To wrap or not to wrap steam heat pipes.


  #1  
Old 10-24-16, 02:00 PM
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To wrap or not to wrap steam heat pipes.

I have a single pipe steam heat system.
My house is about 1,000 square feet.
House is about 60 years old. Not very well insulated. Stories; first: basement, not finished. Second: living area. Third: attic.
The house is not very well insulated. I know, I have to work on that when I have some money.

Brand new boiler as of Jan 2016

Steam pipes only goes to second floor "living area". Nothing to attic. I have complete access to all steam pipes (nothing behind walls etc).

Basically, I have read that it is a good idea to be sure that your steam pipes have insulation on them. Then I have heard that there is no need to have insulation on them. I am talking mainly the steam pipes in the basement.

So I spent money to put fiberglass insulation around the pipes in the basement. My thoughts; wrap the pipes, the steam will stay steam longer if not exposed to the cold basement air and the hot pipes will allow the boiler to come to temp faster as the pipes are still hot. But then if pipes are not wrapped the basement is warmer and the floor on the living area (second floor) will be warmer.

I just don't know what to do. I have had about 6 different people tell me to wrap them or not to wrap them.

The wrapping I did was get R13 fiberglass insulation and wrap the pipe and tape with duck tape.

Even when I insulated the steam pipes in the basement the basement only gets as low in temp to about 44 degrees in really cold weather. So leaving the pipes UN-insulated is not really keeping my basement warmer so my water pipes do not freeze.

What am I supposed to do?

Suggestions and recommendations are welcomed please.

Thanks
 
  #2  
Old 10-24-16, 02:24 PM
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The primary source of heat from steam radiators is the latent heat released when the steam condenses back to water. If the steam condenses in the piping then it can't be condensing in the radiators.

ALL STEAM HEATING PIPING NEEDS TO BE INSULATED! Dedicated condensate piping, so-called "wet" returns, are not as critical when it comes to insulation other than to save energy.

If you need more heat in the basement then consider a radiator or perhaps a hot-water loop from the boiler.
 
  #3  
Old 10-24-16, 03:01 PM
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The primary source of heat from steam radiators is the latent heat released when the steam condenses back to water. If the steam condenses in the piping then it can't be condensing in the radiators.
This part I understand and it makes sense.

ALL STEAM HEATING PIPING NEEDS TO BE INSULATED!
Understood. My pipes are now insulated in the basement with fiberglass insulation wrapped and taped with duck tape.

Dedicated condensate piping, so-called "wet" returns, are not as critical when it comes to insulation other than to save energy.
Yes, of course I want to save energy (in this case fuel oil) but what do you mean by "Dedicated pipes"? Are you referring to the pipe coming from the radiator value back down to the return below ?(the return from the radiator to the pipe below is only about 1 to 2 feet). Sorry; confused.

If you need more heat in the basement then consider a radiator or perhaps a hot-water loop from the boiler.
A radiator or two in the basement (basement not that large; full size of second floor living area) not a bad idea; thanks. I guess the radiator would have to be high in the floor joist so that the water will flow (by gravity) back to the boiler.

But what is a hot water loop?
 
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Old 10-24-16, 03:20 PM
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Any piping below the water line in the boiler would be considered as dedicated condensate piping or a wet return. Since there is no steam in these pipes there will be no condensation reducing the amount of steam going to the radiators. Insulation of these pipes is only for saving energy but if the energy lost through uninsulated condensate piping is used to heat the basement it isn't really wasted.

I guess the radiator would have to be high in the floor joist so that the water will flow (by gravity) back to the boiler.
Not if you use a two-pipe system. The steam would enter at the top of the radiator and the condensate drain from the bottom. The higher above the water level in the boiler the more heat you will get from it but if the middle of the radiator was equal with the water level it would likely output more than enough heat, depending of course on its physical size.

A hot water loop is a connection from the water space in the boiler to a radiator, cabinet convector or baseboard convector that also has a pump to circulate the boiler water through the loop. These require the use of a stainless steel or bronze pump as a standard cast iron pump will rust due to the oxygen in the water. One advantage of using a hot water loop is that you can control it precisely, something much more difficult with a steam system.
 
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Old 10-25-16, 12:09 PM
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if the energy lost through uninsulated condensate piping is used to heat the basement it isn't really wasted.
That text is a widely held misconception. Typically basement walls are uninsulated concrete or building block which loose a lot of heat/btu's. Heat from the boiler and pipes will raise the area temperature at higher cost than heating the rest of the house. Many boiler rooms are the warmest place in the house in spite of bigger heat loss!

Also, some heated boiler room air is used for combustion which only adds to waste heat going up the chimney.

A study by Brookhaven Labs years ago on heating system latent heat losses explored it in detail.

If you use a IR digital thermometer the hot spots are obvious i.e. uninsulated pipes, poorly insulated boilers, etc. I look at anything over 80F to 90F as something to deal with.

I insulated all of the heated pipes and pumps. On a 60 year old Weil McLain boiler added insulating panels on sides, rear, top and front.

The 18” long exhaust from boiler to electric stack vent was acting as 140F/180F “heat pipe”. Wrapped it with aluminum foil insulation. Did the same for the oil fired water heater. Cost was a few dollars and hour's time.

In the small boiler room area now temp stays around 70F. The endless payback for dealing with latent heat losses is lower heating costs.
 

Last edited by doughess; 10-25-16 at 12:30 PM.
 

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