Insulating basement pipes

PSBknS

I have a 4 story apartment building with one pipe steam, and a new gas furnace. Currently I have too much heat in about 53 of the 56 rooms in the building. I recently replaced the boiler, upgraded gas service and gas piping and have had my boiler controls and heat timer adjusted several times. Also all air valves have been checked and upgraded. I am considering insulating pipes in the basement. How much (% savings in fuel) should I expect? Separate from the fuel savings I am hoping that insulated pipes will help get the heat to the end of the line faster so I can heat the last radiators without overheating the other apartments. Any thoughts?

LarryC

Faster heating to end of line. Increase venting.

To speed up the steam reaching the end of the heating mains, generally you would increase the amount venting so that the air in the main is removed faster.  Insulating the mains will reduce the amount of heat lost by reheating cold pipes.  Reducing the heat lost will also enable the mains to fill up with steam faster.



Another place to add vents or increase their size would be at the top of the vertical risers, assuming your steam travels from the basement up to the top of the building and horizontally out to the radiators.  Again, the idea is to remove the air quickly so the steam can enter the piping.



Does the boiler have the ability to burn at two different power levels?  It is called Lo Hi Lo or something similar to that.  The system would initially fire at a high level until the system is up to pressure, then switch to a low level to maintain system pressure.  If the steam pressure drops, the burner will go back to high level.  This helps match the fuel consumption to the actual heat demand of the building.



Too much heat could also be an indication that the steam pressure is turned up too high.  The turn off pressure should be set to about 1 to 1.5 psi max with the turn on pressure set about .5 psi less than max pressure.



Does the piping make noise like people are hammering on it?  How clean is the water in the sight glass?  Does it bounce up and down alot (more than 1/2 inch) when the boiler is operating?



I hope this helps.



P.S.  the owner of this website sells books and one of them is "We Got Steam Heat"  It helps explain how steam heat systems work and what can be done to keep them and You happy.

PSBknS

reply to LarryC

Thank you LarryC. We have already upgraded venting on all the mains in the basement and at the top of the vertical risers. Pressure settings are as you described. I am considering replacing the Pressuretrol with a Vaporstat, but as we use a Heat timer I don't think it makes a difference. We do not have any water hammer in the building. I'll check the water bouncing in the glass as you suggested. I did read a couple of Dan Holohan's books including "We Got Steam Heat." The books are great!

nicholas bonham-carter

insulation on pipes

before you insulate the basement pipes, check the runs to make sure there are no sags from slipped hangers or subsidence, and then insulate. one inch high temp fiberglass pipe insulation [not foam] is best, but if there are budgetary constraints are present, then standard fiberglass foil-backed 2 inch insulation will do for the moment.

the only way you will know if your main venting is adequate, is by having an accurate low-pressure gauge on the same pigtail as your vaporstat. you should see the air escape at a back-pressure of no more than 2 ounces, otherwise you are paying for extra fuel to sqeeeeeze the air out of constipated little openings! likewise, any steam pressure higher than 8 ounces is putting extra money in the pockets of the gas co. the risers could be handled later by having bigger vents on the top radiators, and slower hoffmann 40's on all the intermediate ones. the expected result will be the arrival of steam at all the radiators on any floor simultaneously.

i have 55 radiators, and 1,050,000 btu, and my control is with a honeywell visionpro thermostat with remote sensor in one of the cooler apartments, so i'm on the fence as to whether the heat timer/tekmar control is best or not.

when we replaced the boiler, 3 years ago, and did the pipe insulation, increased venting, vaporstat, and better thermostat, we burned a third less gas, so the gas company replaced the meter, thinking the old one had failed in our favor! like they say "your mileage may vary", but our comfort is greater, and no water-hammer.--nbc