Old house, steam heat, new boiler - still takes 1hr15min to heat all radiators...

mickeylewis123

I'm doing as much reading as I can, and attacking this systematically, but a little frustrated that I haven't made any real progress.

I started by checking the basics - all radiators level, all radiator valves completely opened, all radiator vents are in good shape - mostly new, boiler recently serviced for the season.

I ran an initial system check and timed how long it takes to heat each component - from the boiler riser, to the header, to the three distribution legs, to each of 16 radiators across 3 floors, to the return vents. The riser and header heat up in 5 minutes. Two of the three distribution legs heat up in 6 minutes, the third took 24 minutes! The third leg has only two radiators on it, one on the 2nd floor, one on the 3rd floor, and no main vent. I assume a main vent is a must and will get my plumber to do that. But also surprising is that on this third leg the 3rd floor radiator heats up in 28 minutes but the radiator below it on the 2nd floor takes an hour and 15 minutes to fully heat! Is this because hot air rises?

My return vent pipes for the two hot legs heated up in 16 minutes and 24 minutes.

I also timed each radiator, from when the first tube got hot, until it was hot all the way across. Seven of the 16 heated up in less than 10 minutes, 7 took 15 to 44 minutes, the last 2 didn't heat up at all for over an hour, but then suddenly heated up to full heat at 1hr15 minutes. I put larger vents on the ones taking the longest to heat up, only one of which timed better during my followup test.

On the two legs that heat up the fastest, each one had a working Gorton #1 on it. I was sure if I added additional vents that the system would heat up faster. I added 2 more Gorton #1's to one of the legs and 1 more Gorton #1 on the other. I retested the system from scratch. There was no noticeable difference in heat up times for any of the components!

I lowered my pressuretrol from 1# to 0.5# with a 1# differential. That also didn't result in any significant difference in heating times. (My plumber just told me to raise it back up!)

I also told my plumber I want him to change out the Pressuretrol for a Vaporstat. He said a vaporstat is not meant for a steam boiler, but he'd do it if i want him to do it. I also told him that my pressure gauge is stuck at 5# and never moves. He said pressure gauges never work for more than a year - don't bother changing it. Is that so? Is it worth buying a low pressure gauge and attaching it to the pigtail of the Pressuretrol as mentioned in another article? And can someone provide a drawing on how one would connect both the Vaporstat & the low pressure gauge on the same pigtail?

I also checked my main vents as the system was heating up. I never heard any air releasing, and couldn't feel any air releasing, but when the system got really hot at 1 hour I heard the main vents hissing loudly????

Any thoughts? Questions?

Does anyone know how long it "should" take a single family home steam system like the one i'm describing to heat up? Based on what i'm reading, i don't see any reason why the entire system shouldn't heat all the radiators in as little as 30 minutes - am i right?

Fred

Radiators may not heat all the way across all tubes on each heating cycle unless it it really cold outside and the boiler is required to run for an extended period of time. Your Main vents should not be hissing when the mains are hot. The vents should close. What size (length and diameter) is each of the 3 mains? A good rule of thumb is the equalivent of one Gorton #2 for every 20 feet of 2" Main. It takes about 3.5 Gorton #1's to equal a Gorton #2.
Have you calculated the total of your Radiator EDR? Also look on the boiler plate and it should tell you the Square feet of steam the boiler will output. The Radiator EDR and that number on the boiler plate should be relatively close. There is a remote possibility that the boiler is undersized but that would be an unusual case. We usually see most boilers are over sized.
Don't increase the settings on the Pressuretrol. You set them correctly and that's where they should stay. In spite of what your installer says, you should add a 0 - 3 PSI gauge to your boiler so you can actually see what the boiler is doing when it is running. The standard 0 - 30 PSI gauge that comes with the boiler is useless for that porpose but is required by local codes. You can add the low pressure gauge and a Vaporstat on a Pigtail by simply adding a Tee a coulpe short nipples and a couple elbows on the top of the pigtail. Most of us usually leave our Pressuretrol on the boiler as well to act as a backup to the Vaporstat in case it should fail. Both the Pressuretrol and the Vaporstat should be considered safety devices, if the boiler is properly sized. They only become operational devices when a boiler is over sized and there is a need to control how high pressure gets before the burners are shut down.
From what you have described, I suspect you still need more main venting and you need to make sure the ones you have are working properly. Also, make sure the pigtail that your Pressuretrol is mounted on is not clogged. Take it off and wash the pigtail out.
After you get the main venting correct, then you can start to adjust the venting on the radiators to balance them.

vr608

I commend you on your good research into the issue, this should be very helpful in diagnosing the root cause. I didn't see this in your notes, but did you add any new vents to the slowest main? Fred makes a good case for more venting, the G1 vents will probably not give you the best venting speed, and ultimately venting is dependent on the length of each of the mains.

