Short Cycling Despite First Time Main Vents Installed

Jeff_56

After reading through dozens of posts here on "the wall" relating to the venting of steam radiators and their supply mains.....I am stumped and need some expert advice. I will try my best to include everything that is usually required (including pictures) to provide you with everything you may need to offer a opinion. I apologize for the length but hopefully it will cut down on questions you may have.



A little history:

130 year old House in Central Massachusetts

One pipe Steam radiators (all different sizes)

3 on first floor, 4 on second floor

Installed New Oil fired Steam Boiler (in basement) about 7 years ago (info shown in pictures)

Most of the radiator vents are adjustable heat timer vari-valves



Problem: during start up in the morning from a temp of ~62 deg F to 68 deg F, the boiler runs until all radiators are heating each room, but when it is still a few degrees from the set temperature, pressure builds on the boiler gauge to around 1.5-2.0 psi, and shuts off. About 1 minute later the pressure gets to the cut in setting of 0.5 psi and starts again. After about 2-3 minutes the pressure rises again and everything repeats itself. This can happen about 10-15 times before the remaining 2 degrees of the temp setting is reached and the boiler shuts off.



This just started happening recently. It seemed to coincide around the same time I put a new "nest" thermostat in the house. For reasons I will explain later, I do not think the Nest is related to the issue. One thing the Nest has shown me is my daily usage in a graph that confirms the off and on sequence every morning.



The first thing I did was remove all the vents from the radiators and soaked them in hot vinegar for 30 minutes, then rinsed them and re-installed them. Before I installed them I blew through each one to make sure I had air coming out of the vent, they all seemed fine. I figured if they failed to shut upon getting up to temp then the worse thing would be I would have more venting than I wanted which would only help my issue. The same problem existed after that. After reading through these forums I saw the mention of "Main Vents". I though "i've never seen any in the basement". So I went looking.



There are 2 steam mains coming off of my boiler. One runs about 12 feet with 3 radiators coming off of that run. 2 radiators feed the first floor and one goes up to the second floor. I'll call this the short run. The other main runs about 50 feet in total length around the basement and feeds the other 4 radiators, 2 on the first floor and 2 on the second. All 7 radiators heat without any problems.



So I find that there is NO main vent on the short run anywhere, even though I have had no issues for all the years I have lived here. The other longer main DID have a 3/4" vent at the very end of the long run. I didn't know this because it was in the back of my workbench peg board, which of course only had enough room to "squeeze" in there to remove it. It did not appear to be working (no air came out when I blew in it), so I contorted by body in that tight space to remove the valve, soaked it in hot vinegar for 30 minutes and was able to get a "little" air to pass through it. I re-installed it........next morning same problem.



Next I bought 2 new Gorton air vents. I couldn't fit the Gorton #2 behind the work bench so I installed a Gorton #1 in that location.........next morning same problem. The next night I tried to remove the plug from the end of the short main only to find out that the dead men must have had no desire to see it come off. Even with heat and a 3 foot pipe wrench it wouldn't budge. So I drilled and tapped a 1/2" hole in the side of the short run near the end and installed the Gorton #2 vent. After reading through these forums there was always mention of never having enough vents. So now I had a new Gorton #1 vent in the long run, and a brand new (for the first time) Gorton #2 in the short run. I also had all the previously cleaned Vari-Vents in the wide open position on all radiators............next morning same problem. I may have gone from 15 short cycles to 10, but still had multiple short cycles.



My pressuretrol is set for 0.5 cut in and ~1.5 psi cut-out. The pressure gauge (mounted in a separate location) will slowly read pressure and when it gets to a little over 1.5 psi, the burner shuts off, about 3 minutes later the process starts all over again. So I don't "think" I have a problem with my pigtail unless I concidentally also have a problem with the pressure gauge.



The water in the glass is clean, although when I blow down the low water cut-off each week it does get tinted a bit but clears up quickly. It only bounces in the glass about 3/4" maximum when the boiler is at 1.5 psi and ready to shut off.



Regarding the "Nest" thermostat. I have read all the pros and cons on this high tech gadget, but I have had no issues whatsoever and it seems to be working just fine. I only have 2 wires (red and white) going to the Nest, which is 2nd generation Nest so there should be no need for a "C" wire.



