Bleeding Radiators on a gravity hot water system

[Backdraft436]

When the heating system does not have a circulation pump how do you bleed the radiators? The heater is located in the basement and all the radiators are located on the first floor. The heater make is "Royal".

Thank you.

[Softus]

The venting process is no different without a pump, because it should be done without a pump running anyway.

Can you locate the vent plug on each radiator? If so, that's really all you need to know. I would also take the precaution of making sure that the feed and expansion cistern is not empty or low.

[Backdraft436]

Softus, thanks for the reply.

I have located the vent plug on the radiators. They are opened using a small key.

The water pipe which connects to the heating pipe is closed. There is an expansion tank which is empty with a relief valve off to the side located next to and above the heater between the floor joist.

There is no "feed cistern".

When I open the bleed valve on the radiators, some air comes out but no water. Does the water valve which connects to the heating pipes need to be open in order to "top off" the radiators?

Thanks

[Softus]

OK - so do you have a combi system?

If so, then you should have a filling loop with a pressure guage.
If air stops coming out of the rad vent, then check the pressure and repressurise if necessary.

When all rads are done and all vents closed, repressurise again to the minimum of the range specificed by the boiler manufacturer. Then check the pressure when hot and make sure it's less than the maximum.

Does this answer the question?

[Gasman1015]

Feed and expansion cistern is the same thing, and fills the system.

Relief valve is probably air vent.

You need water.