I second adding the 0-3oz gauge, definitely needed since the one supplied with the boiler is practically useless for the pressures needed to run most of these systems. I have mine on a tee off the pigtail, pic below should help.

Jamie Hall

Lots of questions and comments...

How long are those mains? Opinions vary, but my own opinion is that it should take not more than one minute for each 10 feet of main for you to feel steam at one end until you feel steam at the other. Anything longer, and you need more venting at the end of the main (single pipe steam).

Are the mains insulated for their full length? Even a short uninsulated section will slow things down a lot. A longer section -- or a valve -- may slow things down to a crawl.

Vapourstats are meant for steam boilers, provided they run on low pressure. Single pipe steam you can get away with a pressuretrol, provided it's set the way you set it -- not the way the plumber set it.

It is quite possible -- indeed likely -- that once you have gotten the mains to heat in a reasonable length of time that you will need to fiddle with the radiator vents. You will want to slow down the radiators which heat fastest. On that one with no main vents, don't worry about it until you get that line vented. Then check it again. The third floor radiator starting to get hot first isn't hot air rising, but is very likely that you will need to play with those two radiators' vents to get it right. Patience...

Dave0176

Post some good pics of your near boiler piping.

mickeylewis123

Thanks everyone for your comments. Last night I measured my mains and I was surprised at how long they were.
Right hand main 40',
middle main (the one with no venting on it yet) 17',
the left hand main 32'.
I have 3 x G1 on the right hand main - i'm going to get 2 x G2
I have 2 x G1 on the left hand main - i'm going to get 1 x G2
I have nothing on the middle main - i'm going to get 1 x G2
I don't know how to figure out the size of my main piping, but it looks like 2 1/2"+ (the circumference is approx 9")
Before I spend the $400 on the 4 G2's, is it worth testing the system removing the vents altogether and just leaving the vent pipes open to see how fast everything heats up? If steam starts to come out, i can try to put a vent back on or shut down the boiler. I figure that should be a good test to see if more venting will help - right?

KC_Jones

That is the way to determine the fastest you can go. It is recommended on here quite often actually. Once you have that time (with pipe open) that is your baseline and you vent until you get as close to that time as budget allows. Start timing as soon as the header is hot, stop timing when you see steam. Are the Gorton #1 vents you have in good condition and still working? If so I would use them instead of replacing them all. 3 of them roughly equals a #2 vent. The pipe measurement you posted is actually 2 1/2" pipe (2 7/8" OD) so that dictates even more venting. For that size pipe you would want 1 Gorton #2 vent for roughly every 15' of pipe. I agree with what has been said about a vaporstat. I think this is often misunderstood. The vaporstat or pressuretrol are limit safety devices not controls. They act as controls of sorts when things are sized correctly. The vents and boiler size actually dictate the system pressure. It's not really steam pressure, it's air not able to get out of the way fast enough for the steam which causes backpressure to build. Get the venting right, get a good gauge and then go from there. I will also suggest some pictures of your boiler and piping, this will help make sure you don't have other issues contributing to your problem.

mickeylewis123

Thanks for your comments. The quantity of 4 x G2 is across 3 mains; only 2 G2's on the longest main, one G2 on each of the other 2 mains. Most importantly, thanks for validating my test scenario removing the main vents and just leaving the main vent pipes open.

nicholas bonham-carter

By all means use the G 1's on the shortest main.
Let the system cool down a few degrees.
Put 3/4 full port ball valves on the vent openings, and fire the boiler, until steam comes out of the ball valves, and then close them all at the same time.
While the steam is still rising up into the radiators, look at them all, and see if they are heating up more quickly, and most importantly simultaneously.
What we are trying to do is to fill all the pipes first, and because of the low resistance of multiple main vents, the risers will not begin to fill, until the main vents have closed. Following that, the risers should begin to fill all at the same time.
We are balancing back pressures here, and not time. You can get away with inadequate main vents if you have very small capacity radiator vents, and don't mind paying for extra fuel to force the air out of constipated little vents.--NBC

mickeylewis123

Near boiler piping - header about 16" above the top of the boiler - you can see the 3 distribution legs off the header pipe - any comments?

