lost manual F22 and F25 codes?

Hi, can anyone help?
New boiler working fine on the hot water side ..now have tried to put on CH..fine for x2 days then codes F22 and F25 pop up..have lost my manual ..boiler seems to be firing up, flame sign on but no heating of water...is it air in the system????
Have a plumber on holiday and beginning to dislike cold showers..