Steam Boiler at 0psi

Tim_8

Hi. I have a strange one I hope someone can help me out with. I have a two pipe, gravity return, steam boiler. It has a Honeywell pressuretrol installed which is set to cut in at 0.5 psi and cut out at 1.5 psi. These are both the lowest settings possible on my particular pressuretrol. The problem is the pressuretrol never shuts off the burner. At first I suspected a bad pressuretrol or control wiring, but a manual test of the switch inside the pressuretrol shut off the burner. There is also a gauge connected to the same pigtail with the pressuretrol which never moves off of 0 psi. (This is a new gauge by the way). I also took the pigtail apart along with the connected piping and made sure it was clear. It appears that the boiler never gets above 0psi no matter how long the boiler runs. The only thing that shuts it down is the thermostat. It would run for hours if the stat was calling and never get above 0 psi.

I next suspected that I might have a leak somewhere in the piping going out to the system. I searched high and low and couldn’t find even a tiny leak. The next thing I checked out were the main vents. I thought they might not be closing so I replaced them with new Hoffman no.4's. With my wallet a little lighter and my blood pressure rising the burners continued to blaze and my gauge still sat at 0 psi. I don’t have any vents on the radiators, so that rules them out. I also recently replaced all the steam traps in the system because I found many that weren’t working.

After a lot of reading I thought I might have a hole in the boiler so I performed a hydrostatic test but didn’t find any leaks. There is also no tell tail white smoke coming out of the chimney.

My next line of investigation turned to the boiler water itself because I suspect I’m producing wet steam. I though that I might have a film of oil or something on top of the water. Last season the boiler formed a small leak and the repair man pumped in some stop leak. This took care of the leak but it was about this time that I started to have boiler level troubles. Up and down the level line would go in the sight glass. So I open up a tap near the top of the boiler and skimmed it for well over an hour.
But it still seems that I’m producing wet steam, the water level continues to go up and down, my pressuretrol never shuts off the burner, and the gauge continues to sit at 0psi.

Could it be that there is a lot of sludge build up inside the boiler acting as an insulate? The boiler is old and I’m guessing it has not been very well maintained and probably has never been cleaned. I also checked for soot build up and there was some but nothing out of the ordinary. I cleaned off what I could get to. If I do have the boiler chemically cleaned will this affect the stop leak that was pumped in last season?

Any guidance on where to go from here would be greatly appreciated. Thanks

Unknown

Do the math

Measure the radiators and see if the boiler is the right size.

Noel

Paul Mitchell

oil?

if its oil it could be way down fired and not really getting the steam up.

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Tim_8

Noel, How exactly do you measure the radiators? Is it height x length x width? And once I have these figures what do I compare it to on the boiler to determine if it is undersized?

Paul, The boiler is natural gas. Can it still be underfired?

Steamhead

Some more thoughts

Tim, if that old boiler sprung a leak, it's time to replace it. That "stop-leak" they put in to get you thru the winter is probably the cause of the water line and no-pressure problems. The sealer contaminates the water to the point where it doesn't boil effectively and you get wet steam, which is nearly useless for heating.

For radiator sizing info, get Dan's book "E.D.R." which is a reprinting of many, many radiator catalogs. Order it on the Books and More page of this site. Then you can determine how many Square Feet E.D.R. of radiation you have, and your contractor can use that info to size the new boiler. Also get a copy of Dan's "The Lost Art of Steam Heating" if you haven't already.

From your description, you probably have a Vapor system. These systems operate on 8 ounces or so of pressure. The Hoffman #4A main vents you bought are probably too small for this system. If you measure the length and diameter of your steam mains we can tell you what vents you need. Also, your new boiler should have a Vaporstat instead of a Pressuretrol, so it can stop the burner at the proper point.

Have you located any manufacturer's names on the various components (radiator valves, traps, strange-looking devices around the boiler) of your system? This would help us identify it. Post some pictures if you can too!

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Tim_8

Thanks Steamhead

Steamhead, Thanks for the input. I suspected the stop leak had something to do with it. I planned on replacing the boiler. I purchased a Weil Mclain EG-45 that’s sitting down in the basement ready to be installed, but due to time constraints I was going to try to make it through another heating season with the old boiler. After ordering the new boiler, which I’m not sure if it’s the right size now since I sized it according to my old boiler ( I know, I know, a big no-no) I came to find out I need to replace the mains as well. Weil Mclain calls for a minimum of 2.5 “supply main and a 1.5" return. My current system has a 2" supply and 1" return. So along with the boiler replacement, I have to replace the mains. I plan on doing the job myself. I’m an operating engineer who does a lot of maintanence on various HVAC systems but all the buildings I’ve worked in have been fairly modern. My current building is all electric. So my experience with boilers is limited. But that being said, with a bit of research and some guidance, I’m confident in my ability to tackle the install of the replacement boiler and mains and am looking forward to the challenge and added knowledge and experience to be gained.

