Upstairs Radiator chirping every 1-2 minutes

I recently was without heat, my inspection (very amateur) of the
boiler led me to believe we had a frozen water paper somewhere.

My house has two zones, upstairs and downstairs. Both set to auto,
once I set to manual the heat began working and appears to still be
working.

However, the radiator upstairs has been chirping. It has been about
12 hours since I set to manual. I did promptly set back to auto
seconds after setting to manual and hearing what sounded like hot
water pumped out from the boiler.

Is this something I need to worry about? I have tried bleeding this
radiator and there was a bit of air, but not alot. Do I need to let
it bleed for a long time?

Any help greatly appreciated.

Thanks,

Aaron
.

Relevant Pages