There is only a couple of reasons an AC relay will heat up.
If it does in fact have full voltage of 220vac across the coil, then if the relay armature does not pick up fully for any reason, the impedance of the coil drops dramatically causing high current, this does not happen in DC coil relays.
The other less likely reason is to under-rate the contact current carrying rating of the relay.
You may either have a defective relay or something is preventing the armature from closing completely.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.