main steam line venting questoin

EricG

I have a 1930 2 story 2 family home with a 7 year-old oil-fired boiler.    I get heating in all of the radiators in about 20 minutes.  No issues with water hammer or excessive water usage.  All radiators have new vari-value steam vents with the large radiators full open and the smaller, medium set close to the close position.  



I recently insulated the near boiler piping and the steam hits the radiators very quickly now.    Boilter pressue is registers just about zero on the gauge. 



I have 2  2"  steam supply mains that run from the back of the basement to the front of the house.



Each steam supply main  has old Gorton No 1 air eliminators (3/8" fittings) at the front of the house  where the supply mains turn 90 degrees down and join the wet return line.    One of the supply mains is just getting warm to the touch  and the 3 risers and radiators on this supply line  are ice cold.   On the 2nd supply main I was able to remove and clean the air eilimator and it is working and the piping is hot and the radiators on this supply main are getting hot.



It was difficult to remove the single old air eliminator and I am wondering if there is a way to clear / clean the other air eliminator or any other diagnostics I can do now in the middle of the heating season to try to get heat to the cold radiators.   I have changed the air vents on the 3 radiators and verified tha the radiator values are operational and fully open.



Other maintenance I have done.  - the hartford loop has a faucet drain at the end of the wet return near the boiler and I drained the wet return - some rusty water and then clear water after 10 minutes draining.



There are 2 additional steam mains from the boiler to the rear of the building and the

air eilimators were replaced when the boiler was changed.    All the other radiators in the house except 3 are working properly.

BobC

Old houses settle

The house may have settled over the years, make sure that cool main has got some slope to it.Check it in relation to the other mains, It should be about 1 in of slope for a 10 ft run. Check the radiator runouts for proper slope also.



The only way I've ever cleaned an air vent is by boiling it in vinegar for 10-15 minutes, depending on what kind of thread sealant they used it can be tough getting them out. When installing them i use PFTE paste and or teflon tape - they come out really easy next time around.



Varivalves are very aggressive, try closing the working radiator vents down to the low setting and see if you can force steam down the cool main.



Bob

EricG

main steam line venting question

Thank you for the suggestions



The 2 supply mains run side by side  and are at the same level when they join the wet return.   One gets hot and the other just warm.   I will wait for a warm spell before getting someone to remove the air eliminator.   I don't want to have it snap off and then have no heat.    I ordered replacement Gorton No 1 valves.  With the adapters, it will be tight installing the new ones due the thread size difference.



I will put the vari valves on their lowest settting to see if i can force steam into the cold radiators.   Should I remove the radiator steam vent  on one of the cold radiators to see if I get any steam ?

BobC

It's worth a try

Just make sure you can kill the boiler if steam starts to billow out of the open vent tapping.



Bob