Insulating steam Radiator pipes...

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Old 10-16-11, 02:03 AM
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Insulating steam Radiator pipes...

A little background before my question:
I own a three family home in Boston, Mass that use steam radiators for heat.
I recently converted from oil to natural gas fuel but I still have the radiators. I have 3 new
Burnham natural draft gas boilers (Apprx. 90% Effnt.).
The horizontal pipes in the basement were insulated with the old asbestos type pipe insulation! I had all the asbestos insulation removed.

My question is> Do I now need to re-insulate those pipes again with some other type of insulation in order to prevent allot of heat loss? Or will the heat loss versus cost be minimal
because of the newer and more efficient gas boilers? My house is very large and the amount
of footage needed to insulate all the horizontal pipes for all three floors using fiberglass insulation would be very expensive. Especially if purchasing the fiberglass at retail!
Any advice out there regarding this issue and/or advice as to were to get a deal on fiberglass insulation?
Thanks
 
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Old 10-16-11, 06:56 AM
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Check out: Steam FAQ

There is also a lot of information on steam systems here: Technical Menu
 
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Old 10-16-11, 08:50 AM
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With steam the insulation on the pipes is not so much one of heat loss itself... but of the fact that you want the STEAM to remain STEAM until it gets to it's destination. If the steam pipes aren't insulated, yes they will lose heat... and some of the steam will condense back to water. You don't want that.
 
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Old 10-16-11, 04:05 PM
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heat loss is dramatic through un-insulated steel pipe. for the sake of talking, if you have a 2 and a half inch steam main, every linear foot will emit about 270 btuh, throw a 1" thick piece of insulation on it and it drops to less than 50 btuh. so if your losing that much heat your steam will prematurely condense causing water hammer, unsatisfactory heating and possible spitting vents. insulate your lines!!!
 
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Old 10-16-11, 05:47 PM
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Two other tings to think about when discussing un-insulated mains.
One is the cost. When you heat your water to 212f you now have 212f water. It does not convert to steam until you add another 970 btu's. That's right 970 btu's to change state from a liquid to a vapor. The is 5 times the energy it would take to raise water from 35f to 212f. So you send 212f steam into the piping and it collapses back into condensate and return to the boiler as water. It than needs to be reheated to 212f and then change to a vapor.
You end up with more water in the system as RDSTEAM stated which may cause the system to flood due to low boiler water due to the fact that too much water in up in the system less water in the boiler. This creates slower heating, higher fuel consumption and un-even heating.
 
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Old 10-17-11, 08:15 AM
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I live just north of you near Lowell

How did you get such an efficient boiler from National Grid though? I just did this myself (they completed work last week) but the highest efficiency for steam boilers that they have is 82.1%. The Induced Draft/Power Vent go to 82.2%...

I need to insulate my pipes as well. Thankfully I have a one story ranch with an unfinished basement so I can get to them all easily.

Do you insulate them right up to the boiler? Or do you need to leave some space?

I have a feeling I'll have to either drive to multiple stores or make periodic trips to get enough insulation, they don't look to have that much in stock at any given time (home depot/lowe's, I assume they'll be cheaper).
 
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Old 10-17-11, 03:26 PM
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i would purchase insulation from your nearest plumbing supply house. the depot or lowes will only carry 1/2" wall insulation. you want to get 1" wall.
 
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Old 10-21-11, 11:35 PM
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Hi Geomancer,
Sorry I misspoke when I said 90% efficient!! The boilers are 82.2% or there about. As for the insulation, I'm not sure what I'm going to do, but I know I must insulate the main pipes. I had to remove the old insulation in order to reclaim my basement as a useable space. Were your pipes insulated before the conversion? Did you remove all of the insulation like I did? If so, then just re-insulate the same sections. That's what I'm gonna do. Mine had insulation right up to the boilers. I envy you because you only have a one story ranch, so that can't be that much insulation? I have a very large triple decker with 8 to 9 rooms each floor to heat. So I need many feet of insulation. I saw some bulk deals on Ebay briefly, but I didn't follow up yet. I will let you know what I found after I fully check it out o.k.?
Thanks for your reply!!
 
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Old 10-22-11, 04:49 AM
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Hi RDSTEAM,
Thanks for the great advice as always, but most of the plumbing supply houses are wholesale outfits. I've checked online and I can't seem to find anything reasonable enough! I have a large 3 family and I measured the mains in the basement. I estimate (Roughly) that I will need approximately 375' ft. of 1.50" x 1.00" material and 60'-70' ft. of 2.00" x 1.00" material to cover all the mains. So you can see how expensive it will get fast!
Any other advice as to how do I get this stuff cheaper?
Thanks.......
 
