteamWorks

Fred said:

@New England SteamWorks , I guess that shoots my theory. Lol

Well, they were just as good as mine, -or anyone else's at this point!

GW

So you can pump against a closing taco with no noise? Never tried it. There’s two valves so it’s worth looking into

Yes on the strap on, just shooting ideas on dropping out the steam heat if it’s making a hw B.B. call, maybe not the greatest idea.

If the zones aren’t losing its water, there’s no need to close it, unless of course you want to. Doesn’t seem to be the case here. My first condensate B.B. loop was a second floor zone 25 or so years ago, I was still wet behind the ears and didn’t know it was a risky move back then.

EBEBRATT-Ed

@New England SteamWorks , maybe you will be lucky and fix a few things and it will work. I know (with my luck) if I put my hands on it the whole job would go to crap and I would own it.

I vote for "go big or go home"

Let them hack around with someone else if they don't want to fix it. Then you can come back in and do the right job. just my 2cents

GW

New England Steam Works, Coincidentally---and this just in---I have a red light green light communication---send me an email address if you care to see what I'm talking about gary@wilsonph.com

New England SteamWorks

Up-date: Well, of course it didn't bang again this morning. We are having a spat of warm weather so I guess we'll have to wait. I did confirm that the circulator is in fact pumping away and the zone valve orientation is correct.

DanHolohan

Without the bypass on the hot-water zone, the only thing keeping the very hot water in the upper parts of the hot-water zone in a liquid state is the pressure supplied by the pump. When the pump shuts off, the water in those lines will flash to steam and hammer, if not immediately, then certainly the next time the pump starts.

New England SteamWorks

Thank you Dan!

EBEBRATT-Ed

Not sure this hot water zone can be used with zone valves

DanHolohan

You can do this with zone valves, but the bypass is critical if there's no heat exchanger.

GW

Dan, if it flashes don't you lose the water?

DanHolohan

Gary, if there are no vents up there you don’t lose the prime. It just hammers like hell.

hot_rod

DanHolohan said:

Without the bypass on the hot-water zone, the only thing keeping the very hot water in the upper parts of the hot-water zone in a liquid state is the pressure supplied by the pump. When the pump shuts off, the water in those lines will flash to steam and hammer, if not immediately, then certainly the next time the pump starts.

Same dynamics at work in open, un-pressurized outdoor wood furnaces, if the pressure drops below vapor pressure, water boils. Here is a graph to show that temperature/ pressure relationship.

New England SteamWorks

Thank you @hot rod !

GW

Ok thanks, I’ve neglected to tie a loop at the boiler over the years (copying what the previous guy did) on some of the boiler change outs, I guess I got lucky.

DanHolohan

Gary, it’s the ones that go high over the waterline that see this problem.

GW

Dan, makes sense. I did one 2nd floor a million years ago and don’t recall if I looped the piping at the boiler. I have seen several small 1st B.B. zones work without the connector loop.

I would have thought the flash would blow out the prime, darned Water has a mind of its own I guess

Ironman

hot rod said:

DanHolohan said:

Without the bypass on the hot-water zone, the only thing keeping the very hot water in the upper parts of the hot-water zone in a liquid state is the pressure supplied by the pump. When the pump shuts off, the water in those lines will flash to steam and hammer, if not immediately, then certainly the next time the pump starts.

Same dynamics at work in open, un-pressurized outdoor wood furnaces, if the pressure drops below vapor pressure, water boils. Here is a graph to show that temperature/ pressure relationship.

And that's exactly the same reason why I won't do an ODWB that way. I've gone behind too many that had constant problems because they tried to cheap out and not use a HX.

DanHolohan

If the zone is below the waterline it hold the static pressure of the water and that keeps it from hammering.

DanHolohan

Here's another example of this happening, but with a condensate-transfer pump instead of a zone pump:

https://heatinghelp.com/blog/running-down-a-heating-mystery/

willie13

I was glad to see that the boiler bypass was brought up - in my humble opinion, the most likely source of the banging is flashing steam in that HW loop due to high temperature, low pressure. B&G used to send out bulletins called "Counterpoint" and the one from April 1994 had a drawing and explanation of exactly this situation. I have sent it to countless contractors and others dealing with a HW loop using steam boiler condensate. I also prefer the heat exchanger - sometimes a non used tankless coil opening is the easiest - but many times we see the condensate being used and controlling the temperature with a bypass is critical.

