In addition to the radiator valve hole sizing, much depends on the main vents on the lines. The main vents allow the steam to reach the radiators by venting out the large volume of air in the big pipes so they don't have to vent out slowly through the radiators. In my limited experience they're often undersized. I could not even buy locally the high volume type steam gurus online told me to buy. But when I installed it the heat on that line farthest from the boiler definitely improved.

I used to have steam heat with the big old radiators. Don?t know if you are familiar with how the steam radiator air values work. Look it up if you aren?t.

I recall the further the radiator is away from the boiler the bigger the valve (hole) to get the steam moving quicker. It could also be that the valve is bad.

Steam Radiator Air Valves:

?In general, larger valves are used at the end of long pipe runs (mains) and in colder rooms. Smaller air valves are used nearer to the steam boiler source and in rooms which have a thermostat?

Be careful when working on them.


Also once had a problem with a radiator not being level. The condensate (returned water) was laying in the single pipe system and was blocking the steam from getting to the radiator.

?Condensate is supposed to go downhill by gravity to return to the steam boiler?

Anyone know a way of decreasing time between when first radiator gets hot and last? Four story house and sometimes takes 1 1/2 - 2 hours.