Now I did move the thermostat from the dining room (where there is a radiator) to the kitchen, where there is not a radiator. There is however a radiator in the hall about 8 feet from the thermostat and there is only a difference of about 2 degrees from what the old thermostat reads and the Nest. (even though the old thermostat is not hooked up to the boiler, I left it in the dining room to watch the temperature difference). When the thermostat was in the dining room I had it set for 70 degrees at 5:00 a.m. Because there is a 2 degree difference in the Nest and this old thermostat, I set the Nest for 68 to get the same results.

To make sure that the nest didn't interfere with the cycling of the boiler, I turned "off" the"true radiant" learning setting on the Nest. This feature learns how long your system takes to heat up and uses that info to create a predictable schedule with even heat. It works with in floor radiant as well as traditional radiators. I thought maybe this was somehow "preheating" the system but after getting up at 4:30 this morning to watch the short cycling unfold, I confirmed that it is in fact shutting down on the set cut-out pressure by watching the pressure rise on the gauge to ~1.5 psi.



I was considering buying all new vents for the radiators, but didn't know if that was still feasible considering all that I have already done. The main vents obviously allow the mains to vent and heat up quickly but all the radiators also heat up as I remember them doing before. I realize that even without the one main vent working and the other nonexistent, it required the radiators to vent the system, so if anything I have sped up the steam to the radiators, but perhaps they are still not venting enough before their respective vents close upon receiving steam?



When I installed the boiler about 7 years ago, I removed a radiator from the kitchen. I blew out the wall and put in a sliding door leading to an outside deck plus the kitchen was always hot anyways. The boiler may be a bit oversized by me doing that, but I have never had this problem before, not for the past 6-7 years anyway.



So now I am considering the purchase of all new vents for the radiators (spent all my money on the 2 Gorton vents!) or cleaning out the watersides of the boiler (really don't want to unless I have to). I have also considered removing the pressuretrol and cleaning the siphon, but the corresponding pressure gauge seems to match what the boiler is doing so not sure if that is feasible either. I blow the low water column down at least every week, sometimes much more. The boiler is cleaned every year and is still in very excellent shape.



Other bits of info:



The combustion chamber in the boiler could use a new floor because it is starting to flake when I clean it (even though I am careful).



The Gorton #2 on the short run is as high as I can get it because of the floor above.



The Gorton #1 in the long run is not perfectly straight up, more of a 45 degree angle. I had no choice as you can see from the pictures.



I replaced the vent in the radiator closest to the new thermostat with a Maid O Mist (size C), which has higher venting, to get more heat to the thermostat in hopes of satisfying the thermostat quicker to avoid less short cycles.



All pipes are insulated in basement except for the new Gorton 1/2" line (doing that this week). Some piping going up to the 2nd floor are uninsulated but they have always been that way.



The nozzle in the burner is either a .80 or .85 GPH. I think maybe .85 with a 80 degree. Either way it is the same it always has been since startup.



I had a squirrel in my attic a few weeks ago that I had to have removed, but I don't think he knew enough about boilers to make any changes without my knowledge.



THANKS in advance for any opinion or comment you may have to get me back to the way things used to be......at least with my steam heating system.



Have a look at the pictures. I hope I have included everything important. Sorry some of the pictures are not properly aligned. They uploaded correctly but after publishing them they were rotated. I tried rotating them and re-publishing, but they are still rotated 90 degrees??

Fred

Temp Set back

It sounds like you system is running just like it's suppose to. A 6 degree setback at night is way too much. For steam most suggest you either not set it back or that the max set back be no more than 2 or 3 degrees. It takes so long to heat all the pipes and rads back up that it is debatable if there is any fuel savings using the set back. The short cycles are typical once the boiler gets to pressure and the pressuretrol cuts the burner off until the cut-in pressure is reached which takes just a minute or two and then it only takes a couple minutes for the boiler to reach cut-out again. If I were you, I'd set the temp where I want it and leave it there. I did the same thing a couple years ago with a set-back thermostat and after a year of that and running it the next year at a set temp, I saw no real difference in my gas bill and I don't have the short cycles either.

Your Header on that boiler looks strange but I'm not sure I can make out how its configured from these pictures.  Both risers from the boiler should connect into the horizontal header and then your Mains should take off of the header after the risers with your equalizer coming off of the end of the header. Are you getting any water hammer?

