I am not a plumber but have, I think, enough basic skills to complete this project. I’m wondering if I’m a little short on knowledge about one aspect of the project.
I intend to shorten the loop of a zone on the first floor of my home’s hydronic heating system to permit the house to heat easier, quicker and less expensively by eliminating a portion of the loop that needlessly heats an enclosed sunroom. The sunroom is only used around the holidays and it makes no sense to constantly heat it through the winter months – the french doors leading to the room are always closed due to its non-use. Next summer, I’ll attempt plumbing in another zone just for the sunroom.
Shortening the loop seems simple enough – I need to cut the 3/4 inch copper tubing in two spots and soldering in about 18″ of new tubing, with a union and a 90 degree elbow. 4 soldered joints total.
The furnace is in the basement, below the level of the first floor.
My question involves the method I should use to drain the loop. There’s a valve on the lower portion of the furnace that I believe the water in the loop will come out through when opened (once the feed is closed off). If I simply open up that valve will the fluid actually drain? Or, do I need to provide a means by which air can enter the loop somewhere in the middle of its loop?
There’s nothing installed in the nature of an air vent that I can see in the loop.
Replies
Just shut off your feed and cut out the section of pipe to make your shunt. It'll hiss and spit for a couple of seconds when you pierce through the tubing, but after that it'll just dribble out. Have a bucket or two, and a few towels, handy to catch whatever water drains out from the uphill side of your cuts. No need to drain the entire loop down to the boiler. Make your new connections and refill/bleed the zone as necessary.
By the way, I was assuming in my previous post that the only thing "uphill" was the section of the zone that you were planning to bypass. If you have a whole bunch more zone uphill of your shunt, it may be less aggravation to drain at the boiler as you suggest. To answer your question, no, you do not need to introduce air in order for it to drain. It will drain by simply opening the valve that you described. Air will enter the system via the open valve. Yes, it would probably drain faster if there was a bleeder valve somewhere that you could crack open, but it's not necessary.
OK, thanks very much for the info. That keeps things simple.
Yes, there is quite of bit of length in this loop which is one of the reasons why I want to shorten it and segregate the normally cold sunroom from the main part of the house.
I think it would be easier for me to drain the fluid in the loop out through the valve on the furnace and pipe it outside through a garden hose. It's just water although a previous fill had an anti-freeze/water mix. (Don't really have a problem with pets running loose outside, just a lot of wild animals. And, the ground should drain well unless it's too frozen.)
Hopefully it will be warm enough this weekend here in CT to attempt the fix.Griff