2 pipe steam problems

[elektra]

I have a 2 story house with 2 pipe steam. The second floor was always cold and would only heat up if I moved the thermostat by 3-4 degrees. Since then I have had the following changes.
1.Changed all traps (capsules inside changed).2.Added several new vents on returns and replaced the old ones. 3. changed all near boiler piping with 4 inch pipes (old was 2.5-3 inch). 4.Added thermostatic valves on first floor rads..
Now the second floor heats up better. However even with the thermostat held at 72 degrees there is a variation of 10-15 degrees upstairs in one room particularly but to a lesser extent in all. The colder it gets outside, the hotter the second floor gets and on relatively warm days it is cold upstairs. The thermostat is in good shape verified by thermometers. Any advice.
I have held the temp constant and shut down/opened up valves on the various rads in an effort to balance things. Do I need to relocate the thermostat? Do I need a wireless thermostat? Do I need thermostatic valves on the second floor rads? The pipes to the second fllor run thru my uninsulated garage and I plan on insulating them. Does that have anything to do with this? I have already invested a few thousand on this problem and cant bear it any more. :wall:

[KField]

You have made a great effort in repairing your system. It all sounds like necessary work and may leave only a small amount of fine tuning. You are correct about insulation on the steam mains. All mains should have at least 1/2" of fiberglass insulation on them. Especially the run to the room over the garage you mentioned. Any radiator that doesn't get warm enough does not need a thermostatic radiator valve at this time. Your boiler may be short cycling and not filling the mains with steam. That could account for why the long distance runs don't heat well. What fuel do you use? Possibly you could measure up the radiation and see how close the load is matched to the boiler. I can help you with the calculation. Pipe size and pitch could also play a part in the long runs to the cold radiators. I really think that if it almost works, you are within grasp of a solution.

Ken

[elektra]

Thanks for your encouragement. I have a gas fired boiler- I am waiting for the insulation to come in. The boiler was replaced by the previous owners a few years ago and I assume it was sized right- however they had used the old near boiler pipeing making for an inefficient system. I will report back after installation of insulation. Any advice or opinions on a wireless thermostat would be appreciated.

[KField]

You would be better off to turn the thermostatic valves on the radiator(s) closest to the existing thermostat to a lower setting than to install a different thermostat. You are only going to be changing the problem from one area to another. Don't spend the money on the thermostat yet.

Ken