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

KC_Jones

There really is no "generally speaking", there are so many variables it's hard to say. Since you upgraded the venting that will help keep the pressure down. Once the mains are full that's when I would expect to start seeing some pressure rise, but it's hard to say. My system never builds pressure, but I have a decent match to my radiation.

Dave in QCA

Glad you found the install manual. I was just reading it and yes, the pipe sizes are correct for minimum acceptable, which should allow the boiler to operate correctly.

Something just does not add up here and there must be another problem or ? The problem you identified in the first places is that the radiators are slow to heat up completely. For a boiler that is 80% oversize, this just does not add up. One would expect that the radiators would all heat quickly and completely and that the boiler would then build up pressure and begin to short cycle. But, that is not what you're seeing.

I would suggest clocking your gas meter to verify what the firing rate really is. Perhaps its starving for gas? No way to know without checking it.

Also, please give us a picture of 2 or 3 of your radiators so we can double check your EDR numbers. Include the height along with the pictures.

The issues that you mention regarding some radiator fully heating, and others not, and then very late in the steaming cycle, the pokey ones suddenly heating up.... this sure sounds like radiators venting too fast. When steam goes too quickly into a radiator, the radiator will condense the steam very quickly, so much so that it can actually pull more steam into the radiator. Over vented radiators will HOG the steam and keep it from going evenly to other radiators. I am a fan of Hoffman #40 vents. They are nice and slow and when the whole system is set up with them, they usually operate amazingly evenly. The slow radiators that may remain can then be sped up with a faster Gorton model.

At any rate, I would not think about a 2-stage gas valve at this point, slowing the boiler down will not speed up your system. Actually, 45-60 minutes to fully heat cold radiators, starting the timing when steam has started to go out into the mains, is a reasonable time. But, it should be much more even that you seeing now.

Regarding the copper riser and header. They are a big no no. Often times the sweat joints will eventually crack and leak. However, they were popular her in the Quad Cities about 30 years ago, and I have seen a few that were 20 years old that never leaked. I have seen some that did, too. Insulation would improve the system performance. I am assuming that the mains are insulated.....???? That can make a real big difference in performance. Wrapping with building insulation doesn't count, needs to be fitted pipe insulation to be effective.

Keep plugging away, you'll get this working great.

mickeylewis123

Thanks for the comments and encouragement Dave!

Only a small portion of one of the mains is insulated. I don't want to do the insulation until i get the system pretty much working properly. I understand i can make it work better when i insulate - but it seems i have bigger problems at the moment.

I'll photograph some of the radiators and include my calculations as well as the guide I worked from.

I'd also like to share my test with my detailed numbers. I keep saying that it takes 1:15 to heat up all the radiators fully; when you see the details you can see one of my radiators heats up in 23 minutes! And that one is on the third floor! The second fastest heats up fully in 24 minutes! That one is on a different main, but is also on the third floor!

The slowest one took 1 hour+. That one is on the 3rd and shortest main, is on the 2nd floor, and looks like it is the only radiator on that main (the piping goes into the walls and i'm not exactly sure where the piping goes.)

The 13 other radiators on 2 mains took between 30 minutes and 55 minutes to heat up fully.

Today, when I installed the low pressure gauge, I also installed a 1/2" valve at the end of my shortest main so i could open it and time when the steam was coming out. It took about 30 minutes before steam was noticeable exiting the valve.

Dave in QCA

Wow! Thirty minutes is a VERY long time for steam to make it to the end of a main with an open valve. I am assuming it was a gate or ball valve and not a globe valve, which would have some restrictions in it. If it were me at this point, I would clock that gas meter first thing. Count how many cf go through the meter in 1 minute. Make sure nothing else but the boiler is running.

