Cutting/bleeding baseboard heat

[Mister Moose]

I'm doing a small addition, and have oil fired hot water baseboard heat. I'm going to add some baseboard and remove others. I'm experienced enough with solder and flux to make a leakless joint. I can see the shut off valves on the circuit, both supply and return.

What I'm wondering is after cutting out sections and reattaching, there will be a lot of air. How to best bleed the air?

There are a few 90 degree bends at the baseboard that have what I expect is a bleeder valve. It is a valve stem looking thing extending up from the 90 bend. The outside is hex, and inside there is a small square headed screw head.

There is also a 'T' near the circulator pump that has a knurled knob on the top of the 'T', and it has wept a little over time, turning the copper green. Is this some kind of vent or bleeder?

My questions are:

I expect I can just close both valves, cut the pipe where I want, and hook it back up. When the valves are opened, does the sytem add water as necessary?

Do I bleed from the high point at the valve stem fitting? What kind of wrench fits the tiny square screw?

How do you deal with all the water on the finish floor when bleeding? Seems like it's hard to collect, ie no spout, going to spray straight up.

How do you know when all the air is out?


Thanks much.

 

[SALIV8]

If you're differential pressure valve is working properly is should fill the lines as needed as long as you remove the air (like you are thinking) from the highest point.

So, leave the circ pump off and bleed from the different areas that have a bleeder after your repair is completed. Of course, the highest point will be the last and most important one. The square screw head in side should turn counter clockwise to open and release the trapped air. A bleeder wrench is sold at all heating/plumbing shops and do come in different sizes. so you may want to get each size wrench and then return what doesnt fit.

I go over all the areas more than once until I am confident most air is gone. Watch the pressure gauge at the heater and listen for flow thru the diff pressure valve as you bleed. All of the air should be replaced by water. This may take 3 to 4 times in total. I always double and triple check again after I shut off the circ pump after is has ran a bit. You can hear what's going on inside the pipes so be alert.

 

[vdblu1]

Ideally you won't have to use the bleeders at all. Set the system up to power purge by hooking up a hose. That will remove most air and having a system set up to "pump away" will move the rest to your air separator. I installed a new boiler a few years ago and found a book called "Pumping Away" by Dan Holohan to be a great resource. There is also a website and forum at www.heatinghelp.com that has quite a few helpful pros. I built mine following the book and was impressed with how easy it was to purge and how much quieter it operates.