The supply main comes of the top of the boiler into an elbow and makes a loop around the perimeter of the basement. There is no equalizing line or hartford loop. It is 2 inch in diameter and runs 63'. The end of the main ends up back at the boiler where it is vented and drops down from the ceiling to the floor and returns to the boiler. It is connected to the return by a check valve at this drop. The check valve is about 12" under the water line of the boiler. The return is 1" in diameter and follows along the ceiling on outside of the supply main so its length is about the same. It is also vented in the same place as the supply. The piping is covered in the basement with asbestos which I plan on having removed by a contractor before I replace the boiler and piping. Which is another reason I’d like to make it through this season with the old boiler. $$$$ The take-offs are various sizes from .75" to 1.25" depending on how far down the main they are and or whether they travel to the first or second floor. They all reduce down to a .75" supply and .50" return near each radiator. The take-offs are insulated in the basement but not inside the walls.

The boiler itself is a Peerless super section gas boiler. The only info I have on it is from the tag. The boiler number is 5W 25. Its BTU input per hr. is 146000. Its square foot rating is 780 water. The max working pressure is 15 psi. The direct H.W. storage-water is 80 lbs. . Its equipt with the pressuetrol, a gauge, a McDonnell Miller float type LWCO as well as auto make up water feeder, a gas valve with standing pilot, and a pressure relief valve. Nothing out of the ordinary or strange devices on or near the boiler or piping.

The supply valves on the radiators are probably original. All they have on them is a big OE symbol. The steam traps I replaced also had the OE symbol but they also said OE specialty company. The steam traps were kind of different. They had a tiny orifice at the inlet and outlet side with a float ball at their inlet. I replaced them all with standard bellows type Hoffman 17c’s because someone had taken the float balls out of most of the traps and the radiators weren’t holding the steam.

That’s about it as far as piping and equipment go. Basically just a big tea kettle.

Thanks for the tips on the books. I already ordered “The lost art of steam heating” and am waiting eagerly for it to come in the mail. I’ll also order the other book you mentioned with the E.D.R ratings.

Any further guidance is greatly appreciated.

Steamhead

You have an \"O-E\" Vapor system

but the Hoffman traps will do the same thing as the special elbows.

The steam main does NOT need replacing. The boiler manual refers to the header piping which must be 2-1/2-inch but this feeds into the existing main.

Gotta go- more when I get back.

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Tim_8

Response cut off

Steamhead, your last response "OE Vapor system" was cut short. The only thing that showed up on "The Wall" was the last few sentences.

Steamhead

Must have been a Microsoft moment

but it seems to be working OK now.

To continue: When the boiler is piped in properly, it will deliver dry steam to the system. Now the steam main must fill with steam. This should take about a minute.

Your 63-foot steam main should have a Gorton #2 vent on it. This is the biggest vent made today and will run rings around those Hoffman 4A vents. If you're trying to nurse the old boiler for another winter, installing this vent will make the system heat up faster and the boiler will run less as a result.

The return line, called a "dry return" since it runs above the boiler waterline, should also have a Gorton #2 on it. This will let the air in the radiators vent quickly, again reducing the boiler's run-time.

If you can't find Gorton vents in your area, go to

www.gorton-valves.com

and they will tell you where to get them, or sell them direct if no one in your area handles them. Talk to Ken Kunz and tell him I sent you.

Also, if you're not experienced with steam boiler installation, building a steam header, cutting & threading pipe etc. I strongly recommend you hire a pro to do it. You'll be glad you did!



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Bob_19

One other thing

you mentioned stop-leak was used, the pig-tail was removed, and now both the control and the gauge don't seem to react properly.

Can you tell if the boiler is making steam? are the near boiler pipes getting hot?

A pig-tail needs to have water in the loop which acts to stop live steam from hitting the control and the gauge, the steam will push up on the water in the pig-tail giving the pressure readings.
If a pig-tail is removed and the water is dumpped then re-installed live steam will initially contact your controls usually causing damage to them. When reinstalling a pig-tail water will need to be put into the loop prior to install, if you wait for the steam to condense in the loop damage can occur to the controls.
Just a thought but some of that stop-leak could have gotton up into the pigtail after the treatment causing a blockage starting the initial problem.

Tim_8

Vapor System? Pigtail

Steamhead, you mentioned earlier that I had a vapor system. Could you give me some information on this type of system? How is it different from a regular two pipe gravity return? And what tipped you off that I had a vapor system? Also, I was under the impression that the header and main were the same. What is the difference between the header and main? Thanks for the tip on the gorton #2's. I'll try them out.

Bob, Thanks for the tip on the water in the pigtail. When I initially removed the pigtail there was no water in it. Maybe therein lies one of my problems. I'll try it out. Thanks again. This site has been very helpful.

Bob_19

I'll bite

only a steam system needs a pigtail, trap, for the controls.

Paul Mitchell

could be

nota usual problem though..but if boiler is thatold and was oil at one time it is super inefficient now anyway. read some of the other posts..bottom line is it making steam? and if so it is just time to say goodbye. if you are new to the house and system this could be the way it is. interesting problem though. i assume your house gets to t-stat setting and all radiators get hot.

