Vents and Valves

Pegret

Basically, the functions of the vent and valve on a steam radiator is as follows?
Vent: regulates SPEED at which steam gets to radiator (most open steam arrives fastest)
Valve: regulates how MUCH heat gets to radiator (wide open turned to the left=maximum heat)

KC_Jones

In a one pipe application with vents the inlet valve does nothing, it is left wide open always and is simply there for maintenance. The vent controls the speed and amount as a function of speed. In other words a slow vent will allow the steam to arrive at a certain rate. If the thermostat shuts down before the rad can fill then the slower vent now controlled the amount.

Fred

If you partially close a valve on a one pipe steam system, you will likely prevent water from draining back to the boiler and you may see the radiator vent spit water or even hear some sloshing/hammer/banging at the radiator.

Pegret

Fred, there has been a bit of sloshing which makes me nervous. Also, water in sight glass is now highter-only an inch from top rather than 1/2 full. I am going around now to open the values a bit more but don't want to lose that one radiator that wasn't working before I closed the valves.
Really trying to balance all valves and vents and get heat to all radiators without causing water issues!

Gsmith

On a one pipe steam system the inlet valve on all radiators should be FULLY OPEN AT ALL TIMES. The balancing of the heat given off by the radiators is achieved by changing the vent speed on the vent located on the opposite side of the radiator from the inlet pipe.

Pegret

Opened up all valves which did correct water. Sight glass back to normal and radiators quiet. Because all valves are open now, the problem radiator only heated 1 column out of nine. when I closed valves almost all the way I got full heat in that radiator.
Plumber is confiorming if he can come out tomorrow-exhausting trying to get this system working !

KC_Jones

Have you looked at your main venting yet? It's not a question of having one, it's about having enough.

Need to measure the length and size of mains, if you post that information we can advise how much main venting you need.

Let me reiterate what I said on another post of yours. The main venting is step 1, do nothing else except that as it influences everything else afterward. Looking at the rads first to balance can seriously confuse the issue.

Also the boiler size, I highly recommend you measure the rads and see how well the boiler was sized. Without all the information it is extremely difficult to get things corrected and if the boiler is too over sized, you may only get "so good".

Fred

What size vent is on the problem radiator? It may be too slow or it may not even be working consistently.

Gsmith

As stated above, get the main venting right next. After that you can adjust the radiators for better balance. Most usually you need to slow down the rads in the areas that are too hot, not speed up the rad in the cold room. But after doing the main venting, make a list of the radiators, approximate size and vent on each, maybe some swapping will make the balance better. We can help with that.

Pegret

Thanks for these pointers! When I get my other computer running I'll post a picture of current main vent.
It has been determined that the new boiler is very oversized. By measuring radiators it should be approx 70,000btus but it is actually 150,000btu. Very discouraging to learn this but must now find best way to get this working effectively.

Fred

What size vent is on the problem radiator

Pegret said:

Thanks for these pointers! When I get my other computer running I'll post a picture of current main vent.
It has been determined that the new boiler is very oversized. By measuring radiators it should be approx 70,000btus but it is actually 150,000btu. Very discouraging to learn this but must now find best way to get this working effectively.

Is that 70K BTU's just the connected Radiator EDR? If so, you should add another 33% to the boiler output to accommodate piping and pick-up factors. The boiler would still be way over sized but not by over double.

Pegret

don't know what "connected radiator EDR" means. also, "add another 33% to boiler output" I'm waiting for a plumber to come out who will understand what you're saying. I have not told original plumber that it's been determined that the boiler is way too big.

KC_Jones

You said you measured radiators, we are just trying to clarify what was added up and calculated for our own understanding. It's usually presented as EDR, not in BTU. We have seen many times the mistakes people make doing the BTU calculations, that's why it was asked.

SeanBeans

Why not get a heating guy and not a plumber?

SteamingatMohawk

I suggest you add steam boiler before heating...too many know very little about steam. Anyone you get has to have all the information to properly diagnose what is going on.

