One loop not getting steam--and an odd phenomenon

CapeCodder

Hi, all. I had my old oil-fired boiler replaced with a Peerless gas boiler this summer and am having trouble getting the system working properly. It's a one-pipe system with three loops running out from the drop header. The two loops that heat the front of the house heat up quickly, and the radiators all get steam. The one that serves the back of the house, though, heats very slowly, and unless I crank the thermostat up so the boiler runs longer all the radiators in the back stay cold.

The other odd thing that happens is that the back loop seems to heat from both ends. While the end of the main close to the boiler is slowly heating up, the end of the return close to the boiler also starts to heat up, so it can feel like there's steam in the beginning and end of the loop, but the middle is cold.

Currently there's a Gorton 1 main vent on the shorter front loop and Hoffman 75s on the longer front loop and the malfunctioning back loop. We've had a couple different vents on the back loop, and it's behaved the same way, so I don't think the problem is a failed vent. The back loop is also the last to come off the header--is it possible the two other mains are taking all the steam? The boiler was skimmed two days ago, and the guy who did it said the water looked pretty good even before skimming.

Any thoughts on what might be going on?

vaporvac

Could you post some pics of your near boiler piping? It might explain a few things. How was the system behaving prior?

CapeCodder

Thanks! Here are a few pics. I apologize for the two sideways ones. I'll try to figure out how to correct that. We didn't have this problem prior to the new boiler being installed (although we had plenty of other problems). The problem main is the one closest to the camera in the first picture and on the left of the second.

Fred

One HUGE, obvious problem is the header appears to be no larger that the risers and the mains. The way it is configured, you are trying to feed 3 mains off of a header that is equal in size to each of those mains. There is only so much volume that that header can hold and the steam is going to go down the path of least resistance.

CapeCodder

Thanks, Fred. Would sticking a much bigger main vent on the back loop and smaller ones on the others possibly solve my problem, or is this probably only fixable with a larger header?

Bug512

Looks like the equalizer is the same size as the header.

Are you making any pressure in the boiler ?

Is the boiler sized for the amount of radiators (EDR) ?

I'm sure other will ask for more information.

Fred

Venting may be an issue at some point when you are fine tuning the system but not going to fix this problem. Look at the owners/installation manual that came with the boiler. The minimum header size should be at least one size larger than the risers. Those look like 2-1/2 inch risers so I would have put a 3-1/2 to 4 inch header in, preferably 4 inch. With those unions on each main and eeach riser off of the boiler, it wouldn't be a huge job to replace that header.

CapeCodder

Thanks a lot, Fred and Bugs. That was a huge help. I think the risers are 2", and according to the manual that requires a 3" header. Sounds like I need to talk to the installers about fixing that. Is there any reason a drop header would require different sizing from a conventional header? I'm a little surprised these guys would get the header size wrong. They install a lot of Peerless boilers and specify in their contract that they'll do everything according to manufacturer specs.

Bugs, in answer to your questions, it is sized correctly based on measuring the radiators, and I'm not sure about boiler pressure.

Anyone see any other issues?

KC_Jones

I just pulled the manual for that boiler series. Only the smallest one allows for a 2" header. The next size boiler requires a 2 1/2" header and from the 63-05 through 64-07 it's a 3" header. The bigger boiler require 4" header. Not sure what size you have there, but is obviously not the small one. This information is on page 16 in your IO manual. The problem is most likely that that 2" (looks like 2") pipe can't physically deliver all the BTU's to your system...it may never work in it's current configuration. As was already stated the header needs changed. Do you know what model it is?

CapeCodder

Thanks, KC. I believe it's a 63-05L (I'm watching a toddler this afternoon so haven't been able to spend any time in the basement to make sure). According to the manual it needs a 3" header. And, yes, the current header is 2".

Jamie Hall

If the main is getting hot from both ends, then steam is getting into it from both ends, eh? Steam is not supposed to get into returns...

If steam is getting access to the return for that main, then air can't get out of it. No air out, no steam in, no heat.

so, we need to think about how the steam is getting there.

Where does that return attach to the cold, wet return to the boiler? Is it possible that the water line has been changed, so that what was once a water seal for that return isn't one any more?

Trace that return all the way to the boiler and see how it is sealed from steam and let us know...

Fred

He says the return near the boiler starts to get hot. I suspect he has enough pressure in that boiler, coupled with the equalizer also being the same size as the header, risers and mains that steam in the boiler is pushing some water out of the boiler and into the returns. It looks to me like the Hartford loop is way too high too. Steam is probably flowing into that. Owner's manual should give him the specs there as well.

