Baseboard Radiation

wsdave

First of all I'm constantly reading The Wall and I think you folks are great!
I own a 50 year old, two story house with a one pipe steam system. I love steam!
The previous owners added a foyer in the living room for an oversized front door (makes moving furniture nice).
They removed the original radiator(s) and installed baseboard. I say radiators because there is a supply line that is plugged in the basement. The baseboard runs 10 feet down the wall, turns left for 2 feet then 4 feet into the foyer.
Up until last fall we had no problems but when I preped the system for winter I noticed that the supply valve was leaking. I removed the packing nut and noticed the stem had dropped onto the seat making the valve useless. I replaced it along with the vent with a Maid-O-Mist #5.
Now we are getting water hammer at the end of the boiler's cycle. It was so bad that it blew the vent off the unit.
I double checked the pitch and there was none so I pitched back to the supply valve and checked with a level. It is a good pitch. I checked the other runs and pitched them towards the supply line as best as I could. In fact I've got the end unit pitched so high as it is impossible to put the cover back on.
It is better but I'm still getting the hammer.
I have checked the pressuretrol and it is set at .5 PSI with a 1 PSI differential.
All vents in the house are new with either Hoffman or Maid-O-Mists.
I'm currently awaiting for a 0-3 PSI gage so I can verify the operating pressure is below 2 PSI.
This is the only section I'm having a problem with. The other radiators are original cast iron with the exception of one 8' basboard unit in kitchen.

I'm at the point where I want to install another line running from the end of the baseboard and run it back and tie into the exsisting return below the supply valve in the basement thus removing the counterflow situation.
This exsiting return to the boiler is 1".
I want to install a tee to accomodate the return and the vent.
Would I reduce the return line at a tee intalled at the end of the final run thus running a 1" black pipe back to the return? Is there any restrictions as to elbows and length of pipe run? I would have to bring the line back into the living room then drill a hole to drop into the basment.
I would also need to raise the supply valve to get the unit to pitch downstream.
Sorry for the long post but I wanted to give as much info as possible.
Any suggestions would be greatly appreciated.