Also, if you can put a 45 degree elbow on that gorton and get it upright or move it to a location where it can be upright, it will work much better. Vents don't always open and close properly when they are tilted like that.  

nicholas bonham-carter

short-cycling-oversized boiler

if the short-cycling were happening shortly after start-up, then I would suspect the venting to be insufficient, but in this case the cycling starts up when all the pipes are warmed up, and full of steam.

luckily, you may be able to down-fire the boiler to correct this. 

the piping on the boiler is very unusual, and lacks a proper equalizer, so that may have something to do with it as well. have a look at the manual for the peerless boiler, and compare what you have, with what they require.

try putting a jumper on the terminals which would be connected to the thermostat,  [to simulate a call for heat], and see if the cycling disappears. if you are interested in fuel economy, have the piping corrected, down-fire the burner, and do not use any temperature setbacks. they work on hot air systems, but on steam, you just burn more fuel recovering the higher temperature. with a constant temperature, you can have comfort at a lower setting.

I suppose with the Nest in the kitchen, it knows from its calendar when you have the Thanksgiving turkey in the oven for hours, and can make allowances for the over heated kitchen.--NBC

Jeff_56

Another View of the Piping

Thanks to those who have commented so far, very much appreciated. I have attached another picture of the piping for the boiler. I know it has a "hartford loop" installed.



It's hard to tell from the picture of the long run vent (Gorton #1), but there is not enough room to put another 45 degree fitting to make it stand straight up. There is just enough room right now to unthread the vent valve without cutting into the upper flooring.



I could drill and tap into the pipe before it goes around the back of my peg board above the work bench but it would be back about 4-6 feet from the end of the header.....is that too far? I would suppose a vent that works in an undesirable spot is better than a valve not working in the right location?



I will definitely not cut back the settings for the overnight hours. Maybe only a few degrees. Everyone in the house likes to sleep in cooler temperatures but perhaps this would allow me to adjust the vents on the radiators more by not worrying about the short cycling any more. I need to find that happy medium I guess. I can turn off a lot of the features of the Nest thermostat so it doesn't go into the "away mode" (set at 56 degrees) when it doesn't detect anyone in the house during the day. I wouldn't have spent that much money on a thermostat but it was a gift and it's nice to see on the weekly graph just what the boiler is using for fuel and also being able to control it from outside the house.



I appreciate all the feedback.

Fred

Near Boiler Piping is way wrong

Did you install this boiler or did a contractor do this? The near boiler piping is all wrong. The two risers coming off of your boiler should tie into a horizontal Header. After Past the riser connections, the mains (cant tell if you have one or two) should connect to your Header (the Mains are the trunk lines that your radiator runs branch off of) At the tail end of the header, you should have an equalizer pipe that drops down to near the floor and into the boiler. Your Hartford loop should be connected to the equalizer with a close nipple below the boiler normal water level. If you have the owner's manual for this boiler, look at the installation guidelines for the piping. If you don't have that manual, I suggest you download a copy.  

The vent can be installed as close to the end of the main as possible but definately after your last radiator run on that main. It can also to installed along the return.

Jamie Hall

Just to add to the discussion...

first, your system is behaving exactly as expected when dealing with a combination of a slightly oversized boiler (probably not that much oversize) and a setback. 



The principle is this:  if you wish to raise the temperature of a space from one temperature -- say your 62 -- to another -- say your 68 -- it is going to take a certain amount of heat input to do it.  BTUs.  That's inescapable.  Now your radiation can only pump out BTUs at a certain rate; so and so many BTUs per hour (it's to a very close approximation 240 BTU per hour per EDR).  Then there is the heat loss from the envelope, which varies with the difference between inside and outside air temperature.



So.  It will take the radiation a certain amount of time, determined by the number of BTUs needed to raise the temperature less the heat loss through the envelope, to raise the temperature from the setback.  However, the boiler is slightly oversize, and puts out more BTUs per hour than the radiation can emit.  Once the radiation is all up to temperature, there are only two things that can happen -- either the pressure goes up, since the steam can't condense any more, or the boiler can be turned off on pressure.  The latter saves a good bit of fuel and money in comparison with the former, as well as being much better for the system!



And that is the "short cycling" which you are seeing.  It has nothing at all to do with venting, and all the fiddling with venting in the world won't make a bit of difference to it.  Neither will changing the pressure settings on the boiler, incidentally.



The Nest -- which in my mind is an exceedingly expensive solution to a non-existent problem, but never mind that -- is doing what you ask it to do.  Other programmable thermostats would do the same job if asked to do the same thing.



