Hydronic heating 'refill' question

17 years ago

I'm in the process of renovating my basement and have the existing baseboard heat rerouted and the loop is closed.

My question is, how is all the air in the line going to get out?

I have a valve (garden hose type) on the loop and if it were at the "end" of the loop, I would just keep it open until water comes steadily out, but this valve is at the "beginning" of the loop. If I were to open it, all the water would flow out of that and not fill the line.

I have an expansion tank on top of the boiler and there is an air relief contraption on the top of the expansion tank. My plan was to add water to the closed loop very very slowly and let the expansion tank air relief take care of the air. Will the air from that loop traverse the expansion tank's air relief valve?

I want to make sure I'm not going to blow something up, so please hit me with any flaws in my plan or suggestions on a better way to do it.

Thanks!

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Comments (6)

mr_havac
17 years ago
Correct it now before you go any further. Install a boiler drain back near the return and an isolation valve at the beginning of the loop and another one in the return section just beyond the new boiler drain you just installed and you're good for the life of the system. Now you close off valve #2, open the boiler drain and out goes the air.
baymee
17 years ago
If you're patient, I'm writing up some online DIY courses that might benefit you.

I'm having certificates printed up right now in Texas.
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mr_havac
17 years ago
You should see the big smile on my face right at the moment baymee! :-)
jukeit
Original Author
17 years ago
Thanks for the replies; I appreciate it.

I think I need to understand the flow a little better and I would like to take care of this without any additional work. The system has been in for over 20 years, I can't imagine I'm the first to do this.

The start and returns of the zone loops both connect to the boiler AND the hot water heater. For example, the returns connect to a pipe. One direction of that pipe connects to the water heater. The other connects to the expansion tank and the boiler (this also has the pressure/temp gauge). Similarly at the start of the loop, the "start" pipes connect to another pipe where one direction ties to the boiler and the other ties to the water heater.

Hopefully I explained that well enough. My question is, when the water starts the loop, does it pull from the boiler or the hot water heater? At the return, does the water flow back to the hot water heater or does it flow through the expansion tank and into the boiler?

Thanks!
baymee
17 years ago
Can you provide any pictures? I'm guessing that your boiler stores extra heated water in a water tank and your baseboard draws water from the tank and returns it to the boiler for reheating. Is there a circulator between the boiler and tank?
jukeit
Original Author
17 years ago
I'll try and get some pics, but the more I look at it the more I believe it works as follows:

Supply side pulls from hot water heater/tank. The water that isn't pulled into a zone, runs to the boiler. The boiler kicks water out through the temp/pressure gauge, through the expansion tank - this water joins zone return water and is sent to the hot water heater/tank.

There is a pressure relief valve on the hot water heater/tank. It's my belief that I can open the pressure relief valve on the hot water heater, turn on the water to refill the zone and any excess air will be expelled (if necessary) through the hot water heater's pressure relief valve.

Does that make sense to anyone else? Thanks!

Hydronic heating 'refill' question

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mr_havac

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Hydronic heating 'refill' question

Comments (6)

mr_havac

baymee

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jukeitOriginal Author

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jukeitOriginal Author

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