Abracadabra

CapeCodder said:

The other odd thing that happens is that the back loop seems to heat from both ends. While the end of the main close to the boiler is slowly heating up, the end of the return close to the boiler also starts to heat up, so it can feel like there's steam in the beginning and end of the loop, but the middle is cold.

How far "up" is the return heating up? Past the main vent on that return? Up to the main vent? Is the main vent on that return getting hot?

What vents do you currently have on your radiators? Vent the radiators slow. I'd suggest nothing more than a Gorton/MOM #4/#5 to start.

CapeCodder

Thanks, everyone. This has been hugely informative for someone who doesn't know much about boiler piping. The answers weren't really what I wanted to hear (I was hoping for some easy, quick fix), but it's good to have a better sense of what's going on.

I don't think the Hartford Loop is too high--it's below the boiler water line--but it does get hot fairly early in the boiler firing process, so I guess hot water is getting in there. The return heats up beyond the vent, but it doesn't get as hot as the mains do (I just fired the boiler from cold to check this).

The manual for this boiler recommends a 1 1/4 inch equalizer, and the one on there now is 2 inch, but I gather going bigger isn't such a bad thing (as long as you have the right sized header).

So...I guess what I'm wondering now is if installing the correct-sized 3 inch header and leaving everything else as is will solve my problem or if there's anything else that needs doing.

Thanks again for all the help.

CapeCodder

Last night I wrote to one of the guys (the younger of the two partners) who installed the boiler, suggesting that the 2" header should be replaced with a 3" one. Here are the relevant bits of his reply:

"I spoke with [older partner] this morning and described the situation he is almost certain it is a venting problem he says the 2 inch header should be fine but we want to switch the vents to vent rite #1s [I assume he means #35s] at the same time we will take the measures of the header and if it comes down to increasing header size we have no problem doing that but we would like to excursive our other options first. [Older partner] thinks the vents on there are far too large and are not allowing the system to operate properly."

To me this sounds like trying to solve the problem by making the system less efficient (not to mention that they stated they'd pipe the boiler to the manufacturer's specifications). I could also do that by turning off all the radiators in the front of the house and only using the back ones to heat it. But that wouldn't help my gas bill any. I'd be curious to hear others' thoughts.

Steamhead

I sure hope you haven't given them the final payment!

KC_Jones

If the contract says "to manufacturers specifications" then you should demand that, don't let them try some stuff. If they are talking about main vents...it's essentially impossible for them to be "too big". Too many won't do anything extra for you, but it also won't cause problems....for the most part. It sounds like they are going to try and cover up an incorrect installation with venting somehow. It will never work right. Don't let them mess with the vents MAKE them change the header. Here is the bottom line it's your house, your decisions and you have it in writing. They have no leg to stand on. As steamhead said if you haven't made final payment DON'T and if it was me I would tell them flat out fulfill the contract or there will be no payment. On the surface it looks like they are trying to cheap out hoping you won't notice...don't let them! By the way (this is just my opinion) when they start saying "I am almost certain" and "let's try this" or "maybe it's this"...that sounds like guessing. Personally I pay a professional to KNOW not GUESS. Again just my opinion. One final thing...I don't think anyone is saying the header necessarily fixes the current concern, but it's wrong and certainly isn't helping. Once they get the header fixed it eliminates one possibility and then you/they can move on.

BobC

I agree they are trying to sidestep the issue,I would be polite but firm when talking to them.

Tell them I'm sorry but the piping has to be done per the manufacturers specs before you write the check. If you have already paid tell them you will take them to small claims court if it comes to that.

Bob

Jamie Hall

Have you checked the water line on the new boiler vs. where it was on the old boiler? If the return is getting hot, steam is getting into it and you need to know why.

The rest of this is gravy. Nice gravy, but gravy. Until you find out how steam is getting into that return and fixing it, you're going to have problems.

Fred

I'm willing to bet money that header is a huge part of the problem if not the entire problem. It just doesn't have the capacity to feed those three mains and the steam generated by the boiler is pushing water back into the returns/equalizer and possibly into that header. They may have done something else wrong too, that we can't see but that issue is obvious. Besides that, if you have a problem with the boiler down the road, the manufacturer is very likely to say it was a result of a bad install and they may well refuse to take care of the problem under warranty.