There are two ways to eliminate the cycling on pressure when all radiation is filled.  One is to reduce the firing rate on the boiler at that point -- just as when you are driving a car, you back off on the gas when you reach your desired speed.  You can't just downfire the boiler all the time -- you'd never get the radiation quite full, just as you can't accelerate your car with the same throttle setting you cruise at.



At the present state of the art it is simpler to cycle the boiler to maintain pressure where it belongs than to modulate it -- and only very slightly less efficient.



The other way is considerably simpler: limit your setback, if any, to what can be recovered before the boiler starts to cycle on pressure.  And that depends on the boiler and the attached radiation and, to a certain extent, on the structure.

Jeff_56

Changing the setback temperature

I am going to program the Nest thermostat tonight so there is only a 4 degree setting difference throughout the night. I agree that it would probably run the same amount of time through the night as it would to reheat the entire system early in the morning. The Nest allows you to see exactly how long the boiler ran and how long it took to reach your desired level. Temperatures here in Mass are still cold enough to get a comparison on the Nest with a lower setback compared to last night's larger setback. The low for tonight is 15F.



Then if there is still a lot of short cycles in the morning I will adjust to a 2 degree temperature setback for the following night to see how that performs.



The system was installed by a former brother in law. He had his own HVAC business and "seemed" to know what he was doing (I know, don't say it). I looked over the schematic from the peerless manual with him when he was laying it all out. It appears that the only difference between the schematic in the manual and what was actually performed, was that the "header" that the 2 mains come out from, was very short and the mains came off of that header from the top of the tees that created the header (the center picture in the first posting of mine shows this - the picture is rotated 90 degrees, sorry for any stiff necks this creates). There are returns that come off of both the tails of each header that do go into an equalizing line and the Hartford loop. I will post pictures tomorrow when I get to my computer (posting from an iPad). I suppose the balancing of the system would be improved with a better header coming off of the boiler, but I remember it being an issue due to headroom, stack location, etc... This boiler replaced a 1939 Sears "Indestructo" that was a bear to work on, so I was happy with this new install and everything seemed to run fine from day one. Perhaps It would have run more efficiently all these years with a different header configuration, but it would be difficult and now costly to correct it. At the time the price was right and I welcomed the help.



Here's a few questions.



Seeing the general consensus is that venting isn't as much of a problem as I initially thought because the radiators are working and I have 2 new main vents, can I adjust the vents (down) now on those radiators that I would like to run cooler without it affecting the short cycling, assuming I adjust the setback accordingly? My son's room on the 2nd floor gets very hot, but I have had all the vents on max adjustment since experiencing this issue.



Would their be any explanation as to why this just started happening? The setback I have programmed on my nest thermostat is the same as what was on the old thermostat for the past 5 years. Plus now having the newly installed main vents would help speed up the heating process as well.



Do you think I should cut a section of the floor above the long header's Gorton #1 vent in order to correct it to a straight up position? I have thick floors and may be able to cut a section enough to install and remove the vent. Any chance it is working at a 45 degree angle? I suppose I can squeeze back behind the work bench and see if it's venting and also shutting closed while I'm firing up the system.



Thanks again for everyone's help, much appreciated.

Fred

Header and set back

What you have as a header (or something resembling a short header is definitely not right.You have one riser off of your boiler feeding each of your mains with a bridge between the risers instead of the system/mains being able to take advantage of the full steam from both risers through a true header. I doubt that you have an equal number of radiators/EDR on each of those separate feeds so I don't know how you'd properly balance the system. You can adjust the radiator vents to reduce the heat in the rooms you so desire. I'm not sure, given that header situation, what that will do to the short cycling, especially since you almost have to balance the radiators on each header almost as if it were a separate system.

As far as reducing the set back to 4 degrees, I doubt that will improve the short cycling much. I never had mine set back more than 4 degrees and still had a fair amount of short cycling. When those pipes and radiators cool down, it takes a much longer run cycle to bring them up to temp before you really start getting the house warmer. That additional run time is what brings the pressure up to where the presssuretrol comes into play. Whatever you do, don't increase the cut-out pressures on the pressuretrol. That won't fix anything except burn more fuel. Probably the biggest change that may make you notice the short cycling more now than in the past is the fact this winter has been so much colder than prior years. The boiler has to run longer just to maintain the room temp and the added set-back /catch-up is just more burden on that boiler.

