filling radiator boiler

[Bob Lang]

Hi --

To replace a broken valve on one my radiators, I've drained the water from the hot water heating system in my house. Now I don't know how to refill it! Can anyone help?

I understand that there are manual and automatic filling systems. In either case, must the boiler be on for it to fill? (It is not on now.) All the water supply valves leading to the boiler are already on. However, inline with the supply pipes, there is also what looks like a pressure regulator with a little lever on top. I didn't know if that might be a pressure relief mechanism or if perhaps lifting the lever might allow the water to flow. Any ideas? I can take pictures if that would help.

Thanks!

-Bob

[Edwin Pawlowski]

With the supply valve turned on, it should fill by itself. Yes, the lever on top will open the valve manually. The problem, of course, is the air in the system that must be purged. Thee should be a valve to drain the system. While filling, if you open that valve it should allow the water to flow through and purge the air. Once you do that, turn the heater on, let it come to temperature, then turn up a thermostat so it calls for heat. That will start the circulator and you will again be able to purge residual air. Ed

[Bob Lang]

Replying to my own post here, and thanks to Ed for your reply. In case anyone has a similar system -- it seems that there are many different types -- here's what you do: The boiler does indeed have an automatic filling mechanism, but it may not just start on its own once you empty the system of water. The expansion tank on the boiler has a schrader valve on it (like the valve on your car's tires). Take a bike pump and pump it up to about 12psi. This is what starts the automatic filling system. You'll hear the water start to flow. It may take a few hours, depending on how empty the system is. I haven't turned the heat on to bleed the system yet, but my impression is that the pressurized expansion tank somehow helps regulate air pressure inside the system, reducing the need for bleeding. We'll see :-)

-Bob

[Nate Weber]

You have something going on here. The fill valve and the expansion tank are

2 different items. Normal way to fill would be to pressurize the expansion tank when the system is empty, open a vent, turn on the main supply then raise the fast fill lever. When the system gets to about 10 psi, lower the fast fill lever and allow it to finish. Then you need to fire up the boiler and bleed off the radiators. If you don't get all the air out of the system it will be noisy. The expansion tank allows the water to expand somewhere without blowing a relief valve when it heats up.

Nate

[Information Technology]

Thanks for the reply, Nate. I follow you up to here. What is the fast fill lever? Is that the lever on top of my pressure regulator? No wonder it was taking so long to fill :-) Also, when you say 'open a vent,' what vent do you mean?

(I actually had to drain the thing again because I messed up on installing the radiator valve -- which was why I did it in the first place -- but I think I've got it beat now.)

Thanks again for the reply.

-Bob

[Bob Lang]

Thanks for the reply, Nate. I follow you up to here. What is the fast fill lever? Is that the lever on top of my pressure regulator in the supply line? (Is that why it took so long to fill the first time?) Also, when you say, 'open a vent,' what vent do you mean?

BTW, I will have to be filling it up again (don't ask :-) , so if I do have a fast fill lever, that will come in handy.

Thanks again for the reply.

-Bob

[Nate Weber]

That lever is your fast fill valve. Straight up enables it. You must lower it when filling is complete or it will over pressure the system. As for the vent, you should have a drain valve on your piping manifolds with hose threads on it. Basically you want to purge every part of the system separately if its completely drained. Start by closing the valves on each zone, then open your supply and return manifold vents, fill the boiler until water comes out of these valves then close them up. Each zone should have a purge valve on the return side. Hook your hose up to one, open it then open the supply valve for that zone, purge until water comes from the hose, close the vent then open the zone return valve. Repeat for other zones. If you only drain one zone you do not need to purge the entire system, only that zone.

Nate

[mark Ransley]

BS , ck all the radiators , bleed all, not doing so wont guarntee the system operates at design.

[Nate Weber]

Yes, you have to do that too but it is much faster to purge a empty zone first to get the majority of the air out.

Nate