I have a hot water baseboard (hydronic) heating system, gas boiler. Please refer to diagram of my system below. Ball valves 1 & 2 are supply. Ball valve 3 is return. Zone valves are on supply, circulator pump is on return.
I searched the internet and found a video that covers this, but his system was different than mine. From the information I have gleaned, the steps to drain & repair valve are:
- Turn supply off
- Turn return off
- Open hose bibb to drain pressure/water
- Change valve
My questions: I have two ball valves for supply (1 & 2). Do I need to turn both off? The zone valves are normally closed--I will need to open one, or all after step 2, right? Do I need to open all, or just the one I'm replacing? Also, he didn't open up the bleeder screw on the registers. Wouldn't you need to so air can come into the system to replace the water?
Steps to refill after valve change:
- Turn supply on
- Open supply valve(s)
- Open hose bibb to drain water to purge. Note, may take 10 gallons. If water doesn't flow, open and close pressure reducing valve quickly--make sure pressure doesn't get too high. I don't understand this last part--maybe because he's trying to increase pressure to overcome air in the line?
- After no more bubbles in water, close hose bibb.
- Open return valve
- Close zone valve(s)
My questions: He mentioned monitoring the pressure to make sure it doesn't get too high. What the heck are ya gonna do if it does--run? :)