Watch that Gorton vent. If it opens and closes like it should, I wouldn't cut into the floor. look around and see if you can find a better location before next season.

I'd really like to see you get the near boiler piping corrected but you will have to make that call. It's worth getting an estimate anyway. In the long run it may be the most cost effective thing you can do, both from a fuel consumption perspective and also wear/stress on the boiler, not to mention comfort levels throughout the house. Maybe one of the Pro's can offer an opinion on the effect that may have. 

Jeff_56

Header

Fred, your correct in calling that header a bridge, that's all it is. I can tell you that when the boiler was installed, each of the 2 steam lines coming off the boiler into that bridge both had 4 radiators on their respective line. The long run had 2 radiators on the 1st floor and 2 on the 2nd. The short run had 3 on the first floor and 1 on the second floor. I removed one of the 1st floor radiators (kitchen) so it is different now. I'll have to see if I have pictures of the piping before the insulation was put on. Perhaps there are some unions that would allow for a fix to a correct header situation.



Does the header that the 2 lines coming out of the boiler goes into need to be a certain length, or just long enough to have it able to accommodate 2 lines going in and 2 lines going out from the header. There is very limited head room in this basement so not sure where the header would be located.



My nest has been rescheduled with a setback of 3 degrees. I'll see how well that works. It is a big change compared to the 7-8 degree setback I have been using.



Thanks again for your input. I welcome all opinions and suggestions.

clammy

side note on that header

No one seemed to mention that there is no swing joint for expansion with that bridge crossoverand the way it is piped  ,Repipe that thing before the lack of a swing joint damages your boiler and we all know it.s expensive but cheaper then buying a new boiler.What ever modifacations you have to do to get main vents installed in the proper place just do it .just one other question i see your home is quite old  do you  have wet returns and  are they original or have they been replaced or flushed ,just asking peace and good luck clammy

Fred

Header fix

Jeff, After you take that "bridge out from between the boiler risers,the two risers coming out of the boiler are fine. at the top of those risers you need to install 90 degree elbows (these are the swing joints that clammy refers to and will relieve the stress on the boiler that I mentioned in my earlier email) and nipples and Tee's that will accommodate the header. The header, itself should be one pipe size larger than the risers (if those risers are 2" pipes, the header should be 3" pipe. Tie the risers into that header (you will build your header using whatever length of pipe nipples necessary). Extend the header with additional Tee's and nipples to allow the all Main lines to be tied into the single header after the riser connections, off of the top of the header and towards the equalizer end (these need to be tied in after the boiler risers and not between the risers). Once that is done, put an elbow on the end of the header and take it down to your Hartford loop (a single pipe, not the double loop you have there now). The bottom of the header should be at least 24" or more above your water line in the boiler.

Jeff_56

Header/Swivel Joints

Regarding the wet returns: They were both replaced with new piping when the boiler was installed.



I see a lot of mention of swivel joints in these forums. Is there ever a time when you don't need to use one? I see in a lot of "heres how a proper installation should look like" pictures where there are none. Not unless you consider a union a swivel joint. Which obviously isn't. In my particular situation with that incorrect "header" or more accurately "bridge" between the 2 risers, I can see where that could help.



I have looked through some pictures of when the boiler was replaced 7 years ago to see what was left for old piping and what was new. Everything that is "near boiler" piping is new. I believe there is enough unions in this installation that I could disconnect everything from the risers over to the equalizing line, and have it re-piped correctly so there is a true header with the mains coming off at the right location.



Would anyone care to comment on this question: If a new header with the proper configuration is fabricated (I have seen enough posts now to know how this should be done correctly, i.e., distance above water line, location of risers and mains, equalizer line, etc...), does it matter how many odd twists I may need to make in order to get the mains to connect to the new header? As you can see from the picture there is very limited space and it may require some strategic 45 degree fittings to accomplish this. Assuming the header is horizontal and the risers enter at one end with the mains coming off the other end of the main, and the equalizer coming off of the very end.



Again, thanks for the opinions and suggestions.

Fred

Need the joints

To ensure you don't put stress on the cast iron boiler, you really need those swivel joints. They are simple to put in with the 90 degree elbows off of the top of your boiler risers and they minimize the effects of expansion/contraction on the boiler. minimize the number of turns you have to make to connect your mains but turn them enough to connect to the top of the header.