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Mad Dog

You didn't say that it was not heating the house though

did ya? If she's heating the house ok, who cares? I've seen some large, 2 pipe systems do the same thing. Theyll run for hours and will register only ounces and never kick off the pressuretrol. However, that boiler "stop leak " stuff is nonsense. It will not hold for long. If the boiler is old and caked up inside, it certainly will do exactly what you are saying...never come up to pressure BUT you will know because it won't heat the house either. All the guys gave great advice, but you may be ready for a pro now. That';s what FIND A CONTRACTOR IS FOR> Good luck mad dog

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Mad Dog

Tim, you sound fairly knowledgeable and I love your

GUNG-HO attitude, but this might be over your head. However, if you insist. You must read Lost Art at least 3 times cover to cover (I'm seroius!!!!!)and understyand EVERYTHING that you have to do. Next, follow those manufacturers specs to the TEE or will have nothing but problems. Lost Art will learn you the difference between a header and a main...slow down and read, my man. Mad Dog

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Robert O'Connor_4

To Measure

radiators you need Dans Book:
http://www.heatinghelp.com/shopcart/product.cfm?category=2-59

Any boiler could be under or oversized regardless of fuel.

Regards,
Robert

Steamhead

Vapor

defines a steam system that runs on very low pressure, usually 8 ounces or so, and is almost always 2-pipe. You can design a 2-pipe system for whatever pressure you want, but most of those installed in houses were Vapor.

The "header" is a horizontal pipe that runs 24 inches or more above the boiler's waterline. Its job is to help separate steam from any water that may have gotten up that high. It must be at least 2-1/2 inch diameter on your Weil. The header receives steam from the boiler, and feeds into the steam main that runs through the basement, which can be whatever size the designer determined was needed. At the end of the header is a vertical "equalizer" which makes sure the steam and return connections are at the same pressure, and also drains any water from the header back into the boiler. The return lines feed into the equalizer thru a Hartford Loop.

These are covered in more detail in Lost Art.

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Tim_8

Thanks for all the help

I just wanted to thank everyone who has taken the time to respond. You have all been very knowledgeable and helpful.

Paul, I don't believe the boiler was ever oil. Its original tag says its gas. And yes, the boiler is making steam and the near boiler piping gets hot. From a cold start it takes about 20-30 minutes for all the radiators to start getting warm. I plan on taking Steamheads advise and replacing the vents with Gortan #2's in the hope this will decrease that time alittle.

Robert, Thanks for the tip on the book about radiator sizing. I'll be sure to pick it up.

Bob, Yes the boiler is making steam and the radiators are getting hot.

Steamhead, Thanks for the info on the Gortan #2's and for explaining a vapor system as well as the header function. I don't believe my current system has a header though. The 2" comes right off the top of the boiler goes up 40" to an elbow, heads left for another 30" to another elbow, and then goes into the main loop around the basement. Or is that 30" pipe considered the header?

Mad Dog, Thanks for the input and tips. You guys really know your stuff. I still plan on tackling this myself.Its like I'm standing at the bottom of this large mountain and something inside keeps saying, "climb it, climb it". Why? I"m not sure. Maybe just because it's there and because I think I can. Maybe because I'm married with children and need a bit of excitment in my life. Maybe it's just simply a testosterone thing. But I think it just because I like the challenge of accomplishing something I've never done before. But, believe me, I don't plan on going in blind. I plan on reading "The lost art of seam heating" cover to cover as well as gathering as much other info that I can. I think you and Steamhead may be right about my current system. I think it's a vapor system that's designed to run at a pressure under 1 psi. Thats why the pressuretrol never shuts it down. I'll definetly install a vaporstat with the new system. Any other tips will be greatly appreciated.

Steamhead

It does not have a header

if it's piped the way you described. If this is the case, it was piped wrong.

Here's a boiler with a header, in this case a "drop" header on a Columbia gas boiler. We installed this boiler last month.

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Tim_8

Thing of beauty

Steamhead, That is a thing of beauty. Your a real artist. Very clean neat job.Are all the return lines run in copper?

steve_6

diy installations

I would advise that you don't. You can make very costly mistakes. It sounds like you may have made a big one already in your boiler purchase.The installation is very involved you'll be cutting, threading, and reaming pipe, and thats just the beginning. I really shouldn't say thats the beginning because that is secondary. Your system needs to be sized properly and system heating problems need to be identified so they can be corrected before and during your installation. If your installation is not done properly it can void your warranty as well as give you nothing but grief, and if you have to bring in a pro to fix your problems it could end up costing you a lot more.As the saying goes,I'll charge you this much for your installation, and if you help the price is double.I admire your interest in your system, but don't get in over you head.I'd use the find a contractor section of this web site and hire a pro.

Steamhead

Thanks, Tim

if you lived in the Baltimore area, we could do something like that in your basement! This is the kind of thing that only a pro can do well- I still think you should get one.

We usually do all our wet returns in copper, since black steel ones accumulate sludge much faster than copper. This is a controversial subject on the Wall, but since a wet return doesn't carry steam we've never had a problem with them. Any pipe that carries steam must be black steel.

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