DanHolohan

@willie13, I wrote those Counterpoint columns.

TMcGroy

As a homeowner with an 80 yo low pressure steam boiler who has learned how to maintain/balance it herself through trial & error, IMHO you should just ignore this problem until the banging can be reproduced. I think uninformed/disinterested homeowners have a tendency to exaggerate any "problems" with steam - especially noise - because it is unfamiliar & portends of an explosion or something equally frightening.

That's the only explanation I can come up with as to why steam heat is a thing of the past in most of the country and is being torn out in favor of forced air. The hot water heat pipes in my new (old) house in VT froze this past cold spell, shutting down the heat. Fortunately, the plumber I found to repair/replace the pipes refurbishes radiators in his spare time - saving them from the scrap heap - and am considering having him replace the baseboard system with some of his radiators. I grew up with forced air and hope to never go back to it again. I love steam!

njmmam

piping coming off top of boiler shouldn't have elbows that close

willie13

Dan, I certainly thought the writing style was awfully similar... I should have known it was you! I have all of them in a binder - I haven't scanned them into my computer yet.

DanHolohan

Thanks, Willie. I had a contact with them for a few years after I left the rep. Not everyone there cared for my writing style. I wrote about that incident in my memoir, What Hydronics Taught Holohan. It’s a good story.

Steamhead

TMcGroy said:

That's the only explanation I can come up with as to why steam heat is a thing of the past in most of the country and is being torn out in favor of forced air.

Actually, it's because you can't fix stupid.

BradHotNCold

Homeowner here, no real experience other than two homes with steam heat, one built 1685, the other 1878. In one picture, posted 02/25, why is it not a problem for the condensate return to be piped into the hot water supply? Looks wrong to me...

mikespipe

the worst thing I see is a reduction from 3 to 2 at the boiler and then an elbow just a few inchs up from that reduction. this probably leads to a very wet steam head. an aside comment.for a hot water loop, I have found over the years, that if you are using a 007 or any compact pump . they last much longer if they pump into the boiler. pumping the cooler return rather than the maximum temp . I like Dans comment , in his book, on return temps and plan on adding a bypass loop in the future to increase the retun temperature to the boiler . The reduction of the steam head could also cause water to back up into the return and possibly cause steam to enter the hot water line. Check the steam pressure . it shouls only be 1-2 psi. Is there ever any noise when only the hot water line is running and the boiler temp is low? I doubt if there is. if you turn off the valves to the hot water loop and run the system do you get any banging. if so I would repipe that header. so you have a strait, larger, header coming out of the boiler. if you check out the installation instructions for that model. I am sure there is a minimum height requirement. hope this helps

Jackmartin

The problem is the fact you do not have an expansion tank on the Hotwater loop. The expansion tank allows the increase in volume of water to go somewhere. The water heats up until any desoved Air is pushed out of the water it has no where to go so it acts like a slug of well ,air, it becomes an incompressiable solid ( closed system) and disengages from the water and races towards the area of lowest pressure the end of the baseboards and makes a Big Bang. Install an expansion tank ask yourself if we could get by without a tank for the last 125 years why didn’t we? You cannot run a hydronic system without a point of expansion, physics is never wrong. Also, for the love of Pete ,install a pop valve, what moron installed this hot water loop? All the best Jack

Jackmartin

The problem is in your Hotwater loop. You state you do not have an expansion tank a pop valve ,or any kind of air bleeder. Install an expansion tank off a Hippo bleeder fitting , put a good quality air vent on the top fitting of the hippo fitting. Sarco makes an excellent unit it an air scoop that really works. The air in the system is coming out of solution as the water is heated and because the moron who installed this loop did not make a path for air ,let alone micro bubbles ,the air is becoming an incompressiable slug. The air becomes a soiled bubble and races towards the area of lowest pressure the end of the run , the return elbow of the baseboard, it is moving at terrific speed and it cannot go around the corner so it smash’s into the elbow and it goes bang. Try this, drain out a little water from the hydronic loop and start the heating cycle ,if there is no bang you have provided enough space for everything to coexist. If we could have gotten away without an expansion point for the last 125 years why would we install tanks at all? I cannot imagine the logic of installing any pressurized system without a pop valve what a freaking moron. All the best and good luck Jack .In the event you find out who installed this mess, get him the most elementary book on physics you can and make him read it!

DanHolohan

A simple bypass will fix the problem. This is what we call a Brooklyn Special. I’ve seen more than I can count.

Big Ed_4