Jeff_56

Swivel Joints

I understand the importance of having swivel joints but I must say I cannot find any pictures of any install on this site that shows them having actually been installed. I know what they look like I just located them in a McMaster-Carr catalog. A 2" swivel joint is over $250 each. And it doesn't even say it can be used for steam. Another 2" version that is rated for steam is a "quick maintenance" version for over $500 each! No wonder I don't see any pictures utilizing them.



Am I looking at the wrong item? Why do I not see them on all the "properly installed" pictures here on this site? Is there no other alternative? Why isn't everyone using them if they are required?



I want to do what is best but I need to be able to afford it and spending close to a grand on 2 fittings is outrageous.



I know this is getting away from my initial post regarding my short cycling but I was curious if anyone had an answer to my questions regarding the swivel joints.

Fred

Yes You are

Hey Jeff, You are looking for something that is unrelated to what a swing joint is in the Steam world. When you put those 90 degree elbows on the risers to connect to the header, you have built your "Swing Joints". Those threaded elbows will provide the flex you need to allow the boiler risers to "swing" as a result of Expansion and contraction (ever so sllighty and not noticable but enough to take the stress off of the boiler sections). Building the header as per the instructions above (with the elbows will give you what you need.

Jamie Hall

Swivel joints

are not what is meant, rather swing joints -- and swing joints are any configuration of elbows and nipples which can allow the spacing between one end of a pair of parallel pipes to change relative to the other end.



For example.  Come straight up on two risers.  Elbow over 90 degrees.  Reasonable length of pipe.  Elbow up 90 degrees, continue up.  Or better yet...



Make a drop header with two risers (let's assume 3" risers): go straight up 24", 3" pipe.  Elbow over 90 degrees on both risers.  Go horizontal (pipes parallel) with 3", say 15".  Elbow DOWN 90 degrees.  Go straight down with 3" say 12 inches.  Line from the riser at the front of the boiler, elbow 90 degrees to horizontal 3", in line with the line between risers.  Go back the distance between the risers.  Back riser hooks in with 3x3x3 T.  Now go back a bit more, and hook your steam mains into the top with 3x3xwhatever Ts.  And back a little bit more and hook your equalizer in with a 3x2 reducing elbow, 2" down...

Jeff_56

Swing NOT Swivel

That makes a hell of a lot more sense now. I was searching for swivel joints as it was mentioned in previous replies to my post. I now fully understand the "Swing Joint" concept.



Jamie, I was looking at doing a drop header to allow me the flexibility and room that I will need to correct the piping from my "former" Brother-in-Law. I have seen plenty of examples now from this site on installations using the Swing Joint technique and drop headers. THANKS for clarifying that. As long as my drop header is at the right height from the water line I should be OK. I have that dimension in the installation manual (its at home - I am at work).



As soon as Spring decides to visit Massachusetts I will begin the process of removing my pipe insulation to see what I am up against. The good thing is it looks like the bulk of the drop header can be fabricated somewhere else besides my cramped basement.



As a reward for all your help guys I have attached a picture of the nightmare demolition of the previous 1939 Sears Indestructo boiler that I had to smash to pieces with a sledgehammer and cart out of my house in 5 gallon buckets. I have no bulkhead or other way out of my basement except up through the house, which is a center hall colonial. I will NEVER do that again, it took many years off my life I think. At least it felt that way. I thought you would all get a laugh at what I went through, although you probably have done this many times before.



Thanks again.

clammy

re piping and swing joints

Jeff instead of getting confused by ever body ,look in the installation and operation manual which came with the boiler if you don t have one then down load one .As a general rule just remember that the rise and header sizes in the manual are minimum sizes ,I have installed a few peerless 63/63 steamers and i see it,s only a 112 mbtu .What are the size of your existing steam  mains that you will be tying into your possible new header.I think.If all you have is 2  -2 inch mains i think you would be good with 2 inch risers into a 3 header i would do a  drop header slow that steam down and dry it out plus this way you can come up higher and drop back down to gain room to ty in your existing mains , do a  2 in equalizer and come out of the boiler with a full 2 1/2 nipple and ty your 2 equalizer into that i would do a 1 1/2 Hartford loop and use a mal st ell .Sorry to say i had many photos of steamer i have done but lost my old computer and the pics and got tried of taken pics and posting .You may be able to do a drop header search on the site and find some pics .Peace and good luck clammy