The main is hot, the radiator is cold, and the heating company can't figure out why.

mattmia2

Are you adding the pickup factor at the top of the chart? The actual pickup factor in typical residential systems is usually far less than the standard 30% (or in the case of that chart it looks like 25%).

mattmia2

Even if the connected radiation 100,000 btu/hr and the boiler is 87,000 btu/hr output, it isn't going to underfill it so much that half the system doesn't heat.

dabrakeman

The IN4I is rated for 271sqft EDR. That is the only number you need concern yourself with. The total EDR for your radiators should be within +/-10% of that. If you get a total for your downstairs close to your upstairs then yes it appears you would indeed be considerably undersized. I think everyone here would be more comfortable if you sent a photo of one of your typical radiators from the end view as well as side view. Also send its overall height, width and number of sections. Likely if you did one right you did the rest right... You seem like a smart guy so trust yourself, it is your home.

If they do end up putting in a larger boiler then also they need to fix the near boiler piping. Correct pipe size header and individual takeoffs from the header to each main.

bmearns

I can double check with the resource @KC_Jones provided, but based on the Smithfield doc I linked earlier, I've got 495 square feet of EDR, requiring 118 MBH, so the one they put in is only rated for about 73% of that.

UPDATE: The Weil-McLian guide agrees with the Smithfield one I used.

dabrakeman

Looks like you would be right between the IN61 (450sqft) and IN71 (542sqft). Thus maybe making sure each radiator is detailed as best as possible might be in order.

mattmia2

That 271 square ft of EDR on the ratings plate contains a 30% pickup factor so the output of the boiler is actually 361 square ft of EDR. Unless there is somewhere close to 90 square ft of piping surface there is more capacity available to fill the radiation than the nameplate would imply.

Even with a significantly undersized boiler you will see the radiators all or mostly partially heat, not half of the system not heat at all.

Or as Ed would put it, when someone spends many thousands replacing the boiler and it has the same problem, what will you do next.

Jamie Hall

I wonder if the sizing problem here may be a case of the contractor taking a guess at the size of the boiler based on the size of the house, as is sometimes down by lazier contractors, and adding a bit "just for good measure". Which for that size house might come out to nearly what was installed.

Steam doesn't work that way...

mattmia2

There is one quick wat to find out, close the valves on enough of the radiation on the side that does heat to bring it down to 300 square ft or so and see if the non-heating side heats.

bmearns

"what will I do next" is definitely on my mind. I'm trying to get them to put proper vents on the mains (Gorton #2) but they ran the system with the vents off the main and it still didn't heat up so that doesn't seem to be the primary problem. I'm going to be nagging them about the near-boiler piping, specifically the fact that it splits to the two mains instead of using the two pipes coming out of the boiler. And I'm going to have them measure the relative heights of all the returns against the boiler water level, more accurately than I easily can.

Here's one of our typical radiators, though the largest one in the house. It's 20" tall, 6 tubes and 20 sections. I evaluated this as 60 sq feet EDR, so I'll be interested to see what you all think about that.

dabrakeman

Yes indeed. That would be 60sqft.

Are you sure your contractor does not know what model boiler he took out?

AdmiralYoda

I'm just a homeowner and thanks to this site I'm a slightly educated steam enthusiast at this point. If I brought a contractor in and they were talking BTU and not EDR I'd quickly discount their capability. Steam systems operate in EDR...the boiler states its capacity in EDR. That's the only thing that matters.

To continue the automotive analogy... you brought your vehicle in for an engine replacement. Lets just say that it was a 3.6L V6 with 300 horsepower. The mechanic wants to put in a 225kw AC Induction motor to replace it and says it will fit in the engine bay just fine.

You ask what the heck...will this be the same as my 3.6L motor with 300hp? He says he's never heard of horsepower before but after some digging he finds out that 1 horsepower equals 745.7watts. Well 300hp equals ~224kw so it should work just fine....right?

Would you trust a mechanic that doesn't know what horsepower is?

I'd ask for your money back or to have them hire a pro from this site to teach them what EDR is and how to learn the ABC's on steam heating. At this point I'm confident that you are more knowledgeable then they are just from participating in this one discussion.

KC_Jones

There is still a serious venting problem that a bigger boiler won’t fix and they will still need to change. Of course I'd bet they won't want to do that and after the bigger boiler they will still be scratching their head. Also, they need to go through all the mains with a level and string line to verify correct pitch and no sags.