Steamhead

I'd bet it's a Williamson........... even though it's copper, which is a no-no, the header piping is the full 3-inch of the steam outlet.

mickeylewis123

PeerlessBoilers.com
Boiler No. 63-06-STDG-SP
S/N 612705-200901
Max BTU input per hr 287,500
DOE HTG Capacity or 241,000 water
Gross output btu/hr 238,000 steam
max gas supply pressure in WC 13.5
min gas supply pressure in WC 5.5
normal manifold pressure in wc 3.5
Category No. I
net 746 sq.ft.steam
I=B=R 179,000 btu/hr steam
ratings 210,000 btu/hr water
ANSI z21.13 a-2005.CSA 4.9a low press. Boilers

MAWP, steam 15.0 psi
MAWP, water 50.0 psi
maximum water temp 250 F
CRN 1528.9C

Boiler Model # of Sections Min relief valve capacity lb/hr or mbh Jacket length
63-03 3 99 16 1/8"
63-04 4 148 20 3/8"
63-05 5 198 24 5/8"
63-06 6 241 28 7/8"

KC_Jones

I agree copper is far from the worst thing, but Peerless is one of the few that specifically states threaded fittings in the manual so in this case it isn't piped to their specifications. Agree on a boiler that size really should have used both tappings.

mickeylewis123

Ok - so how bad a shape am i in with this piping? Does it need to be addressed immediately? How much work / cost should it take to correct this?

KC_Jones

The copper should be fixed at the installers expense. They didn't install according to manufacturers instructions so it's wrong and you shouldn't pay for it. As far as the other stuff, that is a question you would have to answer. The piping appears to be to minimum spec so the installer isn't going to do more than that (unless they are a good steam installer which you don't have). The piping that is mentioned works out like this. The way it is will "work" and that's as good as it will get. If you want it to "perform" then you want the improved piping. As Hat stated your velocities are too high with that set up and are certainly sucking water out of the boiler. All that water hinders performance and costs you money (excess fuel usage). Where are you located? We may know a good steam person in your area that could give you an evaluation and what it might take to improve what you have. I think your contractor is completely out of their realm of knowledge based on what you said and the pictures.

KC_Jones

Hatterasguy said:

Another more serious question is why do you have such a large boiler? Did this "plumber" measure all the radiators and determine the total EDR for the system? Does he know what "EDR" is?

I was thinking the same thing, something mansion sized comes to mind.

mickeylewis123

Location: Englewood, NJ

mickeylewis123

My plumber never mentioned anything about EDR. I just read up on it last night, measured my radiators this morning, and got the column and fin counts - haven't got to the computations yet today - but that's next on my list of things to do. I'll post the info as soon as i compute it.

Abracadabra

What the max pressure achieved during a cycle?

mickeylewis123

My EDR calculation for all 16 radiators = 95 - what does this mean for my boiler? Attached are my detailed calculations.

KC_Jones

Calculations are definitely off. The ratings you look up are per section. So if it is 2 EDR and 14 sections that one radiator is 28 EDR. I will take a guess that your SF EDR column is what you looked up on a ratings chart? If so use that number and multiply it by the number of sections. If that is the case, by my rough calculation you would be massively oversized. Go back over your numbers and post back.

mickeylewis123

Thanks! Will rework immediately

mickeylewis123

Revised EDR calculation 413 - see spreadsheet attached

mickeylewis123

I can't tell the pressure. I only have the boiler 30# pressure gauge which is stuck on 5#. My plumber said "don't even replace it - they never last more than a year." I will add a low pressure gauge to my pressuretrol pigtail - but not til after I add my G2 vents which I can't do for another 2 weeks.

KC_Jones

net 746 sq.ft.steam is the rating on that boiler you have 413, so you are 80% over sized. Yikes. How long ago was this installed? Have you made final payment? Even without knowing what you paid, you probably could have gotten a proper install with a properly sized boiler for the same money. The biggest Peerless he should have installed would have been a 63-04. I will reiterate, your plumber is clueless with steam. And his comments about gauges are totally ridiculous.

mickeylewis123

What are the calculations for sizing the boiler based on the radiator EDR? And what are the numbers I compare that to on my boiler specifications?

KC_Jones

You compare to the sq ft steam rating with zero calculation adjustments. Anything else is just wrong. Obviously your installer didn't do any calculations.

SWEI

KC_Jones said:

You compare to the sq ft steam rating with zero calculation adjustments.

You might adjust downward depending on the specifics of the system, but I would certainly not adjust upward without a very good reason.

KC_Jones

Agree, but I can't imagine any situation that dictates an 80% increase?

mickeylewis123

Boiler installed & paid for September 2009!

KC_Jones

In that case I have 2 suggestions for you. First don't ever let that contractor in your house ever again. Second call this guy and get an evaluation of what you are dealing with. He is a good guy and knows steam. @Dave0176
https://heatinghelp.com/find-a-contractor/detail/dl-mechanical-llc

mickeylewis123

Before this, I had a Weil McClain, and was having terrible problems which led to me going for the new one; i can only assume my plumber sized based on the existing one - although somewhat larger - here are the specs to my prior boiler
Weil-McLain Gas Fired Steam Boiler
Model E-9, Series 2
Steam: 700 sq ft
Water: 194.8 mbh
Input: 280,000 BTU/Hr
Output: 224,000 BTU/Hr
Capacity: 224 Lbs/Hr

mickeylewis123

Thanks everyone - i've already reached out to Dave - waiting to hear back

mickeylewis123

I spoke with Dave and he's ready to help, but in the interim a few things have transpired.