What you are seeing is not that unusual in the case of over venting, but it could be from starving for steam as well. In a similar example, a nearly friends house was heating very uneven. Some of the radiators would get blazing hot. Another one, in the dining room where the thermostat was located, the radiator did NOT get hot at all. I stayed stone cold, even after an hour or more. No heat, ever!! A few years earlier when a new boiler was installed, the vents on the first floor radiators were changed out to Hoffman 1A. There were carelessly set at 5 to 8 or so. The upstairs had all Hoffman 40s. I was baffled! I did a little reading and thinking. Went to the handy venting charts. Then I went back and carefully set the 1A vents (its not easy) to about the same venting rate as a Hoffman 40 would have been. The system was cold, and I started it up. First, I was amazed at how evenly all the radiator started to heat, and the dining room, even though it was the end of the line and had not been getting any steam at all, now started to get steam in balance with the rest of the house. When you remember that when steam condenses to water, it shrinks to 1/700th its volume, then realized that a radiator when vented too fast turns into a big vacuum producing device that sucks steam away from everything else.

mickeylewis123

Hi Dave, Tell me more about the clocking of the gas. I'll do it sometime later today, but what am i looking for? When i give you the numbers, what will they tell you? Thanks, Micky

BobC

I think this is what you need -

Bob

gcp13

After putting in the low pressure gauge what does the pressure get to you before it shuts off?A few things that can make things heat very slow are back pitched or level steam mains,as the mains and some radiators start to heat the condensate starts filling the main leaving less space for steam to head to radiators and slowing things down.
Too much pressure can cause air vents to close and not open back up. Shutting off steam to the radiator. Are there drips off the end of mains that are undersized or clogged?

mickeylewis123

When you mentioned how a screaming hot radiator can steal steam from the others on the main i immediately went to the two radiators on the third floor, which are on two different mains, and reduced the vent sizes. I'm using maid o mist vents which have 5 different vent sizes that can be changed. I put the smallest vents on each of them just to see if there was a change. I didn't have time for a full test, so i don't have valid results, but they did both heat up more slowly and the radiators before them in their line may be heating up somewhat faster - although not dramatically. I'll need to run another test when i have an hour and 15 minutes to kill - not easy to find this week.

mickeylewis123

As for the gas meter, i've attached a photo of the meter. There are 2 small dials underneath the counter. The dial on the left revolves very rapidly. The one to the right a little more slowly. I timed one revolution of the one on the right and it took 30.8 seconds. I got your write-up on how to compute PSI from this, but even if i get that calculation, i don't know what it means.

BobC

That indicates you are consuming about 240,000 BTU's per hour vs the 287,500 BTU's the boiler is rated for so you are about 15% underfired by my calculations. The firing rate would have to be adjusted by the actual BTU content of your gas. That is not a bad thing seeing the boiler appears much to large for your system so the problem would appear to be in the piping.

The measurement you took has nothing to do with gas pressure, it just determines your gas consumption.

Bob

mickeylewis123

Got it - so it sounds like my gas feed is ok - right?

Dave in QCA

Yes, it appears that way.

mickeylewis123

Hi Dave,

I just got a chance to run a full test which takes me 1 hr 15 minutes. Results showed that the system is running better based on putting in smaller vents in two of my radiators on the third floor that had been heating up very quickly and getting very hot. With the new smaller vents, now only 6 out of my 16 radiators take 47 mins to 1 hr 7 mins to heat up fully. That's the least number since I started this journey. The other 10 are now heating up in 20 to 35 minutes (average 29) and if i could get them all to do this I'd be a happy camper!

I also got a chance to see how my new 5# pressure gauge works - excellent! It took 1 hr 19 mins for the boiler to hit 2.2# and the Pressuretrol shut off the boiler. It took only 1 min 18 seconds for the pressure to drop to 1.2#, and the boiler kicked on again. I adjusted the Pressuretrol down 1/4 turn and it took 10 minutes til it hit 2.2# again and shut off. I turned the Pressuretrol down 2 full turns more, it took another 1 min 18 secs for the boiler to kick on again at 0.7# and cut back off again at 1.9#. I feel pretty good about this, although I wonder - should pressure drop that fast? And should it take 10 minutes to get back up to pressure?

At this point i'm going to focus on getting the venting right. I have the Groton chart, but that is not very scientific, and doesn't give any insight on how to tune. Are there guidelines or procedures for iterations of testing? Based on what happens in the test, how one might readjust the venting? Ala how you had me look at those 2 radiators on the 3rd floor that got screaming hot really fast and told me to slow them down? Now that I've done that, for example, on one of my mains, the first radiator on the main line, on my first floor, takes 50 minutes to head up - stone cold at the valve for 44 minutes, but the following radiators on the line heat up in 20 min, 31 min, 22 min, 31 min, and the last one 47 min - odd how the first one is so off? But when it did heat up, starting at minute 44, it only took 6 minutes til it was hot all the way across.

