how a forced hot water gas heating system works (hot water heater, sinks, kitchen)

[LadyM17]

Please tell me how the water gets into the pipes. If the system is drained for repair, how does the water get back in? I'm sorry to sound stupid, but when I open the faucet spout there's nothing but air! please explain or send me directions on this type of system from the ground up so I can understand what is wrong here!
thanks everyone and anyone --once you stop laughing!!

[studedude]

You don't say what kind of repair was done. That would determine what valves you need to check. More info please.

[sandinmyshoes]

First,....the boiler is off,.....right?

[Coldjensens]

Our system has a spigot just behind the boiler where you can screw in a garden hose. Simply adding a little water is no big deal. Our system has a lot of chemicals in it though. They added some antifreeze just to be safe if the heat goes off when we are not home. This may be overkill since our pipes are PEX, but it cost nothing and could be invluable. They also added anti corrosion and scaling chemicals (we have cast iron radiators). You have to get the air out which is hard and takes a long long time (at least it did with our system). Most of the air bleeds out by running the system, but then oyu need to add more liquid. We also had to bleed parts of the system to get out air pockets that the automatic air relief thingy did not remove. It was not easy for the professionals to get all the air out. If you have no idea what you are doing, you should probably have someone come in and do it for you.

[desertsun41]

Who did the repair? Did they just repair your the hot water heater and leave you be? There really is nothing to repair in a water heater that is even worth while anyway. The very few parts that can go wrong would cost just as much to buy a whole new heater.

The answer is simple. Turn on the main water valve but not full blast. You will stand at the water heater while opening the pressure relief valve on and off until you get no air left, just water. When water goes in you must release the air or it will compress and if you turned on your faucett the water would shoot out like a rocket ship.

If finding the pressure relief valve scares you then go to your kitchen faucett and turn it on. Then go open your main water valve. The one that shuts ff your whole house is the main one. You can turn of your kitchen faucett when only water flows with no air noise.

[windtimber]

Are we talking about a hot water heater for sinks, showers, etc. or a boiler for hot water [hydronic] whole house heating? I can't make heads or tails of this without more information.