KC_Jones

I can not for the life of me figure out this under sizing of headers?! There was another one on HH recently with an undersized header (the district steam conversion). What does the contractor really save with this? How much labor is put into trying to fix an improper installation versus just doing it correctly to begin with. They don't even need to figure it out the manufacturer tells them right in the manual?! I know I tend to rant on here, but I just can't get my head around it.

SWEI

KC_Jones said:

I can not for the life of me figure out this under sizing of headers?! There was another one on HH recently with an undersized header (the district steam conversion). What does the contractor really save with this?

2" fittings and nipples are on the shelf everywhere, and most plumbers are set up to thread it. 2-1/2" and larger requires a commitment, both from the plumber and the supply house.

CapeCodder

Thanks, everyone. I'm insisting on the header replacement. We'll see where this goes. They were paid long ago--the boiler replacement was done in the summer and this problem didn't become apparent until it got cold. In retrospect I should have posted pictures of the install here as soon as it was done, but I kinda had faith in these guys (I found them on the contractors section of this website after all).

I still don't really think they're trying to jerk me around. What I think is going on is that this is more or less how they always do their installs and that it usually "works", maybe because of the very small main vents they use. I think that's why they're so focused on the large vents. Everything about this install was the way they usually do it except for the main vents, which I supplied.

Fred

Keep us posted on how this turns out. We're all interested. I'm disappointed that the contractor came from this site. They know better.

Jamie Hall

No. If the equalizer is hooked up even remotely correctly, and it looks as though it is, even if the header is ridiculously small it can't develop pressure to back water out into the returns -- the pressure in the equalizer takes care of that.

That's what equalizers do.

If the pressure in the boiler rises to the point where water is backed into the returns due to inadequate venting or oversizing the boiler or whatever, the pressuretrol or vapourstat should shut the boiler down.

Please do me a favour and check the new and old water lines, and find out
why
steam
is
getting
into
that
return.

Before you spend bundle on changing the header etc. etc.

Fred

Jamie, If two of the first three 2" mains are steaming all the steam, do you think there would still be enough steam to supply the equalizer? Just seems to me that the last main isn't getting hardly any steam because that 2" header can't supply 3 mains of the same size as the header so it's not likely that there is sufficient steam to pressurize the equalizer. You certainly have more experience than I.

KC_Jones

SWEI said:

KC_Jones said:

I can not for the life of me figure out this under sizing of headers?! There was another one on HH recently with an undersized header (the district steam conversion). What does the contractor really save with this?

2" fittings and nipples are on the shelf everywhere, and most plumbers are set up to thread it. 2-1/2" and larger requires a commitment, both from the plumber and the supply house.

I understand that, but (again my opinion) taking on a steam job is automatically an implied commitment. If you aren't willing to do it right why are you even willing to do it? Seems to me they are better off avoiding the headache.

KC_Jones

"I still don't really think they're trying to jerk me around. What I think is going on is that this is more or less how they always do their installs and that it usually "works"
This mentality exists everywhere. I deal with this at my job on a daily basis. I ask WHY all the time and usually get that answer. That's the way we always did it. I don't accept that answer and always end up digging up the answer.

Jamie Hall

Fred said:

Jamie, If two of the first three 2" mains are steaming all the steam, do you think there would still be enough steam to supply the equalizer? Just seems to me that the last main isn't getting hardly any steam because that 2" header can't supply 3 mains of the same size as the header so it's not likely that there is sufficient steam to pressurize the equalizer. You certainly have more experience than I.

Oh yes -- no problem with that. The distances involved are very small, so the pressure drop through the header is minimal. Something else is going on here...

KC_Jones

Ok I am still learning...well we never really stop learning. Anyway what about the arrangement of the returns? I know on the steam side specifically the header it's important to always keep the flow in the same direction for various reasons. On his return pipes 2 are on one side of the boiler connection (Hartford loop) and one is on the other side. I can't think of why this would be an issue, but it's something I noticed. He does say the one with the problem is this return that is off by itself, so I can't help but think there is something to it.

Jamie Hall

I missed that detail, KC. All the returns should connect together, well below the water line of the boiler, and then go up to the Hartford Loop nipple, and then T into the line from the equalizer down into the boiler cold return.

Can we, perhaps, have a detailed picture of just that bit of plumbing?

SWEI

KC_Jones said:

SWEI said:

KC_Jones said:

I can not for the life of me figure out this under sizing of headers?! There was another one on HH recently with an undersized header (the district steam conversion). What does the contractor really save with this?

