How do i bleed a radiator that does not have a bleed nipple?
I am assuming that you have a hot water system and live in the US: If you have a baseboard radiator, they do not have bleed nipples and air is bled from the entire loop at once at the boiler. Simply loosening the connection on a cast iron radiator and tightening it up again will not bleed air that is trapped above the connection which are typically at the bottom. It is possible that the radiator was not installed with a bleed valve and a plug was installed in the manufactured hole for the bleed valve. You will have to drain the system and install a bleed valve. You will have to determine where it was designed to go. This would especially be the case for a cast iron baseboard radiator that may have formerly been part of a loop and now is installed as a separate radiator. An upper 3/4 inch tap may have to be removed and bushed down to accept the 1/4 inch bleed valve.