I added venting to each of my 3 mains. I added venting based on the calculations offered above in the thread. I installed 2 x G2 on my longest main (up from 4 x G1), 1 x G2 on my second longest main (up from 2 x G1), and 2 x G1 on my shortest main (up from no main venting at all.) My next test showed no difference in time to heat on the longest and second longest mains, but the shortest main now heats up as fast as the other two - a minor success.

My plumber said my problem was with the model of my low water cutoff, and if he changed it for another type, the system would heat up much faster. He suggested that the low water cutoff was kicking in and that's why I wasn't heating up fast enough. He changed the low water cutoff, but it had no impact on the heating up time.

Finally, I went back to the boiler installation instructions to check their requirements for near boiler piping. My plumber followed the specs exactly! For my boiler, a PB 63-06, 1 x 3" supply connection to 3" header, 1 1/4" equalizer, (but it also specifies a 0.37 GPM evaporation rate - i don't know what that is?)

I was quoted a substantial sum to change out the near boiler piping so I'm not ready to jump to that unless the person doing it GUARANTEES effectiveness upon completion - massive reduction in time to heat up the system and commensurate reduction in cost of gas / fuel. I'm not comfortable asking for a guarantee, and wouldn't even know how to write it up to be enforceable and verifiable - any recommendations?

Otherwise, I believe my next step is installing a 2-stage gas valve and seeing if that has any impact. Based on everything i've read above, it should show a significant impact - correct? How big a job is it to install a 2-stage gas valve?

Thanks all! And Happy New Year!

JohnNY

"My plumber said my problem was with the model of my low water cutoff, and if he changed it for another type, the system would heat up much faster. He suggested that the low water cutoff was kicking in and that's why I wasn't heating up fast enough. He changed the low water cutoff, but it had no impact on the heating up time."

Do you mean you're still using the same plumber for the boiler?
Why would you do that?

Fred

A two stage gas valve isn't going to fix this problem any more than changing the LWCO did. A two stage gas valve will help you get the boiler oputput down closer to your radiator EDR but that's not what is causing you to take an hour and a half to get steam to the radiators. If the LWCO is shutting the boiler down frequently on low water, chances are very good you need to skim that boiler some more. When the boiler ends a heating cycle, is the water level too high in the sight glass? Do you have to drain some water out? If not, have you checked for any leaks throughout the system?
What did Dave suggest? Did he visit the site or did you just talk to him on the phone?
Don't spend money on a two stage gas valve, at this point. Spend that money getting some proffessional eyes on the system and identifying the real problem(s), as it relates to the delayed steam movement through the system.

Jamie Hall

Argh. If the low water cut off were kicking in enough to make it so it didn't heat up fast enough, there's something seriously wrong with the near boiler piping or condensate return piping or pressure. But we knew that. The low water cut off wasn't the problem. He should have known that.

I might add that the boiler installation diagrams are always the minimum which the boiler manufacturer thinks will work at all. Sometimes -- as with a nice big drop header and feeding a steam separator drum which feeds the mains, that works well. Sometimes... not so much.

The big question I have is: does the boiler fire continuously, or is it shutting off and cycling before all the mains and radiators are pretty full?

Dave0176

Fred said:

A two stage gas valve isn't going to fix this problem any more than changing the LWCO did. A two stage gas valve will help you get the boiler oputput down closer to your radiator EDR but that's not what is causing you to take an hour and a half to get steam to the radiators. If the LWCO is shutting the boiler down frequently on low water, chances are very good you need to skim that boiler some more. When the boiler ends a heating cycle, is the water level too high in the sight glass? Do you have to drain some water out? If not, have you checked for any leaks throughout the system?
What did Dave suggest? Did he visit the site or did you just talk to him on the phone?
Don't spend money on a two stage gas valve, at this point. Spend that money getting some proffessional eyes on the system and identifying the real problem(s), as it relates to the delayed steam movement through the system.

I strongly suggested we replace the boiler with the proper sized unit.

I also suggested a 5" header with two 3" boiler risers and using a two stage gas valve to SLOW the steam down to a crawl . But at that point the expense is getting closer to a proper replacement

Fred

So unfortunate, to say the least but what can you do after the fact?

ChrisJ

Hatterasguy said:

JohnNY said:

Do you mean you're still using the same plumber for the boiler?
Why would you do that?

To reinforce the statement by John, walk up to the plumber and tell him:

I knew you were a huge fan of his....

mickeylewis123

I just put in a low pressure gauge on my pigtail with my pressuretrol. How long should it take for the gauge to show pressure? Generally speaking?