Pegret

I do have a heating guy coming next week (I hope!) I am in contact with plumber who installed and have asked him how he calculated size of boiler. Waiting to hear back.
Regarding EDR, have not heard that term used in many conversations with plumbers and Weil-Mclain tech support. But now that I am aware of it I will ask about it with orgianal installer and heat guy who's coming next week.

Pegret

Since installation someone measured all radiators and calculated approx 70,000 btu output (didn';t mention EDR) The boiler I have is 150,000BTU output.

Pegret

After measuring radiators I was told I need 182 sq ft of steam but new boiler is 392 sq ft. or 1.75 cu ft as opposed to 35.2 cu ft.
This sounds more like the EDR measurement, right?

Fred

Pegret said:

Since installation someone measured all radiators and calculated approx 70,000 btu output (didn';t mention EDR) The boiler I have is 150,000BTU output.

My question was the total EDR of the radiators. Which is equal to the Sq. Ft. of steam on the boiler plate. Basically, there are 240 BTU's per EDR or Sq. Ft of steam. If your 70K BTU is only the connected radiators, that would suggest you have about 292 EDR or 292 Sq. Ft of steam on the boiler plate. The boiler plate.
If your number only includes the connected radiators, and that totals 70K BTU, then you need to add 33% more BTU's to that number to determine what a properly sized boiler should output. That would make a boiler, with the Piping and Pick-up Factor about 93K BTU's. As @KC_Jones said, we use the EDR terminology because it can be matched to the Sq. Ft. of steam stamped on the boiler plate without the confusion that comes with calculating BTU's. on the

Pegret

I think I was told I have 392 EDR on the boiler plate but only need 182 EDR. As stated above it was termed in sq feet after measuring the radiators. I appreciate your patience as I try to understand this

Fred

Pegret said:

I think I was told I have 392 EDR on the boiler plate but only need 182 EDR. As stated above it was termed in sq feet after measuring the radiators. I appreciate your patience as I try to understand this

WOW, WOW, WOW, If this is correct, you need to figure out how you get that new boiler replaced with one that closely matches the 182 EDR. That boiler will short cycle on virtually every heat cycle.

Pegret

This all very discouraging. Waiting to hear back from plumber who installed new boiler. I feel the whole thing should be swapped out for the proper size. I imagine I'll have to wait til Spring to do this. Meanwhile one radiator not heating in livingroom. Like I said, hoping the heating guy will be here next week. I will fill him in on history.
BTW, the cycles seem to be normal right now but have not officially timed it.

KC_Jones

Almost double the boiler size you need. I said it before, I’d surely be putting the original contractor to task for replacement with the proper boiler, though my expectations would be very low they would actually do anything. I’m curious to see what the piping on that boiler looks like....I know what my gut is telling me.

Pegret

KC the original piping was wrong when he first installed it so he, finally, repiped, according to Weil McClain manual. Wish I could send photos but other computer is down til tomorrow.

ethicalpaul

Well that, at least, is good. Also send us a picture of the rating plate from the boiler if you like and we can tell you which numbers are the important ones

Pegret

Plumber who installed just responded to my text asking how he sized the new boiler: "I sized it based on the firing rate of your existing boiler" The existing boiler was original to the 1928 house- a "snowman" (again, pictures when I can)

Jamie Hall

Well... that's one way to do it. That poor old snowman probably had an efficiency on the order of 50%. The new boiler should be more like 80%, maybe a smidge more. So if he sized it based on firing rate, that's an automatic 60% oversize right there -- particularly since the old boiler probably accounted for the pickup factor, so you don't get credit for that...

Sigh...

It's so dang easy to do right.

KC_Jones

Jamie Hall said:

It's so dang easy to do right.

I agree with this, but what we see around here would contradict that.

To the OP, you have it in writing him admitting to doing something wrong. Not sure how much value that is with your situation, but yeah that's wrong. You can pull the documentation from the manufacturer and show him it's wrong. I still doubt he will do anything about it, but that wouldn't stop me from fighting for what is right.

