Slow Venting Mains

usndave03

I have been living in my house for about 4 years now and I have always had issues with my steam system. My big issue with my system is that my mains take a very long time to get hot. Sometimes the boiler usually cuts out on thermostat before the steam even reaches the end of my mains. Currently, its taking about 45 min to 1 hour for the steam to reach the end of the mains. I have two mains coming out of my boiler (2 1/2" Pipe). 1 main is 57.5 ft long and the other is 60.9 ft long. Both mains have 9 risers that shoot up into the house. After reading Dan's book I added insulation to all my mains but the risers im not sure about becuse they are not accessible. I think the main vents (1 on each end) are not venting fast enough to get the air out of the steams way but I'm not sure. I have included photos of the main vents at the end of the 2 mains. Thank you for Any advise on how to adjust my system.

KC_Jones

I would suggest you need quantity 2 Gorton #2 vents on each of those mains, possibly even 3 per main given that it's 2 1/2" pipe. It is most likely taking so long because the steam is going up to the rads instead of filling up the mains because the rad vents are acting like main vents. The steam is stupid and lazy, it goes to the path of least resistance.

If you upgrade the main venting, then you will most likely be able to, and have to, rebalance the radiator valves.

You should be able to vent those mains in a few minutes, not an hour.

ChrisJ

Well,

To put main venting into perspective, I have an 11' long 2" main and a 29' long 2" main. On the 11' long I have a single Gorton 1. On the 29' long I have five Gorton #1s. That's on 2" pipe.

When your boiler starts producing steam, do the main vents and radiators vents hiss loudly? Do they make any sound?

Do literally no radiators get steam for the time you listed, or do some close to the boiler start heating sooner?

Can we see some pictures of the boiler and the piping around the boiler?

usndave03

Thanks KC and Chris...The radiators near the boiler do get hot and after 1 hour 30 min all the radiators get hot except for two of them on one side of the house. These Two radiators have never gotten hot (ice cold). However, i was going to deal with those two problem radiators after I get the venting issue in the mains addressed.

The near boiler piping is definitely wrong but I wanted to see if I could fix the venting issue with what I have in place right now. However, if the near boiler piping is more my issue rather than the vents, I am prepared to get it repiped if necessary. I have included photos of the near boiler piping before I insulated it (also I did fix the pigtail orientation as well). The venting at the radiators competing with the venting at the mains makes sense.

Gsmith

near boiler piping is not wonderful, but may work. I suggest improving the main venting that almost always provides improvement. Then slow the venting of radiators that get hot and increase the venting of radiators that are cold. With some experimentation you should be better able to balance the system. Steam systems like to have good near boiler piping, but often are pretty forgiving. Main venting is key and a good and fairly inexpensive place to start (after you have insulated the steam mains).

usndave03

Thanks Gary, I'll start with the insulation and venting upgrade then. 

usndave03

So I took the two main vents off to see how long it would take to vent the mains on open pipes. One main took exactly 23 minutes before I saw steam coming out of the end and the other main took much longer. The last riser on the other main reached 100 degrees at 40 min and the open pipe still seemed to be venting air slowly at 50 min. I stopped the boiler before I saw any steam coming out of the second main.

It took about 14 minutes for the 2 risers out of the boiler to reach a temperature of 177 degrees.

I was hoping to see significant increase in getting the steam to the ends of my mains by taking the vents off but it didn't seem to make much difference. So im wondering if upgrading my vents would really make a difference since I can only vent as fast as the open pipe (ventless). The vent tappings are 3/4" i believe. My pressuretrol is set to cut in at .05 and the differential is at 1.

Does anybody have thoughts before I pull the trigger on a few Gorton #2s?

EBEBRATT-Ed

No boiler should take that long to steam. Something is haywire.

How is the water level when it starts to steam? Steady or bouncing?

Steamhead

Looks like that's an oil-fired boiler with a Carlin gas burner in it. I'd have a knowledgeable pro check to see that the burner was set up properly. Where are you located?

usndave03

Yes it was an oil fired boiler that was converted with the Carlin gas burner by the previous home owner. I called a local HVAC company to take a look at it last year and they told me they set the burner to fire at 150K BTU to 175K BTU. My heating bills have always been astronomical since I bought the house and I have been trying to figure out how to make my system more efficient by reading tons of books and doing internet research. The HVAC guy that came didnt seem to be very knowledgeable on steam systems and what he did didnt seem to help much. I live in Staten Island New York City.

Jamie Hall

As @EBEBRATT-Ed said, something is seriously amiss there. With the open pipe -- or even with the vent -- assuming those mains are insulated, it shouldn't take more than 5 to 6 minutes from the time that steam is raised at the boiler for steam to appear at the end (note: not from when the boiler starts, but from when steam is raised).