Dave, thanks for your help!

KC_Jones

How long does it take just the mains in the basement to get hot? I think we need to start there for sure. For example I and some others feel like 1 minute per 10 feet of main is a good working number, so on your 40' main that should be able to heat up (header hot until end of main hot) in about 4 minutes. Some of us go even faster than that. The times you are listing are honestly completely ridiculous even if they are better. Also you don't want to "get back up to pressure" with residential steam heat like you have, pressure is evil. That's why the boiler shuts down to keep the pressure down. The higher it goes the slower the steam moves. Have you added the main venting yet?

Dave in QCA

Ok, I forget what vents you have put on the radiators. Of the ones that are heating quickly, what vents are on them. What vents are on the others that are slow?

Regarding length of time to build pressure at the boiler, this is a good thing and is normal. The speed at which the pressure drops is also normal. Remember, your radiators are condensing steam and turning it to water. Lots of it... FAST.

One thing that still does not add up... as I recall, it was determined early on that your boiler was considerably oversized, however, it is not behaving like an oversized boiler at all. Could you take a picture of a radiator, tell us its height, and let us confirm the EDR. Maybe you have made an error.

vaporvac

Have you bought the venting book. It's cheap and the money goes to charity. It may help save some time. Your low-pressure gauge is also telling us two things... you ARE probably oversized to build so much pressure so quickly and/or you need MORE Main venting. I have a huge system and build 1lb on a cold day which I consider too much.

nicholas bonham-carter

Gorton make our favorite main vents, but their advice leaves much to be desired in choosing the radiator vents.
Max out your mains at one Gorton #2 for each 20 feet of 2 inch main, and start with Hoffman 1-A's on the radiators.--NBC

Dave in QCA

And.... I always follow with a word of warning on the Hoffman 1A vents. Some don't like them because the have a pretty loud click. And, the adjustment mechanism is touchy. You have to be very careful when adjusting. Anything that is at 3 or above is pretty fast, an probably faster than needed unless it is a Long way from the main. I find using Hoffman 40 works very well with an occasional exception for a slow one.

and.... We are not ALL fans of Gorton main vents.

ChrisJ

Hoffman 1As besides being loud, flat out won't work on my system. They would often, and randomly get plugged with a droplet of water which would stop the radiator from heating. I constantly had to go around with a can of air with a straw and blow them out when it'd happen with a puff of air.

This doesn't happen with Gorton.

Fred

I like my Hoffman 1A's. Like Dave says, you do need to pay attention when adjusting them. The easiest way is to take the cap off, position the number you want on the arrow, hold it in place with one hand and screw the cap back on. It's easy once you do one. I had one new Hoffman that clicked fairly loudly but after running for one heating season, the clicking went away completely. All my other Hoffman's were always silent. I kinda liked the one that clicked. It made it simple to know when/how often the vent opened/closed.

ChrisJ

How can any valve that works like a Hoffman 1A, be silent?
Seems impossible using that "oil can" system?

Either way like I said, they were a no-go for my system not counting the noise.

Fred

ChrisJ said:

How can any valve that works like a Hoffman 1A, be silent?
Seems impossible using that "oil can" system?

Either way like I said, they were a no-go for my system not counting the noise.

Trust me they are.

ChrisJ

Fred said:

ChrisJ said:

How can any valve that works like a Hoffman 1A, be silent?
Seems impossible using that "oil can" system?

Either way like I said, they were a no-go for my system not counting the noise.

Trust me they are.

I'd need to hear them in person.
I think you're loosing your hearing, too many The Who concerts back in the day.

Dave in QCA

I've got a line on some 135 year old carbon rod vents.... I wonder how they work?

Jamie Hall

Dave in QCA said:

I've got a line on some 135 year old carbon rod vents.... I wonder how they work?

Probably just fine, if used as intended -- most of that old stuff does, unless it's flat out broken or worn out!