2" fittings and nipples are on the shelf everywhere, and most plumbers are set up to thread it. 2-1/2" and larger requires a commitment, both from the plumber and the supply house.

I understand that, but (again my opinion) taking on a steam job is automatically an implied commitment. If you aren't willing to do it right why are you even willing to do it? Seems to me they are better off avoiding the headache.

One would think, no?

CapeCodder

Thanks, everyone, for continuing to try to puzzle this out. I'm sorry I haven't been able to contribute anything today--it's been a crazy one (for reasons that have nothing to do with the boiler).

Jamie, I just spent some time looking at the piping around the boiler, and I can't for the life of me see how steam would be getting from the boiler to the returns. All the connections to the boiler are below the boiler waterline. All the piping around the boiler up to the returns was replaced when the new boiler was installed.

KC is right that the problem return connects on the opposite side of the boiler from the other two. I can't get a good picture of that whole side of the boiler because there's a big workbench in the way. In the first two pictures you can see where the problem return attaches to the long horizontal pipe that runs along the back of the boiler. The other two attach at the other end of that pipe, one to the very end of the pipe, the other to a tee a few inches down from the end.

Of all that below-the-waterline pipe, what should and shouldn't get hot during normal boiler operation?

KC_Jones

I would expect all the below water stuff to have some warmth to it, but it also depends on how long the condensate has traveled through uninsulated pipes. Remember it's constantly cooling. I have a similar (but shorter) horizontal pipe on my system and when I am steaming it is warmer than ambient, but not mush warmer. Every system is going to be a little different, but nothing below the water line should be steam hot. I was just spit balling some ideas on this one, like I said not sure if that arrangement even matters. I am one who thinks everything should always flow in the same direction no matter what so that jumped out at me. It definitely sounds like a weird situation. Could you possibly draw a layout of the piping and show what is getting hot and what isn't? Possibly indicate vent locations on the drawing? That might help.

CapeCodder

In this system all the below-water piping gets very hot. Steam hot? I don't know, but I wouldn't like to leave my hand on it for more than a second or two. I might be able to post a drawing but that'll have to wait till tomorrow.

Jamie Hall

All the below water piping gets very hot?

There's something wrong here -- an obvious comment, sorry -- but it sounds to me as though somehow, somewhere, steam is getting into at least one of your returns.

Honestly, at this point without actually looking at the place and checking every pipe and connection, I have to say I wouldn't care to speculate further. All I can suggest at this point is to go over the entire system and see where every single pipe goes, and make sure that all drips and returns go to below water level, and that all traps etc. are working.

I'm still suspicious of the water level of the boiler being significantly below the original piping, and that somewhere there is a seal or bit of what should have been wet return which isn't any more.

KC_Jones

I agree with Jamie something is amiss here big time. Those pipes below the water line should not be that hot, especially since there is no apparent insulation on them. You haven't mentioned what pressure the boiler is running at?! That can effect this for sure. If the pressure is high enough it could push steam into those returns. Do you know what pressure it's running at? Also do those pipes get hot immediately after it starts steaming or does it take a while? Does any of this coincide with the running of the hot water loop? In other words does it do this all the time or only when the hot water loop is running? Or not running?

Fred

Other than that under-sized header, there is nothing else obvious that looks wrong in that near boiler piping. Did they make any changes to the piping anywhere else down the line? When the boiler is running do you see any significant drop in the waterline in the sight glass that might indicate water is being pushed out of the boiler? If not, as Jamie has said, steam is getting into the returns from somewhere. Personally I'm still suspect of that header and those first two mains eating up all the steam to the point that large equalizer and the third main are robbed of what they need to perform as expected but I also understand where Jamie is coming from too. I say look at your owners manual and compare the recommended piping to what you have and see if you notice any obvious deviations. With those vents on the returns and so close to the boiler, it will let steam get pretty far down those return lines in order to shut those vents. that might be what you are feeling. Are those returns hot down near the water line? They would be better actually on the mains after the last radiator run. BTW, when you get that header fixed, you do need much more venting. I use the Hoffman 75 vent too and I have four of them on an antler on a 50 foot main and two on a shorter main. The idea is to vent mains very quickly and one Hoffman just won't do it, especially where your vents are. In addition to pushing air out of the mains, there is some additional air that has to be pushed out of the returns up to that vent. You can use Gorton #2's. You have the headroom and they vent about as fast as 2 Hoffmans or you could make an antler and add another 1 or 2 Hoffmans