correct boiler size & cleaning steam returns

david_36

question # 1:when i do a steam boiler installation,i install a full port ball valve on the return line just prior to it's connection to the hartford loop. when firing up the system, i close this valve, pressurize the system to about 10psi, and then flush out the return line by opening another full port ball valve (on the house return side of the isolation valve) with a hose connected to it. this system has worked fine for me for years. i am sure that there are other heating proffessionals that do this too.the question i have is as follows: how do you accomplish the same results when working in a nicely finished basement, and there is another return line coming off a seperate steam branch, connected to the main return somewhere midway between the end of the steam main - and the boiler room?
question # 2: when totalling up the amount of square feet of steam needed to fill the radiators, i multiplied the amount of sections of recessed cast iron radiators (192) by 2.25 s.f per section. this totals 432 s.f i am looking to install a williamson (weil mc lain) boiler. the EG-50 creates 454 s.f.net and the EG-55 creates 521 s.f net. do the net ratings already take into consideration the amount of square footage of steam needed to fill the steam mains and branches that supply the radiators? my concern with using the larger boiler, is i am looking to reduce short cycling. thanks in advance for taking the time to answer these questions.

Unknown

We steam clean

the returns like you do . Close the ball vlve and let the condensate flow into a bucket or a floor drain until you have steam shooting out the hose . Normal operating pressure works good for us . We use a mild liquid cleaner to help break up the muck .

For those really gunked up returns we backflush the pipe - fill the return from the nearest hot water source and drain the whole thing out . After all is said and done we drain the boiler , refill and skim .

As far as sizing goes , are you sure the 2.25 sq. ft. per section is accurate ? Are all the rads generally the same size by section ? If it's accurate and the steam mains are insulated , I'd go with the EG-50 .