I should note, though, that if the mains are not insulated and the radiators are vented fast, it could take longer -- possibly a lot longer.

There are several very good men to be found in the "Find a Contractor" tab above who work in your area. Might be worth giving one or two of them a call.

usndave03

Thanks Jamie...ill give the "find a contractor"  suggestion a shot.

neilc

please come back and let everyone know what was found

usndave03

I sure will...found a contractor on "Find a Contractor" and they said they were sending there best Steam Guy on Tuesday

clammy

From the looks of the near boiler piping there,s a lot to be desired. Both take off from your piping are wrong and the location of the risers are wrong . I see it looks like a reducing elbow from your header to the main this is not correct .The only way to up your venting time and the performance of your steam boiler is to have it piped according to the mim piping dimensions in the installation and operation manual for your boiler .take a look at some of the steam boiler replacement pics posted on this site and you will surely see how terrible your boiler piping is ,bad near boiler piping is usually the number one cause of under performing steam heating systems and issues w balancing . Wet steam is lazy and does not have much heat nor energy to do its job correctly . In most cases a properly piped ,cleaned and installed steam boiler will always perform better ,provide better heat and have less issues and over all cost less to heat your home then one that’s slapped in . Your main issues are the boiler piping unfortunately and there’s no real miracle fix aside from magic that will get it to perform as it should properly . Any pro that tells u less is pulling your leg . From the looks of it ,it looks like it could use a good water side cleaning ,wanding and flushing and skimming and then possible a good fire side examination and combustion testing and have your burner clocked to ensure that it is neither over or under fired . It may be under fired to try a little less surging and issues from the mid piped boiler I ve have seen it done unfortunately . Best of luck and hopefully the pro that checks it out will find your issues ,but myself I see it as mid piped and under performing due to it but theres most likely some other issues also peace and good luck clammy

clammy

I may also have missed the fact that the boiler does not have a swing joint on the header which is not any thing any of us approve of . I would not recommend that the installation company be asked to do any other work being they didn’t get it right the first time. If they cannot or will not follow a simple piping diagram they should not be doing any type of work on your boiler at all being they are either blind ,can’t read or most likely don’t care nor take any pride in there profession but they will take the money Peace and good luck clammy

usndave03

Thanks Clammy, that's alot of good info right there.  Would if be more cost effective to get a new boiler installed correctly. Im really not sure how old this boiler is or who installed it. I pretty much inherited it from the previous owner. Hopefully the pro I have coming tomorrow will be able to effectively zero in on my boiler issues. 

usndave03

So I had the Pro checking out my boiler today. We measured all the radiators and figured total EDR and verified that the boiler was the proper size. Turns out the Carlin Burner is severely underfired....probably to compensate for surge and poor near boiler piping. So it looks like I will need to repipe the near boiler properly and adjust the burner to fire correctly for the current load. The technician mentioned that oil burners burn hotter than natural gas and when converted to gas this is sometimes not taken into account. So far having a Pro come to evaluate my system was a great suggestion. He was definitely very knowledgeable on the subject. Now just waiting on an estimate to move forward.

nicholas bonham-carter

Oil and gas generate the same heat values, (BTU to BTU), so your problem is in the piping.--NBC

bburd

That boiler is rated to fire 1.75 gallons of oil per hour (the rating plate is visible in one of the pictures). That is approximately 245,000 BTUH input.

If the gas burner is set to fire between 150-175,000 BTUH the boiler is indeed severely underfired.

motoguy128

I believe when you under fire a boiler that much, unless carefully tuned, it will be less efficient.

That being said, increasing main vents, substantially should improve things quite a bit. You may then needs to slow the radiator vents depending on what you have to keep it heating evenly.

No reason you can’t get the main to completely heat up before the first radiator on the loop even starts heating, even with a underfired boiler. That’s the goal.

usndave03

Motoguy128, i was thinking my main vents were lacking as you suggested. So I wanted to see how fast the steam would travel through the mains if I took the vents completely off. Unfortunately, it didn't make much difference at all and it took almost an hour to see steam coming out of the end of the mains. Turns  out you can't vent faster than the open tapping without the vents installed. So the issue had to be at the boiler itself. After taking the suggestion to have a steam pro in my area take a look at my system, he noted that the burner was severely underfired to compensate for the bad near boiler piping. If the burner was fired correctly for my system, the water in the boiler would surge severely and make its way into the mains (hence the previous HVAC guy's decision to down fire the boiler). Problem is it takes forever to make steam and when it does.... The current near boiler piping does not allow for the steam to dry out.  This causes wet steam to move up into the mains (and as someone mentioned....wet steam is lazy). So this Thursday, the pros will be doing the following:

-Repipe existing Peerless wet based steam boiler with a properly sized double tapped 3 inch drop header.
- Repipe return piping near boiler also adding ball valves with drains for future maintenance
- Replpe both steam takeoffs to main. Each main will be connected dlrectly to boiler header with king valves.
- Install all new vaporstat
- Repipe boiler control section using larger diameter pipe and install fittings with proper clean outs.
- Install Digital automatic water feed VXT-120 to track amount of water system
- once the boiler is properly piped, Carlin gas burner will be properly fired to boiler and system requirements.