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Old 10-22-11, 05:34 PM
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Originally Posted by blakk View Post
Hi RDSTEAM,
Thanks for the great advice as always, but most of the plumbing supply houses are wholesale outfits. I've checked online and I can't seem to find anything reasonable enough! I have a large 3 family and I measured the mains in the basement. I estimate (Roughly) that I will need approximately 375' ft. of 1.50" x 1.00" material and 60'-70' ft. of 2.00" x 1.00" material to cover all the mains. So you can see how expensive it will get fast!
Any other advice as to how do I get this stuff cheaper?
Thanks.......
not really, fiberglass insulation isn't really too cheap, whats it nowadays 7$ per section?? unfortunately its something the must be done. by not insulating you are adding an extra heating load to the boiler. along with that will come higher fuel bills, uneven heating and a noisy system. think of it this way, you buy it once and its good forever.(unless it gets wet)
 
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Old 10-23-11, 11:39 PM
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Thanks RDSTEAM,
The truth always hurts, but it also makes you whole!! I knew it all along...I guess I was looking for someone to tell me it was O.K. to try and slide on by!!
You're the best!! Honestly!! You give the strait dope (Truth) always!! Thanks!
Anyways, I think I may have found a place close by that specializes in this type of material. They come highly recommended and seem to be always mentioned by plumbers and businesses I call for information.

Take Care RD
 
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Old 10-23-11, 11:49 PM
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Hi GEOMANCER, try this place in Braintree...

[blakk, send this info to Geo in a private message... this isn't really allowed... sorry - NJT]

Peace........
 

Last edited by NJT; 10-24-11 at 05:05 PM.
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Old 10-24-11, 05:43 PM
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Hello,

What abut using 4' bats of unfaced 3.5" fiberglass? Wrap it around with a half overlap, secure the starting end with a giant cable tie and keep wrapping. After, cover/wrap around the fibergalss with Reflectix and close the Reflectix seam with some nice aluminum tape for neat job. I'd bet it would provide more insualtion value than the super expensive stuff and at significantly lower cost.



Peter
 
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Old 11-23-11, 12:54 AM
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Hi, I just converted to gas from oil..I have a large 3 family with an old single pipe steam radiator system. The new boilers are around 82% efficient. It was installed in the summer, so I'm only now starting to work out the bugs!!
The main problem I'm having is trying to eliminate the noise (water hammering) associated with a steam radiator system. I have tried all the standard remedies related to this problem. I have drained and refilled the boilers several times, keeping the water level a little above half in the sight glass. I have made sure that each and every radiator is pitched towards the valve. I have insulated all the mains in the basement with 1000 degree fiberglass steam pipe insulation. I have even changed many of the vents at the radiators. While these actions have help significantly in reducing the water hammering noise! They have not totally eliminated them!

Any recommendations out there as to what more I can do to completely eliminate this problem?

Thanks......

Blakk.......
 
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Old 11-23-11, 09:44 AM
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Have you followed proper procedure to skim off oil found in new boilers, also check for proper near boiler piping and steam pressure setting.
 
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Old 11-27-11, 03:02 AM
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Yes I have drained and refilled each boiler several times, (When cold of course) and thus have noticed a reduction in the amount of black colored water in the sight glass. However no matter how much I drain them, there still remains some discoloration of the water in the sight glass! I've heard some of that is a result of the increased temperature of the steam cleaning out the rust on the inner walls of the pipes, due to the higher efficiency of gas and the newer boilers!
I have solved most of the WH noise by properly pitching each and every radiator, and installing new vents on some of the radiators!
Also, I have fully insulated all the horizontal mains in the basement with 1" thick fiberglass steam pipe insulation.
There is still some minor noise when the steam first starts to rise...but it's a whole lot better!! It has been relatively warm so far up here in Boston, so until the real cold comes and the boilers are running longer and hotter! I can't say for sure that all the kinks have been worked out yet?

Thanks
 
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Old 11-27-11, 07:12 AM
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To skim a steam boiler you need to install a nipple and valve at or near the water line ,heat the water 120f then add water until it flows out pipe.There are chemicals you can add that will sink the oil to the bottom of the boiler where it can be removed by draining boiler.
 
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Old 11-28-11, 03:41 PM
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Ot

(Blakk - I Don't want to sidetrack, but I would love to know who you found to supply pipe insulation since I'm facing the same problem in the Boston area. Please PM me if you found a good source since it was edited out above. Thanks!!)
 
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Old 11-28-11, 06:55 PM
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Boiler skimming must be done on new boiler jobs. See this link
Skimming a Steam Boiler
 
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Old 12-06-11, 09:54 AM
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Hi Blakk, just a quick thought. You buy insulation once, you buy heating every day for at least 6 months.

Good Luck with it!
Jim
 
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Old 12-19-11, 11:54 AM
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Thanks blakk - can you send me info on where to find some bulk fiberglass insulation? I am in the same exact situation as you are (multi-family with uninsulated black pipe). Thanks
 
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Old 12-20-11, 01:47 PM
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Insulating Steam Pipes

After reading these posts I am wondering how much heat I am losing since I used the 1/2" insulation on many pipes?

Now to add to that, I do not have insulation on the joints. I have many tees and elbows especially those near the boiler that start out at 2-1/2" and are reduced to fit other pipes. How do I insulate the different types of connection joints? Do they sell insulation that is correct for this application because online everything for connections seems to be for water heater pipes not steam.

How much of a pitch is correct for the radiators, most of my radiators are level and I do hear the water hammering when the heat goes on?
 
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