Baseboard Heat

[P3]

I'm helping a friend completely remodel his bathroom, new drywall, tile, tub, etc...

They always complained about lack of heat in a 9' x 6' bathroom with an 8' ceiling. The bathroom is located above a basement and the attic is above the bathroom. One wall is on an exterior wall and will be properly insulated. The room has a 36" hydro baseboard.

When we opened up the walls and when I was removing the closet flange to move the toilet over, I noticed the supply line to the baseboard was only 1/2", increased to 3/4" at the baseboard. Also, the 1/2" lines are connected to 1" lines! I can sweat copper pipe, but never worked with a heating system.

Questions:
>Is the inefficiency of the baseboard heat due to the 1" to 1/2" to 3/4" ?
>I would like to replace all the 1/2" with 3/4", but I am unsure of how to
drain the closed system. Can anyone tell me the steps required?
>Should I install a 48" baseboard or is the 36" sufficient for this size room?

Thank you.

[Sparks]

Yeah that 1/2 to 3/4 to 1 is definetely strange, I've never seen that. I've always seen 3/4" myself. Draining boiler, shut boiler off, let it cool, shut off water supply to boiler, attach hose if you don't want a mess (boiler water can be real nasty) to drain valve and let her drain. The boiler probably has an auto fill valve so when you're done sweating etc, find the fill valve, pull up on lever to apply full water pressure ( leave air bleed open on diaphram tank if so equipped let some air and water bleed out) continue filling but WATCH PRESSURE GAUGE on boiler, do not let it get too high when filling boiler, don't let her go over 30 psi (usually, but depends). When you think you have it filled, then the bleeding process begins, see if there are bleed valves on baseboards, some have em some don't, usually there'll be an auto-air bleed attached to diapragm tank to automatically bleed air but normally you will do a manual bleed first ( sometimes it takes more than once). You must do your best to remove all air from the system, otherwise you will have problems. As far as the baseboard being of sufficient size, there are many variables such as your location, insulation value, windows, doors, etc. If you give me all the info, I could run a heat loss calculation and let you know. I would need to know your winter design temperature as well. ( That was just a generic run-down on draining the boiler, some boilers may differ and special instructions may come into play, also I'm tired and probably missed a few things, I'm sure we'll have more opinions)