Excited to see these guys work and my fingers are crossed that this will rectify my issues. Ill keep everyone posted of course

ethicalpaul

This sounds good, but be sure they show you the Peerless manual with the piping that they are going to be installing.

Believe it or not, there have been people on the forum who paid for a repipe and got one that was no better, or sometimes even worse than they had before.

I would think that since you used "find a contractor" on this site you are in good hands, but it doesn't hurt to make sure.

Good luck!

Fizz

Why not properly fire burner first before investing all that money?

Fizz

What is attached radiation? Boiler firing

EBEBRATT-Ed

@usndave03

Sounds like you have the right contractor. You should be on your way to much better performance and lower fuel bills.

Let us know the end result

usndave03

Fizz, tried to have the burner fired correctly last season and had issues with surging. That's why it was down fired i was told.

Thanks Ethicalpaul...I actually found the manual for my boiler on the internet. Ill ask the contractor if they are taking it into account.

usndave03

Fizz....Total EDR of my radiators is 393.75 Boiler is rated for 471 EDR

Currently the burner is firing at 150kbtu -175ktbu

SteamCrazy

Usndave03 I agree with sounds like you may have found the right guy to do the job. BTW I may not have seen all the pics, but looks like there was no Hartford loop in near boiler piping either. And don't forget to see if the move that one vent of the end of the main. 

usndave03

@SteamCrazy thank you, I'll definitely ask about the Hartford  loop. I thought I had one but I'm not sure.

I may have to wait to move the vent  tapping away from the end of the main becuase i dont seem to have anymore cieling clearance. It would require cutting into the ceiling  and we didnt factor any of that into the estimate). Would it be possible to pipe away from it with 3/4 iron pipe like is see people do when they mastervent their mains? I was hoping to do this part myself once the boiler was piped correctly and making steam fill the mains much quicker than before.


Thought this may have been the Hartford Loop on my boiler but I'm not sure.

SteamCrazy

Oh yes, not ideal design but there. New boiler piping should include the correct set up. On the venting I don't see why you couldn't do it yourself. Hard to see limited space,. But maybe you can find space between joist to get clearance needed. You may need a sawzall, chisel, and hammer to get old fittings off. The use of union to make connection where have to connect to a 3rd pipe for instance where you have that green vent. Is that dropping into a return?  

SteamCrazy

I'm still in the middle of insulating my system, but here's what I did with my venting. Just to give some ideas as you see I used tees to be able to add vents as needed. I used a 18" pipe after all my vent tappings to give that buffer from end of pipe. Good luck

SteamCrazy

usndave03

These are photos Prior to me finishing the ceiling. Both vents are positioned  almost directly above their respective condensate returns and at the end of the mains with little to no offset. I know this is not ideal

usndave03

@SteamCrazy yes! That's what I was hoping to do with my  vents as well...looks awesome 

SteamCrazy

Thanks,   A suggestion with white main with tees I'm not sure if there is another before those two or a coupling if so I'd disconnect at that point add my new tees with correct angle and extend tees to riser so get a swing joint plus the right amount of pipe between main and radiator. If to much work you can disconnect right after two tees and add two tees with  short nipples first tee added is for that other riser and  last tee  for your venting then pipe to connect to condensate line. The second option not as ideal will be better then current setup. Just some suggestions I think with that you will have an idea what to do with other main. Good luck you can do it

SteamCrazy

SteamCrazy

This is the simplest way I think someone else may better idea. But quick solution Blue would be vent from there you can 90deg elbow out with 3/4" extension pipe to 3/4" tees and add as many vents as you need

tomsloancamp

Maybe a stupid question... how come there are two pressuretrols?

SteamCrazy

I believe the only stupid question is the one not asked.  Answer could be redundency (a back up) if I'm not mistaking. 

EBEBRATT-Ed

@usndave03

a couple of things. If you put the vents on longer nipples and get them up as close to the sub floor they will work better.....helps keep the water out if the vent location is not ideal

with 393 EDR you burner input should be ok at 150-175. But this needs to be verified with a combustion test. Some boilers can be doownfired with no problem, some cannot. If the piping fix solves your issues I would not increase the firing rate unless the combustion test shows otherwise. ou want a long burn time and avoid short cycling