single pipe steam

MrBill

I have a 1885ish single pipe steam system. Burnham boiler. The building was built with a storefront and residential units behind and above the store. I'm having problems with the last 2 radiators in the run. (which is the coldest area of the building) one is 1st floor, the other above it. Its like 2 fins out of 11 get hot. when I open the 2nd floor valve and looked down the 1.5 inch pipe, I noticed a 3/4 inch restriction in the pipe that let the steam thru. This connection is under the floor and in the 1st floor ceiling. It looks like the pipe comes in at the ceiling of the first floor and goes up to the second and down to the first floor before connecting with a condensate return. On the first floor (which would be the last radiator) I drilled and tapped the vent hole to put in a 1/4 antler vent. It didn't seem to help. Does anybody know why this would have a restgriction in it? Any suggesation would be appreciated - Bill

dopey27177

If I read you right the restriction is in the riser supply.

If that 3/4" restriction is in the steam riser remove it as it stops the full supply of steam from going up the riser. I am amazed that you do not get banging as the the condensate from the steam condensing collects at the restricted area.

Jake

Hap_Hazzard

If it's vertical it won't cause hammering because there's no wave propagation. It might be forming water pistons in the restriction, but they'd just get blown up into the 1" section and fall apart. It's probably causing some gurgling though. And definitely making it harder for the steam to reach the radiators.

Have you added up the EDR of your radiators and compared it to the EDR of the boiler?

MrBill

Jake, I was thinking the same, although The restriction is between floors it might be hard to remove with out opening the wall. I'm not quite there yet. There are a few things I'll try on Wednesday first.

MrBill

Hap_Hazard. I have not add the EDR's. I don't know how. I'll research this.

MrBill

I'm thinking the restriction might be a washer from the valve that fell down the pipe.

Hap_Hazzard

If you can get the valve off, you should be able to inspect the pipe with one of these. https://www.amazon.com/Seesi-Endoscope-Waterproof-Inspection-Semi-Rigid/dp/B07PBF6DX5

Fred

This sounds strange. Are yopu sure you have a one pipe system? Typically condensate would return through the same pipe that supplies the steam. There isn't typically a second pipe that connects to a condensate return, especially above the water line without a trap somewhere.. Also, how is a 3/4" restriction in a 1 1/2" pipe? Is it laying in an elbow or something?
Pictures would help a lot.