Fred

ChrisJ said:

Fred said:

ChrisJ said:

How can any valve that works like a Hoffman 1A, be silent?
Seems impossible using that "oil can" system?

Either way like I said, they were a no-go for my system not counting the noise.

Trust me they are.

I'd need to hear them in person.
I think you're loosing your hearing, too many The Who concerts back in the day.

That's always a possibility but I think they are silent.

mickeylewis123

Dave -
Two photos attached:
Radiator L/R north w/ Gorton 6; i computed EDR = 18
Radiator L/R west w/ Gorton 6; I computed EDR = 16

mickeylewis123

Based on my test, all the radiators were hot and vents shut after 1 hour an 7 minutes, and the pressure was at about 0.9#. I could adjust the Pressuretrol to shut the boiler off at 0.9#, but is that ok when the differential is 1#? It means the pressure would have to drop to nearly 0# before it came back on.

Fred

@mickeylewis123 , are you sure about the EDR? My chart shows each section to be 2 EDR making those rads 28 and 30 EDR.

Dave in QCA

@Fred I agree with your numbers too, with what I can see. Perhaps we should get the depth measurement too. For some reason these look deeper than standard. I am not sure what numbers the original poster was using, it appears that it is even less than a one column radiator.

Fred

@Dave in QCA , I agree. I too thought the columns looked wider (from side to side) than typical.

Jamie Hall

mickeylewis123 said:

Based on my test, all the radiators were hot and vents shut after 1 hour an 7 minutes, and the pressure was at about 0.9#. I could adjust the Pressuretrol to shut the boiler off at 0.9#, but is that ok when the differential is 1#? It means the pressure would have to drop to nearly 0# before it came back on.

Never set a pressuretrol so that the cut in is less than 0.5. They aren't reliable below that -- and you don't need the hassle of the thing not cutting back in. Your maximum pressure is good for your system.

mickeylewis123

I computed the EDR from a worksheet showing different radiator types - i'm not home right now, but will post it later. Attached is my detailed worksheet on all my radiators - dimensions, type, vent, and EDR calculation.

mickeylewis123

I just noticed something wrong with my EDR attachment - the last line item says "boiler main" w/ no vent and a radiator size - something went wrong when i sorted it; the name / description may be wrong, and the associated vent wrong, ignore them, but the radiator sizes, number of fins, etc, are correct.

Fred

mickeylewis123 said:

I computed the EDR from a worksheet showing different radiator types - i'm not home right now, but will post it later. Attached is my detailed worksheet on all my radiators - dimensions, type, vent, and EDR calculation.

It looks like your calculations are correct IF you are calling the Sections, Fins?? They are actually Sections. From what I see, you used the the number of Sections column from your spreadsheet rather than the EDR column, in your earlier post. There in lies the error, if I'm correct.

mickeylewis123

Correct - what i refer to as fins are actually sections; i used the number of sections an multiplied times the EDR factor to get the results. Someone in an earlier post looked at my pictures of 2 of my radiators and thought they may have a higher EDR than i was computing?

Fred

mickeylewis123 said:

Correct - what i refer to as fins are actually sections; i used the number of sections an multiplied times the EDR factor to get the results. Someone in an earlier post looked at my pictures of 2 of my radiators and thought they may have a higher EDR than i was computing?

What you posted, with the pictures, was just the number of sections, not the EDR.

mickeylewis123

I was just looking at a diagram of a 1-pipe steam system and it specifically shows the main venting at the end of the main, and not at the end of the condensate return. My main vents are at the end of my condensate return????

Abracadabra

mickeylewis123 said:

I was just looking at a diagram of a 1-pipe steam system and it specifically shows the main venting at the end of the main, and not at the end of the condensate return. My main vents are at the end of my condensate return????

Are the returns wet or dry?

Fred

If they are on a dry return (before it drops down and becomes a wet return. That works too. Sometimes they were put on the dry returns because that was the most convenient point on the piping. While the returns don't need to be vented, on a one pipe system, if that's the only place they could put the vents, that's OK. I contend that, in these cases, the amount of air in the dry return has to be factored into the amount of venting you need because steam is going to take the path of least resistance and that is that big main vent. Until it closes, the steam won't go elsewhere. I think others don't feel the air in the dry return needs to be factored in ???