Radiators not getting hot after having 3 new one fitted ?

I've just had 3 new radiators fitted the plumber had to drain down the heating system,since he filled the system up again and switch the heating back on the radiators are not getting hot,the plumber said the system had air in the pipes he kept going in the loft,the radiators got a little warmer he said it would be ok now and left later there was banging from the pipes in the loft called him back he released the air from the pipes and said it would be ok,he also said it would take a couple of days for the system to settle down. After 3 hours the radiators are still not hot ,the room stat is on 30 but the radiators are just warm. He said if the radiators get cold to ring him. The make of the boiler is a Worster it is a condensing boiler. Is this normal







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