I’d bet money with everything being correct and proper venting you wouldn’t have noticed an undersized boiler until the coldest day, if even then.

1900 sq ft house with 495 is 62 btu/sq ft. Probably actually needs 2/3 of that on the very high end, which is 330, that boiler puts out 360. It could have worked, but that's water under the bridge at this point.

Since they are going in with a bigger boiler, and using your numbers, they should put in an IN6. I'd bet they are going to propose an IN7, no way would I want that.

IN6 covers the load with a 21% pickup factor which is more than enough.

IN7 covers the load with a 45% pickup factor, which is way too much in my opinion. You will build pressure, which you don't need and it will waste fuel.

I believe you stated 40 ish feet of main. That would be about 5% added to your total system, and that only really matters if you plan on leaving things completely un insulated and using it for heat in the basement. Insulate it and that numbers basically goes to zero. When one actually looks at the hard numbers, one realizes how oversized things become even using the typical 33% pickup factor. In your case you fall between two sizes and I would always, without hesitation, pick the smaller one.

dabrakeman

Your contractor is far far from perfect from a steam knowledge standpoint but it does sound like he is trying to work with you and make things right.(?) The logistics of "throwing him out" and "getting your money back" are IMHO a bit idealistic at this point. If he was belligerent and not willing to work with you and other expert input (this forum or a consult) then yes you might need to go to litigation but I am sure you both would want to avoid that. The contractors first job here was to size your boiler properly and he did not do that. Sounds like he knows that now and would be willing to swap out the boiler for a properly sized one. Yes maybe the smaller one would have cost slightly less but maybe you use that to cover the work a bit. The second job of the contractor is to follow the installation manual at least to the minimum requirements. The fact that he used both tappings in the boiler and put in a drop header makes me think he tried but maybe missed some details. If it is in the manual and he didn't do it then that is your negotiating point. On the US boiler site under contractors literature you can find the installation manual for these boilers (I also attached).

You both acknowledge you had a working system before the install (that is great for you). The size may be the only issue or it may not be. Understanding what was there before both from the boiler perspective and the piping perspective would be invaluable in understanding what may be contributing to the current issues. I.e. comparison of manual specs may help identify if water line changed from old boiler to new boiler (in your normal is 28.5" above the floor line per the manual on page 18). Pipe sizes are there as well. I do think the Weil-McLain EG boiler manual is a little more complete and informative than the Independence boiler one if you want to look at that as well for reference. Keep the threeway communication going.

MaxMercy

dabrakeman said:

Your contractor is far far from perfect from a steam knowledge standpoint but it does sound like he is trying to work with you and make things right.(?) The logistics of "throwing him out" and "getting your money back" are IMHO a bit idealistic at this point. If he was belligerent and not willing to work with you and other expert input (this forum or a consult) then yes you might need to go to litigation but I am sure you both would want to avoid that.

Agree. The fact that he's willing to replace the boiler with a larger *may* show he doesn't understand the problem (I don't, so I can't comment on that aspect) but not that they are not going to try.

From what I read, the boiler is undersized anyway even if it's not the cause of the steam flow, but getting the right size is a good thing from where I sit.

If the new boiler doesn't fix it, at least they will have the right size now and the rest should be simple (not much left).

mattmia2

If the boiler were too small it would all heat but not completely. do the test where you shut off enough radiators to make it match your calculation.

The bottom of the main being hot but not the top would suggest that the boiler is putting liquid water in the main rather than steam. that tee arrangement at the boiler leaves liquid water with little choice but to go in to the main on the low side of the tee.

bmearns

As some of you have suggested, the contractor is trying to make this right, and he's doing it all for the originally quoted price (i.e., the price of the smaller boiler). I talked to him (briefly) yesterday and he said that based on the measurements his technician did last week, he's going up two sizes from what they just put in: so that would be from the IN4I to the IN6I. He specified the measurements put us between two sizes, so he's going with the bigger one. At least that means their measurement is pretty close to mine (for whatever that's worth).

I've got several things that have been discussed here that I'm going to have them address as well, including the main vents, the T in the near-boiler piping, and checking the returns relative to the new water line. If, after all that, it's still not working well, then it will definitely be time to hire an outside expert.

dabrakeman

If you are at 495 EDR for your standing radiation (per your measurements) then you are between the IN61 and IN71 (IN61 for 450sqft) and IN71 for 542sqft). I think most here would agree to go with the "smaller" of the two since you probably have less than 1.33 pickup factor in your piping, particularly if you insulate everything well. IN61 should be your best choice.