Fred

Not good, as we already know. Now how to fix it. Can't be down fired that much. A two stage valve won't get the firing down enough either. Only other two options are to live with it constantly short cycling (least desirable option) or to get it replaced with one that is correctly sized.
I would suggest the first step is to measure the total Radiator EDR, again (if it was ever done) to confirm that is correct and then go from there. We can help you calculate the EDR with some pictures of each radiator or you can down load an EDR guide by radiator type/size from this site.

Pegret

Someone did come up with that I need 182 sq ft of steam after measuring the radiators last week. Said this boiler is 392 sq ft.

Pegret

Is short cycling when the boiler runs more than it should need to? It doesn't seem to be doing that, but I'm not sure.

Fred

Short cycling is when the boiler produces more steam than the pipes and radiators can condense. When that happens, the Pressuretrol will shut the boiler down (during a heating cycle) until the pressure drops and the boiler can fire again. It will cause the boiler to start and stop multiple times during a single heating cycle. In your case, most likely excessively going on and off with each heating cycle and the colder the outside temps, the more it will short cycle because the boiler will run longer to satisfy the thermostat.

Pegret

OK, thanks. It really doesn't seem to be doing that for some reason.
I can not imagine he is going to swap this boiler for the right size. He's a nice guy but that would still be very unlikely. My bad for not researching more before hiring. I had no idea how complex steam boilers are- this has been quite an education but also so discouraging.

Fred

Pegret said:

OK, thanks. It really doesn't seem to be doing that for some reason.
I can not imagine he is going to swap this boiler for the right size. He's a nice guy but that would still be very unlikely. My bad for not researching more before hiring. I had no idea how complex steam boilers are- this has been quite an education but also so discouraging.

Until you can actually confirm the attached EDR, we're only guessing the boiler is huge compared to that EDR. Maybe it isn't. Maybe it hasn't gotten cold enough where you are to cause the boiler to run long enough to see what it is going to do. Maybe there is a steam leak or main vent that isn't closing and that is releasing pressure. It could be any number of things and, as I said earlier, doing the EDR survey is the starting point.

ethicalpaul

> I had no idea how complex steam boilers are- this has been quite an education but also so discouraging.

The interesting thing to me is, they are not at all complex, relatively speaking. They have almost no moving parts at all! But contractors today seem to often not be familiar with them and that makes them be mysterious to most homeowners too.

Pegret

I just calculated the EDR by measuring my seven , 3 column cast iron radiators and using the chart. It came to 175 EDR sq ft. total for the house.
I looked at a conversion chart for EDR to BTU and it says 175 EDR = 42,000 BTUs per hour.

Does that mean the ideal size of the boiler should have been 42,000 btus?

Fred

Pegret said:

I just calculated the EDR by measuring my seven , 3 column cast iron radiators and using the chart. It came to 175 EDR sq ft. total for the house.
I looked at a conversion chart for EDR to BTU and it says 175 EDR = 42,000 BTUs per hour.

Does that mean the ideal size of the boiler should have been 42,000 btus?

You don't need to convert the 175 EDR to BTU's. Just match it to the Sq. Ft. of steam on the boiler plate. If you insist on using BTU's the it would be the 42K Btu's + 33% more (14K BTU's) fpor piping and pick-up factor = a 56K boiler.
The problem with using BTU's is the boiler manufacturer has already taken the 14K into consideration when they state the SQ. FT. number on the boiler plate.

In any case you need 175 Sq. Ft. of steam and your boiler is 392 Sq. Ft. or about 2.25 times larger than it should be.

Pegret

OK thank you for your caluculations (I don't insist on btu, just thought it may be how it works- learning a lot but still mostly ignorant)
I don't have much faith that I won't have problems in the future and probably won't get the efficiency I was counting with a boiler 2.25 bigger than it should be.
This kind of descrepancy should justify swapping for a proper sized boiler.
Since that isn't likely, I'm hoping the heating guy who is coming here next week can recommend modifications to make up for it.