how to bleed a boiler (gas)?

[slackerinabox]

It's cold! I found some directions online but I have no idea what a gate valve is, or if the directions even apply since they weere from the UK. Most posts are about bleeding radiators, not boilers..

Any suggestions? Since I'm a noob, can you describe the parts that I need to adjust?

 

[peasant]

The principle is exactly the same, bleeding the radiators is exactly the same as bleedding the boiler, only a damn site easier.

Air trapped in the system is easier bled from the radiators, by releasing the valve situated in the top corner of the radiator, allow your system to warm up, turn valve a couple of turns to allow air to escape, when warm water starts to "fizz" through the valves, you can usually tell 'coz your fingers start to get wet, tighten valve back up, move onto next radiator, repeat, until all radiators fully bled.

What you will need is a valve key for your radiators, easily obtained from any hardware store, for coppers, cents, pennies, whatever your small valueless currency is referred too, certainly not big bucks, or equating to a second mortgage.

 

[caddlad]

Bleeding air from hot water lines? OK I'll try......

Are the lines treated with antifreeze? If so consult a pro.

How many zones are in your baseboard system?

I'm no pro so take this advice with that in mind, but this what I had to do to remove the airlock in my radiant baseboard system (not radiators). I have circulator pumps running three zones, two heating loops and a domestic hot water heater. My locks always occurred in the downstairs loop. I have valves at each end (supply and return) of each loop. Every system is different and my method may or may not be appropriate for yours. Once you see it done its not that hard, but you should find the root cause of the problem. Usually a pinhole leak in a copper elbow.

To remove the air from the system you should purge each zone individually. Identify the supply and return side of the boiler and each zone.

The boiler return should have a fitting on a valve for a short length of garden hose.
Attach a hose and put the end in a large bucket.

Close both supply and return valves for all zones except the first one you wish to purge.

Open the valve near the hose on the boiler return line and run water into bucket listening and watching for air and bubbles. Household water will be added to the system as you run the water out.

When you see no more bubbles close all valves.

Empty bucket.

Repeat with all other zones isolating them one at a time. If you remove a big slug of air from an individual zone to may have hit upon the lock. You could check the system and see if you have circulation through the zone and skip the other zones. You may have to tights the bonnet nut on the gate valves when your done, if you notice a small drip near the valve stem. Tighten these very little and only enough to stop the drip.

The air lock should be removed. If it happens repeatedly you need to have a plumber find the leak and/or install bleeders at the high point of each zone.

Good luck.

 

[Fritzo]

Leeches.