Have you asked him what he took out?

bmearns

Well, they finally came to put in the new-new boiler. Based on independent measurements by myself and the heating company, our radiators need about 119MBH (not factoring in pickup). They had put in the IN4I rated for 87MBH, they've now finished the install of the IN6I rated for 144MBH (the in-between size, the IN5I, maybe have been fine at 115MBH, but we went with the 6).

It's May not and we're not running the heat much, but I tested it for a bit this morning and it does seem to have done the trick, all the radiators actually get hot in about the same amount of time as they used to with the old-old boiler. Before next season I'll get the pipes insulated, and I'm get more appropriate vents on the mains, but for now we're back to status quo, at least.

Want to thank everyone here for the suggestions and help, and for the patience with my lack of knowledge

MaxMercy

bmearns said:

Well, they finally came to put in the new-new boiler. Based on independent measurements by myself and the heating company, our radiators need about 119MBH (not factoring in pickup). They had put in the IN4I rated for 87MBH, they've now finished the install of the IN6I rated for 144MBH (the in-between size, the IN5I, maybe have been fine at 115MBH, but we went with the 6).

It's May not and we're not running the heat much, but I tested it for a bit this morning and it does seem to have done the trick, all the radiators actually get hot in about the same amount of time as they used to with the old-old boiler. Before next season I'll get the pipes insulated, and I'm get more appropriate vents on the mains, but for now we're back to status quo, at least.

Want to thank everyone here for the suggestions and help, and for the patience with my lack of knowledge

Good news, at least they stood up for their work even if it took a bit.

Was there any other work done at the same time (like changing near boiler piping or venting) or did just the replacement boiler seem to fix the slow/no heat?

random12345

@bmearns I take an interest in old radiators. I can't be sure, but the one in the photograph looks like it says "Thatcher". Are all of your radiators the same or do you have some that have a different brand name in the circled area? Would you mind checking? I've never seen one of those before. Also, that reflective thing you have behind it was almost certainly designed for a hot water radiator which only gets up to 180 F. At 215 F it may not hold up over time. Aluminum foil works just as well if not better.

bmearns

@random12345 I can't really make out the brand either, but I could certainly believe it says "Thatcher". I checked a few radiators that are easy to get to and they all seem to be the same brand. For your info, the house was built in 1921 in Albany, NY. I'm assuming the radiators are original but can't say for sure.

Thanks for the tip on the reflector!

bmearns

@MaxMercy, I think it was just the boiler replacement. They may have changed something in the near boiler piping, but it looks the same as far as I can tell. It was the same company but a different team doing the install, some older guys who really took their time with it. So I'm not sure if the first team rushed some things or if it was just the size of the boiler.

ethicalpaul

Ironically they have now cemented in place even more the idea that "we'll just pick the next size up, we don't want to have to replace a boiler again" which they even did in your house, picking an oversized boiler to fix what may have been an undersized one.

random12345

https://babel.hathitrust.org/cgi/pt?id=uiug.30112047386849&view=1up&seq=231&skin=2021
@bmearns See pages 225-229 for Thatcher ratings. The width of that rad should be 9.75", and distance from floor to bottom tapping should be 4.5". Hope your new boiler is properly sized this time.

ChrisJ

mattmia2 said:

That 271 square ft of EDR on the ratings plate contains a 30% pickup factor so the output of the boiler is actually 361 square ft of EDR. Unless there is somewhere close to 90 square ft of piping surface there is more capacity available to fill the radiation than the nameplate would imply.

Even with a significantly undersized boiler you will see the radiators all or mostly partially heat, not half of the system not heat at all.

Or as Ed would put it, when someone spends many thousands replacing the boiler and it has the same problem, what will you do next.

Actually,
Even with one sized dead on, if you vent some radiators very fast it can starve others completely for a long time. I had that issue early on. If memory serves, I had 100sqft worth of radiators out of 392 that stayed ice cold under normal conditions. Slowing others down just a little fixed it completely.

mattmia2

The system does have to be balanced to heat evenly....

ChrisJ

mattmia2 said:

The system does have to be balanced to heat evenly....

Absolutely.

I think oversized boilers make starving radiators less of an issue but the system still won't be balanced right.

dabrakeman

You originally calculated an EDR for your radiators of 495. Has that changed? If not then you are properly sized with the IN61 rated at 450sqft.